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CHIMACUM DRAINAGE DISTRICT
GENERAL MAINTENANCE AND
HABITAT ENHANCEMENT PLAN
February 2026
Prepared by Jefferson County Conservation District
with financial support from the Centennial Clea n Water Fund under the
authority of the Washington State Department of Ecology via Jefferson
County Public Health
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Executive Summary ................................................................................................ iii
Section 1: Background ............................................................................................ 1
Section 2: Drainage District Overview .................................................................... 2
2.1 General Characterization .........................................................................................................................2
Table 1. Drainage District Geographical Statistics ..........................................................................................3
2.2 Predominant Drainage Issues ...................................................................................................................4
Figure 1. Excavator with Rake Attachment Removing Reed Canarygrass from Channel ................................5
Section 3: Anticipated Drainage Maintenance ........................................................ 6
Planned Drainage Maintenance by Reach ......................................................................................................6
Figure 2. Typical Water Control Structure for Ditches ....................................................................................7
Table 2. Summary of Anticipated Reed Canarygrass Treatment by Reach .....................................................8
Figure 3. Drainage District Reaches Map ........................................................................................................9
Table 3. Reaches 1, W1, and E1 ....................................................................................................................10
Table 4. Reaches W2, W3, and W4 ..............................................................................................................10
Table 5. Reaches W5 and W6 .......................................................................................................................10
Table 6. Reach W7........................................................................................................................................11
Table 7. Reaches E2 and E3 ..........................................................................................................................11
Table 8. Reach E4 .........................................................................................................................................11
Table 9. Reach E5 .........................................................................................................................................12
Section 4: Drainage Maintenance Preliminary Budget Analysis ........................... 13
Anticipated Maintenance .............................................................................................................................13
Anticipated Near-Term Costs .......................................................................................................................13
Anticipated Long-Term Costs .......................................................................................................................13
Drainage District Assessment Options .........................................................................................................14
Conservation District and Other Sources of Assistance................................................................................15
Section 5: Drainage Maintenance Permitting ....................................................... 16
General Permitting Conditions and Notifications .........................................................................................16
AGENCY and ORGANIZATION CONTACTS .....................................................................................................17
Section 6: Drainage Maintenance Best Management Practices ............................ 18
Watercourse Vegetation Management and Maintenance Dredging ...........................................................18
Aquatic Herbicides .......................................................................................................................................18
Constructed Watercourse Maintenance ......................................................................................................18
Hand Maintenance .......................................................................................................................................19
Beaver Dam Management ...........................................................................................................................19
Culvert Maintenance and Replacement .......................................................................................................19
Bridge Maintenance and Replacement ........................................................................................................19
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Watercourse Revegetation and Bank Stabilization ......................................................................................19
Land Stewardship and Drainage Maintenance .............................................................................................20
Section 7: Special Projects ................................................................................... 21
Sample Annual Work Plan .................................................................................... 23
Appendices – List of Factsheets1F .......................................................................... 24
1. Hydraulic Project Approval .................................................................................................................24
2. Water Pollution Control Acts ..............................................................................................................24
3. Growth & Shorelines Management Acts ............................................................................................24
4. Agency Contact Requirements ...........................................................................................................24
5. Emergency Drainage Maintenance ....................................................................................................24
6. General Drainage Maintenance BMPs ...............................................................................................24
7. Maintenance Dredging BMPs .............................................................................................................24
8. Beaver Dam Management..................................................................................................................24
9. Watercourse Vegetation Management ..............................................................................................24
10. Aquatic Herbicides and Watercourse Maintenance ...........................................................................24
11. Culvert Maintenance and Replacement .............................................................................................24
12. Bridge Maintenance and Replacement ..............................................................................................24
13. Sediment Traps ..................................................................................................................................24
14. Constructed Watercourse Maintenance ............................................................................................24
15. Fish Protection ...................................................................................................................................24
16. Water Quality Protection Measures ...................................................................................................24
17. Hand Maintenance .............................................................................................................................24
18. Watercourse Classifications ...............................................................................................................24
19. Drainage Water Quality ......................................................................................................................24
20. Watercourse Revegetation.................................................................................................................24
21. Bank Stabilization Techniques ............................................................................................................24
22. Farm Practices ....................................................................................................................................24
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EXECUTIVE SUMMARY
This document outlines and describes the routine drainage system maintenance activities proposed
for Jefferson County Drainage District #1, also known as the Chimacum Drainage District. Also
described are potential special projects, including habitat restoration projects . A brief overview of the
drainage district area and the predominant management and maintenance concerns is included. Best
management practice factsheets prepared by Whatcom Conservation District in collaboration with
Whatcom County drainage districts and their local, state, and federal agencies are included as
appendices for guidance to help ensure maintenance activities are carried out with minimal adverse
environmental impacts. A sample annual work plan template is also included.
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SECTION 1: BACKGROUND
The Chimacum Creek valleys with their rich peat soils have been the agricultural lifeblood of Jefferson
County for well over a century. The agricultural development of these valleys was made possible by
major alterations in the natural drainage system, including channelization of Chimacum Creek ,
excavation of many miles of drainage ditches , and installation of miles of subsurface drainage . The
vast majority of the drainage system alterations were undertaken in the 1920s by Jefferson County
Drainage District #1, also known as the Chimacum Drainage District (DD1).
Significantly modified streams and constructed ditches require ongoing maintenance, especially in
areas that are heavily infested with reed canarygrass (RCG) and occupied by beaver. DD1 performed
the necessary maintenance activities, mainly RCG removal, until it became inactive in 1974, leaving
maintenance responsibilities to individual landowners. Management and maintenance of drainage
systems must be performed systematically and comprehensively, irrespective of property lines , to
produce satisfactory results. Most maintenance activities involve significant ecosystem alterations , so
it is critical to employ practices that minimize adverse environmental impacts.
Highly invasive RCG is the primary drainage maintenance challenge. RCG has plagued the low-
gradient waterways of the Chimacum watershed for over half a century, obstructing stream flow and
sediment transport, hindering fish passage, and exacerbating flooding. As it decomposes, RCG
contributes to low dissolved oxygen in the water, further impacting habitat conditions for fish.
Over the past three decades considerable effort toward tree and shrub planting to shade out RCG
and improve riparian habitat. Unfortunately, many of these plantings have attracted beaver s, whose
dam construction results in more flooding and new challenges for woody riparian plant
establishment.
Current conditions are far from ideal, both for agriculture and for aquatic and wetland habitat.
Strategically planned and implemented drainage system rehabilitation and stream and wetland
restoration projects, combined with comprehensive and regular maintenance of RCG and beaver
dams can produce watershed-scale win-win results. Strategically planned and properly executed
drainage maintenance and habitat restoration work can result in reclaimed and maintained farmlands
of long-term importance, while also improving water quality as well as aquatic and wetland habitat.
This plan outlines such a strategy, which includes best management practices for regular drainage
system maintenance activities, and special large-scale projects for drainage system improvement and
ecological restoration . The causes of flooding and inundation throughout DD1, and the associated
impacts on agriculture, infrastructure, and salmonid habitat, are assessed and described in the
companion document Chimacum Drainage District Analysis .
The Drainage Management Guide for Whatcom County Drainage Improvement Districts prepared by
Whatcom Conservation District in 2009 served as a template for this plan. The Geomorphic
Assessment of Chimacum Creek prepared for the North Olympic Salmon Coalition by Natural Systems
Design in 2016 is the primary source of habitat restoration recommendations.
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SECTION 2: DRAINAGE DISTRICT OVERVIEW
2.1 General Characterization
The approximately 6,672-acre Chimacum Drainage District (DD1) encompasses about one-third of the
approximately 23,680-acre Chimacum watershed. The district is shaped like an inverted Y, following
the two branches of Chimacum Creek (CHI) and East Chimacum Creek (ECH), and their adjacent
floodplain areas and some uplands. Chimacum Ridge, which runs between the two stream branches,
is excluded from DD1. The downstream extent of DD1 is approximately river mile (RM) 2.35, roughly
0.5 miles downstream of the confluence of CHI and ECH. The upstream extent is approximately RM
10.55 on CHI, and the tributary Barnhouse Creek to State Route 104. The upstream extent on ECH is
approximately RM 5.95, roughly one mile downstream of the headwaters. The eastern boundary of
the drainage district generally follows State Route 19 (Beaver Valley Road). The western boundary
generally follows West Valley Road. In 2022, Jefferson County reported a total of 586 parcels under
387 separate ownerships in the drainage district .
Streams and Ditches
CHI originates in Delanty Lake at RM 13.1. A small tributary flows out of nearby Peterson Lake, and
the small tributary Fox Creek joins the main channel from the north . Two additional small tributaries
flow out of forested wetlands to the south about 1.5 miles downstream becoming what is presently
known as Barnhouse Creek, which joins CHI at RM 9.6. Naylors Creek flows out of Gibson Lake located
to the west and joins CHI at about RM 5.4. Putaansuu Creek, also flowing from the west, joins CHI at
about RM 4.3. Several other small tributaries and ditches flow into CHI. The CHI stream channel in the
lower 8 miles varies from about 10 to 20 feet in width with vertical or near-vertical banks in most
reaches. Stream gradient downstream of about RM 10 is low to very low, generally less than 2 %, and
as low as 0.1%.
ECH originates in forested wetlands a little over 6.0 miles upstream of the confluence with CHI. The
only named tributary is Swansonville Creek, formerly a tributary to Ludlow Creek, which was diverted
to ECH as part of the early drainage modifications and stream channelization in the early 20th century.
Numerous other small and relatively minor tributaries and ditches flow into ECH from Chimacum
Ridge and the uplands to the east. Average stream channel width on ECH is less than ten feet with
vertical or near-vertical banks. Except for the headwaters above RM 5.5, stream gradient is very low,
generally less than 1%, and as low as 0.1%.
The two stream branches join approximately 2.9 miles upstream of the mouth at Port Townsend Bay.
There are approximately 29.5 miles of main stream channels between the two branches. CHI
comprises a little less than 80% of the average combined flows of the two tributaries. The entire
system is either lake-fed, spring-fed, or rain-fed. Nearly all the stream miles within DD1 have been
straightened or otherwise modified. Most of these modifications occurred about 100 years ago.
There are an estimated 44.5 miles of constructed ditches in DD1. However, because of the highly
modified nature of the waterways in DD1, it is difficult to distinguish between ditches and
straightened natural waterways. The table below (Table 1) provides a rough breakdown of the area
and waterway lengths in the drainage district.
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Table 1. Drainage District Geographical Statistics
Stream Branch Acres Stream
Miles
Modified
Stream Miles
Tributary
Miles
Ditch
Miles
Chimacum Creek 4,488 10.5 8.9 14.9 28
East Chimacum Creek 2,184 5.95 5.55 ?* 14
*Determining tributary miles, particularly in the valley bottom of ECH, is difficult because most tributaries
were substantially modified to function as drainage ditches.
Source: Chimacum Creek Watershed Assessment, Natural Systems Design, 2016
Water Quality
Water quality conditions throughout most of both CHI and ECH are significantly impaired . These
impairments include Washington Department of Ecology 303(d) listings for bacteria, temperature,
and dissolved oxygen. The most significant bacterial contamination occurs between about RM 9.5 to
about RM 7 on CHI. High water temperatures are common throughout the system in July and August
but most significant downstream of about RM 6 on CHI, and between about RM 1 and 2 on ECH. Low
dissolved oxygen occurs in the summer in many areas but is most significant and lethal to salmonids
from about RM 4 to 6 on CHI and between about RM 1 and 2 on ECH. There is a correlation between
high water temperatures and low dissolved oxygen levels – warmer water can hold less oxygen. High
water temperatures and low DO tend to occur where the stream gradient is lowest and RCG is most
prevalent. Streamflow can be imperceptible in these reaches , which are often fully exposed to
sunlight. These reaches are the most challenging areas to establish trees and shrubs due to extensive
flooding and competition from RCG.
Fish Presence
Coho, steelhead, and trout rear throughout the system but spawn primarily upstream of RM 8.5 of
CHI, in Fox and Naylors creeks, and in upper ECH. Summer chum spawn in the lower mile or two of
Chimacum Creek and do not rear in the stream. Lamprey, sculpin, and sticklebacks, which tolerate
poor water quality conditions better than salmonids, are also present throughout the system.
Geology and Soils
The advance and retreat of glacial ice sheets formed the relatively broad, flat Chimacum valleys and
adjacent ridges and terraces. Valley bottoms are up to 3,000 feet wide, with predominantly poorly
drained and relatively deep hydric organic soils (peats and mucks). According to the USDA Soil Survey
for Jefferson County, the parent material for these soils was mainly herbaceous plant material, such
as rushes and sedges. Saturated conditions in the glacial basins and ponded areas devoid of oxygen
resulted in the development of the organic soils .
The water table is at or near the surface of the organic soils. These soils remain stable under
saturated conditions. However, once drained these soils shrink and the exposure to oxygen can result
in rapid organic matter decomposition. Through decomposition, the organic carbon tied up in the soil
organic material converts to carbon dioxide and water through a process called oxidation. The
contribution of carbon to the atmosphere from this oxidation exacerbates climate change.
Initial draining of organic soils often results in substantial oxidation and subsidence. Continued
cultivation can result in a loss of up to one inch per year or more of soil, depending on the depth to
the water table. This explains in part why ground immediately adjacent to waterways where the
water table remains relatively high is higher than the drained and cultivated land farther away from
waterways. Streambanks were also commonly sites for depositing dredged spoils.
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The main challenge of the cultivation of organic soils is water control. Careful water management,
including both drainage and maintenance of a sufficiently high water table, is critical to create
suitably dry conditions for agricultural production but not so dry that the soil disappears through
oxidation.
The areas that are most prone to prolonged flooding and an excessively high water table are the
areas of organic soils that historically experienced frequent flooding and ponding, thus the conditions
that enabled the development of these soils. Once drained, these areas likely experienced significant
subsidence, thus lowering the elevation further and making the land more susceptible to flooding.
However, JCCD has not obtained actual elevation data to confirm this.
Approximately 39% of the total DD1 area (2,603 acres) is comprised of potentially prime farmland
soils. However, the only soil considered prime without a qualifier is Belfast silt loam, heavy variant at
3.3%. The other prime farmland soils are only prime if drained (35.2%) or irrigated (0.7%).
Semiahmoo mucks, which require drainage for good production, comprise most of the land that is in
agricultural production.
Farmland
Approximately 3,234 acres are actively being farmed in DD1, most of which is in permanent cover
with forage crops for pasture, hay, or silage. Most of the remain ing farmland is under annual
cultivation for small grains, vegetables, and vegetable seed crops, with a very small percentage of
land planted with orchards and blueberries. The vast majority of the farmland is in the valley bottoms
where it is subject to flooding and/or excessive saturation. As noted above, if drained these soils are
considered prime farmland soils that are capable of producing six tons per acre of grass -legume hay.
Undrained but under good management, these soils are expected to produce only two tons per acre.
Based on a 2024 analysis conducted by JCCD of 2023 aerial photo imagery, an estimated 1,220 acres
(~38% of total land in production) were rated as being in a fairly productive condition . “Fairly
productive condition” was defined as predominance of desirable forage species with estimated yields
above 50% of potential, or currently under cultivation for annual crops, orchards, or berries.
A total of 1,201 acres of land in the drainage district is protected from development by conservation
easements, most, if not all, held by Jefferson Land Trust. Approximately 730 of these acres (61%) are
farmland; the balance is forestland or habitat. With few exceptions, this land must remain as
designated in the conservation easements. For example, if an easement is to keep the land in
agriculture, it cannot be converted to wetland habitat. Only 267 acres (37%) of the protected
farmland were rated as fairly productive in 2024.
The high percentages of unproductive farmland are due in part to prolonged flooding and excessive
soil saturation (resulting from inadequate drainage system maintenance, flooding from beaver dams,
and land subsidence). However, much of the farmland has been neglected in recent years as farmers
have aged or property has changed ownership. Recent increases in new farmers have proven that
reclaiming the productivity of these lands can be accomplished fairly quickly, especially when factors
contributing to prolonged flooding are addressed .
2.2 Predominant Drainage Issues
The Chimacum watershed has hundreds of acres of once highly productive farmland that are
adversely impacted by excess soil moisture and inundation. Annual flooding is a natural occurrence,
but under normal conditions widespread inundation of adjacent land only lasts a few weeks. In many
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areas this seasonal flooding now extends well into the growing season , sometimes into summer.
Prolonged inundation can kill desirable forage species.
In addition to the economic impacts, the degraded farmland is of limited habitat value, providing little
more than overwintering habitat for migratory waterfowl. During the fall migration, swans, geese,
and some other waterfowl forage primarily on fresh pasture regrowth, which has decreased in
acreage due to increased inundation. Furthermore, stream habitat conditions are poor, characterized
by high water temperatures, low dissolved oxygen, a lack of woody riparian vegetation, and a general
lack of diversity. Farmland inundation and many of these habitat limiting factors result both directly
and indirectly from RCG and beaver.
Reed Canarygrass
Reed canarygrass (RCG) is a persistent problem throughout almost all the waterways of DD1. It is
particularly problematic in the low-gradient stream reaches that are prone to extended inundation .
These areas are typically where organic soils are located.
Other Problem Vegetation
Two other common invasives species in and along waterways are Elodea and bittersweet nightshade
(Solanum dulcamara). Elodea is a perennial submersed aquatic plant that grows entirely underwater.
Bittersweet nightshade is a perennial vine that grows over other vegetation . RCG commonly
outcompetes both species except where Elodea has established in deeper stream channels .
Thick stands of willow have developed along some stream reaches, mostly because of past riparian
forest restoration efforts. Willow attracts beaver, leading to dam construction and further flooding.
Willows also topple over across and into waterways, continuing to grow and obstruct stream flow.
Willows are particularly problematic in the organic soils of the lower reaches of ECH.
Beaver
The small, slow-flowing waterways of DD1 provide ideal habitat for beavers, which have increased in
numbers over the past couple decades as their habitat has improved because of riparian forest buffer
establishment. Beaver and their dams have been observed throughout DD1, with the highest
concentrations and most severe impacts on ECH where willow, a preferred food and dam-building
material, is abundant.
Figure 1. Excavator with Rake Attachment Removing Reed Canarygrass from Channel
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SECTION 3: ANTICIPATED DRAINAGE MAINTENANCE
Anticipated drainage maintenance work is listed by reach in the tables below, including a summary of
reed canarygrass (RCG) treatments and reach-by-reach maintenance. Annual maintenance priorities
will be identified and described by the DD1 board in a work plan that they prepare and approve each
year. A sample annual work plan template is included at the end of this document. Note that these
tables and the accompanying map refer to CHI and ECH as West Chimacum Creek and East Chimacum
Creek respectively (with reaches abbreviated by W and E).
In addition to major RCG removal work within waterways and monitoring/management of beaver
activity, individual landowners are encouraged to mow herbaceous vegetation along waterways.
Mowing typically does not require a permit. For best results, mowing should occur at least twice a
year. RCG should be mowed when the plants are at or near flowering stage to weaken plants and
inhibit rhizome development, and again before the fall rains begin. The second mowing reduces the
amount of vegetation in waterways prior to the flooding season.
Planned Drainage Maintenance by Reach
Listed in the table below (Table 2) are the anticipated near-term and long-term RCG treatments for
the two main channel reaches and major tributary streams. Mechanical clearing refers to mechanical
removal of RCG from the stream channel, such as by excavator, as well as mowing channel banks with
tractor-driven mowers. Hand clearing may include the use of hand mowers, brush cutters, and string
trimmers, as well as herbicide applications.
Currently, an estimated 4.75 miles of stream channel is heavily infested with RCG, requiring periodic
mechanical treatment to remove the RCG. In the long-term, mechanical treatments may be reduced
to less than two miles if woody buffers are established to shade out the RCG. Reaches where
mechanical treatment is listed as the long-term treatment have organic soils, are prone to prolonged
inundation, and have proven exceedingly challenging for establishment of trees and shrubs. If
mechanical removal is performed once every two to three years, only about two to three miles need
to be treated annually.
Roughly one-third of the 4.75 miles of stream heavily infested with RCG are in areas that are currently
rated as very marginal farmland. RCG treatment in these areas is unlikely to result in significant
upland benefits without major investments in pasture/hayland renovation. Some of these areas are
good candidates for wetland restoration, provided such restoration does not adversely impact
adjacent properties. Nevertheless, RCG removal from stream channels has shown to improve water
quality by increasing dissolved oxygen, and streamflow benefits can extend a considerable distance
upstream of the treated area.
Tributary ditches commonly require less frequent maintenance – typically just mowing. Furthermore,
ditches are conducive to hedgerow planting for long-term RCG control. Shaded tributary ditches will
also result in cooler water flowing into the main stream channels (in 2016, the consulting firm Natural
Systems Design estimated there were 28 miles of unvegetated tributary ditches). It is very likely that
some ditches are no longer serving their intended purpose, thus are candidates for and
decommissioning. This will require site specific analysis.
Drainage districts in Whatcom County have had good success reducing their ditch maintenance by
planting hedgerows. Planting methods that include placement of cardboard over the RCG, placement
of jute matting over the cardboard (to prevent displacement by wind), and live staking through the
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cardboard with red osier dogwood, black twinberry, Pacific ninebark, and Douglas spirea have proven
successful in the Tarboo Valley. One can also plant b are-root and potted stock in the cardboard, but
this may require herbicidal treatment around the planting holes to minimize RCG growth around the
base of the plants.
Whether a ditch is a regulated waterway must be determined on a case-by-case basis in consultation
with the Washington Department of Fish & Wildlife (WDFW), as most ditches flow into fish-bearing
streams.
Controlling water levels in ditches and adjacent soils is possible with water control structures, such as
the one in the image below. One can also use control structures such as these to prevent fish access
into constructed waterways, thus potentially eliminating permitting requirements .
Figure 2. Typical Water Control Structure for Ditches
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Table 2. Summary of Anticipated Reed Canarygrass Treatment by Reach
Stream Reach Miles Near-Term Treatment Long-Term Treatment
West Chimacum Creek
W2 RM 3.65-3.75 0.1 Hand clear. Interplant woody buffer. Hand clear, beaver control.
W2 RM 3.75-4.0 0.25 Hand clear. Interplant woody buffer on right bank.
Establish new woody buffer on left bank.
Hand clear, beaver control.
W2 RM 4.0-4.2 0.2 Hand clear. Interplant woody buffer. Hand clear, beaver control.
W3 RM 4.2-4.45 0.25 Mechanically clear. Establish new woody buffer on
both banks.
Hand clear, beaver control.
W3 RM 4.45-5.0 0.55 Mechanically clear. Interplant woody buffer on right
bank. Establish new woody buffer on left bank.
Hand clear, beaver control.
W3, W4 RM 5.0-6.1 1.1 Mechanically clear. Mechanically clear.
W4 RM 6.4-6.7 0.3 Mechanically clear. Establish new woody buffer on
both banks.
Hand clear, beaver control.
W4 RM 6.7-6.9 0.3 Hand clear. Interplant woody buffer. Hand clear, beaver control.
W5 RM 7.25-7.35 0.1 Hand clear. Establish new woody buffer on right
bank.
Hand clear, beaver control.
W5 RM 7.35-7.9 0.55 Mechanically clear. Mechanically clear.
W5 RM 7.9-8.05 0.15 Mechanically clear. Interplant woody buffer. Hand clear, beaver control.
W5, W6 RM 8.05-8.4 0.35 Hand clear. Interplant woody buffer. Hand clear, beaver control.
W6 RM 8.4-8.95 0.55 Mechanically clear. Interplant woody buffer. Hand clear, beaver control.
W7 RM 9.4-9.95 0.55 Hand clear. Interplant woody buffer. Hand clear, beaver control.
Barnhouse Cr 0.5 Mechanically clear. Establish new woody buffer. Hand clear, beaver control.
East Chimacum Creek
E2 RM 1.0-2.75 1.75 Mechanically clear. Interplant woody buffer. Hand clear, beaver control.
E2, E3 RM 2.75-2.95 0.2 Mechanically clear. Mechanically clear, beaver
control.
E3 RM 2.95-3.4 0.45 Mechanically clear. Replace willows with conifers and
other beaver-adapted species.
Hand clear, beaver control.
E3, E4 RM 3.4-3.6 0.2 Hand clear. Interplant woody buffer. Hand clear, beaver control.
E4 RM 3.6-4.3 0.7 Mechanically clear. Establish new woody buffer. Hand clear, beaver control.
E4 RM 4.3-4.5 0.2 Restore meandering stream channel and establish
new woody buffer.*
Hand clear, beaver control.
E5 RM 4.8-5.5 0.7 Hand clear. Interplant, establish new woody buffer. Hand clear, beaver control.
Swansonville Cr 0.3 Hand clear. Establish new woody buffer. Hand clear, beaver control.
*See Ecological Restoration Project Priority #2 (Kodama Farm) in Special Projects section below.
More detailed annual drainage maintenance actions by stream reach are presented in the tables that
follow. Where woody buffer establishment is listed, the miles count each side of the stream. For
example, if 0.25 miles of buffer establishment is proposed along each side of the stream, 0.5 miles is
listed. More specific maintenance activities will be listed and described in an annual work plan
schedule (see template work plan schedule at the end of this section).
Drainage needs may change over time or even unexpectedly. For example, beaver pond levelers may
need to be installed, or in the event there is unanticipated siltation, such as may occur resulting from
upstream erosion, dredging and/or sediment pond construction may become necessary. Any
proposed dredging work or sediment pond construction would require detailed planning, permits,
and extensive consultation with regulatory agencies.
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Figure 3. Drainage District Reaches Map
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Table 3. Reaches 1, W1, and E1
Reach Description
Reaches of CHI and ECH downstream of SR 19 and downstream of confluence. Total
stream channel length: ~2.3 miles.
Maintenance Dredging None planned.
Vegetation
Management
RCG is extensive in Reach 1, but no vegetation maintenance or control activities are
planned.
Woody Buffer
Establishment
None planned.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Three culverts identified
in Reach E1 (two stream, one ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Three beaver dams identified in Reach 1. Monitor quarterly for new dams, and lower
or remove as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
Table 4. Reaches W2, W3, and W4
Reach Description
CHI between SR 19 and Center Road crossing. Total stream channel length: ~3.6
miles. Tributaries Putaansuu and Naylors creeks.
Maintenance Dredging None planned.
Vegetation
Management
Approximately 2.65 miles of heavy RCG growth in main channel and most ditches.
Remove RCG from RM 4.2-6.7 every 2-3 years at minimum. Ditch banks should be
mowed at least twice annually.
Woody Buffer
Establishment
Interplant 2.0 miles of existing woody buffers and establish 1.6 miles of new buffers
to RM 5.0.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Sixteen culverts
identified (nine stream, seven ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Monitor main channel and tributaries quarterly for new d ams, and lower or remove
as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
Table 5. Reaches W5 and W6
Reach Description
CHI reaches between Center Road crossing and West Valley Road. Total stream
channel length: ~2.35 miles.
Maintenance Dredging None planned.
Vegetation
Management
Approximately 1.5 miles of heavy reed canarygrass growth in main channel, including
0.4 miles of newly planted hedgerow buffer, and most ditches. Remove RCG from
RM 7.35-8.05 every 2-3 years at minimum and from 8.4-8.95 until woody buffer is
established. Mow 0.4 miles of newly planted hedgerow buffer at least twice annually
and monitor for in-channel RCG. Mow ditch banks at least twice annually.
Woody Buffer
Establishment
Interplant 2.1 miles of existing woody buffers and establish 0.1 miles of new buffers,
except for RM 7.35-7.9.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Seven culverts identified
(two stream, five ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Monitor main channel and tributaries quarterly for new d ams, and lower or remove
as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
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Table 6. Reach W7
Reach Description
CHI reach between West Valley Road and upstream end. Barnhouse Creek and
tributaries. CHI stream channel length: ~1.55 mi. Barnhouse and tributaries: ~7 mi.
Maintenance Dredging None planned.
Vegetation
Management
Approximately 1.1 miles of reed canarygrass growth in main channel and most
ditches. Remove RCG from Barnhouse Creek until woody buffer is established . Mow
tributary and ditch banks at least twice annually.
Woody Buffer
Establishment
Interplant 1.1 miles of existing woody buffers and establish 1.0 mile of new buffers
on Barnhouse Creek.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Seven culverts identified
(three stream, four ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Monitor main channel and tributaries quarterly for new d ams, and lower or remove
as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
Table 7. Reaches E2 and E3
Reach Description SR 19 upstream to Peat Plank Road. Stream channel length: 2.5 miles.
Maintenance Dredging None planned.
Vegetation
Management
Heavy reed canarygrass growth in ECH and most ditches, except for forested
reaches. Excess willow growth. Remove RCG from RM 1.0-2.76 and 2.95-3.4 until
woody buffer established, and RM 2.75-2.95 every 2-3 years at minimum. Mow ditch
banks at least twice annually. Remove willow and replant with conifers.
Woody Buffer
Establishment
Interplant 3.7 miles of existing woody buffers and replace willow from RM 2.95-3.4
with species that are less favored by beaver.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Eight culverts identified
(four stream, four ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Monitor main channel and tributaries quarterly for new d ams, and lower or remove
as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
Table 8. Reach E4
Reach Description Peat Plank Road upstream to Bishop property. Stream channel length: 1.3 miles.
Maintenance Dredging None planned.
Vegetation
Management
Heavy reed canarygrass growth in main channel and most ditches, except for
forested reaches. Excess willow growth. Remove RCG from RM 3.6-4.3 every 2-3
years at minimum. Mow ditch banks at least twice annually. Selectively remove
willow and replant with conifers.
Woody Buffer
Establishment
Interplant 0.2 miles of existing woody buffers and establish 1.4 miles of new buffers.
Restore new meandering stream channel and establish woody buffer at RM 4.3-4.5.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Seven culverts identified
(four stream, three ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Monitor main channel and tributaries quarterly for new d ams, and lower or remove
as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
12
Table 9. Reach E5
Reach Description
North end of Bishop property (~0.25 miles upstream of Tall Tree Lane) to upstream
end of drainage district, including Swansonville Creek. ECH channel length: 1.15
miles, Swansonville Creek: 2+ miles.
Maintenance Dredging None planned.
Vegetation
Management
Moderate reed canarygrass growth in main channel and ditches, except for forested
reaches. Remove RCG from main channel as needed. Mow ditch banks at least twice
annually.
Woody Buffer
Establishment
Establish 1.4 miles of existing woody buffers on ECH and 0.6 miles on Swansonville
Creek.
Culvert Maintenance
and Replacement
Monitor culverts and keep clear of debris and beaver dams. Fifteen culverts
identified (ten stream, five ditch).
Aquatic Herbicides None planned.
Beaver Dam
Management
Monitor main channel and tributaries quarterly for new d ams, and lower or remove
as needed and permissible.
Hand Maintenance Woody vegetation impeding flow pruned as needed.
13
SECTION 4: DRAINAGE MAINTENANCE PRELIMINARY BUDGET ANALYSIS
This section includes a summary of anticipated drainage maintenance work, and a preliminary
analysis of the near-term and long-term costs. Revenue-generating options, including property
assessments, are presented along with potential other sources of technical and financial assistance
for plan implementation.
Anticipated Maintenance
The most significant Chimacum Creek drainage maintenance needs are as follows:
• Reed canarygrass (RCG) management
o Approximately seven miles of stream channel require periodic (once every two to three
years) treatment to remove RCG from the channel.
o Unknown length of ditches requires RCG control .
o Annual mowing of ditch banks and some stream banks , which can lessen the need for RCG
removal from the waterways.
• Beaver and beaver dam management
o Beaver activity, particularly new dam construction, should be monitored at least a couple
times per year. Removal or alteration of dams over one year old may require mitigation.
o Management options include installation of beaver deceivers and pond levelers, as well as
trapping.
Anticipated Near-Term Costs
The current estimated cost for RCG removal is roughly $15,000 per mile. If one -third of the seven
miles of stream channel are treated each year, the annual cost would be approximately $35,000 (2.33
miles x $15,000). Treatment once every three years is a viable option, especially if banks are mowed.
If banks are not mowed, treatment every other year ma y be necessary in some stream reaches. The
costs of beaver monitoring and management are unknown.
Anticipated Long-Term Costs
Establishment of woody riparian buffers along waterways, including hedgerows along narrow
waterways and forested buffers along wide channels, will suppress RCG growth, thus substantially
reduce the need for RCG control. It is estimated that over five of the seven miles of stream channel
currently plagued with RCG could support woody buffer establishment. Approximately 1.85 miles of
stream channel are in areas of organic soils that are prone to extensive flooding that makes
successful woody vegetation establishment extremely challenging.
Establishing woody buffers to the point where RCG is sufficiently suppressed that it no longer
constricts water flow will require at least a decade of maintenance. However, state and federal
programs currently exist to cover the costs of woody buffer estab lishment and maintenance.
Jefferson County Conservation District (JCCD) has utilized such programs for decades and has
committed to continuing to pursue these programs for both habitat restoration and RCG control .
Eventually, RCG removal could be reduced to about two miles of stream channel, which if done every
other year would cost about $15,000 (current estimated cost) annually, or $10,000 annually if done
once every three years.
14
Drainage District Assessment Options
Drainage districts have the power to assess properties within their boundaries in order to generate
revenue to perform drainage functions. A common method of assessing propert ies is to divide the
district into benefit zones based on flooding vulnerability (hence, drainage improvement benefits).
Benefit zones are typically determined based on land elevation relative to stream channel elevation.
For example:
• Lands with elevations 5 feet or less above the stream channel elevation (Benefit Zone 1) could
be assessed at 100%.
• Lands with elevations 5 to 15 feet above the stream channel (Benefit Zone 2) could be
assessed at 50%.
• All other lands (Benefit Zone 3) could be assessed at 25%.
One rationale for assessing lands that do not directly benefit from drainage activities, such as Benefit
Zone 3 presented in the example above, is that upland areas contribute to flooding in lowland areas.
In 2025 the Jefferson County GIS specialist analyzed the drainage district using the above example
and produced the following results:
• Benefit Zone 1 (<5’) = 1,896 acres
• Benefit Zone 2 (5-15’) = 1,091 acres
• Benefit Zone 3 (>15’) = 3,537 acres
Using the above example, at a 100% assessment rate of $2 per acre, $6,779 could be generated,
broken down by benefit zone as follows:
• Benefit Zone 1 (<5’) = 1,896 acres x $2 = $3,792
• Benefit Zone 2 (5-15’) = 1,091 acres x $1 = $1,091
• Benefit Zone 3 (>15’) = 3,537 acres x $0.50 = $1,769
Some lands would likely be exempted from assessments for various reasons or assigned a lower
assessment rate because of conversion to wetland habitat (thus not or minimally benefiting from
drainage activities).
Given the near-term availability of technical and financial assistance from Jefferson County
Conservation District (see below), the amount of assessment revenues generated in the example
above likely far exceed the near-term needs. Thus, assessment rates could be reduced or collected
assessment revenues could be reserved for future needs.
Drainage district assessments also must pay for administrative expenses, such as insurance,
commissioner bonding, and elections. These expenses are not currently known. However,
commissioner election costs would be substantial if elections are conducted by the Jefferson County
Auditor’s Office. State law requires drainage districts to contract with their county auditor to conduct
elections if the district has fewer than 500 qualified voters. A 2022 analysis by the Jefferson County
GIS specialist indicated that DD1 had a total of 387 separate ownerships. Eligible voters are registered
to vote in Washington State and own property within the boundaries of the district. Each owner of
land in the district may cast two votes (or one per spouse or domestic partner), including two per
corporation, partnership, or government entity. Therefore, DD1 could conduct its own elections. If
only one person files, no election is held.
15
Conservation District and Other Sources of Assistance
Jefferson County Conservation District (JCCD) is prepared to contribute staff time for technical
assistance, such as for permit application and compliance, beaver monitoring, grant writing, and
woody buffer establishment, for the foreseeable future. In addition, JCCD has access to state grant
funding to support RCG removal (currently through June 2027 but anticipated to continue into the
near future). Slightly more than $80,000 was awarded for the 2025-27 biennium from this source.
The funds are utilized by the conservation district for cost sharing on a variety of conservation
practices throughout Jefferson County. Funds are typically dispensed on a first -come, first-served
basis. Most practices require a 25% match; however, practices in which the applicant receives little or
no benefit, such as riparian restoration, do not require any match. Other state grant funding is
available for riparian restoration projects. The conservation district completed several projects in
2025 and has additional projects planned for 2026. Additional funding from JCCD may also be
available to assist with drainage maintenance and habitat enhancement activities .
The North Olympic Salmon Coalition (NOSC), one of several regional fisheries enhancement
organizations across the state, plays a key role in fish habitat restoration and enhancement. This can
include everything from small-scale enhancement to major stream channel re -meandering. NOSC was
the lead organization for a comprehensive Chimacum watershed habitat restoration project and has
led efforts to plan for and implement beaver management projects. NOSC currently has grant funding
for a pilot stream channel re-meander project on upper ECH (Kodama Farm), and planning for a
second project on lower ECH (Glendale property).
The USDA Natural Resources Conservation Service has programs to assist with riparian and wetland
restoration. Most programs are implemented through contracts with individual landowners;
however, some programs, such as the Regional Conservation Partnership Program (RCPP), involve
local partners, such as conservation districts or drainage districts that coordinate project
implementation with multiple landowners. RCPP is a competitive program, but if awarded, funds are
readily available for the proposed activi ties. For DD1, this would most likely include riparian and
wetland restoration. Wetland restoration can include enrollment in the Wetlands Reserve Easement
program, which pays landowners to convert farmlands to wetlands, including both restoration and
easement payments. Preparation and submittal of an RCPP proposal would likely be done as a
partnership with DD1, JCCD, NOSC, and Jefferson Land Trust. The land trust would likely play a critical
role preparing and holding easements.
16
SECTION 5: DRAINAGE MAINTENANCE PERMITTING
The following factsheets describe drainage maintenance permitting requirements.0F
1
Factsheet #1 Hydraulic Project Approval
Factsheet #2 Water Pollution Control Acts
Factsheet #3 Growth & Shorelines Management Acts (Critical Areas Ordinance)
Factsheet #4 Agency Contact Requirements
Factsheet #5 Emergency Drainage Maintenance
General Permitting Conditions and Notifications
Below are the general conditions and notifications pertaining to drainage maintenance activities .
Individual permits address more detailed specifications and requirements and may differ from what is
described here or in the associated factsheets. For example, the Hydraulic Project Approval for reed
canarygrass removal from Chimacum watershed waterways only allows for instream work from July 1
through August 31. The Washington Department of Fish & Wildlife (WDFW) and the Department of
Ecology have reviewed these guidelines and their comments have been incorporated; however, the
factsheets have not been updated due to a lack of unspecified comments. Further consultation with
WDFW may be necessary.
Maintenance Dredging (typically limited to constructed ditches)
Thirty-day notice to WDFW Habitat Biologist.
Survey or other information provided to WDFW Habitat Biologist with notification.
Source of sediment identified and corrected to prevent or reduce future dredging.
Signed landowner agreements for a minimum of 15’ native shrub hedgerows on both sides of the
dredged area delivered to WDFW Habitat Biologist prior to any dredging.
Site visit with WDFW Habitat Biologist prior to project implementation.
Watercourse Vegetation Management
Fourteen-day notice to WDFW Habitat Biologist.
Culvert Maintenance and Replacement:
Maintenance requires 14-day notice to WDFW Habitat Biologist.
Replacement requires 30-day notice with design drawings and specifications.
Aquatic Herbicides
WSDA permit required.
Bridge Maintenance and Replacement
Maintenance requires 14-day notice to WDFW Habitat Biologist.
Replacement requires 45-day notice with design drawings and specifications.
Beaver Dam Management
Removal or modification of new beaver dams, less than one month old, requires three-day notice
to WDFW Habitat Biologist.
1 Section 5 is adapted from the Drainage Management Guide for Whatcom County Drainage Improvement Districts,
developed in 2009. The factsheets are from that guide; thus, may include references to Whatcom County-specific permit
requirements, regulations, regulatory agencies, and tribal partners.
17
Removal or modification of older beaver dams, more than 1 month old, requires 14-day notice to
WDFW Habitat Biologist and a site visit.
Hand Maintenance
Fourteen-day notice to WDFW Habitat Biologist.
AGENCY and ORGANIZATION CONTACTS
0BFederal Agencies
US Army Corps of Engineers
Seattle District Regulatory Branch
206-764-3495
206-764-6602
Natural Resources Conservation Service
Port Angeles Field Office
(360) 406-5449
aaron.oman@usda.gov
Tribes
Jamestown S’Klallam Tribe
360-683-1109
info@jamestowntribe.org
Port Gamble S’Klallam Tribe
360-297-6293
Washington State Agencies
Department of Fish & Wildlife
WDFW Region 6
Area Habitat Biologist
360-522-6035
adam.samara@dfw.wa.gov
Department of Ecology
SW Regional Office
300 Desmond Dr SE
Lacey, WA 98503-1274
360-407-6300
Local
Jefferson County Community Development
(360) 379-4450
gballard@co.jefferson.wa.us
Jefferson County Public Health
360-385-9444
mdawson@co.jefferson.wa.us
Jefferson County Public Works
360-385-0890-1
roads@co.jefferson.wa.us
Jefferson County Conservation District
(360) 385-4105
info@jeffersoncd.org
Jefferson County Noxious Weed Control Board
360-316-9332
sdegroot@co.jefferson.wa.us
Non-Governmental Organizations
Jefferson Land Trust
360-379-9501
info@saveland.org
North Olympic Salmon Coalition
360-379-8051
outreach@nosc.org
18
SECTION 6: DRAINAGE MAINTENANCE BEST MANAGEMENT PRACTICES
The BMPs detailed in the factsheets listed below will be adhered to for all drainage system
maintenance work. Note that the instream work window stated in the Whatcom County factsheets is
August 1 through September 30; however, for Chimacum Creek the instream work window is July 1
through August 31 or as otherwise stated in Hydraulic Project Approval permits . Factsheets #7
through #17 describe specific drainage maintenance work, and factsheet #6 describes general BMPs
that apply to all types of drainage maintenance work.
Factsheet #6 General Maintenance BMPs
Watercourse Vegetation Management and Maintenance Dredging
Reed canarygrass (RCG) is the most common impediment to drainage in DD1. Mechanical mowers
(rotary or flail designs) are used to control vegetative material from the water line to the top of the
bank. Regular bank mowing can reduce the need for removal of RCG from waterways. RCG growing in
the channel is commonly removed utilizing an excavator with a rake attachment or clamshell bucket to
“pluck” floating mats of reed canarygrass from the channel. Dredging is generally limited to wholly
artificial constructed ditches, as needed, by utilizing a hydraulically operated boom-type excavator
operated from the top of bank. The excavator is typically equipped with a wide, flat -bottomed bucket
with a lid that is designed to remove reed canarygrass and accumulated sediments. Deposit all
removed vegetative material landward of the channel such that it will not return to the water and can
later be moved back into the adjoining field or be hauled away.
Factsheet #7 Maintenance Dredging
Factsheet #9 Watercourse Vegetation Management
Factsheet #14 Constructed Watercourse Maintenance
Factsheet #15 Fish Protection
Factsheet #16 Water Quality Protection Measures
Aquatic Herbicides
An aquatic formula of glyphosate can treat r eed canarygrass growing in the channel bottom and on
streambanks. Although there are environmental impacts associated with herbicidal treatments, these
impacts are less than mechanical dredging. Applications are made in late summer or early fall when the
practice is most effective.
Factsheet #10 Aquatic Herbicides and Watercourse Maintenance
Constructed Watercourse Maintenance
Landowners or DD1 can maintain their constructed watercourses using the BMPs listed in:
Factsheet #14 Constructed Watercourse Maintenance
19
Hand Maintenance
Removal of minor obstructions can keep a watercourse open and flowing. Removing obstructions by
hand is less impactful than other practices such as dredging. Hand maintenance can also include use of
hand mowers, brush cutters, and string trimmers to ma intain vegetation on stream and ditch banks .
Factsheet #17 Hand Maintenance
Beaver Dam Management
Beaver dams are another common impediment to drainage in DD1. When dams are of sufficient size to
impact property, they are typically removed by hand, often simultaneously with beaver trapping. If a
dam is located in a natural or unnatural constriction point such as a culvert or area where the channel
narrows, one can utilize “beaver deceivers” or “flow levelers ”. Removal of large dams using a tracked
excavator may be necessary in rare circumstances.
Factsheet #8 Beaver Dam Management
Factsheet #15 Fish Protection
Factsheet #16 Water Quality Protection Measures
Culvert Maintenance and Replacement
Maintain culverts to ensure normal flow passes through the culvert consistent with its design
specifications. This typically includes dredging of a ditch adjacent to culvert openings and occasional
cleaning-out of the culvert interior. Cleaning is usually performed through the use of high-pressure
water, mechanical dredging, or by hand. Repair or replacement is necessary when damage or normal
deterioration occurs to the extent that prevents optimum water flow or an unsafe crossing situation.
When replacement is necessary, use bridges when possible and design new culverts using WDFW’s
Water Crossing Design Guidelines.
Factsheet #11 Culvert Maintenance and Replacement
Factsheet #15 Fish Protection
Factsheet #16 Water Quality Protection Measures
Bridge Maintenance and Replacement
Properly maintain bridges in order to ensure normal flow under the bridge while also continuing to
provide equipment or foot access across a watercourse. Repair or replacement is necessary when
incidental damage occurs to a bridge that prevents optimum water flow or results in an unsafe crossing
situation. Repair or replacement activities typically occur above the high -water line. Bridge
replacement may involve significant engineering and permitting challenges.
Factsheet #12 Bridge Maintenance and Replacement
Watercourse Revegetation and Bank Stabilization
Watercourse banks that are well vegetated with trees and shrubs have numerous advantages,
including stabilizing banks, long-term control of reed canarygrass and other noxious weed growth,
providing wildlife and pollinator habitat, and shading and cooling t he water. A major disadvantage of
20
woody vegetation is the improved habitat it provides for beavers and other problematic wildlife.
Techniques for revegetating drainage system watercourses are described in Factsheet #20. Other
techniques for stabilizing banks along watercourses are describe d in Factsheet #21.
Factsheet #20 Watercourse Revegetation
Factsheet #21 Watercourse Bank Stabilization Techniques
Land Stewardship and Drainage Maintenance
The primary purpose of drainage systems and their maintenance is to enable farming and reduce
flooding. Various upland land management practices that can reduce drainage maintenance work,
including livestock exclusion, field borders, and filter strips, and stormwater management are
described in the following factsheet:
Factsheet #22 Farm Practices & Drainage Maintenance
21
SECTION 7: SPECIAL PROJECTS
The drainage district may sponsor or co-sponsor special projects beyond routine maintenance and the
permits that cover such maintenance. These projects might include special drainage system projects,
such as decommissioning of obsolete drainage ditches, planting woody riparian buffers along ditch and
stream channels to compete with reed canarygrass, conversion of willow-dominated riparian areas to
other species that are not as preferred by beaver, installing beaver pond levelers, and removal of
sediment buildup in specific reaches of drainage ways.
In addition to projects to support the proper functioning of the drainage system, the drainage district
could undertake or partner with other organizations to implement habitat improvement or restoration
projects. WDFW has identified numerous culverts as barriers to fish passage, and many of these are
candidates for corrective action. Some stream reaches are candidates for major restoration work ,
including reconstruction of natural channel meanders and riparian forest buffer establishment. Some
reaches that chronically flood well into the growing season or otherwise are characterized by
marginally productive farmland may be candidates for large-scale wetland restoration.
In 2018, the North Olympic Salmon Coalition and partners identified and prioritized the ecological
restoration projects below. The consulting services of Natural Systems Design, Inc. were hired to
complete preliminary analyses , which are detailed in the report titled Chimacum Creek Restoration and
Protection Strategy. Updated information for each potential project is provided below.
Priority 1. Mozaic Farm (former Yarr Farm) Riparian Easement and Restoration – Reach W5, CHI RM
7.4-7.7
Farmland protection easement established. Preliminary design and wetland delineation
completed in 2021.
Priority 2. Kodama Farm Riparian Easement and Restoration – Reach E4, ECH RM 4.3
Preliminary design completed, easement established, final design and construction funding
awarded. Construction planned for 2027.
Priority 3. Holt Property: Fastlane Farm Riparian Easement and Restoration – Reach W7, CHI RM
9.4-9.9
Preliminary design completed in 2014 for large-scale stream remeander. Small-scale
alternatives were proposed in 2024; however, landowner is currently not interested in pursuing
restoration.
Priority 4. Short’s Family Farm Riparian Easement and Restoration – Reach W4, CHI RM 5.1-6.1
Farmland protection easement established, property purchased by Port of Port Townsend in
2024, followed by community visioning for future farming and ecological restoration work.
Priority 5. Ovenell Farm Property Riparian Easement and Restoration – Reach E3, ECH RM 3.0-3.5
No activity.
Priority 6. Goularte Property; Ruby Ranch Riparian Easement and Restoration – Reach E4, ECH RM
3.7-4.1
No activity.
Priority 7. Brown Farm Reach Scale Restoration – Reach W2, CHI RM 3.7-4.1
22
No activity.
Priority 8. Willowwood Farm (former Bundy Farm) Reach Scale Restoration – Reach W6, CHI RM 8.7
Hedgerow installed through the Conservation Reserve Enhancement Program is in early stages
of establishment along stream and major tributary ditch. Easement established through land
trust to prevent development of farmland.
Projects of this nature will require additional planning, design, and engineering to ensure desired
results, obtain permits and funding, and minimize adverse environmental impacts , including impacts to
neighboring properties. Any wetland restoration is contingent on willing participation by landowners
and may require the purchase of easements or property acquisition.
Another possible special project is storage of winter water for use during the remainder of the year.
The Quilcene-Snow Watershed Water Resources Management Rule (WRIA 17 water rule) prohibits
new outdoor uses of water in the Chimacum sub-basin; however, winter water is available for new
water rights if it can be stored. Whether or not this is feasible or how this might work is yet to be
determined. However, with projections of wetter winters characterized by more intense storm events
and drier summers, management and storage of winter runoff is worth pursuing. Such a project would
require considerable study and would be best overseen by entities that are engaged in watershed
drainage system management and maintenance.
23
SAMPLE ANNUAL WORK PLAN
Chimacum Drainage District
2026 Annual Work Plan
Reach Maintenance Activity Date(s) Notes
24
APPENDICES – LIST OF FACTSHEETS1F
2
1. Hydraulic Project Approval
2. Water Pollution Control Acts
3. Growth & Shorelines Management Acts
4. Agency Contact Requirements
5. Emergency Drainage Maintenance
6. General Drainage Maintenance BMPs
7. Maintenance Dredging BMPs
8. Beaver Dam Management
9. Watercourse Vegetation Management
10. Aquatic Herbicides and Watercourse Maintenance
11. Culvert Maintenance and Replacement
12. Bridge Maintenance and Replacement
13. Sediment Traps
14. Constructed Watercourse Maintenance
15. Fish Protection
16. Water Quality Protection Measures
17. Hand Maintenance
18. Watercourse Classifications
19. Drainage Water Quality
20. Watercourse Revegetation
21. Bank Stabilization Techniques
22. Farm Practices
2 BMP Factsheets are from the Drainage Management Guide for Whatcom County Drainage Improvement Districts, developed in 2009. Some of these factsheets
include references to Whatcom County-specific regulations, regulatory agencies, and tribal partners.
Page 1 of 3
Permitting Factsheet #1HYDRAULIC PROJECT APPROVAL
Washington State Department of Fish & Wildlife
Introduction
All fish have habitat needs related to water quality,
quantity, and to the other physical and biological features
of the stream or body of water in which they live. For
example, salmon and steelhead spawn and live for a
time in a stream before going to the ocean. They require
an ample supply of clean, cool, well-oxygenated water.
Adults need clean gravel in which to spawn and juvenile
fish require in-stream cover such as tree parts, boulders,
or over-hanging banks to hide from predators. Vegetated
stream banks shade the water from the warming effects
of the sun. Insects drop off overhanging vegetation and
provide food.
Construction activity in or near the water has the
potential to kill fish directly. More importantly, this
activity can also alter the habitat that fish require for a
long time after the construction work is complete. Direct
damage or loss of habitat results in a direct loss of fish
production. Direct killing of fish is usually a one-time
loss. Damaged habitat, however, can continue to cause
lost production of fish for as long as the habitat remains
altered. Major construction projects individually have a
large potential for damage, but more habitat is lost from
the cumulative effects of many smaller projects, each with
a minimal level of impact.
The Law
All construction projects in State waters are governed
by RCW 77.55. Known as the “Hydraulic Code”,
any person or government agency must first obtain an
approval from the Washington Department of Fish and
Wildlife (WDFW) before commencing work. Approval
is given in the form of a Hydraulic Project Approval or
“HPA”. A “hydraulic project” is the performance of any
work that will use, divert, obstruct, or change the natural
flow or bed of any of the salt or freshwaters of the state.
So, before installing a flood gate, dredging, or removing
a beaver dam in a jurisdictional watercourse, a HPA must
be obtained. Failure to obtain a HPA before engaging in
any work within or above state waters, including drainage
maintenance activities, is a gross misdemeanor. Every
Good
Fish Habitat
Poor
Fish Habitat
Minimal
Fish Habitat
Page 2 of 3
person convicted of a gross misdemeanor defined in
Title 9A RCW shall be punished by imprisonment in the
county jail for a maximum term fixed by the court of not
more than one year, or by a fine in an amount fixed by
the court of not more than five thousand dollars, or by
both such imprisonment and fine. Additionally, WDFW
may levy civil penalties of up to one hundred dollars per
day for violation of the Hydraulic Code. It is also a gross
misdemeanor to violate any requirements or conditions of
a Hydraulic Project Approval.
When is an HPA needed?
The law requires that any person, organization, or
government agency wishing to conduct any construction
activity that will use, divert, obstruct, or change the bed
or flow of state waters must do so under the terms of
a permit (called the Hydraulic Project Approval-HPA)
issued by the Washington State Department of Fish and
Wildlife. State waters include all marine waters and fresh
waters of the state, except those watercourses that are
entirely artificial, such as irrigation ditches, canals, and
storm water run-off devices. The major types of activities
in freshwater requiring an HPA include, but are not
limited to: stream bank protection; construction or repair
of bridges, piers, and docks; pile driving; channel change
or realignment; conduit (pipeline) crossing; culvert
installation; dredging; gravel removal; pond construction;
placement of outfall structures; log, log jam, or debris
removal; installation or maintenance of water diversions;
and mineral prospecting. It is important to emphasize that
the above are only examples of major types of activities
requiring a HPA and that any construction activity that
uses, diverts, changes, or obstructs the bed or flow of
state waters requires a HPA. Approval of a permit is valid
for a period of up to five years from the date of issuance.
Drainage maintenance on modifi ed natural watercourses will require a HPA
How do I apply for a HPA?
The form to apply for a HPA is called a Joint Aquatic
Resource Permit Application (JARPA). A JARPA
consolidates seven permit application forms for federal,
state, and local permits and is used to apply for a HPA
and also for Water Quality Certifications or Modifications
from the Department of Ecology, Aquatic Resource
Use Authorizations from the Department of Natural
Resources, and Army Corps of Engineers permits. The
form can be found at http://www.ecy.wa.gov/biblio/
ecy07015.html. Copies of the JARPA form must be
submitted to all participating agencies that require a
permit for your project, including the Department of Fish
and Wildlife. There is no charge for the HPA. A similar
JARPA for work on the Lummi Indian Reservation is also
available.
A complete written application for a permit may be
submitted in person or by mail and must contain the
following:
General plans for the overall project.1.
Complete plans and specifications of the 2.
proposed work within the ordinary high water
line in freshwater.
Complete plans and specifications for the proper 3.
protection of fish life.
Notice of compliance with any applicable 4.
requirements of the State Environmental Policy
Act or other applicable laws.
Prior to JARPA review, State Environmental Policy Act
(SEPA) compliance must be completed, usually by the
Whatcom County SEPA official. SEPA is a Washington
State policy that requires state and local agencies to
consider the likely environmental consequences of a
proposal before approving or denying the proposal. A
“SEPA Checklist” can be obtained from Whatcom County
Planning and Development Services. This checklist
serves as a means to address all environmental issues
associated with your project. Within 30 days of receiving
your Checklist, the Whatcom County SEPA official will
make one of three determinations:
DNS - A Determination of Non-significance 1.
means the project is unlikely to have a significant
adverse environmental impact.
MDNS - A Mitigated Determination of Non-2.
significance means the project may have some
adverse impacts but that those impacts are
mitigated for in the project proposal.
EIS - In cases where the risk of adverse 3.
environmental impacts are high, an EIS
determination will be made, meaning the
applicant must complete an Environmental
Impact Statement for their project.
Page 3 of 3Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
EXEMPTION - Some project proposals may 4.
receive a SEPA Exemption for small construction
maintenance projects. Dredging projects of any
size are not SEPA exempt.
The Washington State Department of Fish & Wildlife
will grant or deny approval within forty-five calendar
days of the receipt of a complete application and notice of
compliance with any applicable requirements of the State
Environmental Policy Act (SEPA). Protection of fish life
is the only ground upon which approval of a permit may
be denied or conditioned.
HPA Conditions for Drainage Maintenance
Projects
Drainage maintenance projects must include measures
designed to minimize negative impacts to natural
resources. Some common conditions necessary for
drainage maintenance work include:
Work Window - the time period when the fewest fish •
are present and the streamflows are lowest. Unless
otherwise noted, the work window is August 1 to
September 30.
Fish distress and water quality - When water is •
present, Best Management Practices (BMPs) must
be implemented to minize immediate impacts to fish
and to prevent the downstream release of sediment-
laden water.
BMP Factsheets #s 6-17 describe numerous BMPs •
necessary to protect fish and other natural resources.
Habitat Improvement Projects designed to offset •
or “mitigate” for the negative impacts from work
within the watercourse will likely be required and
should be included in any permit application.
A pre-application or post-application site visit with a
WDFW Habitat Biologist is usually arranged to review
a proposed project. Drainage Improvement Districts in
Whatcom County should have 5-year HPAs addressing all
of their potential maintenance projects.
Note: Diking District #1 is located partially on the
Lummi Indian Reservation and is subject to tribal laws
for activities that occur on Reservation lands. The
Lummi Nation Water Resources manager (360 384-2212)
should be contacted regarding permitting requirements.
Fish excluded from a drainage maintenance project
Typical Timing Windows
Modifi ed Watercourses August 1 to Septemer 30
Dry Constructed Watercourses Anytime watercourse is dry
Wet Constructed Watercourse August 1 to October 30
Page 1 of 2
Permitting Factsheet #2
WATER POLLUTION CONTROL ACTS
Drainage Maintenance Regulations
Introduction
Agriculture is a major contributor to the State’s
economy and has an equally important role in affecting
the quality of the State’s surface water. Agriculture’s
role in affecting water quality is important because the
surface waters upon which our communities rely for
benefi cial uses such as irrigation, fi sh habitat, domestic
use, livestock watering, recreation and manufacturing
either originate or are affected by the rivers, creeks and
ditches that fl ow through agricultural lands. Most of
these agricultural lands were historically forest lands.
This water eventually fi nds its way into the Puget
Sound or the Strait of Georgia. Recently, the decline
of water quality has been so pronounced that there is a
new “community effort of citizens, governments, tribes,
scientists and businesses working together to restore and
protect Puget Sound”. To achieve these important goals,
farmers will have to join with this new alliance.
The Laws
Clean Water Act 33 USC § 1251 et seq. and Washington
State Water Pollution Control Act 90.48 RCW and
Lummi Nation Water Resources Protection Code (Title
17) for Lummi Indian Reservation Lands. The Clean
Water Act (CWA) establishes the basic structure for
regulating discharges of pollutants into the waters of the
United States and regulating quality standards for surface
waters. The basis of the CWA was enacted in 1948 and
was called the Federal Water Pollution Control Act. It
was significantly reorganized and expanded in 1972 and
became known as the “Clean Water Act” (CWA) with the
amendments of 1977.
Under the CWA, it is unlawful to discharge any
pollutant from a point source into navigable waters,
unless a permit is first obtained. Additionally the
U.S. Environmental Protection Agency (EPA) has set
water quality standards for all contaminants in surface
waters. It has also set wastewater standards for industry.
The standards describe how much pollution can be
allowed after All Known And Reasonable Technologies
(AKART) have been applied. Point sources are discrete
conveyances such as pipes and man-made ditches.
Under Section 404 of the CWA, a Department of Army
Corp of Engineers (ACOE) permit is normally required
for the discharge of dredged or fill material into the
waters of the U.S. “Waters of the U.S.” include navigable
and interstate waters, their tributaries, and certain adjacent
and abutting wetlands. An exception to this requirement
is where the discharge is incidental to maintenance but
not construction of drainage ditches. Before an ACOE
permit can be issued the Washington Department of
Ecology (WDOE) or the Lummi Nation (for work on
Lummi Indian Reservation Lands) must “certify” that the
proposed work complies with the applicable provisions
of the CWA and applicable state or tribal laws. Failure
to obtain a permit under the CWA can result in civil
penalties up to $25,000 per day and fines of $10,000 per
incident.
WDOE and the Lummi Nation have been delegated
authority from EPA to implement certain sections of the
CWA. The WDOE is also charged with implementing
the State’s Water Pollution Control Act (WPCA). The
effect of these two laws is the extension of water quality
standards to surface and ground waters. The water
quality standards are established to sustain public health
and public enjoyment of the waters and the propagation
and protection of fish, shellfish, and wildlife. Whether
or not dredging requires an ACOE discharge permit,
Drainage Maintenance can be a significant source of sediment release
Page 2 of 2
the activity cannot result in a violation of water quality
standards. If maintenance activities do not follow
AKART and generate pollution, it can result in a fine or
penalty of $10,000 per day. Water quality standards that
are commonly exceeded due to drainage activitiy include
temperature and turbidity. Where pollution already
exists in the “background”, it need not be controlled or
improved. However, you must avoid increasing pollution
beyond a specified amount. By incorporating appropriate
BMPs and procedures in your DMP and by following
the BMPs in the field, one can avoid problems with the
CWA, WPCA, and tribal laws and meet the goals of the
Puget Sound Partnership. Factsheet #16 Water Quality
Protection Measures, Factsheet #19 Drainage Water
Quality and Factsheet #22 Farm Practices provide
detailed information on how to farm and maintain
drainage without running afoul of water quality standards.
In 1987, Congress changed the federal Clean Water Act
by declaring the discharge of stormwater from certain
industries and municipalities also be regulated. Due to
this change, certain stormwater discharges now require
a National Pollutant Discharge Elimination System
(NPDES) permit or water quality discharge permit. The
U.S. Environmental Protection Agency (EPA) delegated
the Department of Ecology the authority to implement
these permits in Washington State in two phases.
In Phase I, only certain industries, large construction
sites, and a few of the largest municipalities were required
to have an NPDES permit. The Phase II regulations
expanded the requirement for NPDES stormwater
permits. This potentially sweeps within its requirements
special purpose districts (such as a Drainage Improvement
District) when boundaries cross into a city or county
jurisdiction subject to a Phase I or Phase II stormwater
permit.
Additionally, a third party can petition WDOE to
determine that the DID is a significant contributor of
pollution to surface waters. Note that the DID need only
be the conduit and not the generator of the pollution. So,
DIDs should work closely with landowners to ensure that
their operations result in clean water leaving their lands
and entering into the drainage system.
With a designation of a DID as a “significant
contributor of pollution”, it must develop a stormwater
program that addresses the following six main elements:
Public Education and Outreach •
Illicit Discharge Detection and Elimination •
Post-Construction Runoff Control •
Public Participation/Involvement •
Construction Site Runoff Control •
Pollution Prevention/Good Housekeeping•
Action Agenda For Puget Sound
Water quality standards have proven to be inadequate
in and of themselves to protect Puget Sound. Beginning
in 1987 a series of management plans were developed
to coordinate actions of Federal, State, Local and Tribal
governments to stem the declining water quality of the
Sound. Twenty years later and faced with the continued
serious decline “as indicated by loss of and damage
to critical habit, rapid decline in species populations,
increases in aquatic nuisance species, numerous toxics
contaminated sites, urbanization and attendant storm
water drainage, closure of beaches to shellfish harvest
due to disease risks, low-dissolved oxygen levels causing
death of marine life, and other phenomena” the legislature
created a new agency through passage of RCW 90.71.
Known as the Puget Sound Water Quality Protection
Act, an “Action Agenda” is being crafted to recover and
protect Puget Sound. The action agenda is to consist
of the goals and objectives expressed in the legislation
including implementation strategies to meet measurable
outcomes, benchmarks, and identification of responsible
entities. All governmental entities within Puget Sound
are expected to exercise their existing authorities to
implement the applicable provisions of the action agenda.
Since drainage systems can convey nutrients, pathogens,
sediment and other pollutants, it is reasonable to expect
that Drainage Improvement District activities will come
under close scrutiny by this new agency in the near future
as the Action Agenda is developed and implemented.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
Permitting Factsheet #3
GROWTH & SHORELINES MANAGEMENT ACTS
(Whatcom County Critical Areas Ordinance)
Shorelines Management Act 90.58 RCW
Recognizing that the shorelines of the state are among
our most valuable and fragile natural resources, the
State Legislature passed the Washington State Shoreline
Management Act (SMA) in June 1971. The SMA was
overwhelmingly passed by public initiative in 1972.
Under the SMA, each county and city was required to
prepare a shoreline “master program” in accordance with
the shoreline guidelines issued by the State Department of
Ecology in 1972.
The Whatcom County Shoreline Management Program
(SMP), WCC Title 23, is the document that implements
the goals and policies of the SMA at the local level. It
was adopted in 1976. Under the provisions of the SMA,
all development within shorelines of the state is required
to comply with the provisions of local shoreline master
programs. Drainage maintenance activities may be
considered “development” or may be exempt under some
circumstances. Whatcom County jurisdiction includes
stream channels and all associated wetlands, floodways
and upland areas within 200 feet of the Ordinary High
Water Mark (OHWM).
Whatcom County Planning and Development Services
(PDS) and the Washington State Department of Ecology
(DOE) share joint authority and responsibility for the
Whatcom County SMP. PDS is the primary agency
responsible for implementation of the Whatcom
County SMP. DOE is responsible for supervising
the administration of the code, ensuring proper
implementation, and assuring consistency with the
SMA. Because the Whatcom County master program
is approved and adopted by DOE, it has the authority of
state law.
that protect “critical areas” and existing “shoreline
values”. Critical areas that may be impacted by drainage
maintenance activities include wetlands and Habitat
Conservation Areas (“HCAs”). The standard protection
for wetlands range from 25 feet to 300 feet depending
upon the type of activity and level of function of the
wetland. The buffer widths for streams range from 50
feet for non-fish bearing steams, to 100 feet for fish
bearing streams and 150 feet for shoreline streams. These
standard buffer widths may be reduced with a Farm
Conservation Plan or for Drainage Improvement Districts
a Drainage Maintenance Plan. Failure to comply with the
County’s CAO can result in an stop work order and a civil
offense punishable by $1,000 fine for each offense. Each
day of work constitutes a separate offense.
Drainage maintenance activities are allowed only
after Notification to the Whatcom County critical areas
Technical Administrator 10 days prior to initiating work
provided that all the following are met:
The maintenance is necessary to support ongoing 1.
agricultural operations;
The maintenance activity does not expand the 2.
dimensions of the drainage channel beyond the
original, lawfully established dimensions;
The agricultural activities are conducted pursuant 3.
to an approved farm conservation plan or drainage
management plan;
The project proponent or landowner obtains a 4.
Hydraulic Project Approval (HPA), if required from
the Washington Department of Fish and Wildlife
(WDFW), prior to the maintenance activity;
The project proponent or landowner provides a 5.
copy of the HPA to the Technical Administrator as
part of the written notification. No other written
notification is needed.
Whatcom County permit applications and notices
necessary to perform drainage maintenance are likely to
include:
State Environmental Policy Act checklist•
Natural Resource Notification of Activity•
Endangered Species Act (ESA) Checklist for •
Development within the ESA Potential Impact Area
Growth Management Act 36.70A RCW
In 1990, the Growth Management Act (‘GMA”) was
enacted by the State legislature in response to rapid
population growth and concerns with suburban sprawl,
environmental protection, quality of life, and related
issues. Whatcom, along with twenty-six other counties,
was required to adopt county-wide planning policies
Permitting Factsheet #4
AGENCY CONTACT REQUIREMENTS
Watercourse
Type
Activity
Description
No
Agency
Contact
JC
DCD
WDFW
HPA
Ecology
Storm
Water
Ecology
Permit
Army
Corps of
Engineers
Constructed
Watercourse
Maintenance
Dredging
Sediment
Removal X
Bank Vegetation
Management Mowing X
Culvert
Maintenance
Debris Removal
or Headwall
Repair
X
Bridge
Maintenance
Debris Removal
or Abutment
Repair
X
Herbicide
Applications
Aquatic
Herbicide
Applications
X X
Beaver Dam
Removal
Beaver Dam
Modification or
Removal X
Sediment Trap
Maintenance
Sediment
Removal X
Hand
Maintenance
Vegetation
removal X
Modified
Watercourse
Maintenance
Dredging
Sediment
Removal X X X X X
Bank Vegetation
Management Mowing X X
Culvert
Maintenance
Debris Removal
or Headwall
Repair
X X X X
Bridge
Maintenance
Debris Removal
or Abutment
Repair
X X X X
Herbicide
Applications
Aquatic
Herbicide
Applications
X X
Beaver Dam
Removal
Beaver Dam
Modification or
Removal
X X
Sediment Trap
Maintenance
Sediment
Removal X X X X X
Hand
Maintenance
Vegetation
Removal X X
JCDCD - Jefferson County Department of Community Development
WDFW - Washington Department of Fish and Wildlife
Ecology - Washington State Department of Ecology
Page 1 of 1
Permitting Factsheet #5Emergency Drainage Maintenance
Introduction
Circumstances will arise as a result of weather or other
factors where drainage maintenance work must be done
outside of designated work windows and/or require the
actions that deviate from the Best Management Practices
(BMPs) in a Drainage Management Plan (DMP). In the
event of a drainage maintenance emergency, the following
protocols will apply:
Constructed Watercourses
Notification to the Washington Department of Fish and
Wildlife (WDFW), Whatcom County Planning and
Development Services (WCPDS) and U.S. Army Corps
of Engineers (ACOE) is not required for emergency
repair activities in constructed watercourses identified in
a Drainage Improvement District’s (DID’s) DMP. BMP
implementation is voluntary but careful monitoring of
water quality is necessary to ensure downstream waters
are not impacted.
Factsheet # 16 Water Quality Protection Measures
Modified Natural Watercourses
Emergency approval is required by WDFW and
emergency notification is required to ACOE (when an
ACOE permit was required) for any emergency repair
activities occurring in Modified Natural Watercourses
identified in a DID’s DMP.
WDFW Emergency Contacts:
Jeff Kamps (Area Habitat Biologist) -
(360) 466-4345 Ext. 271
Brendan Brokes - (360) 466-4345 Ext. 253
Emergency Hotline - (360) 902-2537
In most cases WDFW will issue a verbal emergency
maintenance approval, with the understanding that
the proposed work is necessary to address emergency
drainage conditions. The DID will schedule an on-site
meeting with the WDFW Area Habitat Biologist as
soon as possible, but not more than 30 days after work
is completed. The purpose of this on-site meeting will
be to determine if additional measures will be necessary
to restore fish habitat that may have been damaged as a
result of an emergency action undertaken by the DID.
ACOE Emergency Contacts:
(for DIDs with watercourses needing a ACOE permit)
Randel Perry - Skagit/Whatcom and FERC/Special
Assignment - (206) 764-6985
FAX number - (206) 764-6602
1. Make sure you make a good faith effort to contact
the Corps Regulatory Branch before proceeding with
work, i.e., at least leave a voice mail and fax stating
whatever information you have available. The fax
number for everyone located in the main office in
Seattle is (206) 764-6602. If a permit is required and
no contact was made, we could consider the work a
knowing and willful violation.
2. Information to give the Corps - if you are unable to
speak with someone directly, leave as much of the
following information on voice mail and follow up
with more details as soon as possible.
• Where the work is located (highway, river mile, nearest
waterbody, nearest city, etc.).
• What work is being performed (replacement of lost
riprap, bank protection, replacement of lost uplands,
large woody debris being placed, cleaning of a culvert,
etc.).
• Include a discussion (amounts, location, etc.) of any
temporary fill/work, when the material will be removed,
and how the area will be restored.
• How the work is being performed (clean excavation with
backhoe, pushing of material with bulldozer, blasting out
the culvert with water, etc.).
• If any of the proposed work is in wetlands or below the
plane of ordinary high water (freshwater) or below the
plane of mean higher high or mean high water (tidal).
• Relationship of the proposed work to previously existing
structures (replacing what previously existed or adding
different structures, etc).
• Photos, if available, can often be very helpful.
• Anything else that could help us to determine what is
being proposed (reference previously issued permits for
work at the site).
• Include what coordination with the NMFS/USFW
(Services) for ESA/EFH has occurred.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 1
BMP Factsheet #6
General Drainage Maintenance BMPs
Introduction
Drainage Maintenance work such as dredging, mowing
or beaver dam removal will have negative impacts to
natural resources. Best Management Practices (BMPs)
have been developed to minimize the environmental
impacts. This Factsheet contains general BMPs that
should be used when implementing any type of drainage
maintenance project. BMP Factsheets #7 to #17 describe
additional BMPs needed for specific types of drainage
maintenance work.
BMPs
Operate equipment only from the top of the 1.
channel bank. Watercourse crossings are not
allowed.
Equipment shall not enter or cross the channel 2.
when water is present.
Existing vegetation shall be retained on the 3.
sidewalls of the channel to the maximum extent
possible.
Work will take place from the north or east banks 4.
whenever possible.
Disturbance of the channel banks and woody stem 5.
riparian vegetation shall be held to the absolute
minimum necessary to access the channel and to
conduct the drainage maintenance activity.
Disturbance of woody stem riparian vegetation 6.
shall be limited to one side of the channel at any
given location along the watercourse.
Along the shoreline, disturbed soils at risk of 7.
entering the watercourse shall be protected from
erosion using vegetation and/or other means.
Dredged, excavated, or bucket mowed materials 8.
shall be deposited landward of the top of the
channel bank.
Dredged, excavated, or bucket mowed materials 9.
shall not be stockpiled below the top of the
channel bank.
Project activities shall be conducted in a way that 10.
minimizes the introduction of silt-laden water into
the watercourse.
Pilings or lumber treated with creosote or 11.
pentachlorophenol shall not be used for project
construction.
All treated wood shall be professionally treated 12.
and completely cured prior to installation below
the high water line in order to minimize leaching
into the water or substrate.
Wet concrete shall be prevented from entering the 13.
watercourse. Footings, foundations and/or super
structures constructed with fresh concrete shall be
sufficiently cured prior to contact with water to
avoid leaching. Forms and impervious materials
shall remain in place until the concrete is cured.
All debris or deleterious material resulting from 14.
drainage maintenance activities shall be removed
from the watercourse and prevented from re-
entering the channel.
No petroleum products or other deleterious 15.
materials shall be allowed to enter the surface
waters in the channel.
If a fish kill occurs or fish in distress are observed, 16.
in-water drainage maintenance activities shall
immediately cease and the Area Habitat Biologist
(AHB) shall be immediately contacted.
Removal of trash and plant debris blocking 17.
culverts, bridges, and floodgates shall not be
subject to a timing limitation.
Whenever rock is used to armor the channel bank 18.
in the immediate vicinity of a drainage structure
(culvert, floodgate, bridge, pump facility), the rock
shall be composed of clean, angular material of a
sufficient durability and size to prevent its being
broken up or washed away by high water.
The footprint of a maintained, repaired or replaced 19.
drainage structure (culvert, floodgate, bridge,
pump facility, trash rack) below the high waterline
shall not exceed the footprint of the original
drainage structure below the high waterline.
Emergency work that must be done outside the 20.
normal work window of August 1 to September
30 must be verbally approved by the AHB prior to
implementation.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
BMP Factsheet #7 Maintenance Dredging
Best Management Practices
Dredging BMPsIntroduction
General BMPs
Timing Limitations: Whenever water is present 1.
in the channel, maintenance dredging below the
waterline shall only occur from August 1 through
September 30 of any year for the protection of
migrating juvenile and adult salmon.
NOTIFICATION REQUIREMENT: A 2.
representative of the Drainage Improvement
District or contractor shall notify the Washington
Department of Fish and Wildlife Area Habitat
Biologist (AHB) of the project start date.
Notification shall be received by the AHB prior
to the start of dredging activities. Note: This
notification assumes that the DID has obtained all
appropriate permits prior to work.
Dredging shall be conducted with hand tools and/3.
or a tracked excavator equipped with a clam shell
or lidded bucket to minimize fallback.
Each pass with the excavator bucket in the channel 4.
shall be complete.
Dredging shall be held to the absolute minimum 5.
necessary to achieve the target channel width,
depth and gradient.
The channel banks shall be sloped such that the 6.
resulting channel banks are stable.
Maintenance dredging shall not straighten or 7.
shorten the existing channel alignment.
Existing large woody material embedded in 8.
the channel bank or streambed shall be left
undisturbed and intact.
Maintaining drainage by dredging is a common and
proven method to remove nuisance vegetation and
accumulated sediments. Dredging is also the practice
with the most negative impacts to natural resources. Fish,
fish habitat and water quality are significantly impacted
during and after dredging. Informational Factsheets
#20 Watercourse Re-vegetation and #22 Farm Practices
suggest methods that will prevent sediments and nuisance
vegetation from impacting the watercourse, thereby
reducing the need for dredging.
Additionally, BMP Factsheet #15 Fish Protection and
Factsheet #16 Water Quality Protection Measures provide
detailed Best Management Practices (BMPs) to minimize
impacts to fish and water quality during dredging. The
following general BMPs apply to all maintenance
dredging work:
Lidded bucket on tracked excavator
Temporary silt fence
Page 2 of 2
Silt Management
When water is present in the channel, maintenance 9.
dredging activities in and immediately upstream
of a watercourse reach that has been identified as
juvenile salmonid rearing habitat in the Drainage
District’s Drainage Maintenance Plan shall
implement silt management provisions 10 through
14.
Prior to initiating maintenance dredging 10.
activities, a temporary silt fence shall be installed
immediately downstream of the watercourse reach
to be dredged. The temporary silt fence shall be
installed across the watercourse and perpendicular
to the water flow.
The temporary silt fence shall remain in place for 11.
the duration of the maintenance dredging activity.
If watercourse flows are encountered that 12.
exceed the design capacity of the silt fence, the
maintenance dredging activity shall stop until the
watercourse flows subside.
Prior to the removal of the temporary silt fence 13.
from the watercourse, silt that has accumulated
behind the silt fence shall be removed to the
greatest extent possible.
The temporary silt fence shall be removed within 14.
2 days of completing the maintenance dredging
activity.
BMP Factsheet # 16 Water Quality Protection Measures
provides detailed information on sediment management.
Fish removal
Fish Removal
When water is present in the channel, the 15.
provisions in BMP Factsheet #15 Fish Protection
shall be implemented prior to initiating
maintenance dredging activities in watercourse
reaches that have been identified as juvenile
salmonid rearing habitat in the Drainage District’s
Drainage Maintenance Plan.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 4
BMP Factsheet #8
BEAVER DAM MANAGEMENT
Introduction
Beavers are North America’s largest rodent and perhaps
are second only to humans in their ability to alter the
environment. Beaver dams can cause drainage problems
on managed watercourses and impounded water can
cause property damage.
Pursuant to RCW 77.55 a permit must be issued for
work that will use, obstruct, change, or divert the bed
or flow of state waters. To remove or modify a beaver
dam on a natural or modified watercourse, you must
have a Hydraulic Project Approval (HPA) issued by the
Washington Department of Fish & Wildlife (WDFW).
In emergency situations (when an immediate threat to
property or life exists), verbal approval from WDFW may
be obtained for work necessary to solve the problem. A
Drainage Improvement District may hold a five year HPA
covering beaver dam management as a component of
their Drainage Management Plan.
Beaver pelts were once integral to the economy of
North America, until beavers were nearly trapped out of
existence in the late 1700s and early 1800s when demand
for their pelts peaked in Europe. Beaver populations
rebounded in the 1900s but remained at relatively low
and stable levels due to sport and commercial trapping
influence. In 1998 and 1999 beaver pelt prices fell
dramatically, eliminating incentives for commercial
trappers. Concurrently, a trapping initiative was passed
in Washington
banning leg hold
traps. Sport trappers
proved unwilling
to use livetraps so
beaver populations
have grown steadily,
largely unchecked
since the late 1990s.
Beavers eat a wide
variety of plants
including grasses,
pond lilies, cattails,
Beaver Control
corn, other herbaceous plants, and a variety of woody
plants. Beaver dams create habitat for many animals and
plants and provide essential habitat for juvenile salmon,
particulary Coho. In winter, deer and elk frequent beaver
ponds to forage on shrubby plants that grow where
beavers cut down trees for food or to use in making
their dams and lodges. Weasels, raccoons, and herons
hunt frogs and other prey along the marshy edges of
beaver ponds. Migratory waterbirds use beaver ponds as
nesting areas and resting stops during migration. Ducks
and geese often nest on top of beaver lodges, since they
offer warmth and protection, especially when lodges are
formed in the middle of a pond. The trees that die as a
result of rising water levels attract insects, which in turn
feed woodpeckers, whose holes later provide homes for
other wildlife. Additionally, beaver ponds collect and
slowly release stormwater and are a natural means of
flood control and groundwater recharge.
In some situations it may make more sense to
accomodate beavers and their dams rather than attempt
to remove them. Low lying marginal farmlands may
be more productive as beaver wetlands and could be
enhanced through the Conservation Reserve Enhancement
Program or other programs.
The beaver is classified as a furbearer (WAC 232-12-
007). A trapping license and open season are required to
trap or shoot a beaver. The property owner, the owner’s
immediate family, an employee, or a tenant of property
may shoot or trap a beaver on that property if a threat to
crops exists (RCW 77.36.030). In such cases, no special
trapping permit is necessary for the use of live traps.
However, a special trapping permit is required for the
use of all traps other than live traps (RCW 77.15.192,
77.15.194; WAC 232-12-142). There are no exceptions
for emergencies and no provisions for verbal approval.
All special trapping permit applications must be in
writing on a form available from the WA Department of
Fish and Wildlife (WDFW).
Page 2 of 4
Beaver Dam Modification and Removal
BMPs
Dams can be removed during the work window •
of August 1st to September 30th using a Drainage
Improvement District’s (DID) five year permit.
Dams needing removal outside the work window or •
on land outside a DID require prior contact with the
Washington State Department of Fish and Wildlife
(WDFW) Area Habitat Biologist (AHB) and a
Critical Areas notification to Whatcom County. See
Permiting Factsheets #1 - 5 for more information.
Remove dam materials slowly and by hand or •
with hand tools to the extent possible. Chain saws
and winches can be used to dislodge and remove
material.
If large equipment is needed it must be stationed •
at the top of the bank, road or bridge. See BMP
Factsheet #6 for general BMPs.
If large woody material 6 feet or longer and 4 inches •
or greater in diameter is embedded in the streambank
it shall be left undisturbed.
The water level should drop by no more than 1” per •
hour and 12” in 24 hours.
Remove enough dam material to reach the desired •
water level and to ensure that the dam location does
not generate more running water sounds than the rest
of the channel. The sound and feel of rushing water
triggers the dam building instinct in beaver and may
well result in a new dam constructed in the same
area.
Monitor the upstream and downstream for signs of •
stranded or stressed fish. If a fish kill occurs or fish
are observed in distress, cease work immediately and
contact the AHB. Then implement Fish Protection
BMPs before additional dam work is completed.
See BMP Factsheet #15 Fish Protection.
Monitor downstream for turbidity and sedimentation. •
If suspended sediments are being released from the
Beaver Dam -- Flow Control Devices
The water level can also be managed by installing •
a “flexible leveler” (Figure 1). The advantages
include maintaining an acceptable pond level, not
risking the repair of dams or construction of new
dams nearby and not displacing the beaver family.
Maintain at least a 3’ pond depth so that the beaver •
colony will stay rather than move elsewhere and
potentially cause other problems.
The pipe should extend at least 10’ upstream and •
downstream of the dam and be of adequate size
(usually 4” to 12”) to convey enough water flow to
maintain the desired water level.
The upstream end should be protected with a wire •
cage made of 6”x8” welded steel cattle panels to
prevent plugging and noise. The cage should remain
submerged
to prevent
the beaver
from
plugging the
wire mesh.
This type •
of device
is only
effective if
small flows
through the
dam are
required.
They will
not provide
effective
drainage
where large
flows are
required.
Beaver Dam Management on Modified
Watercourses
Where unacceptable flooding is affecting property
(including agricultural fields) or roads, dam modification
or removal should be considered. While dam removal is
an option, it can be very frustrating and ineffective if the
beavers repair the breach very quickly.
Not all beaver problems can or should be handled the
same way. Flow control devices and beaver deceivers
may be more effective than continued maintenance of
beaver dams or the outright removal of beavers and their
dams. The important feature of these techniques is to
reduce the beavers’ dam building instinct in response to
the sound of running water.
Flexible Leveler at Tennant Lake
Dam breach
dam or pond, the installation of sediment control
measures will be necessary. See Factsheet #16
Water Quality Protection Measures.
Page 3 of 4
FLEXIBLE LEVELER
Figure 1
Beaver Dam Management on Constructed
Watercourses
Beaver dams less than one year old on a constructed
watercourse may be removed or modified as needed
using the methods listed above. If the dam has been
in place for a number of years, then the pond, adjacent
riparian areas and the downstream channel are often
considered valuable fish and wildlife habitat. In most
cases a Whatcom County Critical Areas notification will
be needed prior to any dam modification or removal. See
Factsheet #3 Growth & Shorelines Management Acts.
Beaver Deceiver on Schneider Ditch
Beaver Deceivers
To a beaver, a culvert probably looks like a hole in •
an otherwise fine dam. Beavers will almost always
try to dam these holes.
Rather than continuing to remove dam materials, •
a beaver deceiver may be a permanent solution
needing very little maintenance (Figure 2).
Construct in a trapezoidal shape with 10’ to 16’ side •
lengths.
Construct with 6”x8” welded steel cattle panels to •
maximize fish passage.
Monitor regularly for maintenance needs.•
Note: Flow Control Devices and Beaver Deceivers
may have negative impacts to fish passage. Consult the
WDFW Area Habitat Biologist for site specific BMPs
prior to any installation.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 4 of 4
BEAVER DECEIVER
Figure 2
Page 1 of 2
BMP Factsheet #9WATERCOURSE VEGETATION
MANAGEMENT
Mowing Bank Vegetation BMPs
(Grass and Blackberry)
Mowing Watercourse Vegetation BMPs
Introduction
Maintaining vegetation on watercourse channel banks
and in the watercourse may be an inexpensive and
effective way to maintain drainage. However the removal
of vegetation and dead vegetation left in the watercourse
can be detrimental to water quality and to fish habitat.
Please remember:
All types of plants growing near waterways can •
provide shade. This shade can reduce water
temperatures and provide fish habitat.
Vegetation roots are an invaluable means to stabilize •
stream banks and prevent erosion.
Steep channel banks can be destabilized by •
aggressive mowing or herbicide use. Resulting
erosion can both inhibit good drainage and degrade
fish habitat and water quality.
There is a • big difference between maintaining grass,
blackberries or noxious weeds along the channel
and doing anything to adversely affect native trees
and shrubs that can have significant benefit to water
quality, fish habitat and to drainage.
Mowing vegetation of any kind on the channel bank •
below the Ordinary High Water Mark will require
a Hydraulic Project Approval (HPA) from the
Washington State Department of Fish and Wildlife
(WDFW).
Mowing vegetation within the standard Critical •
Areas buffer requires notification to Whatcom
County prior to work.
Permitting •
Factsheet #1
Hydraulic
Project
Approval and
#3 Growth
and Shorelines
Management
Acts provide
detailed
information
on permitting
requirements.
Fall and winter are the preferred times of year for 1.
mowing vegetation along watercourses. Mowing
during fall/winter months allows for riparian
vegetation to green up along the ditch during the
summer months and provide shade to help keep
water temperatures cool. Vegetation along the
banks of a watercourse also provides protective
cover for juvenile fish and shades out instream
vegetation.
Dry watercourses or watercourses where the 2.
streambanks would be too wet and unstable in the
fall can be mowed at any time.
General Mowing BMPs
(Grass and Blackberry)
Timing Limitations: When water is present 1.
mowing shall take place in the low flow period of
August 1 to September 30.
Mowing equipment can only cut and remove 2.
vegetation from the channel and shall not alter the
channel profile or the slope of the channel banks.
Large woody material embedded in the bank or 3.
streambed shall be left undisturbed and intact.
Remove mowed material from the watercourse so 1.
it does not reduce drainage efficiency.
Prevent mowed material from reentering the 2.
channel, as the decay of material can lower
oxygen levels in the water downstream, thereby
harming fish.
Continual mowing becomes quite expensive over 3.
time. Often this practice is done in advance of
more long term solutions to vegetation control
such as Watercourse Re-vegetation, Factsheet
#20.
Page 2 of 2
Native trees and shrubs provide critical functions along
all types of watercourses. They provide food for fish and
other aquatic animals, filter sediment and other pollutants,
and shade the watercourse, keeping temperatures low
and reducing vegetation in the water. Roots from native
woody plants create a dense mat, preventing erosion and
bank failure.
Vegetation Management (Trees & Shrubs)
Good
Fish Habitat
Poor
Fish Habitat
Minimal
Fish Habitat
Tree & Shrub Management BMPs
Leave native trees and shrubs intact unless it is 1.
absolutely necessary to access the channel.
Prune vegetation by hand if possible and only on 2.
one side of the channel (north or east).
Vegetation on the south and west sides should be 3.
left to provide shading for the watercourse.
Prune vegetation in the fall or winter months so 4.
that vegetation shades the water during summer
to help keep water temperatures cool.
All fallen debris from hand-cutting or pruning 5.
should be cleared from the watercourse to prevent
flow blockages and to prevent decaying material
from reducing oxygen levels in the water and
harming fish.
The vegetation pruning area should only be wide 6.
enough to allow equipment access to conduct
maintenance. Vegetation removal should be
minimized as much as possible.
Maintain the integrity of the ditch by keeping the 7.
vegetation roots in place and bottom and bank
side slopes intact.
If maintenance activities inadvertently damage 8.
native vegetation, the native vegetation should be
replanted. See Factsheet #20 Watercourse Re-
vegetation for helpful guidelines.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
BMP Factsheet #10 AQUATIC HERBICIDESandWATERCOURSE MAINTENANCE
Introduction
Aquatic herbicide applications are an effective means
of maintaining drainage in watercourses where Reed
canarygrass infestation traps sediment and impedes flow.
However, the use of herbicides in and around water also
has potential negative impacts to water quality and to fish
habitat and is strictly regulated by the Washington State
Department of Ecology (WDOE) and the Environmental
Protection Agency (EPA).
Do I need permits?
A National Pollutant Discharge Elimination System •
(NPDES) permit must be obtained before aquatic
herbicides can be applied to water.
Applicators must be licensed by the Washington •
State Department of Agriculture.
Notification and posting are required before •
herbicide application and there may be additional
mitigation proposed to protect rare plants or
threatened and endangered species.
The general permit covers the discharge of products
used to control noxious weeds in waters of Washington
State. Under the Washington State Water Pollution
Control Act, a permit is required to discharge pollutants
that alter the biological or chemical characteristics of a
water body.
How: Permit coverage can be applied for on-line at:
http://www.ecy.wa.gov/programs/wq/pesticides/final_
pesticide_permits/noxious/noxious_index.html.
Who: Drainage Improvement Districts, individual
landowners, or the licensed applicator can act as the
applicant and hold the permit.
What weeds: This permit applies only to plants on
Washington State’s noxious weeds list such as Purple
loosestrife or Reed canarygrass. It is a violation of the
permit to treat any native aquatic plants.
Note: Additional Federal requirements are needed for
work on Lummi Indian Reservation lands.
What are the Advantages?
Aquatic herbicides can be less expensive than other •
aquatic plant control methods, especially when used
to control wide-spread infestations of state-listed
noxious aquatic weeds.
Occasional use will extend channel maintenance •
intervals.
Aquatic herbicides are very effective if used in •
combination with long term practices such as
Watercourse Re-vegetation (see Informational
Factsheet #20) to shade out noxious weeds.
What are the Disadvantages?
Herbicides applied to vegetation on watercourse •
banks may kill the plant roots stabilizing the bank,
resulting in erosion, bank failure, and additional
dredging expense to clear the channel.
Herbicides may have restrictions relative to •
swimming, drinking, fishing, irrigation, and
water use. Check the label and general permit for
restrictions.
Herbicide use may have unwanted impacts to people •
who use the water and to the environment.
In addition to nuisance plants, non-targeted plants •
may be negatively affected or killed by some
herbicides.
Depending on the herbicide used, it may take •
several days to weeks or several treatments during a
growing season before the herbicide controls or kills
treated plants.
Aquatic herbicide on Reed canarygrass
Page 2 of 2
Aquatic Herbicide BMPs
Use only when permits have been secured. •
Use only licensed applicators. •
Limit applications to vegetation in the channel •
bottom.
Do not apply to stream bank vegetation or bank •
stability will be lost.
Apply in late summer and early fall for best results. •
Spring and early summer applications rarely result •
in a lethal dose but may be effective in reducing
growth rates and maintaining drainage throughout
the summer.
Bank Failure following herbicide application
Good
Fish Habitat
Poor
Fish Habitat
Minimal
Fish Habitat
Is this a long term solution?
Aquatic herbicides can be one useful component of a
drainage maintenance plan for a Drainage Improvement
District or landowner. However their use is limited.
For example, if field sediments are eroding into the
watercourse, farm practices such as replacing bare ground
with vegetative filter strips will save costs and soil over
the long term. Reed canarygrass provides some cover and
habitat for fish. Repeated annual herbicide treatments
will eliminate this habitat unless it is replaced with
another vegetative cover. (See Informational Factsheet
#20 Watercourse Re-vegetation).
Reed canarygrass controlled using shade
As treated plants die and decompose in the water, •
low oxygen conditions will develop that can kill
fish, insects and other aquatic life.
Some expertise in using herbicides is necessary •
in order to be successful and to avoid unwanted
impacts.
Many people have strong feelings against using •
chemicals in water. Find out what your neighbors
think about chemical use before deciding to treat
your water plants with herbicides.
Some cities or counties may have policies forbidding •
or discouraging the use of aquatic herbicides. Check
before hiring an aquatic herbicide applicator.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 4
BMP Factsheet #11CULVERT MAINTENANCE
& REPLACEMENT
Introduction
Road crossing culverts are common on all types of
watercourses and are critical infrastructure for field
and farm access. But if undersized or poorly installed,
culverts can be a problem because they impede or block
fish passage to important habitat. Culverts that impede
fish passage have been identified as one of the most
limiting factors to healthy stocks of migrating salmon
and other fish species. In comparison, well constructed
bridges are superior to culverts in allowing drainage and
fish passage. Consider replacing culverts with bridges
(see BMP Factsheet #12 Bridge Maintenance and
Replacement).
Drainage Improvement Districts (DIDs) may include
and permit culvert maintenance and replacement as
part of their Drainage Maintenance Plan (DMP) if Best
Management Practices (BMPs) listed in this Factsheet are
adopted.
Culvert Replacement and Fish Passage
When replacing or installing a culvert in natural
watercourses or modified natural watercourses, the design
will largely be based on criteria necessary to ensure fish
passage and avoid impacts to fish habitat. There are five
common conditions at culverts that create barriers to
migrating fish:
Excess drop at the culvert outlet•
Salmon jumping at culvert.
High velocity within the culvert•
Inadequate depth within the culvert•
Turbulence within the culvert•
Debris and sediment accumulation at the culvert •
inlet or internally
The Washington Department of Fish & Wildlife
(WDFW) has published extensive information on
culvert design and installation. This guidance should
be used when replacing an existing culvert or installing
a new culvert. It is recommended that installations
on constructed watercourses also use WDFW criteria
because it ensures that new culverts are properly sized
and will not impede drainage. See Factsheet #4 Agency
Contact Requirements. Additional fish passage criteria
can be found at http://www.nwr.noaa.gov/Salmon-
Hydropower/FERC/upload/fish_passage_design.pdf.
Culvert Maintenance BMPs
Every watercourse structure will require periodic
maintenance. Culverts often become plugged or their
capacity reduced because of debris or vegetative material.
Headwalls may need occasional maintenance to prevent
erosion and collapse. In conducting maintenance
activities consider:
Timing Limitations: When water is present, 1.
culvert maintenance shall only occur from August
1 to September 30 when flows are low.
Debris or vegetative material can be removed by 2.
hand without timing limitations to prevent the
need for larger repairs.
Maintenance work on culverts in modified natural 3.
watercourses are subject to Agency Contact
Requirements, see Permitting Factsheet #4.
Headwall repair should take place during the dry 4.
season when the work can be completed out of
the water.
If water is present when removing large quantities 5.
of debris, vegetation or accumulated sediments,
additional measures must be taken to minimize
impacts to aquatic life and water quality. See
BMP Factsheet #16 Water Quality Protection
Measures for more details.
Page 2 of 4
Culvert Location
Even the best designed culvert has the potential
to become a fish passage barrier, drainage barrier or
maintenance headache. Look at your farm or Drainage
Improvement District from a big-picture perspective and
find ways to have as few culverts as possible. Location
considerations include:
Make the culvert as short as possible without •
deviating from the direction of the upstream and
downstream channel course by more than 30
degrees.
Choose an area with minimal and consistent stream •
gradient, not areas where the gradient is steep or
transitioning.
No-Slope Design Option
Successful fish passage can be expected if the culvert
is sufficiently large and is installed flat, allowing the
natural movement of bedload to form a stable bed inside
the culvert. Bedload is the sediments making up the
watercourse bottom such as gravel and soils. Design
criteria for a No-Slope culvert are:
Undersized culvert with unstable road crossing
Width equal to or greater than the average channel •
bed width at the elevation the culvert meets the
streambed. Make the culvert the same width as
the channel to maximize both water flow and fish
passage.
A flat gradient. (No slope)•
The downstream invert is countersunk below the •
channel bed by a minimum of 20 percent of the
culvert diameter or rise.
The upstream invert is countersunk below the •
channel bed by a maximum of 40 percent of the
culvert diameter or rise.
The possibility of upstream headcut has been taken •
into account.
There is adequate flood capacity.•
Combining the requirements of countersinking the
outlet and the culvert width for a circular culvert, the
diameter must be at least 1.25 times the channel bed
width. The information typically needed for a No-Slope
Design Option culvert includes:
The average natural channel-bed width.•
The natural channel slope.•
The elevation of the natural channel bed at the •
culvert outlet.
The evaluation of potential headcut impacts •
upstream of the culvert.
Channel-bed Width
Use the average of at least three typical widths in
free flowing and unconstrained areas upstream and
downstream of the culvert location. For the purpose of
culvert design, the channel-bed width is defined as the
width of the bankfull channel. The bankfull channel is
defined as the stage when water just begins to overflow
into the active floodplain. Many incised streams or
modified watercourses are no longer connected to the
floodplain. In these situations the channel bed width may
also be determined from the Active Channel Width and
Ordinary High Water Mark (OHWM). The OHWM can
usually be identified by physical scarring along the bank
Culvert Replacement
Culvert Replacement or Installation
Three design options have been approved by WDFW:
The No-Slope Design Option results in reasonably •
sized culverts without requiring much in the way
of calculations. The No-Slope option is almost
always the best choice for lowland agricultural
watercourses.
The Hydraulic Design Option is based on velocity, •
depth and maximum turbulence requirements for a
target fish species and age class.
The Stream Simulation Design Option involves •
constructing an artificial stream channel inside the
culvert, thereby providing passage for any fish that
may be migrating through the reach.
Page 3 of 4
Channel Slope
The calculation for average channel slope is based on
water-surface elevations and a distance along the channel
that is at least 40 channel widths long, or 400 feet.
Once these determinations are made, a culvert
design can be finalized. In fish bearing watercourses
it has become common place to fill the bottom 20%
of the culvert with “fish gravel” to both stabilize the
bed material and enhance a little fish habitat. It may
be advisable to hire professional help to ensure an
appropriate design and long lasting installation.
Culvert Replacement
Culvert Replacement BMPs
Timing Limitations: When water is present in the 1.
channel, culvert work below the waterline shall
occur between August 1 and September 30.
The damaged culvert and associated fill shall 2.
be removed from the watercourse and deposited
upland so that it cannot re-enter the watercourse.
The culvert shall be placed on a flat gradient 3.
with the bottom of the culvert placed below the
level of the streambed a minimum of 20 percent
of the culvert diameter for a round culvert, and
20 percent of the culvert’s rise for an elliptical
culvert. The 20 percent placement below the
streambed shall be measured at the culvert outlet.
(see above for more details).
The culvert shall be constructed to pass the 100-4.
year peak flow with considertation of the debris
likely to be encountered.
The culvert shall be maintained free of debris to 5.
ensure unimpeded drainage and fish passage.
Fill associated with the culvert installation and 6.
approach material shall be structurally stable and
shall be composed of material that, if eroded into
the watercourse, shall not be detrimental to fish
life.
Fill associated with the culvert installation and 7.
approach material shall be protected from erosion
to the 100-year peak flow.
If an existing culvert is replaced by a bridge 8.
structure, then the existing culvert and associated
fill shall be completely removed from the
watercourse and the new bridge shall be subject
to the bridge provisions discussed in Factsheet
#12 Bridge Maintenance and Replacement.
When water is present in the channel, fish must 9.
be removed from the impacted area prior to any
work. Factsheet #15 Fish Protection provides
more detailed information.
When water is present in the channel, measures 10.
must be implemented to ensure that contaminated
water does not leave the work site. Factsheet
#16 Water Quality Protection Measures provides
more detailed information.
Leave riparian vegetation along the banks of the 11.
watercourse.
All disturbed areas must be re-graded and 12.
stabilized by seeding or re-vegetating the riparian
area upon completion. This helps to prevent
surface erosion and/or sedimentation of the
watercourse.
Concrete
If any concrete, cast-in-place concrete, or grouting
works are to be undertaken, a high potential exists for
concrete and/or concrete leachate to enter a watercourse.
Concrete, concrete leachate, grout and other uncured
concrete substances (e.g. concrete bags for headwall
construction) are deleterious and highly toxic to fish and
other aquatic organisms.
To perform any concrete-related works, all water must
be completely isolated prior to the commencement of
any instream works. In addition, measures must be taken
to prevent the incidence of concrete from entering a
watercourse, ravine or storm sewer system for a minimum
of 72 hours after the works have been completed. This is
to ensure that the concrete has fully cured.
or shore, or by other distinctive signs such as the lower
line of perennial vegetation. This scarring is the mark
along the bank where the action of water is so common
as to leave a natural line impressed on the bank. That
line may be indicated by erosion, shelving, change in
soil characteristics, destruction of terrestrial vegetation,
presence of litter or debris, or other distinctive physical
characteristics.
Page 4 of 4
Figure 1
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
BMP Factsheet #12BRIDGE MAINTENANCE AND
REPLACEMENT
Introduction
In fish bearing waters, bridges are preferred as water
crossing structures in order to ensure free and unimpeded
fish passage and to preserve spawning and rearing
habitat. Other structures which may be approved, in
descending order of preference, include: temporary
culverts, bottomless arch culverts, arch culverts, and
round culverts. Professional engineering assistance
should be used for bridges over natural watercourses and
modified natural watercourses. Multiple landowners
should consider constructing a single shared bridge rather
than individual crossings.
Approval Requirements
Maintaining or replacing bridge structures requires
Hydraulic Project Approval (HPA) from the Washington
State Department of Fish & Wildlife (WDFW) with
review by Whatcom County Critical Areas and Flood
Division. Drainage Improvement Districts (DIDs)
can permit, maintain and replace bridges on modified
watercourses using their Drainage Management Plan
(DMP) and using the Best Management Practices (BMPs)
listed below.
Work on bridges over Constructed watercourses
requires only Whatcom County Planning and
Development Services notification if located within a
critical area. The written notification must be sent to the
Technical Administrator at least 10 business days prior to
beginning and should include:
Bridge design drawings and specifications. •
Type of equipment to be used.•
Manner in which the equipment will be used. •
Best Management Practices to be used. •
Bridge construction may also require a permit from the
Army Corps of Engineers.
Bridge Replacement BMPs
Timing Limitations: When water is present 1.
in the channel, the bridge work below the
waterline shall occur only from August 1 through
September 30 of any year for the protection of
migrating juvenile and adult salmon.
Damaged bridge elements shall be removed 2.
from within the banks of the watercourse and
deposited upland so that they cannot re-enter the
watercourse.
New bridge footings or foundations shall be 3.
constructed landward of the channel high
waterline at the project site.
Excavation for the bridge footings or foundations 4.
shall only occur landward of the high waterline of
the watercourse.
The bridge shall be constructed to pass the 100-5.
year peak flow with consideration for debris
likely to be encountered.
Fill associated with the bridge or water crossing 6.
structure installation shall be protected from
erosion to the 100-year peak flow.
Armoring of the channel banks to protect 7.
the bridge footings or foundations with rock
materials shall be limited to the bank area
immediately under the footprint of the bridge.
Approach material for the bridge shall be 8.
structurally stable and be composed of material
that, if eroded into the watercourse, shall not be
detrimental to fish life.
Alteration or disturbance of bank vegetation 9.
must be limited to that necessary to construct the
project.
Livestock crossing made of recycled concrete bridge panels
Page 2 of 2
Livestock crossing made of retired rail flatcar
Bridge Maintenance BMPs
Vegetative and other debris should be removed by 1.
hand (if possible) at any time before it builds up
and threatens the structure.
Measures shall be implemented to ensure that any 2.
waste materials from sandblasting and painting
do not enter the watercourse.
Limit pruning of native trees and shrubs to the 3.
minimum needed to provide bridge access.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
BMP Factsheet #13 SEDIMENT TRAPS
Introduction
A sediment trap is generally an easily accessible
constructed ‘basin’ or depression on a watercourse
where sediment settles out and accumulates, allowing
for its removal. Sediment trap maintenance (removal
of accumulated sediment) is necessary to ensure proper
function. A well-functioning sediment trap enables you
to trap and remove sediments regularly from one location
rather than having to maintain an entire watercourse
reach, saving money and reducing negative impacts to
aquatic life and water quality.
Prior to installing a new sediment trap, investigate
other means to control sediment input into surface waters,
such as installing riparian buffers and grass filter strips.
Sediment traps should not be located in areas with gravel
or cobble spawning substrates and should be located
downstream far enough to to preclude upstream head-cut
of spawning areas. Log weirs can be installed to reduce
the potential of head-cuts, but need to ensure fish passage.
The streambank next to the sediment trap should be
planted with native trees and shrubs, leaving a small area
to provide access.
Impacts
Sediment traps are not naturally occurring features of a
watercourse. Sediment traps can have both benefits and
drawbacks to fish and other aquatic life.
Benefits:
Fish may benefit from deep pools •
creating refuge below the water column
in constructed or modified watercourses.
Downstream habitat may be improved •
as a result of smaller quantities of fine
sediment accumulations below the
sediment trap.
Drawbacks:
Downstream habitat may be degraded •
and lose complexity if course
sediments (gravel, wood) are trapped.
In seasonal watercourses fish may •
become stranded in the sediment trap
rather than moving downstream as flows decrease.
Large or regularly maintained sediment traps •
may not be shaded well enough to keep water
temperatures low enough to support aquatic life.
Upstream head cutting may be a problem if •
sufficient gradient exists. The result can be channel
destabilization and increased erosion upstream.
Flow control structures may be needed at either end •
of the sediment trap. These structures will impede
the natural flow of water and may impact fish
passage.
Locating a Sediment Trap
Locate a sediment trap where accumulations of •
sediment consistently occur, such as the point where
two constructed ditches meet or at a significant
break in slope where water velocity slows and
sediment accumulates as it drops out of the water
column.
Permitting
Constructing a new sediment trap requires individual
permitting and is not included in a Drainage Improvement
District’s (DID) Drainage Management Plan (DMP).
Maintaining existing sediment traps within DIDs can
be permitted as a component of the DMP if the Best
Management Practices (BMPs) listed below are followed.
Page 2 of 2
Maintaining Sediment Traps
Accumulated sediments should be removed •
periodically, every 1 to 10 years depending upon
sediment load.
Clean the trap when it’s half full. Do not allow •
sediments to build up, overflow the trap and
accumulate downstream.
Clean sediments in the late summer or early fall •
when the water is the lowest. If the watercourse
is dry you can maintain the trap at any time, see
Factsheet #1 Hydraulic Project Approval.
Best Management Practices for Sediment
Trap Maintenance
Work must be completed during the time period 1.
of August 1 to September 30 when water levels
are low.
Fish must be removed prior to maintenance work. 2.
Refer to Factsheet #15 Fish Protection.
All work must be conducted during favorable 3.
weather and low water conditions. If heavy rain
occurs unexpectedly, delay maintenance until
water levels recede.
Sediments or muddy water should not be released 4.
downstream. Monitor closely and implement
Sediment Control BMPs when needed.
Leave riparian vegetation along the banks of the 5.
watercourse.
Excavation should be limited to the design 6.
profile. Deepening the trap may cause bank
failure and erosion.
Equipment used to complete drainage 7.
maintenance activities shall only operate from the
top of the channel bank and not from within the
watercourse.
All equipment used must be in good repair and 8.
be free of excess oil and grease. All hydraulic
equipment used in the watercourse must use
environmentally sensitive hydraulic fluids.
A spill containment kit must be readily accessible 9.
on site in the event of a spill. Any spills of
deleterious substance into a watercourse must be
immediately reported to WDOE
Refueling of equipment should be conducted a 10.
minimum of 50’ away from any watercourse
Dredged materials must be placed landward in 11.
such a way that its re-entry into the watercourse
is prevented. It may be added to adjacent fields
or hauled off site.
Note: The most cost effective drainage maintenance
BMP is to identify the source of sediments and prevent
them from entering the watercourse. See Informational
Factsheet #22 Farm Practices.
Constructing a Sediment Trap
The size of a sediment trap depends on the velocity •
of the water entering the trap and the size of particles
that are to be filtered out. Heavier sediments such as
gravel and sand settle out faster than fine sediments
such as silt or clay. Qualified professionals should
be consulted.
In lowland agricultural areas small traps may be •
simply constructed by widening and deepening a
portion of the constructed ditch.
Generally, the effective length of the sediment trap •
should be at least twice the width of the basin. To
ensure slope stability the bank side slopes should be
2 horizontal to 1 vertical or flatter with a maximum
height of 10ft.
A combination of sluice gates or flashboard risers •
and bypass channel or bypass pipe may be useful to
facilitate maintenance.
An easily accessible location such as a road crossing •
may also be appropriate if riparian vegetation exists
or is planned, Factsheet #20 Watercourse Re-
vegetation.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
BMP Factsheet #14
CONSTRUCTED WATERCOURSE MAINTENANCE
Constructed Watercourse Maintenance
BMPs
Introduction
Drainage Improvement Districts (DIDs) can maintain
constructed ditches without a Hydraulic Project Approval
permit from the Washington Department of Fish and
Wildlife. Nor is a permit from the Department of
Army Corps of Engineers needed if the watercourse
is determined to be “non-navigable”. However Best
Management Practices (BMPs) must be implemented
to avoid polluting downstream natural or modified
watercourses. Informational Factsheet #18 Watercourse
Classifications defines “constructed” and a DID’s
map should have all watercourses color coded by
classification.
Local Regulations
Whether wet or dry, if the constructed watercourse lies
within a Whatcom County designated “Critical Area” or
a “Critical Area Buffer”, a notification must be sent to
the Whatcom County Technical Administrator at least
10 business days prior to beginning work. The written
notification is valid for up to five years and should
include:
Type, timing, frequency and sequence of •
maintenance activity to be conducted.
Type of equipment to be used (hand or mechanical).•
Manner in which the equipment will be used. •
Best management practices to be used. •
Critical Areas include: Wetlands, Frequently Flooded
Areas, Critical Aquifer Recharge Areas, Geologically
Hazardous Areas, or Habitat Conservation Areas.
Constructed watercourses in active agricultural land are
generally not critical areas.
General:
Only remove material sufficient to keep the 1.
original ditch depth or to maintain a steady slope
between culvert inverts. Excavating deeper will
not improve drainage and may result in unstable
banks and erosion.
Place excavated material in a location so that it 2.
cannot re-enter the watercourse.
Equipment used to complete drainage 3.
maintenance activities shall only operate from the
top of the channel bank.
All equipment used on the site must be in good 4.
repair and be free of excess oil and grease.
If the watercourse is Dry:
Work can be done at any time.5.
Maintain the channel early enough in the year 6.
that vegetation may stabilize soils prior to the
rainy season.
Page 2 of 2
Install temporary Check Dams, Triangular 7.
Silt Dams, Silt Fence, Straw Wattles or other
measures to prevent exposed sediments from
moving once the rainy season has begun.
Maintain a 25 foot to 300 foot grass lined swale 8.
at the downstream end of the watercourse to filter
out any released sediments when water flows.
If the watercourse is Wet:
Conduct maintenance activities during periods of 9.
lowest flow (August 1 to October 30th).
Dredge from upstream to downstream to allow 10.
vegetation in the channel to help filter and trap
sediment.
Install a silt curtain or other means to block or 11.
filter the muddy water flowing downstream.
If fish in distress are observed, cease work and 12.
use Fish Protection techniques from Factsheet
#15 in this series. Also contact your WDFW
Area Habitat Biologist for assistance (see Agency
and Organization Contacts, Factsheet #5).
Monitor closely for muddy water leaving the 13.
constructed watercourse. Muddy, sediment-laden
water must not be allowed to enter natural or
modified natural receiving waters downstream.
Before this occurs, consider the following
tips and refer to Factsheet #16 Water Quality
Protection Measures for more guidance.
Pause the maintenance work frequently and allow 14.
suspended sediments to settle out.
Install temporary coffer dams, additional silt 15.
screens, bypass pumps, or other means to reduce
the impact.
Remember, it is OK and expected that water in 16.
the constructed ditch you are maintaining will
be muddy. But it’s not OK for that muddy water
to be allowed to flow downstream and adversely
impact other watercourses.
Recently maintained constructed ditch
Grass strip left intact temporarily to filter sediments
Muddy water from a constructed ditch flowing into a fish-
bearing stream
Cleaning Subsurface Drain Tiles
Subsurface drain tiles may need to be maintained or
flushed periodically due to the buildup of sediment or
iron ochre.
To minimize impacts on the watercourses downstream
when cleaning drain tiles consider the following:
Install a control structure (or block the ditch •
downstream) to prevent sediment and iron ochre
from moving into the receiving waters of a natural or
modified watercourse.
Install a sediment trap at the downstream end of •
the ditch to collect contaminated water. Pump the
collected water into an area where it will not re-enter
the ditch. Clean the sediment trap prior to opening
the control structure and allowing flow to proceed
downstream.
More useful BMPs can be found in • Factsheet #16,
Water Quality Protection Measures.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
BMP Factsheet #15 FISH PROTECTION
Fish Removal BMPs
Introduction
It doesn’t matter to fish whether a watercourse is
labeled as natural, modified natural, or constructed. Fish
will make use of the watercourse at some life stage if
there is water of sufficient quality and quantity and if
there are no obstructions to access. Maintenance of any
watercourse presents the potential to harm fish or fish
habitat. This fact sheet will help you determine when and
how to conduct fish removal so as to minimize harming
fish and avoid incurring civil and criminal penalties.
Projects where fish removal is necessary will likely
require a Hydraulic Project Approval (HPA) from the
Washington State Department of Fish and Wildlife
(WDFW). See Factsheet #1 Hydraulic Project Approval
for more information on the permitting process. The HPA
will have detailed directions for fish removal activities.
Guidelines in this Factsheet are general approaches to
fish removal methods, the HPA will serve as the primary
protocol for fish removal.
What is fish Removal?
A fish removal involves collecting fish from an isolated
watercourse reach where maintenance work is being done
and relocating the fish upstream or downstream of this
section.
When do I conduct Fish Removal?
Modified Watercourses
Fish must be removed from the watercourse prior to
any in-water maintenance activity. It is understood that
fish removal may not be entirely effective when there is a
dense Reed canary grass infestation.
Qualified staff must be on site at all times during 1.
drainage maintenance work.
Isolate the work area by placing a 2. block net at
the top and bottom end of the section planned for
maintenance.
Select a fish collection method or methods (see 3.
below) best suited to the watercourse.
Repeat this method or sequence of methods three 4.
times to make sure all the fish have been captured
from the isolated section.
Monitor the work area, affected downstream area, 5.
and spoils closely for signs of fish in distress.
If fish are observed in distress, pause the work and 6.
capture fish using dip nets and buckets of fresh
water.
Immediately relocate fish to an area of clean, free 7.
flowing water.
Continue to monitor and remove fish when 8.
needed.
Pausing work frequently to maintain relatively 9.
good water quality is the best method to ensure
minimum impacts to any remaining fish.
Remove block nets when maintenance work is 10.
complete and water quality impacts have settled.
Fish rescued from work area must be
relocated to a upstream or downsteam site
A constructed ditch can provide valuable habitat for fish
Constructed Watercourses
Fish are assumed to not be present in constructed
watercourses. However, if fish are observed in distress
during in-water maintenance activities then fish removal
BMPs should be implemented.
Page 2 of 2
Seine net: a net with weights along the bottom and
floats at the top to enable the net to stand in water.
Typically, seine nets with a small mesh size (1/8”–1/4”)
are adequate for trapping or moving young fish in small-
sized channels. These types of nets are relatively small
and easy to maneuver in smaller channels. One technique
is to encircle and then remove schools of fish using dip
nets. Another is to drag the net downstream, encouraging
fish to move below the channel reach planned for
maintenance. Both of these techniques can be made more
effective by first removing some of the water by means
of a coffer dam or water diversion, then seining and
removing fish in the remaining pools.
Electrofishing: passes electric current through the
water that attracts and stuns fish and is most effective in
small streams and rivers. Electro-fishing is commonly
done on foot using a backpack shocking device or
from a boat with a boat-shocker. Special training and
certification is required to electrofish. Electrofishing can
be highly stressful to fish. Mortality can be extremely
high in warm water conditions.
What Else Do I Need to Know?
If you do not have the expertise and equipment or time
to perform your own fish removal, you can hire someone
to do this for you. Fish removal work is specialized and it
is recommended that a professional be hired.
It is the responsibility of both the Drainage
Improvement District holding permits and the contractor
performing work to ensure that all appropriate means
have been utilized to avoid negative impacts to fish.
Electrofishing with a Backpack Shocking Device
Fish Removal Techniques:A common practice is to use a lower risk method (i.e.
seine netting and dip nets) for the first two passes and
then use a more exhaustive approach (i.e. electrofishing)
for the third and final pass. Once each pass is done,
immediately relocate the removed fish into an upstream
or downstream portion of the watercourse.
Stream Seine Net
Fish Biologist with dip net
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 6
BMP Factsheet #16
WATER QUALITY PROTECTION MEASURES
Introduction
It probably goes without saying that one cannot muck
around in a wet ditch without stirring up the mud.
Stirring up too much mud (sediment) without taking
necessary protective measures or without obtaining a
permit can land you in trouble with the agencies charged
with protecting water quality. Too much sediment can
cause significant harm to fish, fish habitat and other
beneficial uses, and water quality standards have been
set under Federal, State, and Tribal law to protect these
values. This Factsheet provides guidance on how to
conduct common watercourse maintenance activities
without risking a stop work order or a fine when water
quality impacts occur. Generally, any activity that
impacts water quality will require a Hydraulic Project
Approval permit from Washington State Department of
Fish and Wildlife (WDFW). See Permitting Factsheet #1
Hydraulic Project Approval for more details.
Potential Impacts of Sediment Releases:
Injury or death of fish. Sediment can clog or abrade •
fish gills, causing suffocation or tissue damage.
Inability to feed. Since fish are visual feeders, •
sediment in water can impair their ability to forage
for food.
Infill habitat. Sediment may settle in pools or riffle •
habitats. This may impact salmonid egg viability or
Muddy water leaving a maintained watercourse
The Laws:
When undertaking any watercourse maintenance
activity, controlling sediment and erosion is essential
to ensure protection of fish and other aquatic species.
The Federal Clean Water Act (CWA) Section 1251 &
Washington State Water Pollution Control Act 90.48
(WPCA) prohibits the discharge of any pollutant from
a point source into navigable waters or waters of the
State. Tribal laws similarly prohibit pollutant discharges
on the Lummi Indian Reservation. The Washington
State Department of Ecology is charged with enforcing
these laws for most of Whatcom County. The Federal
Environmental Protection Agency (EPA) and the Lummi
Natural Resources Department enforce these laws on the
Lummi Indian Reservation. The CWA Section 404 and
the River & Harbors Act of 1899 Section 10 require a
Federal Permit before discharging dredged fill materials
into the waters of the U.S. or before working on structures
in or affecting navigable water. The Department of
Army Corps of Engineers is charged with enforcing these
laws. Knowing what water quality standards and permit
requirements apply before engaging in any maintenance
activities are the first steps to avoid liability.
Under all circumstances, maintenance activities must
follow “All Known And Reasonable Technologies”
(AKART) to avoid violating water quality standards for
sediment releases, commonly referred to as “turbidity”.
Where turbidity already exists in the “background, it need
not be controlled or improved. However, maintenance
activities must avoid increasing pollution beyond a
specified amount. Prior to undertaking any work for
Sediment Control, refer to the following factsheets in
this series: BMP Factsheet #15 Fish Protection and
Permitting Factsheet #4 Agency Contact Requirements.
may affect food and nutrient sources by covering
benthos (bottom-dwelling organisms) upon which
fish depend for food.
Clogging of irrigation intake screens and potential •
damage to downstream irrigated crops.
Page 2 of 6
Water Quality Guidance for Drainage
Maintenance:
Helpful definitions and typical site plan:
Total Maintenance Dredging Work Zone – The
watercourse reach scheduled for maintenance during
the year’s work window including the Immediate
Maintenance Dredging Work Zone and the Sediment
Control Zone.
Immediate Maintenance Dredging Work Zone - The
watercourse reach scheduled for maintenance during the
year’s work window. The reach should be noted in a
Drainage Improvement District’s Drainage Management
Plan.
Sediment Control Zone – This area begins at the
downstream edge of the Immediate Maintenance
Dredging Work Zone and continues downstream for 200
feet. Typically one to three silt curtains are placed in this
zone to capture and settle suspended sediments (see Best
Management Practice (BMP) section below).
Point of Compliance – The point established at
the downstream end of the Temporary Mixing Zone
and identified on site with a stake or some other type
of visible marker. This is the point where turbidity
observations or measurements are taken to monitor
compliance with Clean Water Act regulations.
Work Day – The length of watercourse planned for
maintenance work in one day. The lowest section of a
watercourse’s Immediate Maintenance Dredging Work
Zone will be completed in the first day with additional
Measuring Sediment Releases:
Sediment and erosion control measures should be in
place both during and after works that have the potential
to cause sedimentation of a watercourse. Suspended
sediments are usually measured as “turbidity” and are
measured as Nephelometric Turbidity Units or NTUs.
Turbidity is the cloudiness or haziness of a fluid caused
by individual particles (suspended solids) that are
generally invisible to the naked eye, similar to smoke in
air.
Turbidity can be measured in a number of ways; the
most common are:
Turbidity meter – This tool measures the intensity •
of light scattered at 90 degrees as a beam of light
passes through a water sample. A meter may
be available from the Whatcom County Public
Works River & Flood Division or the Whatcom
Conservation District.
Secchi disk – This inexpensive tool uses a black and •
white disk in the water to measure the relative clarity
of water.
Visual inspection – Significant sediment releases are •
easily visible to the naked eye.
Aquatic Life Turbidity Criteria – Applies to all natural
and modified natural watercourses and constructed
watercourse reaches within 300 feet of their confluence
with a natural or modified natural watercourse.
Salmonid Spawning, Rearing and Migration areas •
- 5 NTU over natural background levels when
background is 50 NTU or less. If background levels
are above 50 NTUs then the increase should not
exceed 10% over background levels.
Salmonid Rearing and Migration • Only areas – 10
NTU over background when
background is 50 NTU
or less and a maximum
20% increase when the
background turbidity is more
than 50 NTU.
Turbitity Monitoring
Page 3 of 6
Sediment Control BMPs:
No single BMP or combination of BMPs will work
under all conditions. Therefore, in approaching the
problem of managing sediment, it is essential that you be
vigilant in observing any impacts of your maintenance
activities and adaptively apply different or additional
BMPs in order to keep the discharge of pollution to less
than what is allowed. Again, there is no single magic
solution to control sediment release. Follow the process
of:
Create an adaptive management strategy before 1.
work begins;
Start with simplest cost-effective strategies;2.
Closely monitor water quality to see if your 3.
maintenance activities are making conditions
worse; and,
Implement additional BMPs until the impacts are 4.
within water quality standards.
The following BMPs will help control sediment release
during channel maintenance activities.
Dry Season. If at all possible, plan your •
maintenance work for the driest time of year, usually
August – September. If there is less water flowing
overall, it is less likely that dirty water will flow out
of your worksite. Plan your crops to make sure the
watercourse is accessible during the dry season.
Adverse Weather. Suspend drainage work in adverse •
weather. Heavy summer rains can both increase
flows beyond what you may be prepared for and
may stir up sediments. Wait for low water levels to
return prior to proceeding with maintenance work.
Spoils placement. Place excavated materials well •
away from the watercourse to ensure they will not
erode back into the watercourse.
Monitor closely. Inspect the water downstream of •
your work site at the end of the appropriate mixing
zone (usually 100 feet). Various tools are available
to measure turbidity, however visual monitoring can
be an effective measurement. A general rule is that
if the water above your project looks clear then it
needs to look as clear below your work area.
Lidded Bucket. Use an excavator equipped with •
a clamshell or lidded bucket to prevent muddy
water from falling back into the watercourse and
increasing the level of contamination. This type
upstream reaches repeated until the planned work is
complete.
Temporary Mixing Zone – When a channel
maintenance project has received all permits and
approvals and BMPs are being implemented to minimize
the release of sediments, then a temporary mixing zone
can be used to allow sediments to settle out of the water
as follows:
For waters up to 10 cubic feet per second (cfs) at the •
time of disturbance, the point of compliance shall be
100 feet downstream from the activity causing the
turbidity exceedance.
For waters above 10 cfs up to 100 cfs flow at the •
time of construction, the point of compliance shall
be 200 feet downstream from the activity causing the
turbidity exceedance.
Turbidity Best Management Practices (BMPs)
Diagram – A generic site diagram that generally
illustrates watercourse maintenance dredging activities,
application of BMPs and integrated fish removal
procedures. See Figure #1.
Page 4 of 6
of equipment will probably be required in your
Hydraulic Project Approval permit (HPA).
Work Direction. Conduct maintenance activities •
from upstream to downstream to allow the
downstream vegetation to screen and trap suspended
sediments. Note: Impacts to fish may be less if
work takes place downstream to upstream. Consult
with the WDFW Area Habitat Biologist to determine
the best site specific strategy.
Pause your work. If you see muddy water in •
imminent danger of leaving your mixing zone, the
easiest BMP is to stop, let the sediments filter out,
then start again. After a little trial and error you
should be able to set a sustainable work pace.
Channel Blocking. Block the channel downstream •
to slow water flow and allow sediments to fall out.
Multiple installations may be needed to capture all
the sediment.
Fabric silt curtain. Constructed of woven filter *
fabric with weights at the bottom and floats at the
top.
Coffer Dam or Check Dam. Rock, plywood, *
sandbags or other temporary structure to stop
water flows and let sediments filter out.
Water Diversion*. Pump some or all water around •
the work site and then return it to the channel.
Isolating the work area and diverting flowing water
around the worksite is the most effective method to
ensure clean water law compliance. Pump intakes
need to have fish screens meeting WDFW criteria to
avoid entraining fish.
Water Removal. Pump some or all the muddy water •
leaving the work area into an adjacent area for on
site infiltration.
Coordination with Fish Removal Activities. A •
silt curtain may be useful at the upstream end of
the Work Day reach to isolate the reach after fish
removal and to temporarily slow the flow of water
through the reach.
*Deviation from this BMP may be allowed if WDFW
or equivalent freshwater habitat biologist indicates
pumping water around or from a channel maintenance
project will create a more negative aquatic biological
impact than the release of in-place sediments to
downstream areas.
Additional Information on Instream BMPs:
Fabric Silt Curtain
Drainage Improvement Districts typically own their
own silt curtains. They are made of woven fabric with
tapered sides, weighted bottom and a float at the top.
These inexpensive curtains are easy to install and can be
moved as work progresses.
Curtains 12’ to 16’ wide and 6’ to 8’ high can be •
utilized in most watercourses.
Functions are to filter some muddy water as it •
passes through and to slow the water flow, allowing
suspended sediments to drop out.
Install 1 – 3 curtains at 100 foot intervals beginning •
100 feet below your work area.
Anchor the curtain sides with 8’ to 10’ heavy •
duty metal T posts as tightly to the edge of the
watercourse as possible. The fabric curtain will
naturally form to fill the channel profile.
Monitor curtains closely to ensure they are •
functioning. Your point of compliance for turbidity
is usually 100’ below the most downstream curtain.
Coffer Dam or Check Dam
Coffer dams are used to isolate a channel reach in order
to complete maintenance work. For greater effectiveness,
coffer dams may be combined with other methods such
as clean water bypasses or pumps. Coffer dams can be
made of a variety of materials (rock, sandbags, wood,
etc). Considerations in their use include:
Dam materials must be anchored into the banks of •
the ditch to prevent seepage and erosion around the
edges of the dam.
A common practice is to line the channel with a tarp •
Fabric Silt Curtain slowing flow and allowing sediments to settle
Simple Coffer Dam slows the water flow allowing sediments to settle
Page 5 of 6
and then anchor it with a sandbag wall to ensure a
tight installation.
If there is water in the channel but little or no •
flow, temporary coffer dams may be the most
cost effective means to isolate the channel and
confine muddy water. Once sediments settle out,
remove coffer dams slowly to prevent the release of
sediments downstream.
If there is significant water flow, a coffer dam •
upstream can temporarily block this flow or create a
source for clean water diversion.
A downstream coffer dam will help prevent muddy •
water from leaving the work area, prevent clean
water downstream from flowing back into the work
area and becoming contaminated, and can be used in
combination with a muddy water removal pump.
Monitor frequently. Extra material (for example, •
more sandbags) should be kept on site to raise the
dam if water behind the dam threatens to spill over
into the work area or if muddy water threatens to
overflow out of the work area. Immediately repair
any scour, gaps, or holes around the dam to prevent
failure.
Completely remove the dam once the maintenance •
work is complete.
Water Diversion
A water diversion redirects the water flow temporarily
around the section of the watercourse where work is
being conducted. Clean water is moved around the
worksite to prevent contamination and then returned to
the watercourse below the work area. Pumps are most
commonly used however; in some cases an alternative
channel or bypass flume may be used to transport some
water or all water around the work site and then return
it to the channel. Considerations in the use of water
diversions include:
The pumped diversion is suitable for intermittent •
and low flow streams that can be pumped. Pump
capacity must be sufficient to handle the flow.
Downstream sediment transport can almost be •
eliminated.
Temporary coffer dams are constructed upstream •
and downstream of the work area.
A pump intake screen meeting WDFW standards •
should be installed to protect fish and other aquatic
life.
An energy dissipation device should be installed to •
prevent scouring where water is pumped back into
the stream.
As water in the worksite recedes, monitor closely for •
distressed or stranded fish. See Factsheet #15 Fish
Protection.
Although pumping water can be expensive, sediment •
removal is less expensive and easier in a dry channel
where an operator can see and maintain grades.
Water Removal
Pump water out of the worksite or pump some
or all muddy water from the lower end of worksite
before it contaminates receiving waters downstream.
Considerations in the use of water removal include:
If there is little or no flow and either no fish present •
or fish have been removed, the maintenance project
site can be isolated using coffer dams. Remaining
water can be pumped into an adjacent area for onsite
infiltration.
Another practice is to pump out muddy water •
trapped above a coffer dam or turbidity curtain
before it flows downstream.
An adjacent grass field is commonly used to receive •
and filter contaminated water.
Nearby grass lined ditches may also work well to •
filter sediments out before water eventually returns
to the channel.
Do not pump water into adjacent natural wetlands.•
Do not pump all the water out of a channel leaving •
downstream aquatic life to die.
Monitor closely to ensure that muddy water does •
not re-enter the channel. Be prepared to move the Minimal flow in work area after water is pumped around site
Diverted water returned to watercourse downstream
Page 6 of 6
outflow pipe often to prevent over saturation of
fields.
Bank Erosion Controls
Exposed soils on banks and slopes are susceptible to
erosion and can result in significant sediment loads. If
steep banks are sloped back or if dredge spoils must be
placed uphill from the work area, then measures should
be taken to minimize any potential erosion. Where
exposed earth is adjacent to a watercourse, controlling
erosion can be as simple as seeding as soon as possible to
establish vegetative cover and prevent sediment entry into
the watercourse during the rainy season.
Erosion Control Seed Mix - Any exposed soils •
should be immediately seeded with an appropriate
seed mix such as:
Mulch & Mats. Spreading straw over exposed soils •
reduces the erosive energy of rainfall and is a quick
and inexpensive means to control erosion. Erosion
control fabrics made of fine mesh and either straw or
coconut fibers work well on steeper or erosion prone
slopes.
Silt Fencing. If excavated sediments are susceptible •
to erosion, install a silt fence below the sediments to
prevent erosion. Silt fence should be trenched into
the existing soil 4” to 6” and staked every 6’ to 10’.
Straw Wattles. Partially trenched into the soil and •
staked, straw wattles are another effective means to
control erosion.
Stormwater Manual. WDOE’s “• Stormwater
Management Manual for Western Washington”
contains detailed information about these and other
useful BMPs for erosion control.
Monitoring:
Visual or measured monitoring for turbidity should •
be conducted every hour.
Monitor at the upstream edge of the • Immediate
Maintenance Dredging Work Zone, and at the
downstream Point of Compliance.
Record observations on a Water Quality Turbidity •
Monitoring Report Form.
Each time there is an observed differential in •
turbidity, additional BMPs listed above should be
implemented.
Should three successive hourly visual monitorings •
continue to identify problems after all practicable
BMPs have been implemented; the operator will
contact the Department of Ecology or the Lummi
Naural Resources Department for work conducted
on the Lummi Indian Reservation and advise them
of the situation. The purpose of the phone call is to
report the occurrence, discuss BMPs being employed
and consult with the department on appropriate
actions to address the situation.
Chewings or annual blue grass 40%
Festuca rubra var. commutate or Poa ann
Perennial rye 50%
Lolium perenne
Retop or colonial bentgrass 5%
Agrostis alba or Agrostis tenuis
White dutch clover 5%
Trifolium repens
Erosion control fabric installed after maintenance work
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
Informational Factsheet #17HAND MAINTENANCE
Introduction
Maintaining watercourse drainage using only hand
tools is a technique that humans have utilized since
agricultural practices began. It is simple, when you see
grass or other types of obstructions blocking a channel
and flooding a farm field, reach in and pull it out. Nova
Pacific Environmental working out of Vancouver B.C.
has developed a system to utilize this age old practice as
a more environmentally benign way to maintain drainage.
Crews can work down a channel pulling back grass and
removing obstructions to maintain drainage with minimal
impact to aquatic habitat.
Permits
Any work below the ordinary high water mark of
natural or modified natural watercourses requires a
Hydraulic Project Approval from the Washington State
Department of Fish and Wildlife (see Permitting Factsheet
#1). Work within critical areas also requires a Natural
Resource Notification of Activity with Whatcom County
(see Permitting Factsheet #3). A Drainage Improvement
District can permit Hand Maintenance work through the
development and approval of their Drainage Management
Plan.
Advantages
Longer work window, June 15th to October 30th. •
Reduces impacts to fish and other aquatic resources.•
Eliminates the need for fish exclusion.•
Eliminates the need for water quality BMPs. •
Allows native riparian plantings to stabilize and •
function.
Cost competitive alternative to maintenance •
dredging.
Before
During
After
photo courtesy of Nova Pacific Environmental
photo courtesy of Nova Pacific Environmental
photo courtesy of Nova Pacific Environmental
Page 2 of 2
Disadvantages
Treatments will likely need repeated over time. •
The need for hand maintenance will be reduced
when combined with improved farm practices
to reduce sediment inputs and when combined
with Watercourse Re-vegetation to stabilize the
streambanks and shade out undesirable aquatic
vegetation.
Not effective if sediment buildup is the primary •
drainage problem.
When To Use
Hand Maintenance may be a useful practice in many
situations including:
Where land use constraints prevent longer term •
solutions such as Watercourse Re-vegetation.
As an interim means to maintain drainage as native •
tree and shrub buffers are established.
As a low impact means to maintain isolated •
obstructions in areas with riparian vegetation.
Hand Maintenance BMPs
Work must be completed between June 15th and 1.
October 30th.
Work will take place using hand tools from the 2.
top of the bank whenever possible.
If workers must work from channel bottom, areas 3.
with gravel substrate will not be disturbed.
If workers must work from channel bottom, 4.
sediments will not be disturbed and allowed to
move downstream.
If sediments are disturbed, water quality 5.
protection BMPs must be implemented (see BMP
Factsheet #16).
Native woody vegetation will be left intact as 6.
much as possible.
Work must be conducted during favorable 7.
weather and low water conditions. If heavy rain
occurs unexpectedly, delay maintenance until
water levels recede.
Before After
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 3
Informational Factsheet #18
WATERCOURSE CLASSIFICATIONS
Introduction
Watercourses in lowland Whatcom County may
often look similar but have very different histories and
sources. This classification system will help to define
watercourses so you will know what permit requirements
and Best Management Practices (BMPs) are necessary
in order to perform drainage maintenance work.
Watercourses are defined primarily by their history and
source of water. The following definitions will apply to
watercourses occurring within Whatcom County Drainage
Improvement Districts (DIDs) or other agricultural lands:
Natural Watercourse (Red)
Natural watercourses have not been significantly
altered from their historical flow path or floodplain in
any manner and have headwaters (usually from wetlands
or springs). Natural watercourses do not typically
exist within DID boundaries of Whatcom County
and maintenance work on natural watercourses is not
addressed by a Drainage Manangement Plan (DMP).
Any kind of work in or around a natural watercourse will
require individual permitting.
Modified Watercourse (Yellow)
Modified watercourses are historically natural systems
that have been previously diverted, dredged, straightened,
and/or diked.
Appropriate permits including a HPA from WDFW •
are required for any drainage maintenance work. A
completed and approved DMP packaged with permit
applications will enable WDFW to issue five year
HPAs allowing drainage maintenance work on these
watercourses.
A DMP must be approved by Whatcom County •
Planning and Development Services before any
maintenance activities can occur within 150 feet of
any “shoreline” watercourse and within 100 feet for
all other watercourses.
Permit applications for work on modified •
watercourses must also be sent to the Army Corps of
Engineers (ACOE). Maintenance exemptions may
be granted for some watercourses or ACOE permits
may be required.
BMPs listed in the DMP must be implemented to •
minimize impacts to fish and water quality and to
Page 2 of 3
Constructed Watercourse (Green)
Constructed watercourses, also known as ditches,
convey drainage water from an individual farm, or
supply water to an individual farm property. Constructed
watercourses do not have headwaters or other natural
water sources. They may hold water permanently or
intermittently. The presence of water necessitates use
of Best Management Practices. Drainage Maintenance
work on constructed watercourses can be done without
permits as long as the work does not impact natural or
modified watercourses downstream. If water is present,
BMPs listed in your DMP must be implemented to avoid
violation of State Water Quality Standards or Tribal Water
Quality Standards for lands under the jurisdiction of the
Lummi Nation Natural Resources Department.
avoid violation of State Water Quality Standards or
Tribal Water Quality Standards for lands under the
jurisdiction of the Lummi Nation Natural Resources
Department.
Page 3 of 3 Drainage Slough RoadExample Watercourse Classification MapMar, 2009Cartographer: Andrew PhayConstructed WatercourseModified WatercourseNatural Watercourse·03006009001,200150Feet1:3,600Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 2
Informational Factsheet #19
DRAINAGE WATER QUALITY
Introduction
Water draining off a farm, whether from subsurface
drains or from overland flows, presents an opportunity for
pollution to enter watercourses and result in a violation(s)
of water quality standards. The pollutants that are most
likely to be generated from agricultural operations or
Drainage Improvement District (DID) operations include:
Pathogens (fecal coliform, • E Coli bacteria)
Nutrients (e.g. Nitrates and Phosphorus)•
Pesticides (insecticides, fungicides, herbicides)•
Sediment (field runoff, bank failures, stormwater •
from development)
Landowners may be held responsible for pollutants
released into watercourses from their land. DIDs also
may be held accountable for the quality of water leaving
their district boundaries, much like cities and other
municipalities are held responsible for their stormwater
releases. Both can be subject to $10,000/day fines for
water quality violations.
Under certain circumstances, DIDs may be required
to obtain a municipal stormwater permit. One way
this could happen is if a third party petitions the
Washington State Department of Ecology (WDOE) or
the Environmental Protection Agency (EPA) to determine
that the DID is a significant contributor of pollution to
surface waters. The DID need only be the conduit and
not the source of the pollution. A stormwater permit will
impose significant regulatory burdens, see Factsheet #2
Water Pollution Control Acts. DIDs should work closely
with landowners to ensure that landowners’ operations
result in clean water leaving their lands and entering the
drainage system
Water Quality Guidelines
Farmland drainage systems in Whatcom County
typically follow a familiar pattern. Water is collected
in subsurface drains, which flow into constructed
watercourses, which lead into modified and natural
watercourses. Finally it is discharged into Bellingham
Bay, Lummi Bay, Birch Bay or Drayton Harbor. Along
the way water can be used for a variety of beneficial uses
including: drinking, irrigation, crop washing, livestock
water, swimming, boating and for shellfish culture.
Poor drainage water quality can affect the usefulness
of the water supply for downstream members of your
community.
This same water supports fish (including Endangered
Species Act listed species) and other aquatic life.
Important water quality criteria include water temperature
and dissolved oxygen levels. Both criteria are critical to
fish life and are directly affected by land uses, specifically
the quality of or lack of riparian buffers (native trees and
shrubs) along watercourses.
Criteria for drainage water quality are based on end
use and the potential impact on aquatic habitat. The
drainage water quality criteria selected should not alter
or impair the use of the water sources for other purposes.
For example, water with high levels of pathogens is not
available for downstream vegetable farms to irrigate their
crops because of the potential for contamination and
resulting illnesses.
Water Quality Monitoring
The California spinach E.Coli outbreak of 2006
underscores the potential for having widespread and
costly impacts due to poor water quality. Short of such
drastic effects on people, fish or animals, water quality
sampling is necessary to determine if drainage water is
polluted beyond the water quality standard.
When to Sample
Samples should be collected when the risk of
contamination is highest. The risk of drainage water
contamination is elevated following the first significant
rains of the season. It is also higher when there are
increased activities on the ground such as when farmers
are spreading manure, commercial fertilizers, or
pesticides.
Where to sample
Landowners may consider sampling immediately
Page 2 of 2
upstream and downstream of their property and a
Drainage Improvement Districts may want to sample at:
Its boundaries to see if it is a potentially signifi-1.
cant contributor to pollution.
A specific area where there is a suspected source 2.
of pollution.
Collecting and Storing Samples
The laboratory should be able to provide containers
for samples. Samples may need to be kept at a cool
temperature and need to be taken to the lab within a
certain time for the test to be accurate. For pathogens,
samples should be submitted to a lab on the same day of
sampling. Be sure to ask the lab to confirm any of these
requirements.
Watercourse Maintenance Activities
Watercourse maintenance, whether implemented by
landowners or by Drainage Improvement Districts can
be significant sources of water borne sediments that must
be monitored and controlled. Detailed information about
how best to do this can be found in Factsheet #16 Water
Quality Protection Measures.
Controlling Contaminant Sources
The best way to manage pollutants in a watercourse
is at the source, whether it be an agricultural operation,
development, or human influenced stream bank
erosion. Factsheet #21 Bank Stabilization Techniques
and Factsheet #22 Farm Practices provide detailed
information on how to manage these sources.
Stormwater Management Monitoring
Although it is not required to have a stormwater permit
and to monitor regularly under that permit, a DID should
be aware of the water quality conditions entering and
leaving its boundaries. This is so the DID can proactively
take steps to avoid being put under permit by encouraging
landowners within its boundaries to take steps to protect
water quality. Also, since cleaning ditches is expensive,
adopting a policy that discourages erosion and sediment
runoff from fields can save everyone money.
River and stream water quality monitoring data are
available from Washington Department of Ecology
(WDOE). WDOE maintains a website at: http://www.
ecy.wa.gov/programs/eap/fw_riv/rv_main.html#4.
Another source of information is your local Watershed
Planning Unit. For Water Resource Inventory Area No.
1 (WRIA1), which covers most of Whatcom County,
the Whatcom County Public Works Department collects
and maintains water quality data. The DID may want
to conduct some sampling to establish a “baseline” of
information. Baseline conditions are those which exist
before some event that affects water quality occurs,
such as development in the watershed or addition of an
industrial discharge. Comparing data collected before
and after an event is one way of assessing its impact on
water quality.
Additional means to control contaminant
sources:
Controlled Drainage
Controlled drainage refers to holding back water within
a ditch or reservoir by means of an instream structure.
Such a structure would have adjustable or removable
boards to control runoff.
For the first rainfall of the season or if there is rain-•
fall soon after manure, fertilizers or pesticides have
been applied to the field, water would be impounded
to prevent contaminated water from immediately
entering a sensitive watercourse.
The drain water could be held for treatment or •
released later in the season when stream flows are
higher.
These same structures could be used to impound •
water for passive subsurface irrigation during the
summer growing season. Control boards would be
removed in the spring to allow cultivation, then re-
placed in the summer for subsurface irrigation, then
removed again in the fall for harvest.
Interrupting Macropores
Direct movement of manure or fertilizers to subsurface
drains can occur through macropores, relatively large
holes or cracks in the soil that allow direct access
from the soil surface to the subsurface drains. If these
macropores can be interrupted and the direct conduit to
the drains closed, the soil will act as a filtering agent to
allow nutrients to be taken up by the crop and pathogens
to die off in the soil. Macropores can be interrupted by
tilling the field before applying manure.
Subsurface Drainage System Control
Discharges from subsurface drainage systems may
contain nutrients or other deleterious substances that are
toxic to fish or that degrade water quality for irrigation
purposes. Discharged water from subsurface drainage
systems may be controlled by:
Installing a water control structure at the down-•
stream end of the drainage ditch.
Having all subsurface lateral drainage lines con-•
nected to a collector pipe. A control valve on the
collector pipe may then be used to control discharge
of contaminated drainage water.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 4
Informational Factsheet #20
WATERCOURSE RE-VEGETATION
What is it?
Watercourse re-vegetation is the removal of noxious
weeds and planting of native trees and shrubs on the
banks and land adjacent to watercourses.
Why is it called re-vegetation?
Most watercourses had native vegetation growing on
their streambanks at one time. Vegetation was often
removed thinking that improved drainage would result.
The long term result, however, has been poor drainage
due to the growth of invasive Reed canarygrass. Re-
vegetating the streambanks with native trees and shrubs
will recreate shade and inhibit the growth of invasive
grasses.
Channel full of Reed canarygrass
Why do it?
Historically Drainage Improvement Districts (DID) and
many landowners have had a scorched earth policy of
removing all vegetation from the banks of watercourses.
Trees and shrubs can get in the way of maintenance
equipment. Trees and shrubs are also materials that
beavers use to dam up the watercourse and flood
farmland. In light of these perceived disadvantages, why
have 26 miles of DID watercourses in Whatcom County
been re-vegetated over the past four years with more
planned in the future? Read on and you will find that
there are significant advantages to re-vegetating the banks
of watercourses.
Perhaps most important to landowners is that re-
vegetating the banks and land adjacent to a watercourse
can save money otherwise spent on dredging because
the shade-providing and bank-stabilizing vegetation can
lengthen the interval between channel cleaning. The roots
and shoots stabilize stream banks and reduce erosion.
If the dirt doesn’t get in the channel to begin with, then
you don’t have to pay to get it out. Dense infestations of
aquatic weeds, like Reed canarygrass, inhibit the flow of
water. As the water flow slows, sediment falls out and is
deposited in the channel. The shade created by trees and
shrubs suppresses the growth of grass and helps keep the
water flowing.
Maintenance activities such as dredging kill fish and
remove habitat features that fish require for survival.
State law requires that a Hydraulic Project Approval
(HPA) application be denied when, in the judgment of the
WA Department of Fish & Wildlife, the project will result
in direct or indirect harm to fish life unless adequate
mitigation can be assured by conditioning the HPA or
by modifying the proposal (WAC 220.110.30). Further,
dredging projects shall incorporate mitigation measures
as necessary to achieve no-net-loss of productive capacity
of fish and shellfish habitat (WAC 220.110.130). The
requirement for mitigation does not include irrigation
ditches, canals, storm water run-off devices, or other
entirely artificial watercourses, except where they exist
in a natural watercourse that has been altered by humans
(WAC 220-110-020(83).
Even a narrow Hedgerow of native shrubs will shade out the Reed
canarygrass
Page 2 of 4
Native trees and shrubs mitigate against negative
impacts to fish and fish habitat by:
Protecting the stream bank against erosion.•
Preventing the invasion of noxious weeds.•
Reducing the negative impact of weeds growing in •
the channel - short and long term.
Providing shade, thereby reducing water temperature •
otherwise heated due to direct exposure to sunlight.
Dissipating concentrated overland flow, filtering •
sediment, and increasing infiltration in the planted
corridor area adjacent to stream.
Providing other fish habitat benefits – leaf litter, •
small woody debris, terrestrial insects dropping into
the water and cover from vegetation where possible.
Integrating the riparian area into a functional part of •
the agro-ecosystem, rather than a strip of unmanaged
land producing undesirable impacts on the farming
operations of landowners.
Other advantages to Bank Re-vegetation
include:
Visual – Riparian vegetation increases the
attractiveness of the farm environment by contributing
blooming plants, fall colors, and a visual distinction
between fields. A hedgerow of native woody vegetation
is much more attractive than the look of tall, dry,
unmowed grass.
Water Quality – Flooding or heavy rainfall can cause
concentrated overland flow that carries silt and other
materials. The above ground part of vegetation breaks
up concentrated flow and traps and filters out sediment
before it reaches the open watercourse, thus increasing
infiltration of water. Roots of vegetation can absorb
nutrients and other compounds from the infiltrated water.
Bank Stability – Woody plants form a dense root mat
in the soil, preventing bank erosion.
Fish Habitat – If the watercourse has fish in it, the
improvements to fish habitat from riparian re-vegetation
are direct. If the watercourse is not fish bearing but flows
into a watercourse that is fish bearing, the benefits are
indirect.
Shade – Shrubs and trees growing on or at the top of
the bank will in time produce dense shade. Shade over
water reduces the heating effect of direct sunlight, thereby
improving fish habitat. Shade inhibits the growth of
undesirable vegetation in ditches and on ditch banks that
may restrict water flow.
Food – Vegetation supplies food to fish both directly
and indirectly. Insects falling into the water from the
leaves are eaten by fish. Indirectly, vegetation provides
leaf litter and other organic matter that is eaten by the
insects that are in turn food for fish.
Low Cost – Watercourse bank planting is a relatively
inexpensive technique for bank stabilization and required
mitigation. The plants can be installed relatively quickly
with a minimum amount of labor. Funding for this work
can often be found from governmental agencies or non-
profit groups.
Increased Bio-diversity – Native vegetation planted
along ditch banks increases the range of plant and animal
species (organisms that live in or on the vegetation) that
can be found along the waterway. Native woody plants
will primarily attract native bird species that do not
adversely affect crops or livestock and may provide some
benefit such as insect control.
Disadvantages of Bank Re-vegetation
Weeds – Planting must be managed to prevent noxious
weeds from becoming established. A densely planted
area is not vulnerable to weed infestation. However, if
not mowed regularly, weeds may become established in
the “edge” area between the planted bank and field.
Insects and Plant Diseases – Select native plant
species because they usually do not host problem insects
or plant diseases that may spread to nearby crops. Non-
native plants tend to attract nuisance species such as
European starlings.
Birds – Many landowners are concerned that planting
trees and shrubs will increase the local bird population.
While good for bio-diversity and insect control reasons,
most berry, tree fruit, and corn producers do not want to
do anything that will increase the number of birds that
may feed on their crops. However, native plants tend
to attract native song birds that do not cause problems.
Non-native plants may attract non-native nuisance
bird species such as European starlings that can have
significant impacts to crops and livestock.
Rodents and Ungulates – Voles, mice, beaver, pocket
gophers, and muskrats are all rodents that can become
a problem with increased vegetation along a ditch.
Ungulates such as deer and elk may use the cover of
vegetation planted along the ditch to move into a farm
property.
Other animals and people – Predators such as
coyotes can use vegetation along watercourses as cover.
Vegetation can also provide cover for people entering the
farm property without knowledge of the landowner.
Page 3 of 4
How to Re-vegetate a Bank
Technical Considerations
For planting purposes the bank slope should be no
steeper than 2:1 (2 horizontal lengths for 1 vertical
length). If soils are fine silts and sands and planting is the
only stabilization technique being used, lower gradient
slopes of 3:1 to 4:1 are more appropriate.
Plantings are most successful on banks where moderate
erosion is anticipated and where the bank is not actively
slumping. If slope failure is extensive or there is erosion
at the toe of the bank, planting vegetation on the bank
will not solve the problem. In these situations another
technique of bank stabilization should be used in
conjunction with the streamside planting.
Planting should take place in original soil, not in fill.
Fill areas should use bio-engineering to stabilize the
disturbed soil. It is important that the planting develops
into a stable ecosystem that will require minimal
maintenance once established. Woody plant material
takes time to produce enough root and stem growth to
stabilize and protect the bank. Seeding grass or grass
and clover mixtures will provide faster green cover until
the woody material becomes established. It may be
necessary to use interim non-plant protection measures,
such as biodegradable or synthetic geotextiles, or crib
walls. Vegetation cover alone may not protect the bank
from eroding in high velocity flows.
Plant Selection
Effective bank revegetation uses a mix of plant species
to incorporate structural diversity along the bank. Plants
should be selected based on their ability to grow under
the conditions where they will be planted and on their
capability to perform the desired function. Functions
may include quick growth, strong roots to resist erosion,
ability to produce shade, production of berries for birds
(or no berry production for no birds) or the ability to
produce a marketable crop.
For all methods described below, it is important to
get expert advice on the types of plant species that will
Hedgerows can be colorful and provide food for native songbirds
survive in specific conditions and the requirements
for planting techniques and maintenance to ensure the
planting will thrive.
When to Plant
Ideally planting should be done in the spring or late fall.
Planting can be done at other times of the year; however,
plant survival is likely to be lower. Adequate moisture
must be supplied to the plants throughout the growing
season, particularly if un-rooted cuttings have been used.
Solid seedling protectors should be installed on each plant
to protect the plant from rodent damage and to facilitate
maintenance.
Deciduous trees provide good shade over watercourses
Monitoring
Plantings should be monitored throughout the growing
season to make sure the plants are doing well. Soil
moisture may be dependent on the depth to the water
table; soils may dry out during low water in mid
summer. Frequent causes of planting failures are weed
competition, drought, browsing by small and large
animals, and incorrect plant selection for the site.
Live Staking
Cuttings from woody plants are often readily available
and easy to install. This is referred to as ‘live-staking’.
Live staking is used in many bio-engineering practices to
stabilize soil or stake other materials in place. The plants’
roots stabilize the bank by binding soil particles together
and removing moisture from the soil.
The best time for stake installation and harvesting is the
late fall or early spring. Get professional advice when
considering planting at other times.
Ideally cuttings should be planted as soon after
collection as possible. If the cuttings are to be stored,
they should be kept moist and stored at low temperature
(-1° C to -4° C).
Live staking does not immediately provide slope
Page 4 of 4
stabilization; it takes a couple of years for the plants to
become established. Plantings on moist, well drained
banks that are not subject directly to erosive forces will
be most successful. Seeding will provide protection to
the exposed soil. The stakes in Figure 2 also have plastic
tubing around the base to protect the plantings from
rodents.
Installation of Live Stakes
The stake should be no smaller than the diameter of a
thumb or index finger, 1/2” to 1 1/2”, and 36” long. Be
sure to protect the cuttings from drying out between the
harvesting and planting.
Install the stakes in a gridwork approximately 3’ on
center. Actual spacing will depend on the plant type and
eventual size of the plant.
Push the stake in by hand or tap it in gently with a soft
mallet until two-thirds of the stake is below the ground.
If the soil is very hard use a dibble tool or other type of
probe to make a pilot hole.
Presoaking cuttings 24 to 72 hours before planting has
shown to increase plant survival rates. However, soaking
also softens the wood. In order to prevent damage to the
cutting, a probe should be used to create a pilot hole. The
pilot hole should be slightly smaller than the diameter of
the cutting to ensure good soil-plant contact. If the hole
is larger than the cutting, pour a slurry of water and native
soil into the hole with the cutting. In all cases, press
down the soil around the base of the planted cutting with
your boot in order to collapse any air pockets near the
cutting. Irrigate after planting if possible.
Willow livestakes planted for bank stabilization
Container or Root Stock Planting
Container grown and bare root stock can be purchased
from nurseries or transplanted from areas away from the
slope. Pre-rooted plants, as opposed to live staking, can
offer a faster but more expensive solution to some slope
stabilization projects. Many more species of plants are
available as rooted than as live stakes.
Planting of Container or Bare Root Stock
Loosen the root balls before placing the plants in pre-
dug holes. The plants should be monitored and irrigated
until the root system is well established.
Hedgerow after one summer of growth
Seeding
Seeding with grass and clover creates a shallow root
zone in the first foot of soil. This protects the soil surface
from surface runoff and wind. Seeding is usually used
in conjunction with other planting techniques and is
intended to provide temporary erosion control. Some
grass species will provide very rapid green cover if
required. However, grass can be very competitive with
the woody species, so needs to be controlled in the area
around the planted shrubs or trees.
Woody vegetation provides stronger bank protection
against slumping.
For best results a custom seed mixture for the site
and the season is recommended. WA Dept. of Ecology
(WDOE) recommends the following seed mix for
temporary erosion control:
Chewings fescue or annual blue grass 40%
Festuca rubra var. commutate or Poa ann
Perennial rye 50%
Lolium perenne
Retop or colonial bentgrass 5%
Agrostis alba or Agrostis tenuis
White dutch clover 5%
Trifolium repens
One season growth of seed mix planted in the spring
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 4
Informational Factsheet #21WATERCOURSE BANK
STABILIZATION TECHNIQUES
Introduction
You know how expensive it is to clean a ditch. Costs
of repeated work due to bank failure can be avoided
by maintaining a proper bank slope and appropriate
vegetative cover. When a bank sloughs into the channel,
not only does it reduce how much water can pass through
the channel, it also releases sediment downstream that
negatively impacts water quality and fish habitat. The
suspended sediment can clog fish gills and smother
spawning eggs in gravels downstream. Good bank
stabilization is good for your pocket book and for the
environment.
The Washington Department of Fish and Wildlife has
published “Integrated Streambank Protection Guidelines”
that provide much more detailed ways to assess and
design bank stabilization projects than what is provided in
this Factsheet.
Soil Structure
In low gradient streams and constructed ditches typical
in western Washington, the soil structure and vegetation
are the most important aspects of system stability. Sands,
peat, and loose loam soils often have bank wall failures.
For these soils the banks of a watercourse should be
generally sloped between 2H:1V to 4H:1V (horizontal to
vertical ratio). Gently sloped banks will help maintain
Bank failure caused by vegetation removal
Bank Stabilization Techniques
Bank stabilization techniques vary according to site
conditions, potential cause of failure, and consideration
of positive or negative impacts to fish habitat. Common
techniques include:
Erosion Control Seeding•
Bank Re-vegetation•
Bio-Engineering•
Large Wood or Rock Revetments•
Erosion Control Seeding
Seeding is good for immediate protection of the soil
surface and prevents erosion from runoff and wind.
Seeding is often used in conjunction with tree and
shrub plantings that provide much more long term bank
stability. Seeding can be quickly and inexpensively
applied to slopes. On steeper or more unstable slopes
seeding should be used in combination with straw, erosion
control fabric, or other measures. Seed mixes designed
for erosion control can be purchased from most seed
distributors and should follow the following formula:
Erosion Control Seed Mix - Any exposed soils •
should be immediately seeded with an appropriate
seed mix such as:
Chewings or annual blue grass 40%
Festuca rubra var. commutate or Poa ann
Perennial rye 50%
Lolium perenne
Retop or colonial bentgrass 5%
Agrostis alba or Agrostis tenuis
White dutch clover 5%
Trifolium repens
bank stability, prevent slumping and filling in of the
channel due to erosion, and will increase flood capacity.
Roots from grass, shrubs or trees are the cement that will
bind together soil particles and prevent failures.
Page 2 of 4
Bank Re-Vegetation
In addition to seeding, planting native trees and/or
shrubs along the banks offers more significant bank
protection. The root systems of the native trees and
shrubs can withstand the erosive capability of higher
water flows in a natural way. Bank re-vegetation is also
very effective in mitigating the erosive effects of overland
flood flows eroding down the banks as waters recede.
Factsheet #20 Watercourse Re-vegetation provides
detailed information about bank planting. Common
methods include:
Hedgerows – Narrow (15’) width native shrub •
buffers densely planted to maximize bank
stabilization and stream benefit without impacting
adjacent farm fields.
Riparian Forest Buffers – Wider (35’ minimum) •
width native tree and shrub plantings designed to
restore some natural watercourse functions.
Livestaking – Native willow species and red osier •
dogwood can be planted with vegetative cuttings at
low cost. Plant densely close to the water edge for
best results.
Bare Root or Container Plants – Local nurseries •
produce and sell native trees and shrubs either bare
root (without soil) or containerized (in pots). Bare
root plants are less expensive but have a shorter
season within which to plant (December to March).
Containerized plants are more expensive but are
available nearly year round.
Established tree and shrub planting
Dense native tree and shrub planting
Bio-Engineering
Bio-engineering techniques for bank stabilization
incorporate the use of riparian vegetation and wood
cuttings that are installed in the bank to provide structural
stability. Bio-engineering techniques are used to enhance
slope stability, control sediment generation, and maintain
bio-diversity. Native willow species and red osier-
dogwoods are the most common choices of woody plant
material to work with. Some bio-engineering techniques
include:
Wattles - Bundles of live cuttings staked into •
trenches. The wattle placement breaks up the slope
by creating terraces with shallower slopes than the
original bank. As the cuttings take root, the root
system binds the soil together and helps to stabilize
the bank.
Brush Mattress - An interlaced layer of live branches •
placed on the bank and held in place with untreated
twine and live or dead stakes. This technique is
useful where high flows may erode exposed banks
before vegetation is established
Brush Layers - Horizontal alternating layers of •
soil and live branches. This creates a continuous
reinforced bench within the bank. This technique
is useful in projects that require cut and fill, where
Vegetated Geogrid using Coir fabric and Willow livestakes
Cover crop using Erosion Control Seed Mix
Page 3 of 4
there are large quantities of loosened soil on the
slope, or where the bank is slumping.
Vegetated Geogrids - Similar to brush layers except •
natural or synthetic geotextiles are wrapped around
the exposed soil between brush layers, anchoring the
ends of the geotextile in the fill material. Vegetated
geogrids are appropriate for steeper slopes that have
limited room for bank shaping. This technique is
used to reinforce the area of toe erosion and for
projects that require filling or rehabilitation of
seriously eroding and slumping banks.
Tree Revetments - Involve the grading of a slope •
to 2H:1V then cabling durable green coniferous
trees, such as cedar or pine into the bank slope. The
trees should have a diameter of 18” to 36”. The
branches of the trees will dissipate water velocities
and the stream’s energy. Sediment settles out behind
the branches and can help to rebuild an eroded
bank. This technique is most effective when used
in locations where ditch banks are rapidly eroding
and require protection from toe erosion and bank
scouring. Other bio-engineering or planting is
recommended to protect the upper banks.
Cribwalls - Basically a ‘live’ log wall, built crib-•
style, to protect eroding banks. Vegetation is planted
between the logs used to build the wall. This reduces
the water velocity and provides shelter for fish. This
technique is useful when slopes cannot be cut back
or to prevent toe erosion in large areas of scour.
Cribwalls do not need to be built up the entire bank.
Wattles or brush layers may be installed on the upper
bank.
Vegetated Rolls - Usually made of coconut fiber •
bound together with twine. However, these rolls
may also be made of other materials that provide the
same effect. The rolls are flexible and able to mold
Rock Revetments
Rock revetments were once commonly used for bank
stabilization, but now should be considered a last resort
because of their damage to aquatic resources and to
permitting dificulty. Only where banks are subjected to
high velocity flows or where the bank toes need to be
stabilized, may revetments be necessary. When a bank is
armored with rock, there tends to be other bank failures
upstream or downstream as the watercourse adapts to
the constriction. Rock-armored banks also negatively
impact fish habitat by: providing minimal cover, creating
turbulent conditions, and preventing bank re-vegetation.
Riprap is the placement of angular rocks of various •
sizes along the stream banks. The rocks lock
together to help to stabilize the banks thus providing
a hard layer of protection outside of the softer,
easily erodible stream bank materials like sand or
fine sediments. The advantage of riprap is that it
remains stable at most flow levels, it is durable,
easy to install and easy to maintain. However, large
projects can be costly and riprap restricts natural
channel movement, looks unnatural, and can cause
other erosion problems upstream and downstream of
where it is placed.
Rock Toe Keys are the bottom half of the riprap •
structure. These are used in conjunction with other
bio-engineering techniques that protect the upper
bank. The rock toe keys stabilize the toe and are
installed up to the normal water level.
Rock Revetment combined
with Large Woody Debris
to existing curves. Therefore, little site disturbance
occurs during installation. This technique is useful
for providing temporary toe protection of slopes
while vegetation becomes established. It is not
effective for permanent toe protection.
Page 4 of 4
Tips for Bank Stabilization
Bank stabilization on natural or modified watercourses
using ‘soft’ engineering techniques, such as planting and/
or seeding, may be undertaken pursuant to a Drainage
Management Plan or farm plan at any time of year with
only a 10 business day Critical Areas notification to
Whatcom County Planning and Development Services.
Bank stabilization on constructed ditches can be •
done at any time, however, measures should be
taken to prevent any sediment release or harm to any
fish. See Factsheets #16 Water Quality Protection
Measures and Factsheet #15 Fish Protection.
Joint Plantings incorporate riprap and live stakings •
to produce a vegetated armored bank. These are
effective in areas where the banks require more
protection than vegetation alone can provide and
require some vegetation for habitat creation. The
vegetation and root structure will bind the riprap
to the slope and create more natural looking bank.
Establishing vegetation in riprap can be tricky and
requires monitoring and irrigation during the first
years to ensure plant survival.
The use of large woody debris integrated into the •
bankline will enhance habitat features and enhance
bank stability.
Bank stabilization using any form of ‘hard’ •
engineering technique, such as bio-engineering or
rock revetements on natural or modified natural
watercourses will require a Washington Department
of Fish and Wildlife Hydraulic Project Approval
(HPA) and is likely to require a permit from the
Army Corps of Engineers. See Factsheet #4 Agency
Contacts Requirements and Factsheet #1 Hydraulic
Project Approval.
All works must be conducted during favorable •
weather and low water conditions.
Works must be conducted in isolation of flowing •
water. The method chosen should be appropriate
for the amount of flowing water in the watercourse.
For further details see Factsheet #16 Water Quality
Protection Measures.
Work must be undertaken in a manner so as to •
prevent the release of silt, sediment or sediment-
laden water, raw concrete or concrete leachate,
or any other deleterious substance. For further
details see Factsheet #16 Water Quality Protection
Measures.
Machinery must work from the top of bank and not •
from within the watercourse.
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.
Page 1 of 4
Informational Factsheet #22FARM PRACTICES & DRAINAGE
MAINTENANCE
Introduction
Adequate drainage is an essential component of any
agricultural operation in Whatcom County. Maintaining
drainage in open watercourses can have detrimental
effects on aquatic life and water quality. Drainage
maintenance is also expensive. Removing sediments
(dredging) from a modified watercourse can cost as much
as $3.00/linear foot of channel when excavation, fish
protection and water quality protection Best Management
Practices (BMPs) are included. Mitigation for the
impacts to fish habitat can add considerably more expense
to any maintenance project.
The most cost effective action that a Drainage
Improvement District (DID) or landowner can take is
to prevent sediments from reaching the watercourse in
the first place. To do this, a landowner can implement
appropriate farm practices and a DID can proactively
encourage landowners within their districts to adopt
farm practices that prevent runoff and sedimentation.
The result of better farm practices will be less channel
maintenance expenditures and less need for high
assessments to fund channel maintenance.
Impacts can come from urban development as well as
from agricultural operations. Often the urban sources
are upstream from an individual farm or DID boundary.
Adopting polices that will encourage those landowners to
follow best management practices to prevent sediment are
to everyone’s benefit.
Agricultural Operations
The natural and modified natural watercourses that
are often a part of a DID system are considered critical
areas and are protected under Whatcom County’s Critical
Areas Ordinance. Like DIDs, farmers have responsibility
under the ordinance to ensure that their actions do not
negatively impact these environmentally sensitive areas.
Farmers can do this by developing and implementing
Conservation Farm Plans.
A conservation farm plan identifies farming and
ranching activities and the practice(s) necessary to avoid
potential negative impacts (resource concerns) from those
activites. Practice selection depends upon the types of
livestock raised and crops grown. Some examples of
common practices that will help to prevent farm related
sediments from reaching watercourses include:
Filter Strips
A filter strip is a width of herbaceous vegetation
located between crop land, pastures, or disturbed land
and environmentally sensitive areas such as watercourses
and wetlands and is designed to trap sediments and other
contaminants.
Used along the down slope edge of crop fields to •
protect an adjacent watercourse.
Generally planted with perennial grass species. •
Traps and filters sediment and other contaminants •
before they reach the watercourse.
Filter strip widths should be determined based on •
hydrologic soil characteristics, density and height of
Page 2 of 4
the filter strip vegetation, and runoff volume. The
minimum width for sediment control is 20 feet.
Size the width of filters to match seeding and •
harvesting equipment.
Choose grass species that are able to take up high •
amounts of nitrogen and phosphorus, grow fast, and
tolerate frequent mowing.
Inspect the filter strip after major storm events and •
repair any gullies that have formed. Redistribute
unevenly deposited sediment accumulation greater
than 6 inches. Reseed disturbed areas.
To maintain filter strip function, periodically regrade •
the filter strip area and re-establish the vegetation
when needed.
Filter strips are most effective when combined with •
watercourse re-vegetation using native trees or
shrubs.
Field Border
A field border is strip of permanent vegetation
established at the edge of or around the perimeter of a
crop field.
Use perennial grasses or shrubs. •
Minimum border width may be mandated by •
Nutrient Management Plans.
Locate borders around the entire perimeter of the •
field, or as a minimum, in areas where runoff enters
or leaves the field.
Design to accommodate equipment access and other •
operations.
Select herbaceous plants and shrubs that provide •
habitat for beneficial insects. Mowing, harvesting,
and pesticide applications should be scheduled
to accommodate the life cycles of the beneficial
insects.
Or, select plants that provide a habitat that causes •
pest insects to congregate. Use mechanical,
cultural, and/or chemical techniques to reduce pest
populations when and where they congregate in the
field border.
Watercourse Re-vegetation
Watercourse re-vegetation is the removal of noxious
weeds and planting of native trees and shrubs on the
banks and land adjacent to watercourses. Woody plants
once existed along all natural and modified natural
watercourses and even colonized many constructed
watercourses. These plants provided many functions for
fish and other wildlife and helped to buffer the water from
adjacent land uses. Over the last few decades, these trees
and shrubs have been systematically removed in an effort
to improve drainage because fallen trees or broken limbs
can fall in the channel and impede flow. The unintended
result however has been decreased drainage capacity and
the need for frequent maintenance due to increased field
runoff and the the invasion of Reed canarygrass.
Public or private funding is often available for •
watercourse re-vegetation through government
agencies and non profit groups.
Native trees or shrubs protect or improve water •
quality by creating shade that lowers the water
temperature and helps to maintain or raise dissolved
oxygen levels. Native plants also buffer the stream
from land based contaminants such as sediment,
nutrients and pesticides.
Native trees or shrubs provide food and habitat for •
fish including Endangered Species Act listed Salmon
species.
Roots from woody plants create a dense mat that •
prevents erosion and bank failure.
Trees or shrubs dissipate concentrated overland flow, •
filter sediment and increase infiltration away from
Hedgerow planting and filter strip buffering the watercourse from
cornfield
Field border consisting of Douglas Spirea
Native shrub Hedgerow buffering watercourse
Page 3 of 4
the stream.
Shade created by native trees and shrubs also helps •
to control shade intolerant invasive weeds, primarily
Reed canarygrass, that trap sediments and impede
drainage.
Riparian Forest Buffers include both native trees and •
shrubs and are a minimum of 35’ wide.
Hedgerows consist of native shrub species and are •
15’ wide. Hedgerows are usually combined with a
filter strip to ensure watercourse protection.
Livestock Exclusion
Livestock erode stream banks, releasing sediments and
other contaminants that negatively affect water quality,
fish habitat and drainage.
Fences should be designed to contain the animal •
species targeted.
Clean livestock watering sources should be provided •
well away from the watercourse.
Plan for a buffer area (filter strip, field border, •
Native shrub Hedgerow shading watercourse
riparian forest buffer, hedgerow) between fences and
watercourses.
Cover Crops & Relay Crops
Grasses and other herbaceous plants established for
seasonal cover protect field soils in the rainy season.
Unprotected soils can erode into watercourses impairing
water quality, degrading fish habitat and impeding
drainage.
Reduces erosion from wind and water. •
Increases soil organic matter. •
Prevents weed invasions. •
Provides supplemental forage.•
The cover crop should be harvested or tilled in as •
late as feasible to maximize plant growth and still
prepare for the new crop.
Manure Management
Livestock operations of all sizes generate manure.
When managed properly, manure is the best fertilizer for
crop ground But when managed poorly, manure can be a
significant source of contaminated runoff.
Dairies and other concentrated animal feeding •
operations are required to have custom Farm
Conservation Plans that prescribe a system of
collection, transfer, storage, containment and
handling facilities. Protocols are identified to test
and land apply manure. All of these practices help
to keep waste out of surface and ground waters.
Low-impact agricultural operations, defined by •
not exceeding one animal unit per acre of grazable
pasture, are not required to have custom farm
plans but should store, compost and utilize manure
according to the Whatcom County “Tips on Land
& Water Management” booklet available from
Whatcom County Planning & Development Services
or the Whatcom Conservation District.
Livestock exclusion fence preventing animal access to the stream
Nosepumps provide livestock water away from the watercourse
Page 4 of 4
Urban Growth & Stormwater Runoff
With increasing frequency, agricultural watercourses
are impacted by stormwater runoff from upland
development.
Impervious surfaces (roads, driveways, roofs, etc.) •
prevent rainwater from naturally infiltrating the soil
and instead send it downstream as stormwater.
Increased flows may contain sediment and other •
contaminants that can impact drainage, water quality
and fish habitat downstream.
Increased flows can also erode watercourse banks, •
causing more impacts downstream.
Downstream landowners and elected DID
commissioners should become involved early on in the
planning stage of urban developments to help ensure
that adequate consideration is given to their potential
impacts on DID watercourses. This can be done by
letting City and County planning departments know that
the DID wants to weigh in on new development and
by providing the contact information for where to send
notices of permit requests. In addition, commissioners
may determine that by receiving new stormwaters from
upland developments they are providing an unfunded
benefit to those developments. A DID may then choose
to pursue collection of the operational maintenance costs
from those developments. 85.32.050 RCW.
Growth in agricultural areas increases stormwater runoff
Content Copyright 2009 Whatcom Conservation District
Published with support from the Centennial Clean Water Fund under the authority of the
WA State Dept. of Ecology
Users of this Factsheet are responsible for obtaining and following
all appropriate permits and following all laws and regulations.