HomeMy WebLinkAboutBLD2020-00639 - 05 STORMWATER 115 E Railroad Ave., Suite 310, Port Angeles, WA 98362
(360) 912-5191 www.gounitedengineering.com
December 4, 2020
STORMWATER MANAGMENT PLAN FOR PARCEL
#965000230, KALA POINT #6, LOT 429, PORT TOWNSEND,
WASHINGTON 98368
1.0 BACKGROUND AND SCOPE OF WORK
United Engineering, Inc. was retained by Anderson Homes, LLC. to prepare a Stormwater
Management Plan for a single-family residential project located on Jefferson County Tax
Parcel #965000230 on Pinecrest Dr. in the Kala Point area south of Port Townsend, WA.
A three-bedroom single family residence is proposed to be constructed. The home will be
served by a concrete driveway off of Pinecrest Dr. This plan will conform to the 2012
Stormwater Management Manual for Western Washington as amended in 2014.
2.0 SITE CONDITION
Existing Conditions
The site is a 17,658 sf parcel. The site has an overall slope of roughly 3% from the north
downward to the south. It is currently undeveloped. The surrounding parcels are
developed with single family homes on similar parcel sizes. Existing site vegetation
includes dense forest with thick brush underlayment.
Soil Conditions
Per the United States Department of Agriculture Natural Resources Conservation
Services (NRCS) Web Soil Survey, site soils for are as follows:
• Clallam Gravelly Sandy Loam.
• Hydrologic soil group Type D.
• Depth to the water table of 18” – 36”.
• Infiltration rate of 0.00 to 0.06 inches per hour.
The soil logs from the septic system design dated July 28, 2020 confirmed the NRCS
soils present. There is typically a brown sandy loam surface layer to a depth of
approximately 18”-28”. A compact layer was found in one of the test pits at a depth of 18 ”.
Mottling was present in all of the test pits at approximately 24 ” deep. The mottling layer
indicates the presence of a potential water table at that depth. These indicate an available
soil horizon of approximately 18”. The findings of these soil investigations will make
infiltration BMPs infeasible due to the limited vertical separation from the water table. The
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septic system design chosen was an alternate system with an aerobic treatment unit and
a drip system drainfield.
3.0 DRAINAGE DESIGN
New Development
The proposed single-family residence will result in about 6,109 square feet of new
impervious surfaces, of which about 4,186 square feet will be non-pollution generating
impervious surfaces (new roof), and about 1,923 square feet will be pollution generating
impervious surfaces (new concrete driveway). The project results in more than 5,000
square feet of new hard surfaces, so all Minimum Requirements, as outlined in the
Department of Ecology’s 2012 Stormwater Management Manual for Western Washington
as amended in 2014 (SWMMWW), apply.
Minimum Requirement #1 – Preparation of Stormwater Site Plans
See Appendix I.
Minimum Requirement #2 – Construction Stormwater Pollution Prevention
For description of Best Management Practices (BMPs) listed below for Elements #1
through #9, and except where specifically noted otherwise, refer to the SWMMWW.
Element #1 – Preserve Vegetation/Mark Clearing Limits
Before land disturbing activity begins, the clearing limits must be marked with high
visibility (BMP C103). The native top soil and existing vegetation must be retained
in an undisturbed state to the maximum degree practical.
Element #2 – Establish Construction Access
Unless a written variance is granted in advance, a stabilized construction entrance
(BMP C105) for this project shall be provided via Lakeview Dr. See the Stormwater
Site Plan and referenced detail sheets, Appendix IV, for specific location and
details for the stabilized construction entrance.
Any sediment tracked off the site must be cleaned thoroughly at the end of each
day, or more frequently if determined necessary, by shoveling, sweeping,
transporting to a controlled sediment disposal area, street washing, and/or other
necessary and appropriate measures.
Element #3 – Control Flow Rates
Because of the dense vegetation downslope of the site and the generally flat
topography, stormwater flows are not expected to concentrate in any significant
volume or flow rate. Dispersion systems that will serve roofs, pavements,
sidewalks, and other impervious areas must be constructed as soon as possible
to avoid any flow concentration. Activities such as roof gutter and downspout
installation, paving, and similar construction activities, must be promptly completed
in the proper sequence to control flows and minimize the potential for erosion and
sedimentation. Silt fence (BMP C233), wattles (BMP C235), and/or other
appropriate BMPs must be used as necessary for control of flow rates.
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Element #4 – Install Sediment Controls
Silt fence and straw wattles will serve to control sedimentation of the disturbed
areas. The silt fence should be installed downslope of the construction areas as
shown on the stormwater site plan. Straw wattles should be placed in the existing
swale along the north right of way of the property.
Element #5 – Stabilize Soils
Soils must not remain exposed and unworked for more than the time periods set
forth below:
• May 1 to September 30: 7 days.
• October 1 - April 30: 2 days.
Bare soils, particularly bare slopes, and soil stockpiles must be protected from
erosion with sediment trapping measures. To the maximum extent possible,
stockpiles must be located away from storm drain inlets, waterways, and drainage
channels.
Temporary and permanent seeding (BMP C120), mulching (BMP C121), nets and
blanketing (BMP C122), plastic covering (BMP C123), top-soiling and/or
composting (BMP C125), and/or other appropriate BMPs must be used as
necessary for stabilizing of soils.
Additionally, post-construction soil quality and depth enhancement (BMP T5.13;
refer to Building Soil; Guidelines and Resources for Implementing Soil Quality and
Depth BMP T5.13, 2016 Edition) must be implemented to improve infiltration
capacity of the newly created and restored lawn areas.
Element #6 – Protect Slopes
No slopes over 4 feet high or cut slopes steeper than 2:1, and no fill slopes steeper
than 3:1 are expected. If slopes are created that exceed these thresholds,
blanketing or other effective temporary measures shall be taken to prevent erosion.
Slope construction and slope stabilization should be scheduled during dry weather
(usually May 1 to September 30) to minimize potential for erosion.
Temporary and permanent seeding (BMP C120), mulching (BMP C121), nets and
blanketing (BMP C122), plastic covering (BMP C123), and/or other appropriate
BMPs must be used as necessary for protection of slopes.
Element #7 – Protect Drain Inlets
Inlet protection shall also be placed in all existing and new catch basins and
inlets that could potentially receive stormwater flows directly from the site.
Storm drain inlet protection (BMP C220), use of oil-absorbent-rated catch basin
inlet fabric insert bags, and/or other appropriate BMPs must be used as necessary
for inlet protection.
Inlet protection must not obstruct vehicle traffic on the site.
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Element #8 – Stabilize Channels and Outlets
This project does not have any channels or outlets where concentrated flows could
leave the site and enter natural or man-made bodies of water or wetlands.
Element #9 – Control Pollutants
All chemicals, liquid products, petroleum products, and other materials that have
the potential to pose a threat to human health or the environment must be provided
with secondary containment and protection from weather, vandalism, and/or other
adverse circumstances. Secondary containment means placing tanks and/or
containers within an impervious structure capab le of containing 110% of the
volume contained in the largest tank or container within the containment structure.
Fueling, maintenance, and repair of heavy equipment and vehicles must include
use of spill prevention and control measures.
Washout of concrete trucks, dumping of excess concrete, and similar activities
shall not be performed on-site. Washout of concrete trucks, dumping of excess
concrete, and similar activities shall only be performed in off-site locations
specifically approved for such activities.
Proper concrete handling (BMP C151), saw cutting and surfacing pollution
prevention (BMP C152), proper material delivery, storage, and containment (BMP
C153), and/or other appropriate BMPs must be used as necessary for control of
pollutants.
Any and all spills associated with this project, either on site or off site, must be
reported to the proper authorities and thoroughly cleaned up to meet applicable
City, County, State, and/or Federal standards.
Element #10 – Control Dewatering
In the unlikely event that dewatering is required, water from dewatering operations
shall be discharged in such a manner that it does not result in erosion and
sedimentation. Special care shall be taken to avoid sedimentation of existing and
new stormwater control facilities.
Element #11 – Maintain BMPs
All temporary and permanent erosion and sediment control BMPs must be
maintained and repaired as needed to assure continued performance of their
intended function in accordance with BMP specifications. All temporary erosion
and sediment control BMPs shall be removed within 30 days after achieving final
site stabilization or after the temporary BMPs are no longer needed.
An adequate supply of appropriate spare materials shall be kept on site for
maintenance of BMPs (BMP C150).
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Element #12 – Manage the Project
Accurate and timely BMP installation, monitoring, and maintenance, SWPPP
preparation and up-dating as necessary, and record-keeping of construction
SWPPP activities for the project, shall be under the supervision of a Certified Erosion
and Sediment Control Lead (BMP C150 and BMP C160).
To the extent possible, work shall be schedule to take advantage of normal
seasonal dry weather conditions (BMP C162).
Element #13 – Protect Low Impact Development BMPs
Stormwater control facilities shall be protected from sedimentation and other
harmful processes. Silt fence (BMP C233), wattles (BMP C235), oil absorbent
fabric catch basin inlet bags, and/or other appropriate BMPs must be used as
necessary to protect stormwater facilities.
Minimum Requirement #3 – Source Control of Pollution
All known, available and reasonable source control BMPs must be applied to this
project to prevent stormwater from coming into contact with pollutants. Source control
BMPs must be selected, designed, and maintained according to the 2019 SWMMWW.
Construction-related pollution control is addressed above under Minimum Requirement
#2, Element #9 above.
Dust control may be achieved by sprinkling dry soils with water, but not to the point that
the dust control water creates turbid runoff.
Pollutant Source Specific BMP S411 – BMPs for Landscaping and Lawn Management
shall be implemented per the SWMMWW and appendices in this report.
Minimum Requirement #4 – Preservation of Natural Drainage Systems and Outfalls
Stormwater will be dispersed to prevent concentration of runoff. Little to no impact will
occur to any existing natural drainage channels.
Minimum Requirement #5 – Onsite Stormwater Management
Per Jefferson County Stormwater Worksheet L, List #1 will be followed to meet this
minimum requirement.
For lawn and landscaped areas BMP T5.13, Post -Construction Soil Quality and Depth
will be applied to disturbed areas which will not be converted into impervious surface. An
8” layer of topsoil meeting the specifications detailed in the BMP explanation in the
SWMMWW will be placed throughout the lawn area and other disturbed areas by
amending the existing soil with imported compost material.
Due to the limited available soil profile, none of the BMPs on the list are feasible for this
project. As such, roof area runoff will be discharged through an above ground level
spreader pipe downslope of the residence. This will help to dissipate the energy from the
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roof downspouts and will also direct the runoff away from the septic system. This BMP
The outlet of the footing drain will also connect to the level spreader facility.
Driveway runoff will be use sheet flow dispersion in accordance to BMP T5.12. Full
dispersion is not feasible due to the siting criteria not being able to be met. Permeable
Pavement is not feasible due to the limited soil profile available for infiltration.
Minimum Requirement #6 – Runoff Treatment
The total pollution generating hard surface in is less than the 5,000 square foot threshold,
therefore stormwater treatment facilities are not required to be constructed.
Minimum Requirement #7 – Flow Control
The total effective impervious surface created by this project is less than the 10,000
square foot threshold to meet the standard flow control requirement, therefore no flow
control facilities are required to be constructed.
Minimum Requirement #8 – Wetlands Protection
No known wetlands exist on the site.
Minimum Requirement #9 – Operation and Maintenance
An operations and maintenance manual for on-site stormwater facilities can be found in
Appendix III.
4.0 THE LIMITATIONS OF OUR INVESTIGATION AND FINDINGS
The observations and conclusions of this report apply only to the subject property and
they are not transferable to nearby or adjoining property. This report was prepared for
Anderson Homes LLC., and may be used by others only with permission. United
Engineering, Inc. warrants this report was conscientiously prepared in accordance with
the practice of professional civil engineering. No other warranty, either express nor
implied, is provided.
Respectfully,
Zachary N Slota, P.E.
Principal Engineer
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12/4/2020
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Appendix I – Soils Information
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Appendix III – O & M Manual
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KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL, APPENDIX A
APPENDIX A
MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,
CONVEYANCE, AND WATER QUALITY FACILITIES
This appendix contains the maintenance requirements for the following typical stormwater control and water quality
facilities and components (ctrl/to follow the link):
No. 1 – Detention Ponds (p. A-2)
No. 2 – Infiltration Facilities (p. A-3)
No. 3 – Detention Tanks and Vaults (p. A-5)
No. 4 – Control Structure/Flow Restrictor (p. A-7)
No. 5 – Catch Basins and Manholes (p. A-9)
No. 6 – Conveyance Pipes and Ditches (p. A-11)
No. 7 – Debris Barriers (e.g., Trash Racks) (p. A-12)
No. 8 – Energy Dissipaters (p. A- 13)
No. 9 – Fencing (p. A-14)
No. 10 – Gates/Bollards/Access Barriers (p. A-15)
No. 11 – Grounds (Landscaping) (p. A-16)
No. 12 – Access Roads (p. A-17)
No. 13 – Basic Bioswale (grass) (p. A-18)
No. 14 – Wet Bioswale (p. A-19)
No. 15 – Filter Strip (p. A-20)
No. 16 – Wetpond (p. A-21)
No. 17 – Wetvault (p. A-23)
No. 18 – Stormwater Wetland (p. A-24)
No. 19 – Sand Filter Pond (p. A-26)
No. 20 – Sand Filter Vault (p. A-28)
No. 21 – Stormfilter (Cartridge Type) (p. A-30)
No. 22 – Baffle Oil/Water Separator (p. A-32)
No. 23 – Coalescing Plate Oil/Water Separator (p. A-33)
No. 24 – Catch Basin Insert (p. A-34)
No. 25 –Drywell BMP (p. A-35)
No. 26 –Gravel Filled Infiltration Trench BMP (p. A-35)
No. 27 –Gravel Filled Dispersion Trench BMP (p. A-36)
No. 28 –Native Vegetated Surface / Native Vegetated Landscape BMP (p. A-37)
No. 29 –Perforated Pipe Connections BMP (p. A-37)
No. 30 –Permeable Pavement BMP (p. A-38)
No. 31 –Bioretention BMP (p. A-39)
No. 32 –RainWater Harvesting BMP (p. A- 40)
No. 33 –Rock Pad BMP (p. A-40)
No. 34 –Sheet Flow BMP (p. A-40)
No. 35 –Splash Block BMP (p. A-41)
No. 36 –Vegetated Roof BMP (p. A-42)
2016 Surface Water Design Manual – Appendix A 4/24/2016
A-1
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 1 – DETENTION PONDS
Maintenance
Component
Defect or Problem Conditions When Maintenance Is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Any trash and debris which exceed 1 cubic foot
per 1,000 square feet (this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Trash and debris cleared from site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Top or Side Slopes
of Dam, Berm or
Embankment
Rodent holes Any evidence of rodent holes if facility is acting
as a dam or berm, or any evidence of water
piping through dam or berm via rodent holes.
Rodents removed or destroyed and
dam or berm repaired.
Tree growth Tree growth threatens integrity of slopes, does
not allow maintenance access, or interferes with
maintenance activity. If trees are not a threat or
not interfering with access or maintenance, they
do not need to be removed.
Trees do not hinder facility
performance or maintenance
activities.
Erosion Eroded damage over 2 inches deep where cause
of damage is still present or where there is
potential for continued erosion. Any erosion
observed on a compacted slope.
Slopes stabilized using appropriate
erosion control measures. If erosion
is occurring on compacted slope, a
licensed civil engineer should be
consulted to resolve source of
erosion.
Settlement Any part of a dam, berm or embankment that
has settled 4 inches lower than the design
elevation.
Top or side slope restored to design
dimensions. If settlement is
significant, a licensed civil engineer
should be consulted to determine
the cause of the settlement.
Storage Area Sediment
accumulation
Accumulated sediment that exceeds 10% of the
designed pond depth.
Sediment cleaned out to designed
pond shape and depth; pond
reseeded if necessary to control
erosion.
Liner damaged
(If Applicable)
Liner is visible or pond does not hold water as
designed.
Liner repaired or replaced.
Inlet/Outlet Pipe. Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Emergency
Overflow/Spillway
Tree growth Tree growth impedes flow or threatens stability of
spillway.
Trees removed.
Rock missing Only one layer of rock exists above native soil in
area five square feet or larger or any exposure of
native soil on the spillway.
Spillway restored to design
standards.
4/24/2016 2016 Surface Water Design Manual – Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 2 – INFILTRATION FACILITIES
Maintenance
Component
Defect or Problem Conditions When Maintenance Is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Any trash and debris which exceed 1 cubic foot
per 1,000 square feet (this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Trash and debris cleared from site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Infiltration Pond,
Top or Side Slopes
of Dam, Berm or
Embankment
Rodent holes Any evidence of rodent holes if facility is acting
as a dam or berm, or any evidence of water
piping through dam or berm via rodent holes.
Rodents removed or destroyed and
dam or berm repaired.
Tree growth Tree growth threatens integrity of dams, berms
or slopes, does not allow maintenance access,
or interferes with maintenance activity. If trees
are not a threat to dam, berm, or embankment
integrity or not interfering with access or
maintenance, they do not need to be removed.
Trees do not hinder facility
performance or maintenance
activities.
Erosion Eroded damage over 2 inches deep where cause
of damage is still present or where there is
potential for continued erosion. Any erosion
observed on a compacted slope.
Slopes stabilized using appropriate
erosion control measures. If erosion
is occurring on compacted slope, a
licensed civil engineer should be
consulted to resolve source of
erosion.
Settlement Any part of a dam, berm or embankment that
has settled 4 inches lower than the design
elevation.
Top or side slope restored to design
dimensions. If settlement is
significant, a licensed civil engineer
should be consulted to determine
the cause of the settlement.
Infiltration Pond,
Tank, Vault, Trench,
or Small Basin
Storage Area
Sediment
accumulation
If two inches or more sediment is present or a
percolation test indicates facility is working at or
less than 90% of design.
Facility infiltrates as designed.
Liner damaged
(If Applicable)
Liner is visible or pond does not hold water as
designed.
Liner repaired or replaced.
Infiltration Tank
Structure
Plugged air vent Any blockage of the vent.Tank or vault freely vents.
Tank bent out of
shape
Any part of tank/pipe is bent out of shape more
than 10% of its design shape.
Tank repaired or replaced to design.
Gaps between
sections, damaged
joints or cracks or
tears in wall
A gap wider than ½-inch at the joint of any tank
sections or any evidence of soil particles entering
the tank at a joint or through a wall.
No water or soil entering tank
through joints or walls.
Infiltration Vault
Structure
Damage to wall,
frame, bottom, and/or
top slab
Cracks wider than ½-inch, any evidence of soil
entering the structure through cracks or qualified
inspection personnel determines that the vault is
not structurally sound.
Vault is sealed and structurally
sound.
2016 Surface Water Design Manual – Appendix A 4/24/2016
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 2 – INFILTRATION FACILITIES
Maintenance
Component
Defect or Problem Conditions When Maintenance Is Needed Results Expected When
Maintenance Is Performed
Inlet/Outlet Pipes Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place.
Any open manhole requires immediate
maintenance.
Manhole access covered.
Locking mechanism
not working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove
One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
Large access
doors/plate
Damaged or difficult
to open
Large access doors or plates cannot be
opened/removed using normal equipment.
Replace or repair access door so it
can opened as designed.
Gaps, doesn't cover
completely
Large access doors not flat and/or access
opening not completely covered.
Doors close flat; covers access
opening completely.
Lifting Rings missing,
rusted
Lifting rings not capable of lifting weight of door
or plate.
Lifting rings sufficient to lift or
remove door or plate.
Infiltration Pond,
Tank, Vault, Trench,
or Small Basin Filter
Bags
Plugged Filter bag more than 1/2 full. Replace filter bag or redesign
system.
Infiltration Pond,
Tank, Vault, Trench,
or Small Basin Pre-
settling Ponds and
Vaults
Sediment
accumulation
6" or more of sediment has accumulated. Pre-settling occurs as designed
Infiltration Pond,
Rock Filter
Plugged High water level on upstream side of filter
remains for extended period of time or little or no
water flows through filter during heavy rain
storms.
Rock filter replaced evaluate need
for filter and remove if not
necessary.
Infiltration Pond
Emergency
Overflow Spillway
Rock missing Only one layer of rock exists above native soil in
area five square feet or larger, or any exposure
of native soil at the top of out flow path of
spillway. Rip-rap on inside slopes need not be
replaced.
Spillway restored to design
standards.
Tree growth Tree growth impedes flow or threatens stability of
spillway.
Trees removed.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 3 – DETENTION TANKS AND VAULTS
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Any trash and debris which exceed 1 cubic foot
per 1,000 square feet (this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Trash and debris cleared from site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Tank or Vault
Storage Area
Trash and debris Any trash and debris accumulated in vault or
tank (includes floatables and non-floatables).
No trash or debris in vault.
Sediment
accumulation
Accumulated sediment depth exceeds 10% of
the diameter of the storage area for ½ length of
storage vault or any point depth exceeds 15% of
diameter. Example: 72-inch storage tank would
require cleaning when sediment reaches depth of
7 inches for more than ½ length of tank.
All sediment removed from storage
area.
Tank Structure Plugged air vent Any blockage of the vent.Tank or vault freely vents.
Tank bent out of
shape
Any part of tank/pipe is bent out of shape more
than 10% of its design shape.
Tank repaired or replaced to design.
Gaps between
sections, damaged
joints or cracks or
tears in wall
A gap wider than ½-inch at the joint of any tank
sections or any evidence of soil particles entering
the tank at a joint or through a wall.
No water or soil entering tank
through joints or walls.
Vault Structure Damage to wall,
frame, bottom, and/or
top slab
Cracks wider than ½-inch, any evidence of soil
entering the structure through cracks or qualified
inspection personnel determines that the vault is
not structurally sound.
Vault is sealed and structurally
sound.
Inlet/Outlet Pipes Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 3 – DETENTION TANKS AND VAULTS
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place.
Any open manhole requires immediate
maintenance.
Manhole access covered.
Locking mechanism
not working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove
One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
Large access
doors/plate
Damaged or difficult
to open
Large access doors or plates cannot be
opened/removed using normal equipment.
Replace or repair access door so it
can opened as designed.
Gaps, doesn't cover
completely
Large access doors not flat and/or access
opening not completely covered.
Doors close flat; covers access
opening completely.
Lifting Rings missing,
rusted
Lifting rings not capable of lifting weight of door
or plate.
Lifting rings sufficient to lift or
remove door or plate.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Structure Trash and debris Trash or debris of more than ½ cubic foot which
is located immediately in front of the structure
opening or is blocking capacity of the structure
by more than 10%.
No Trash or debris blocking or
potentially blocking entrance to
structure.
Trash or debris in the structure that exceeds 1/3
the depth from the bottom of basin to invert the
lowest pipe into or out of the basin.
No trash or debris in the structure.
Deposits of garbage exceeding 1 cubic foot in
volume.
No condition present which would
attract or support the breeding of
insects or rodents.
Sediment Sediment exceeds 60% of the depth from the
bottom of the structure to the invert of the lowest
pipe into or out of the structure or the bottom of
the FROP-T section or is within 6 inches of the
invert of the lowest pipe into or out of the
structure or the bottom of the FROP-T section.
Sump of structure contains no
sediment.
Damage to frame
and/or top slab
Corner of frame extends more than ¾ inch past
curb face into the street (If applicable).
Frame is even with curb.
Top slab has holes larger than 2 square inches
or cracks wider than ¼ inch.
Top slab is free of holes and cracks.
Frame not sitting flush on top slab, i.e.,
separation of more than ¾ inch of the frame from
the top slab.
Frame is sitting flush on top slab.
Cracks in walls or
bottom
Cracks wider than ½ inch and longer than 3 feet,
any evidence of soil particles entering structure
through cracks, or maintenance person judges
that structure is unsound.
Structure is sealed and structurally
sound.
Cracks wider than ½ inch and longer than 1 foot
at the joint of any inlet/outlet pipe or any
evidence of soil particles entering structure
through cracks.
No cracks more than 1/4 inch wide at
the joint of inlet/outlet pipe.
Settlement/
misalignment
Structure has settled more than 1 inch or has
rotated more than 2 inches out of alignment.
Basin replaced or repaired to design
standards.
Damaged pipe joints Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
the structure at the joint of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of inlet/outlet pipes.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Ladder rungs missing
or unsafe
Ladder is unsafe due to missing rungs,
misalignment, rust, cracks, or sharp edges.
Ladder meets design standards and
allows maintenance person safe
access.
FROP-T Section Damage T section is not securely attached to structure
wall and outlet pipe structure should support at
least 1,000 lbs of up or down pressure.
T section securely attached to wall
and outlet pipe.
Structure is not in upright position (allow up to
10% from plumb).
Structure in correct position.
Connections to outlet pipe are not watertight or
show signs of deteriorated grout.
Connections to outlet pipe are water
tight; structure repaired or replaced
and works as designed.
Any holes—other than designed holes—in the
structure.
Structure has no holes other than
designed holes.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Cleanout Gate Damaged or missing Cleanout gate is missing.Replace cleanout gate.
Cleanout gate is not watertight.Gate is watertight and works as
designed.
Gate cannot be moved up and down by one
maintenance person.
Gate moves up and down easily and
is watertight.
Chain/rod leading to gate is missing or damaged. Chain is in place and works as
designed.
Orifice Plate Damaged or missing Control device is not working properly due to
missing, out of place, or bent orifice plate.
Plate is in place and works as
designed.
Obstructions Any trash, debris, sediment, or vegetation
blocking the plate.
Plate is free of all obstructions and
works as designed.
Overflow Pipe Obstructions Any trash or debris blocking (or having the
potential of blocking) the overflow pipe.
Pipe is free of all obstructions and
works as designed.
Deformed or
damaged lip
Lip of overflow pipe is bent or deformed.Overflow pipe does not allow
overflow at an elevation lower than
design
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Metal Grates
(If Applicable)
Unsafe grate opening Grate with opening wider than
7/8 inch.Grate opening meets design
standards.
Trash and debris Trash and debris that is blocking more than 20%
of grate surface.
Grate free of trash and debris.
footnote to guidelines for disposal
Damaged or missing Grate missing or broken member(s) of the grate. Grate is in place and meets design
standards.
Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place.
Any open structure requires urgent
maintenance.
Cover/lid protects opening to
structure.
Locking mechanism
Not Working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
Remove
One maintenance person cannot remove
cover/lid after applying 80 lbs. of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 5 – CATCH BASINS AND MANHOLES
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Structure Sediment Sediment exceeds 60% of the depth from the
bottom of the catch basin to the invert of the
lowest pipe into or out of the catch basin or is
within 6 inches of the invert of the lowest pipe
into or out of the catch basin.
Sump of catch basin contains no
sediment.
Trash and debris Trash or debris of more than ½ cubic foot which
is located immediately in front of the catch basin
opening or is blocking capacity of the catch basin
by more than 10%.
No Trash or debris blocking or
potentially blocking entrance to
catch basin.
Trash or debris in the catch basin that exceeds
1/3 the depth from the bottom of basin to invert
the lowest pipe into or out of the basin.
No trash or debris in the catch
basin.
Dead animals or vegetation that could generate
odors that could cause complaints or dangerous
gases (e.g., methane).
No dead animals or vegetation
present within catch basin.
Deposits of garbage exceeding 1 cubic foot in
volume.
No condition present which would
attract or support the breeding of
insects or rodents.
Damage to frame
and/or top slab
Corner of frame extends more than ¾ inch past
curb face into the street (If applicable).
Frame is even with curb.
Top slab has holes larger than 2 square inches
or cracks wider than ¼ inch.
Top slab is free of holes and cracks.
Frame not sitting flush on top slab, i.e.,
separation of more than ¾ inch of the frame from
the top slab.
Frame is sitting flush on top slab.
Cracks in walls or
bottom
Cracks wider than ½ inch and longer than 3 feet,
any evidence of soil particles entering catch
basin through cracks, or maintenance person
judges that catch basin is unsound.
Catch basin is sealed and is
structurally sound.
Cracks wider than ½ inch and longer than 1 foot
at the joint of any inlet/outlet pipe or any
evidence of soil particles entering catch basin
through cracks.
No cracks more than 1/4 inch wide at
the joint of inlet/outlet pipe.
Settlement/
misalignment
Catch basin has settled more than 1 inch or has
rotated more than 2 inches out of alignment.
Basin replaced or repaired to design
standards.
Damaged pipe joints Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
the catch basin at the joint of the inlet/outlet
pipes.
No cracks more than ¼-inch wide at
the joint of inlet/outlet pipes.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 5 – CATCH BASINS AND MANHOLES
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Metal Grates
(Catch Basins)
Unsafe grate opening Grate with opening wider than
7/8 inch.Grate opening meets design
standards.
Trash and debris Trash and debris that is blocking more than 20%
of grate surface.
Grate free of trash and debris.
footnote to guidelines for disposal
Damaged or missing Grate missing or broken member(s) of the grate.
Any open structure requires urgent
maintenance.
Grate is in place and meets design
standards.
Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place.
Any open structure requires urgent
maintenance.
Cover/lid protects opening to
structure.
Locking mechanism
Not Working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
Remove
One maintenance person cannot remove
cover/lid after applying 80 lbs. of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 6 – CONVEYANCE PIPES AND DITCHES
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Pipes Sediment & debris
accumulation
Accumulated sediment or debris that exceeds
20% of the diameter of the pipe.
Water flows freely through pipes.
Vegetation/roots Vegetation/roots that reduce free movement of
water through pipes.
Water flows freely through pipes.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Damage to protective
coating or corrosion
Protective coating is damaged; rust or corrosion
is weakening the structural integrity of any part of
pipe.
Pipe repaired or replaced.
Damaged Any dent that decreases the cross section area
of pipe by more than 20% or is determined to
have weakened structural integrity of the pipe.
Pipe repaired or replaced.
Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000
square feet of ditch and slopes.
Trash and debris cleared from
ditches.
Sediment
accumulation
Accumulated sediment that exceeds 20% of the
design depth.
Ditch cleaned/flushed of all
sediment and debris so that it
matches design.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Vegetation Vegetation that reduces free movement of water
through ditches.
Water flows freely through ditches.
Erosion damage to
slopes
Any erosion observed on a ditch slope.Slopes are not eroding.
Rock lining out of
place or missing (If
Applicable)
One layer or less of rock exists above native soil
area 5 square feet or more, any exposed native
soil.
Replace rocks to design standards.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 7 – DEBRIS BARRIERS (E.G., TRASH RACKS)
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed.
Site Trash and debris Trash or debris plugging more than 20% of the
area of the barrier.
Barrier clear to receive capacity
flow.
Sediment
accumulation
Sediment accumulation of greater than 20% of
the area of the barrier
Barrier clear to receive capacity
flow.
Structure Cracked broken or
loose
Structure which bars attached to is damaged -
pipe is loose or cracked or concrete structure is
cracked, broken of loose.
Structure barrier attached to is
sound.
Bars Bar spacing Bar spacing exceeds 6 inches.Bars have at most 6 inches spacing.
Damaged or missing
bars
Bars are bent out of shape more than 3 inches. Bars in place with no bends more
than ¾ inch.
Bars are missing or entire barrier missing. Bars in place according to design.
Bars are loose and rust is causing 50%
deterioration to any part of barrier.
Repair or replace barrier to design
standards.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 8 – ENERGY DISSIPATERS
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed.
Site Trash and debris Trash and/or debris accumulation.Dissipater clear of trash and/or
debris.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Rock Pad Missing or moved
Rock
Only one layer of rock exists above native soil in
area five square feet or larger or any exposure of
native soil.
Rock pad prevents erosion.
Dispersion Trench Pipe plugged with
sediment
Accumulated sediment that exceeds 20% of the
design depth.
Pipe cleaned/flushed so that it
matches design.
Not discharging water
properly
Visual evidence of water discharging at
concentrated points along trench (normal
condition is a “sheet flow” of water along trench).
Water discharges from feature by
sheet flow.
Perforations plugged. Over 1/4 of perforations in pipe are plugged with
debris or sediment.
Perforations freely discharge flow.
Water flows out top of
“distributor” catch
basin.
Water flows out of distributor catch basin during
any storm less than the design storm.
No flow discharges from distributor
catch basin.
Receiving area over-
saturated
Water in receiving area is causing or has
potential of causing landslide problems.
No danger of landslides.
Gabions Damaged mesh Mesh of gabion broken, twisted or deformed so
structure is weakened or rock may fall out.
Mesh is intact, no rock missing.
Corrosion Gabion mesh shows corrosion through more
than ¼ of its gage.
All gabion mesh capable of
containing rock and retaining
designed form.
Collapsed or
deformed baskets
Gabion basket shape deformed due to any
cause.
All gabion baskets intact, structure
stands as designed.
Missing rock Any rock missing that could cause gabion to
loose structural integrity.
No rock missing.
Manhole/Chamber Worn or damaged
post, baffles or side of
chamber
Structure dissipating flow deteriorates to ½ or
original size or any concentrated worn spot
exceeding one square foot which would make
structure unsound.
Structure is in no danger of failing.
Damage to wall,
frame, bottom, and/or
top slab
Cracks wider than ½-inch or any evidence of soil
entering the structure through cracks, or
maintenance inspection personnel determines
that the structure is not structurally sound.
Manhole/chamber is sealed and
structurally sound.
Damaged pipe joints Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
the structure at the joint of the inlet/outlet pipes.
No soil or water enters and no water
discharges at the joint of inlet/outlet
pipes.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 9 – FENCING
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Erosion or holes
under fence
Erosion or holes more than 4 inches high and 12-
18 inches wide permitting access through an
opening under a fence.
No access under the fence.
Wood Posts, Boards
and Cross Members
Missing or damaged
parts
Missing or broken boards, post out of plumb by
more than 6 inches or cross members broken
No gaps on fence due to missing or
broken boards, post plumb to within
1½ inches, cross members sound.
Weakened by rotting
or insects
Any part showing structural deterioration due to
rotting or insect damage
All parts of fence are structurally
sound.
Damaged or failed
post foundation
Concrete or metal attachments deteriorated or
unable to support posts.
Post foundation capable of
supporting posts even in strong
wind.
Metal Posts, Rails
and Fabric
Damaged parts Post out of plumb more than 6 inches.Post plumb to within 1½ inches.
Top rails bent more than 6 inches.Top rail free of bends greater than
1 inch.
Any part of fence (including post, top rails, and
fabric) more than 1 foot out of design alignment.
Fence is aligned and meets design
standards.
Missing or loose tension wire.Tension wire in place and holding
fabric.
Deteriorated paint or
protective coating
Part or parts that have a rusting or scaling
condition that has affected structural adequacy.
Structurally adequate posts or parts
with a uniform protective coating.
Openings in fabric Openings in fabric are such that an 8-inch
diameter ball could fit through.
Fabric mesh openings within 50% of
grid size.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 10 – GATES/BOLLARDS/ACCESS BARRIERS
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Chain Link Fencing
Gate
Damaged or missing
members
Missing gate.Gates in place.
Broken or missing hinges such that gate cannot
be easily opened and closed by a maintenance
person.
Hinges intact and lubed. Gate is
working freely.
Gate is out of plumb more than 6 inches and
more than 1 foot out of design alignment.
Gate is aligned and vertical.
Missing stretcher bar, stretcher bands, and ties. Stretcher bar, bands, and ties in
place.
Locking mechanism
does not lock gate
Locking device missing, no-functioning or does
not link to all parts.
Locking mechanism prevents
opening of gate.
Openings in fabric Openings in fabric are such that an 8-inch
diameter ball could fit through.
Fabric mesh openings within 50% of
grid size.
Bar Gate Damaged or missing
cross bar
Cross bar does not swing open or closed, is
missing or is bent to where it does not prevent
vehicle access.
Cross bar swings fully open and
closed and prevents vehicle access.
Locking mechanism
does not lock gate
Locking device missing, no-functioning or does
not link to all parts.
Locking mechanism prevents
opening of gate.
Support post
damaged
Support post does not hold cross bar up.Cross bar held up preventing vehicle
access into facility.
Bollards Damaged or missing Bollard broken, missing, does not fit into support
hole or hinge broken or missing.
No access for motorized vehicles to
get into facility.
Does not lock Locking assembly or lock missing or cannot be
attached to lock bollard in place.
No access for motorized vehicles to
get into facility.
Boulders Dislodged Boulders not located to prevent motorized
vehicle access.
No access for motorized vehicles to
get into facility.
Circumvented Motorized vehicles going around or between
boulders.
No access for motorized vehicles to
get into facility.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 11 – GROUNDS (LANDSCAPING)
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash or litter Any trash and debris which exceed 1 cubic foot
per 1,000 square feet (this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Trash and debris cleared from site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Trees and Shrubs Hazard Any tree or limb of a tree identified as having a
potential to fall and cause property damage or
threaten human life. A hazard tree identified by
a qualified arborist must be removed as soon
as possible.
No hazard trees in facility.
Damaged Limbs or parts of trees or shrubs that are split or
broken which affect more than 25% of the total
foliage of the tree or shrub.
Trees and shrubs with less than 5%
of total foliage with split or broken
limbs.
Trees or shrubs that have been blown down or
knocked over.
No blown down vegetation or
knocked over vegetation. Trees or
shrubs free of injury.
Trees or shrubs which are not adequately
supported or are leaning over, causing exposure
of the roots.
Tree or shrub in place and
adequately supported; dead or
diseased trees removed.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 12 – ACCESS ROADS
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000
square feet (i.e., trash and debris would fill up
one standards size garbage can).
Roadway drivable by maintenance
vehicles.
Debris which could damage vehicle tires or
prohibit use of road.
Roadway drivable by maintenance
vehicles.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Blocked roadway Any obstruction which reduces clearance above
road surface to less than 14 feet.
Roadway overhead clear to 14 feet
high.
Any obstruction restricting the access to a 10- to
12 foot width for a distance of more than 12 feet
or any point restricting access to less than a 10
foot width.
At least 12-foot of width on access
road.
Road Surface Erosion, settlement,
potholes, soft spots,
ruts
Any surface defect which hinders or prevents
maintenance access.
Road drivable by maintenance
vehicles.
Vegetation on road
surface
Trees or other vegetation prevent access to
facility by maintenance vehicles.
Maintenance vehicles can access
facility.
Shoulders and
Ditches
Erosion Erosion within 1 foot of the roadway more than 8
inches wide and 6 inches deep.
Shoulder free of erosion and
matching the surrounding road.
Weeds and brush Weeds and brush exceed 18 inches in height or
hinder maintenance access.
Weeds and brush cut to 2 inches in
height or cleared in such a way as to
allow maintenance access.
Modular Grid
Pavement
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Damaged or missing Access surface compacted because of broken
on missing modular block.
Access road surface restored so
road infiltrates.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 13 – BASIC BIOSWALE (GRASS)
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Any trash and/or debris accumulated on the
bioswale site.
No trash or debris on the bioswale
site.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Swale Section Sediment
accumulation
Sediment depth exceeds 2 inches in 10% of the
swale treatment area.
No sediment deposits in grass
treatment area of the bioswale.
Sediment inhibits grass growth over 10% of
swale length.
Grass growth not inhibited by
sediment.
Sediment inhibits even spreading of flow. Flow spreads evenly through swale
Erosion/scouring Eroded or scoured swale bottom due to
channelization or high flows.
No eroded or scoured areas in
bioswale. Cause of erosion or scour
addressed.
Poor vegetation
coverage
Grass is sparse or bare or eroded patches occur
in more than 10% of the swale bottom.
Swale has no bare spots and grass
is thick and healthy.
Grass too tall Grass excessively tall (greater than 10 inches),
grass is thin or nuisance weeds and other
vegetation have taken over.
Grass is between 3 and 4 inches
tall, thick and healthy. No clippings
left in swale. No nuisance
vegetation present.
Excessive shade Grass growth is poor because sunlight does not
reach swale.
Health grass growth or swale
converted to a wet bioswale.
Constant baseflow Continuous flow through the swale, even when it
has been dry for weeks or an eroded, muddy
channel has formed in the swale bottom.
Baseflow removed from swale by a
low-flow pea-gravel drain or
bypassed around the swale.
Standing water Water pools in the swale between storms or
does not drain freely.
Swale freely drains and there is no
standing water in swale between
storms.
Channelization Flow concentrates and erodes channel through
swale.
No flow channels in swale.
Flow Spreader Concentrated flow Flow from spreader not uniformly distributed
across entire swale width.
Flows are spread evenly over entire
swale width.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 14 – WET BIOSWALE
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Any trash and/or debris accumulated at the site. No trash or debris at the site.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Swale Section Sediment
accumulation
Sediment depth exceeds 2 inches in 10% of the
swale treatment area.
No sediment deposits in treatment
area.
Erosion/scouring Eroded or scoured swale bottom due to
channelization or high flows.
No eroded or scoured areas in
bioswale. Cause of erosion or scour
addressed.
Water depth Water not retained to a depth of about 4 inches
during the wet season.
Water depth of 4 inches through out
swale for most of wet season.
Vegetation ineffective Vegetation sparse, does not provide adequate
filtration or crowded out by very dense clumps of
cattail or nuisance vegetation.
Wetland vegetation fully covers
bottom of swale and no cattails or
nuisance vegetation present.
Insufficient water Wetland vegetation dies due to lack of water. Wetland vegetation remains healthy
(may require converting to grass
lined bioswale
Flow Spreader Concentrated flow Flow from spreader not uniformly distributed
across entire swale width.
Flows are spread evenly over entire
swale width.
Inlet/Outlet Pipe Sediment
accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 15 – FILTER STRIP
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Any trash and debris accumulated on the filter
strip site.
Filter strip site free of any trash or
debris
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass Strip Sediment
accumulation
Sediment accumulation on grass exceeds 2
inches depth.
No sediment deposits in treatment
area.
Erosion/scouring Eroded or scoured swale bottom due to
channelization or high flows.
No eroded or scoured areas in
bioswale. Cause of erosion or scour
addressed.
Grass too tall Grass excessively tall (greater than 10 inches),
grass is thin or nuisance weeds and other
vegetation have taken over.
Grass is between 3 and 4 inches
tall, thick and healthy. No clippings
left in swale. No nuisance
vegetation present.
Vegetation ineffective Grass has died out, become excessively tall
(greater than 10 inches) or nuisance vegetation
is taking over.
Grass is healthy, less than 9 inches
high and no nuisance vegetation
present.
Flow Spreader Concentrated flow Flow from spreader not uniformly distributed
across entire swale width.
Flows are spread evenly over entire
swale width.
Inlet/Outlet Pipe Sediment
accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 16 – WETPOND
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Any trash and debris accumulated on the
wetpond site.
Wetpond site free of any trash or
debris.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Side Slopes of Dam,
Berm, internal berm
or Embankment
Rodent holes Any evidence of rodent holes if facility is acting
as a dam or berm, or any evidence of water
piping through dam or berm via rodent holes.
Rodents removed or destroyed and
dam or berm repaired.
Tree growth Tree growth threatens integrity of dams, berms
or slopes, does not allow maintenance access,
or interferes with maintenance activity. If trees
are not a threat to dam, berm or embankment
integrity, are not interfering with access or
maintenance or leaves do not cause a plugging
problem they do not need to be removed.
Trees do not hinder facility
performance or maintenance
activities.
Erosion Eroded damage over 2 inches deep where cause
of damage is still present or where there is
potential for continued erosion. Any erosion
observed on a compacted slope.
Slopes stabilized using appropriate
erosion control measures. If erosion
is occurring on compacted slope, a
licensed civil engineer should be
consulted to resolve source of
erosion.
Top or Side Slopes
of Dam, Berm,
internal berm or
Embankment
Settlement Any part of a dam, berm or embankment that
has settled 4 inches lower than the design
elevation.
Top or side slope restored to design
dimensions. If settlement is
significant, a licensed civil engineer
should be consulted to determine
the cause of the settlement.
Irregular surface on
internal berm
Top of berm not uniform and level.Top of berm graded to design
elevation.
Pond Areas Sediment
accumulation (except
first wetpool cell)
Accumulated sediment that exceeds 10% of the
designed pond depth.
Sediment cleaned out to designed
pond shape and depth.
Sediment
accumulation (first
wetpool cell)
Sediment accumulations in pond bottom that
exceeds the depth of sediment storage (1 foot)
plus 6 inches.
Sediment storage contains no
sediment.
Liner damaged (If
Applicable)
Liner is visible or pond does not hold water as
designed.
Liner repaired or replaced.
Water level (all
wetpool cells)
Cell level(s) drops more than 12 inches in any 7-
day period.
Cell level(s) drops less than 12
inches in any 7-day period.
Algae mats (first
wetpool cell)
Algae mats develop over more than 10% of the
water surface should be removed.
Algae mats removed (usually in the
late summer before Fall rains,
especially in Sensitive Lake
Protection Areas.)
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 16 – WETPOND
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Design planting and
vegetation survival
and maintenance
Sparse or dying design planting, or when design
plantings are not thriving across 80% or more of
the design vegetated areas within the pond;
invasive vegetation e.g., cattails
Design plantings and vegetation are
thriving and appropriately spaced
across 80% or more of the design
vegetated areas within the pond;
invasives removed including root
clumps
Gravity Drain Inoperable valve Valve will not open and close.Valve opens and closes normally.
Valve won’t seal Valve does not seal completely.Valve completely seals closed.
Emergency
Overflow Spillway
Tree growth Tree growth impedes flow or threatens stability of
spillway.
Trees removed.
Rock missing Only one layer of rock exists above native soil in
area five square feet or larger, or any exposure
of native soil at the top of out flow path of
spillway. Rip-rap on inside slopes need not be
replaced.
Spillway restored to design
standards.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 17 – WETVAULT
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from
facility site.
Treatment Area Trash and debris Any trash and debris accumulated in vault
(includes floatables and non-floatables).
No trash or debris in vault.
Sediment
accumulation
Sediment accumulation in vault bottom exceeds
the depth of the sediment zone plus 6 inches.
No sediment in vault.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Vault Structure Damage to wall,
frame, bottom, and/or
top slab
Cracks wider than ½-inch, any evidence of soil
entering the structure through cracks, vault does
not retain water or qualified inspection personnel
determines that the vault is not structurally
sound.
Vault is sealed and structurally
sound.
Baffles damaged Baffles corroding, cracking, warping and/or
showing signs of failure or baffle cannot be
removed.
Repair or replace baffles or walls to
specifications.
Ventilation Ventilation area blocked or plugged.No reduction of ventilation area
exists.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Gravity Drain Inoperable valve Valve will not open and close.Valve opens and closes normally.
Valve won’t seal Valve does not seal completely.Valve completely seals closed.
Access Manhole Access cover/lid
damaged or difficult to
open
Access cover/lid cannot be easily opened by one
person. Corrosion/deformation of cover/lid.
Access cover/lid can be opened by
one person.
Locking mechanism
not working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove
One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
Access doors/plate
has gaps, doesn't
cover completely
Large access doors not flat and/or access
opening not completely covered.
Doors close flat; covers access
opening completely.
Lifting Rings missing,
rusted
Lifting rings not capable of lifting weight of door
or plate.
Lifting rings sufficient to lift or
remove door or plate.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 18 – STORMWATER WETLAND
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from
facility site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Side Slopes of Dam,
Berm, internal berm
or Embankment
Rodent holes Any evidence of rodent holes if facility is acting
as a dam or berm, or any evidence of water
piping through dam or berm via rodent holes.
Rodents removed or destroyed and
dam or berm repaired.
Tree growth Tree growth threatens integrity of dams, berms
or slopes, does not allow maintenance access,
or interferes with maintenance activity. If trees
are not a threat to dam, berm, or embankment
integrity or not interfering with access or
maintenance, they do not need to be removed.
Trees do not hinder facility
performance or maintenance
activities.
Erosion Eroded damage over 2 inches deep where cause
of damage is still present or where there is
potential for continued erosion. Any erosion
observed on a compacted slope.
Slopes stabilized using appropriate
erosion control measures. If erosion
is occurring on compacted slope, a
licensed civil engineer should be
consulted to resolve source of
erosion.
Top or Side Slopes
of Dam, Berm,
internal berm or
Embankment
Settlement Any part of a dam, berm or embankment that
has settled 4 inches lower than the design
elevation.
Top or side slope restored to design
dimensions. If settlement is
significant, a licensed civil engineer
should be consulted to determine
the cause of the settlement.
Irregular surface on
internal berm
Top of berm not uniform and level.Top of berm graded flat to design
elevation.
Pond Areas Sediment
accumulation (first
cell/forebay)
Sediment accumulations in pond bottom that
exceeds the depth of sediment storage (1 foot)
plus 6 inches.
Sediment storage contains no
sediment.
Sediment
accumulation (wetland
cell)
Accumulated sediment that exceeds 10% of the
designed pond depth.
Sediment cleaned out to designed
pond shape and depth.
Liner damaged (If
Applicable)
Liner is visible or pond does not hold water as
designed.
Liner repaired or replaced.
Water level (first
cell/forebay)
Cell level drops more than 12 inches in any 7-
day period.
Cell level drops no more than 12
inches in any 7-day period.
Water level (wetland
cell)
Cell does not retain water for at least 10 months
of the year or wetland plants are not surviving.
Water retained at least 10 months of
the year or wetland plants are
surviving.
Algae mats (first
cell/forebay)
Algae mats develop over more than 10% of the
water surface should be removed.
Algae mats removed (usually in the
late summer before Fall rains,
especially in Sensitive Lake
Protection Areas.)
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 18 – STORMWATER WETLAND
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Vegetation Vegetation dead, dying, or overgrown (cattails) or
not meeting original planting specifications
across more than 20% of the entire design
vegetated area within the pond.
Plants in wetland cell surviving
across 80% or more of the entire
design vegetated area within the
pond and not interfering with wetland
function.
Gravity Drain Inoperable valve Valve will not open and close.Valve opens and closes normally.
Valve won’t seal Valve does not seal completely.Valve completely seals closed.
Emergency
Overflow Spillway
Tree growth Tree growth impedes flow or threatens stability of
spillway.
Trees removed.
Rock missing Only one layer of rock exists above native soil in
area five square feet or larger, or any exposure
of native soil at the top of out flow path of
spillway. Rip-rap on inside slopes need not be
replaced.
Spillway restored to design
standards.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 19 – SAND FILTER POND
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from
facility site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover
(not in the treatment
area)
Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Pre-Treatment (if
applicable)
Sediment
accumulation
Sediment accumulations in pond bottom that
exceeds the depth of sediment storage (1 foot)
plus 6 inches.
Sediment storage contains no
sediment.
Liner damaged (If
Applicable)
Liner is visible or pond does not hold water as
designed.
Liner repaired or replaced.
Water level Cell empty, doesn't hold water.Water retained in first cell for most
of the year.
Algae mats Algae mats develop over more than 10% of the
water surface should be removed.
Algae mats removed (usually in the
late summer before Fall rains,
especially in Sensitive Lake
Protection Areas.)
Pond Area Sediment
accumulation
Sediment or crust depth exceeds ½-inch over 10
% of surface area of sand filter.
No sediment or crust deposit on
sand filter that would impede
permeability of the filter section.
Grass (if applicable) Grass becomes excessively tall (greater than 6
inches) or when nuisance weeds and other
vegetation start to take over or thatch build up
occurs.
Mow vegetation and/or remove
nuisance vegetation.
Side Slopes of Pond Rodent holes Any evidence of rodent holes if facility is acting
as a dam or berm, or any evidence of water
piping through dam or berm via rodent holes.
Rodents removed or destroyed and
dam or berm repaired.
Tree growth Tree growth threatens integrity of dams, berms
or slopes, does not allow maintenance access,
or interferes with maintenance activity. If trees
are not a threat to dam, berm, or embankment
integrity or not interfering with access or
maintenance, they do not need to be removed.
Trees do not hinder facility
performance or maintenance
activities.
Erosion Eroded damage over 2 inches deep where cause
of damage is still present or where there is
potential for continued erosion. Any erosion
observed on a compacted slope.
Slopes stabilized using appropriate
erosion control measures. If erosion
is occurring on compacted slope, a
licensed civil engineer should be
consulted to resolve source of
erosion.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 19 – SAND FILTER POND
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Sand Filter Media Plugging Drawdown of water through the sand filter media,
takes longer than 24 hours, and/or flow through
the overflow pipes occurs frequently. A sieve
analysis of >4% -100 or >2% -200 requires
replacing sand filter media.
Sand filter media surface is aerated
or the surface is scraped and
replaced, and drawdown rate is
normal.
Prolonged flows Sand is saturated for prolonged periods of time
(several weeks) and does not dry out between
storms due to continuous base flow or prolonged
flows from detention facilities.
Excess flows bypassed or confined
to small portion of filter media
surface.
Short circuiting Flows become concentrated over one section of
the sand filter rather than dispersed or drawdown
rate of pool exceeds 12 inches per hour.
Flow and percolation of water
through the sand filter is uniform and
dispersed across the entire filter
area and drawdown rate is normal.
Media thickness Sand thickness is less than 18 inches.Rebuild sand thickness to a
minimum of 18 inches.
Underdrains and
Clean-Outs
Sediment/debris Underdrains or clean-outs partially plugged or
filled with sediment and/or debris. Junction
box/cleanout wyes not watertight.
Underdrains and clean-outs free of
sediment and debris and are
watertight.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Rock Pad Missing or out of
place
Only one layer of rock exists above native soil in
area five square feet or larger, or any exposure
of native soil.
Rock pad restored to design
standards.
Flow spreader Concentrated flow Flow from spreader not uniformly distributed
across sand filter.
Flows spread evenly over sand filter.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 20 – SAND FILTER VAULT
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from
facility site.
Noxious weeds Any noxious or nuisance vegetation which may
constitute a hazard to County personnel or the
public.
Noxious and nuisance vegetation
removed according to applicable
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in
height.
Grass or groundcover mowed to a
height no greater than 6 inches.
Pre-Treatment
Chamber
Sediment
accumulation
Sediment accumulation exceeds the depth of the
sediment zone plus 6 inches.
Sediment storage contains no
sediment.
Sand Filter Media Sediment
accumulation
Sediment depth exceeds ½-inch on sand filter
media.
Sand filter freely drains at normal
rate.
Trash and debris Trash and debris accumulated in vault (floatables
and non-floatables).
No trash or debris in vault.
Plugging Drawdown of water through the sand filter media,
takes longer than 24 hours, and/or flow through
the overflow pipes occurs frequently. A sieve
analysis of >4% -100 or >2% -200 requires
replacing sand filter media.
Sand filter media drawdown rate is
normal.
Short circuiting Seepage or flow occurs along the vault walls and
corners. Sand eroding near inflow area.
Cleanout wyes are not watertight.
Sand filter media section re-laid and
compacted along perimeter of vault
to form a semi-seal. Erosion
protection added to dissipate force
of incoming flow and curtail erosion.
Vault Structure Damaged to walls,
frame, bottom and/or
top slab.
Cracks wider than ½-inch, any evidence of soil
entering the structure through cracks or qualified
inspection personnel determines that the vault is
not structurally sound.
Vault replaced or repaired to provide
complete sealing of the structure.
Ventilation Ventilation area blocked or plugged.No reduction of ventilation area
exists.
Underdrains and
Cleanouts
Sediment/debris Underdrains or clean-outs partially plugged, filled
with sediment and/or debris or not watertight.
Underdrains and clean-outs free of
sediment and debris and sealed.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 20 – SAND FILTER VAULT
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place.
Any open manhole requires immediate
maintenance.
Manhole access covered.
Locking mechanism
not working Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.Cover /lid can be removed and
reinstalled by one maintenance
person.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
Large access
doors/plate
Damaged or difficult
to open Large access doors or plates cannot be
opened/removed using normal equipment.
Replace or repair access door so it
can opened as designed.
Gaps, doesn't cover
completely Large access doors not flat and/or access
opening not completely covered.
Doors close flat; covers access
opening completely.
Lifting Rings missing,
rusted Lifting rings not capable of lifting weight of door
or plate.
Lifting rings sufficient to lift or
remove door or plate.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 21 – STORMFILTER (CARTRIDGE TYPE)
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Facility Documentation Update facility inspection record after each
inspection.
Maintenance records are up to date.
Provide certification of replaced filter media. Filter media is certified to meet
Stormfilter®specifications.
Site Trash and debris Any trash or debris which impairs the function of
the facility.
Trash and debris removed from
facility.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oils, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Life cycle System has not been inspected for three years. Facility is re-inspected and any
needed maintenance performed.
Vault Treatment
Area
Sediment on vault
floor
Greater than 2 inches of sediment.Vault is free of sediment.
Sediment on top of
cartridges
Greater than ½ inch of sediment.Vault is free of sediment.
Multiple scum lines
above top of
cartridges
Thick or multiple scum lines above top of
cartridges. Probably due to plugged canisters or
underdrain manifold.
Cause of plugging corrected,
canisters replaced if necessary.
Vault Structure Damage to wall,
Frame, Bottom,
and/or Top Slab
Cracks wider than ½-inch and any evidence of
soil particles entering the structure through the
cracks, or qualified inspection personnel
determines the vault is not structurally sound.
Vault replaced or repaired to design
specifications.
Baffles damaged Baffles corroding, cracking warping, and/or
showing signs of failure as determined by
maintenance/inspection person.
Repair or replace baffles to
specification.
Filter Media Standing water in
vault
9 inches or greater of static water in the vault for
more than 24 hours following a rain event and/or
overflow occurs frequently. Probably due to
plugged filter media, underdrain or outlet pipe.
No standing water in vault 24 hours
after a rain event.
Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media.
Underdrains and
Clean-Outs
Sediment/debris Underdrains or clean-outs partially plugged or
filled with sediment and/or debris.
Underdrains and clean-outs free of
sediment and debris.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place.
Any open manhole requires immediate
maintenance.
Manhole access covered.
Locking mechanism
not working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove
One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 21 – STORMFILTER (CARTRIDGE TYPE)
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
Large access
doors/plate
Damaged or difficult
to open
Large access doors or plates cannot be
opened/removed using normal equipment.
Replace or repair access door so it
can opened as designed.
Gaps, doesn't cover
completely
Large access doors not flat and/or access
opening not completely covered.
Doors close flat and cover access
opening completely.
Lifting Rings missing,
rusted
Lifting rings not capable of lifting weight of door
or plate.
Lifting rings sufficient to lift or
remove door or plate.
Inspection Frequency Maintenance conditions are site-specific,
depending on pollutant loading.
FIRST YEAR POST CONSTRUCTION: Monthly
during wet season, every other month during dry
season
FOLLOWING FIRST YEAR: Continue monthly
until site-specific frequency is established, then
follow that schedule
AT A MINIMUM, FOLLOWING FIRST YEAR:
Annually (or quarterly if used as primary
treatment) and following significant storms.
Inspect Stormfilter facility for any
maintenance deficiencies; maintain
or replace as required per
established site-specific schedule
and manufacturer’s requirements.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 22 – BAFFLE OIL/WATER SEPARATOR
Maintenance
Component
Defect Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Any trash or debris which impairs the function of
the facility.
Trash and debris removed from
facility.
Contaminants and
pollution
Floating oil in excess of 1 inch in first chamber,
any oil in other chambers or other contaminants
of any type in any chamber.
No contaminants present other than
a surface oil film.
Vault Treatment
Area
Sediment
accumulation
Sediment accumulates exceeds 6 inches in the
vault.
No sediment in the vault.
Discharge water not
clear
Inspection of discharge water shows obvious
signs of poor water quality- effluent discharge
from vault shows thick visible sheen.
Effluent discharge is clear.
Trash or debris
accumulation
Any trash and debris accumulation in vault
(floatables and non-floatables).
Vault is clear of trash and debris.
Oil accumulation Oil accumulations that exceed 1 inch, at the
surface of the water in the oil/water separator
chamber.
No visible oil depth on water.
Vault Structure Damage to Wall,
Frame, Bottom,
and/or Top Slab
Cracks wider than ½-inch or evidence of soil
particles entering the structure through the
cracks, or maintenance/inspection personnel
determines that the vault is not structurally
sound.
Vault replaced or repaired to design
specifications.
Baffles damaged Baffles corroding, cracking, warping and/or
showing signs of failure as determined by
maintenance inspection personnel.
Repair or replace baffles to
specifications.
Gravity Drain Inoperable valve Valve will not open and close.Valve opens and closes normally.
Valve won’t seal Valve does not seal completely.Valve completely seals closed.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place.
Any open manhole requires immediate
maintenance.
Manhole access covered.
Locking mechanism
not working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does
not work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove
One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
Large access
doors/plate
Damaged or difficult
to open
Large access doors or plates cannot be
opened/removed using normal equipment.
Replace or repair access door so it
can opened as designed.
Gaps, doesn't cover
completely
Large access doors not flat and/or access
opening not completely covered.
Doors close flat and cover access
opening completely.
Lifting Rings missing,
rusted
Lifting rings not capable of lifting weight of door
or cover/lid.
Lifting rings sufficient to lift or
remove cover/lid.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR
Maintenance
Component
Defect Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Any trash or debris which impairs the function of
the facility.
Trash and debris removed from
facility.
Contaminants and
pollution
Floating oil in excess of 1 inch in first chamber,
any oil in other chambers or other contaminants
of any type in any chamber.
No contaminants present other than
a surface oil film.
Vault Treatment
Area
Sediment
accumulation in the
forebay
Sediment accumulation of 6 inches or greater in
the forebay.
No sediment in the forebay.
Discharge water not
clear
Inspection of discharge water shows obvious
signs of poor water quality - effluent discharge
from vault shows thick visible sheen.
Repair function of plates so effluent
is clear.
Trash or debris
accumulation
Trash and debris accumulation in vault
(floatables and non-floatables).
Trash and debris removed from
vault.
Oil accumulation Oil accumulation that exceeds 1 inch at the water
surface in the in the coalescing plate chamber.
No visible oil depth on water and
coalescing plates clear of oil.
Coalescing Plates Damaged Plate media broken, deformed, cracked and/or
showing signs of failure.
Replace that portion of media pack
or entire plate pack depending on
severity of failure.
Sediment
accumulation
Any sediment accumulation which interferes with
the operation of the coalescing plates.
No sediment accumulation
interfering with the coalescing
plates.
Vault Structure Damage to Wall,
Frame, Bottom,
and/or Top Slab
Cracks wider than ½-inch and any evidence of
soil particles entering the structure through the
cracks, or maintenance inspection personnel
determines that the vault is not structurally
sound.
Vault replaced or repaired to design
specifications.
Baffles damaged Baffles corroding, cracking, warping and/or
showing signs of failure as determined by
maintenance/inspection person.
Repair or replace baffles to
specifications.
Ventilation Pipes Plugged Any obstruction to the ventilation pipes.Ventilation pipes are clear.
Shutoff Valve Damaged or
inoperable
Shutoff valve cannot be opened or closed. Shutoff valve operates normally.
Inlet/Outlet Pipe Sediment
accumulation
Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet
pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged Cracks wider than ½-inch at the joint of the
inlet/outlet pipes or any evidence of soil entering
at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at
the joint of the inlet/outlet pipe.
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place.
Any open manhole requires immediate
maintenance.
Manhole access covered.
Locking mechanism
not working
Mechanism cannot be opened by one
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Mechanism opens with proper tools.
Cover/lid difficult to
remove
One maintenance person cannot remove
cover/lid after applying 80 lbs of lift.
Cover/lid can be removed and
reinstalled by one maintenance
person.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR
Maintenance
Component
Defect Condition When Maintenance is Needed Results Expected When
Maintenance is Performed
Large access
doors/plate
Damaged or difficult
to open
Large access doors or plates cannot be
opened/removed using normal equipment.
Replace or repair access door so it
can opened as designed.
Gaps, doesn't cover
completely
Large access doors not flat and/or access
opening not completely covered.
Doors close flat and cover access
opening completely.
Lifting Rings missing,
rusted
Lifting rings not capable of lifting weight of door
or plate.
Lifting rings sufficient to lift or
remove door or plate.
NO. 24 – CATCH BASIN INSERT
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Media Insert Visible Oil Visible oil sheen passing through media Media inset replaced.
Insert does not fit
catch basin properly
Flow gets into catch basin without going through
media.
All flow goes through media.
Filter media plugged Filter media plugged.Flow through filter media is normal.
Oil absorbent media
saturated
Media oil saturated.Oil absorbent media replaced.
Water saturated Catch basin insert is saturated with water, which
no longer has the capacity to absorb.
Insert replaced.
Service life exceeded Regular interval replacement due to typical
average life of media insert product, typically one
month.
Media replaced at manufacturer’s
recommended interval.
Seasonal
maintenance
When storms occur and during the wet season. Remove, clean and replace or install
new insert after major storms,
monthly during the wet season or at
manufacturer’s recommended
interval.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 25 – DRYWELL BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Plugging, obstructions Any cause limiting flow into drywell.Drywell able to receive full flow prior
to and during wet season.
Site Trash and debris Trash or debris that could end up in the drywell
is evident.
No trash or debris that could get into
the drywell can be found.
Pipes Inlet is plugged The entrance to the pipe is restricted due to
sediment, trash, or debris.
The entrance to the pipe is not
restricted.
Vegetation/roots Vegetation/roots that reduce free movement of
water through pipes.
Water flows freely through pipes.
Plugged Sediment or other material prevents free flow of
water through the pipe.
Water flows freely through pipes.
Broken or joint leaks. Damage to the pipe or pipe joints allowing water
to seep out.
Pipe does not allow water to exit
other than at the outlet.
Structure Basin leaks Holes or breaks in the basin allow water to leave
the basin at locations other than per design.
Basin is sealed and allows water to
exit only where designed.
Filter Media Filter media plugged Filter media plugged.Flow through filter media is normal.
Inspection Frequency Annually and prior to and following significant
storms.
Inspect drywell system for any
defects of deficiencies.
NO. 26 – GRAVEL FILLED INFILTRATION TRENCH BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Blocking, obstructions Debris or trash limiting flow to infiltration trench. Infiltration trench able to receive full
flow prior to and during wet season.
Site Trash and debris Trash or debris that could end up in the
infiltration trench is evident.
No trash or debris that could get into
the infiltration trench can be found.
Pipes Inlet is plugged The entrance to the pipe is restricted due to
sediment, trash, or debris.
The entrance to the pipe is not
restricted.
Vegetation/roots Vegetation/roots that reduce free movement of
water through pipes.
Water flows freely through pipes.
Plugged Sediment or other material prevents free flow of
water through the pipe.
Water flows freely through pipes.
Broken or joint leaks. Damage to the pipe or pipe joints allowing water
to seep out.
Pipe does not allow water to exit
other than at the outlet to the trench.
Structure Flow not reaching
trench
Flows are not getting into the trench as
designed.
Water enters and exits trench as
designed.
Cleanout/inspection
access does not allow
cleaning or inspection
of trench
The cleanout/inspection access is not available. Cleanout/inspection access is
available.
Filter Media Filter media plugged Filter media plugged.Flow through filter media is normal.
Inspection Frequency Annually and prior to and following significant
storms.
Inspect infiltration trench system for
any defects of deficiencies.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 27 – GRAVEL FILLED DISPERSION TRENCH BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Blocking, obstructions Debris or trash limiting flow to dispersion trench
or preventing spreader function.
Dispersion trench able to receive full
flow prior to and during wet season.
Site Trash and debris Trash or debris that could end up in the
dispersion trench is evident.
No trash or debris that could get into
the dispersion trench can be found.
Pipes Inlet is plugged The entrance to the pipe is restricted due to
sediment, trash, or debris.
The entrance to the pipe is not
restricted.
Vegetation/roots Vegetation/roots that reduce free movement of
water through pipes.
Water flows freely through pipes.
Plugged Sediment or other material prevents free flow of
water through the pipe.
Water flows freely through pipes.
Broken joint or joint
leaks.
Damage to the pipe or pipe joints allowing water
to seep out.
Pipe does not allow water to exit
other than at the outlet to the trench.
Cleanout caps Cleanout caps are broken, missing, or buried. Cleanout caps are accessible and
intact.
Structure Flow not reaching
trench
Flows are not getting into the trench as designed. Water enters and exits trench as
designed.
Perforated pipe
plugged
Flow not able to enter or properly exit from
perforated pipe.
Water freely enters and exits
perforated pipe.
Flow not spreading
evenly at outlet of
trench
Outlet flows channelizing or not spreading evenly
from trench.
Sheet flow occurs at the outlet of the
trench.
Cleanout/inspection
access does not allow
cleaning or inspection
of perforated pipe
The cleanout/inspection access is not available. Cleanout/inspection access is
available.
Filter Media Filter media plugged Filter media plugged.Flow through filter media is normal.
Inspection Frequency Annually and prior to and following significant
storms.
Inspect dispersion trench system for
any defects of deficiencies.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 28 – NATIVE VEGETATED SURFACE / NATIVE VEGETATED LANDSCAPE BMP
Maintenance
Component
Defect or Problem Condition When Maintenance is Needed Results Expected When
Maintenance Is Performed
Site Trash and debris Trash and debris accumulated on the native
vegetated surface/native vegetated landscape
site.
Native vegetated surface site free
of any trash or debris.
Vegetation Native vegetation
type
Less than two species each of native trees,
shrubs, and groundcover occur in the design
area.
A minimum of two species each of
native trees, shrubs, and
groundcover is established and
healthy.
Native vegetated area Less than 90% if the required vegetated area has
healthy growth.
A minimum of 90% of the required
vegetated area has healthy growth.
Undesirable
vegetation
Weeds, blackberry, and other undesirable plants
are invading more than 10% of vegetated area.
Less than 10% undesirable
vegetation occurs in the required
native vegetated surface area.
Vegetated Area Soil compaction Soil in the native vegetation area compacted. Less than 8% of native vegetation
area is compacted.
Insufficient area Less than 3.5 square feet of native vegetation
area for every 1 square foot of impervious
surface.
A minimum of 3.5 square feet of
native vegetation area for every 1
square foot of impervious surface.
Excess slope Slope of native vegetation area greater than 15%. Slope of native growth area does
not exceed 15%.
Inspection Frequency Annually Inspect native vegetation area for
any defects of deficiencies
NO. 29 – PERFORATED PIPE CONNECTIONS BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Blocking, obstructions Debris or trash limiting flow into perforated pipe
system or outfall of BMP is plugged or otherwise
nonfunctioning.
Outfall of BMP is receiving
designed flows from perforated pipe
connection.
Inflow Inflow impeded Inflow into the perforated pipe is partially or fully
blocked or altered to prevent flow from getting
into the pipe.
Inflow to the perforated pipe is
unimpeded.
Pipe Trench Area Surface compacted Ground surface over the perforated pipe trench is
compacted or covered with impermeable material.
Ground surface over the perforated
pipe is not compacted and free of
any impervious cover.
Outflow Outflow impeded Outflow from the perforated pipe into the public
drainage system is blocked.
Outflow to the public drainage
system is unimpeded.
Outfall Area Erosion or landslides Existence of the perforated pipe is causing or
exasperating erosion or landslides.
Perforated pipe system is sealed off
and an alternative BMP is
implemented.
Inspection Frequency Annually and prior to and following significant
storms.Perforated pipe system is operating
as designed.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 30 – PERMEABLE PAVEMENT BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Surface cleaning/
vegetation control
Media surface vacuumed or pressure washed
annually, vegetation controlled to design
maximum. Weed growth suggesting sediment
accumulation.
No dirt, sediment, or debris clogging
porous media, or vegetation limiting
infiltration.
Porous Concrete,
Porous Asphaltic
Concrete, and
Permeable Pavers
Trash and debris Trash and debris on the pavement interfering
with infiltration; leaf drop in fall season.
No trash or debris interfering with
infiltration.
Sediment
accumulation
Sediment accumulation on the pavement
interfering with infiltration; runoff from adjacent
areas depositing sediment/debris on pavement.
Pavement infiltrates as designed;
adjacent areas stabilized.
Infiltration rate Pavement does not infiltrate at a rate of 10
inches per hour.
Pavement infiltrates at a rate greater
than 10 inches per hour.
Ponding Standing water for a long period of time on the
surface of the pavement.
Standing water infiltrates at the
desired rate.
Broken or cracked
pavement
Pavement is broken or cracked.No broken pavement or cracks on
the surface of the pavement.
Settlement Uneven pavement surface indicating settlement
of the subsurface layer.
Pavement surface is uniformly level.
Moss growth Moss growing on pavement interfering with
infiltration.
No moss interferes with infiltration.
Inflow Inflow to the pavement is diverted, restricted, or
depositing sediment and debris on the
pavement.
Inflow to pavement is unobstructed
and not bringing sediment or debris
to the pavement.
Underdrain Underdrain is not flowing when pavement has
been infiltrating water.
Underdrain flows freely when water
is present.
Overflow Overflow not controlling excess water to desired
location; native soil is exposed or other signs of
erosion damage are present.
Overflow permits excess water to
leave the site at the desired location;
Overflow is stabilized and
appropriately armored.
Permeable Pavers Broken or missing
pavers
Broken or missing paving blocks on surface of
pavement.
No missing or broken paving blocks
interfering with infiltration.
Level surface Uneven surface due to settlement or scour of fill
in the interstices of the paving blocks.
Pavement surface is uniformly level.
Compaction Poor infiltration due to soil compaction between
paving blocks.
No soil compaction in the interstices
of the paver blocks limiting
infiltration.
Dead grass Grass in the interstices of the paving blocks is
dead.
Healthy grass is growing in the
interstices of the paver blocks.
Inspection Frequency Annually and after large storms, and as needed
seasonally to control leaf drop, evergreen
needles etc.
Permeable pavement is functioning
normally.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 31 – BIORETENTION BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Vegetation Vegetation to be watered and pruned as
needed and mulch applied to a minimum of 2
inches to maintain healthy growth.
Healthy vegetation growth with full
coverage as designed.
Bioretention Area Trash and debris Trash and debris in the bioretention area; leaf
drop in the fall season.
No trash or debris In the bioretention
area.
Sediment
accumulation
Sediment accumulation in the bioretention area
interfering with infiltration.
Water in the bioretention infiltrates as
designed.
Ponding Standing water in the bioretention area for
more than two days.
Standing water infiltrates at the
desired rate.
Inflow Inflow not getting into bioretention;
debris/sediment blockage at inlet features;
native soil is exposed or other signs of erosion
damage is present.
Unobstructed and properly routed
inflow into bioretention area; inlet is
stabilized and appropriately armored.
Overflow outlet Overflow water not controlled by outlet
features; native soil is exposed or other signs
of erosion damage is present.
Outlet features control overflow;
overflow is stabilized and appropriately
armored.
Underdrain Underdrain is not flowing when bioretention
area has been infiltrating water.
Underdrain flows freely when water is
present.
Vegetation Plant health Plants not thriving across at least 80% of the
entire design vegetated area within the BMP;
overly dense vegetation requiring pruning.
Healthy water tolerant plants in
bioretention area, plants thriving
across at least 80% of the entire
design vegetated area within the
facility.
Plant species Plants not water tolerant species.Plants are water tolerant.
Weeds Weeds growing in bioretention area.No weeds in bioretention area.
Watering Planting schedule requires frequent watering
(approx. weekly Year 1, bimonthly Years 2 and
3) for new facilities, and as needed for
established plantings or dry periods
Plants are established and thriving
Pest Control Signs of pests, such as wilting or chewed
leaves or bark, spotting or other indicators;
extended ponding period encouraging
mosquitoes
Plant community is pest-free when
following an approved Integrated Pest
Management plan; bioretention
functioning normally and ponding
controlled as needed for pest control
Containment Berm
and Earthen Slopes
Erosion;Erosion occurring at earthen slopes or
containment berm side slope.
Erosion on the containment berm and
side slopes has been repaired and the
cause of the erosion corrected.
Voids created by
nuisance animals
(e.g., rodents) or tree
roots
Voids affecting berm integrity or creating leaky
pond condition
Voids have been repaired; facility is
free of nuisance animals following an
approved Integrated Pest
Management plan.
Settlement Any part of the containment berm top has less
than 6 inches of freeboard from the maximum
pond level to the top of the berm.
A minimum of 6 inches freeboard from
the maximum pond level to the top of
the berm.
Amended Soil Soil nutrients Soil not providing plant nutrients.Soil providing plant nutrients.
Bare spots Bare spots on soil in bioretention area.No bare spots, bioretention area
covered with vegetation or mulch
mixed into the underlying soil.
Compaction Poor infiltration due to soil compaction in the
bioretention area.
No soil compaction in the bioretention
area.
Inspection Frequency Annually and after large storms, and as
needed seasonally for pruning, plant
maintenance, pest control and to control leaf
drop, evergreen needles etc.
Bioretention facility is functioning
normally; plant community is thriving
and pest-free.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 32 – RAINWATER HARVESTING BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Storage volume No rain water in storage unit at the beginning of
the rain season.
Maximum storage available at the
beginning of the rain season (Oct.
1 st).
Collection Area Trash and debris Trash of debris on collection area may plug filter
system
Collection area clear of trash and
debris.
Filter Restricted or plugged Filter is partially or fully plugged preventing water
from getting in to the storage unit.
Filter is allowing collection water
into storage unit.
Inspection Frequency Annually and after large storms Rain harvesting equipment is
functioning normally.
Maintenance log A Maintenance log must be kept and available for
review by KC staff.
Maintenance log is kept and is
available to KC staff.
NO. 33 – ROCK PAD BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Trash and debris accumulated on rock pad site. Rock pad site free of any trash or
debris.
Rock Pad Area Rock pad size Rock pad is not 2 feet by 3 feet by 6 inches thick
or as designed.
Rock pad is 2 feet by 3 feet by 6
inches thick or as designed.
Vegetation Vegetation is seen growing in or through rock
pad.
No vegetation within rock pad area.
Rock Exposed soil Soil can be seen through the rock pad.Full thickness of the rock pad is in
place, no soil visible through rock
pad.
Inspection Frequency Annually and after large storms Rock pad is functioning normally.
NO. 34 – SHEET FLOW BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Trash and debris accumulated on the sheet flow
site.
Sheet flow site free of any trash or
debris.
Sheet flow area Erosion Soil erosion occurring in sheet flow zone.Soil erosion is not occurring and
rills and channels have been
repaired.
Concentrated flow Sheet flow is not occurring in the sheet flow zone. Sheet flow area is regraded to
provide sheet flow.
Inspection Frequency Annually and after large storms Rain harvesting equipment is
functioning normally.
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 35 – SPLASH BLOCK BMP
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Site Trash and debris Trash and debris accumulated on the splash
block.
Splash block site free of any trash or
debris.
Splash Block Dislodged Splash block moved from outlet of downspout. Splash block correctly positioned to
catch discharge from downspout.
Channeling Water coming off the splash block causing
erosion.
No erosion occurs from the splash
block.
Downspout water
misdirected
Water coming from the downspout is not
discharging to the dispersal area.
Water is discharging normally to the
dispersal area.
Inspection Frequency Annually and after large storms.Rain harvesting equipment is
functioning normally.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 36 – VEGETATED ROOF BMP (Retained from the 2009 SWDM for reference)
Maintenance
Component
Defect or Problem Conditions When Maintenance is Needed Results Expected When
Maintenance is Performed
Preventative Vegetation Vegetation to be watered and pruned as needed
to maintain healthy growth.
Healthy vegetation growth with full
coverage as designed.
Site Trash and debris Trash and debris has accumulated on the
vegetated roof.
Vegetated roof free of any trash or
debris.
Waterproof
Membrane
Leaking Waterproof membrane breached.Waterproof membrane has no tears
or holes allowing water through it.
Drainage Layer Drainage pathway Drainage layer flow plugged or obstructed. Drainage layer passing water with
no obstruction.
Drainage Overflow Drainage of overflow is obstructed.Overflow has no obstruction.
Growth Media Compaction Soil in the growth media area compacted. No part of the growth media is
compacted.
Erosion Growth media washed out.Growth media is not being washed
away.
Nutrients Plants are not thriving.Growth media has proper nutrients
to support plant growth.
Vegetation Vegetation Type Vegetation species not succulents, grass, herbs,
and/or wildflowers adapted to harsh conditions.
Correct species of vegetation is
used.
Vegetation Area Healthy vegetation covers less than 90% of
vegetation area.
Healthy vegetation covers more
than 90% of vegetation area.
Undesirable
Vegetation
Weeds and other undesirable plants are invading
more than 10% of vegetated area.
No undesirable vegetation occurs in
the vegetated area. No herbicides
or pesticides used to control
undesirable vegetation.
Special Vegetation Special vegetation not thriving.Special vegetation is kept healthy
and inspected on frequent
schedule.
Border Zone Access Border zone limited by vegetation overgrowth or
other means.
Border zone is kept open so
vegetated area is accessible.
Gravel Stop Containment Gravel stop does not contain overflow or divert it
to a designed outlet.
Overflow water is only exits from
the designed outlet.
Inspection Frequency Annually and after large storms.Rain harvesting equipment is
functioning normally.
Vegetation inspected monthly.Vegetation is kept healthy and
thriving.
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