HomeMy WebLinkAboutBLD2004-00799 Stormwater Management Plan STORMWATER CONTROL PLAN
CONSTRUCTION STORMWATER
POLLUTION PREVENTION PLAN
RYAN RESIDENCE
LOT 59
WOODLAND HILLS NO. 2
PORT TOWNSEND
JEFFERSON COUNTY
PERMIT # OLD
04 - 0799
JEFFERSON COUNTY DCD
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prepared by
ASP '`OVE.
APPROVED a
MICHAEL.I. ANDERSON SITE 'L •
STORM WATER PLAN PE&PLS No. 27665
JAN 2 •
JAN 2 6 2005 ��
IEFFER •N CO,
DEPT.OF COM !TY D VELOPMENT
JEFFERSON CO NTY sti;NATURE:
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TABLE OF CONTENTS
PROJECT OVERVIEW PAGE 3
EXISTING CONDITIONS SUMMARY PAGE 3
OFFSITE ANALYSIS PAGE 3
NEW DEVELOPMENT PAGE 4
3.1.1 STEP 1 ; 3.1.2 STEP 2 -3.1.3 STEP 3 -
3.1.4 STEP 4- PAGE 5
CONSTRUCTION SWPPP
3.1.5 STEP 5 - PAGE 7
3.1.6 STEP 6 ; 3.1.7 STEP 7 ; 3.1.8 STEP 8- PAGE 8
PERMANENT STORMWATER CONTROL PLAN PAGE 9
SPECIAL REPORTS AND OTHER PERMITS
O &MMANUAL
BOND QUANTITIES WORKSHEET
ATTACHMENT NO. 1 - STORMWATER PLAN
ATTACHMENT NO. 2 - JEFFERSON COUNTY BMP PACKET
ATTACHMENT NO. 3 - HYDROLOGY CALCULATIONS
ATTACHMENT NO. 4 - OPERATIONS &MAINTENANCE
MANUAL INSTRUCTIONS FOR
PROPOSED FACILITIES
2 of 9
r ,
STORMWATER CONTROL PLAN
ENGLE RESIDENCE
WOODLAND HILLS EC 1 5 2004
PROJECT OVERVIEW
The site is located in the community of Woodland Hills, Jefferson County and consists of Lot 59
of Woodland Hills Phase No. 2 on Parkridge Drive. The site is also known as Assessor's APN
999 900 159.
Currently, the property is undeveloped with ground cover consisting of native grasses, shrubs
and several trees of varying species. The property slopes from north to south with a modest grade
of approximately 4%toward the rear of the property away from Parkridge Drive. Current storm
water runoff is characterized by sheet flow. There is no contributing offsite storm water affecting
the site.
The proposed site drainage system consists of runoff from the roofs and gravel driveway areas
being directed to an underground infiltration trench. The drainage components will comply with
the "Large Project" standards of Jefferson County and with the"STORMWATER
MANAGEMENT MANUAL for WESTERN WASHINGTON" (SMM) dated August, 2001.
EXISTING CONDITIONS SUMMARY
There are no natural drainage features within or adjacent to the site. The soils are classified as
"Clallam gravelly sandy loam" (CmC) as shown on the Soil Survey of Jefferson County
prepared by the United States Department of Agriculture Soil Conservation Service. The
existing trees located outside of the building envelope,the septic field areas and the gravel
driveway area will be incorporated into the final landscaping of the property.
OFFSITE ANALYSIS
The downstream conditions consist of paved streets with roadway ditches and an underground
storm drain system that deposits the storm water onto the adjacent Rhody Drive, SR 19. This
system of graded roadway ditches do provide a measure of storm water quality by the flow
through the native grasses before the storm water enters Chimacum Creek and Port Townsend
Bay two miles downstream. With the proposed infiltration of the storm water on-site, it is not
anticipated that storm water drainage from the site will have any affect to the offsite setting.
NEW DEVELOPMENT
As provided in the SMM,
Section 3.1.1:
STEP 1- Collect and analyze Information on Existing Conditions:
As noted above,the site is characterized as undeveloped forested land, sloping to the southwest
3 of 9
at an approximate rate of 4 percent. The soil was identified in Clallam(CmC) soils. There are
no areas of high potential for erosion or sensitive/critical areas on the site.
Section 3.1.2 STEP 2-Prepare Preliminary Development Layout
The site plan has been prepared with the goals outlined in the SMM by setting the
proposed buildings at locations to minimize land disturbance. Please see attached site plan.
Section 3.1.3 STEP 3-Prepare Offsite Analysis
As noted,the downstream conditions are developed with streets and underground storm
drains in a rural environment. There are no anticipated downstream areas unduly affected by
development of this single family residence.
Section 3.1.4 STEP 4-Determine and Read the Applicable Minimum Requirements
As provided in Section 2.5,Section 2.4.1 All new development shall be required to
comply with Minimum Requirement#2. In addition, the following developments shall comply
with Minimum Requirements #1 through #10:
Projects that create or adds 5,000 square feet, or more, of new impervious surface area.
The project proposes 7,620 square feet of new impervious area. This proposed cover is
4.2%of the 4.22 acres (184,000 square feet) of the site, Lot59 of the Woodland Hills Phase 2.
SECTION 2.5.1 MINIMUM REQUIREMENT#1 :PREPARATION OF STORMWATER
SITE PLAN
Please see attached "Stormwater Plan—Ryan Residence".
SECTION 2.5.2 MINIMUM REQUIREMENT#2: CONSTRUCTION STORMWATER
POLLUTION PREVENTION(SWPP)
All new development and redevelopment shall comply with Construction SWPP
Elements #1 through #12 below:
Element 1:Mark Clearing Limits
The SWPP plan clearing limits consist of the outside edge of the gravel driveway and 20
feet outside the proposed single family residence perimeter.
Element 2:Establish Construction Access
At the location of the proposed driveway, a construction access will be established with
quarry spalls to minimize tracking sediments onto Parkridge Drive. See BMP C105 for
details.
4 of 9
DEC 1 5 2004
.; rC94
Element 3: Control Flow Rates
The proposed infiltration system is located approximately 300 feet from the
southwesterly property line. Any overflow from the new catch basin would approximate
sheet flow conditions and would not unduly affect the downstream properties. Further
downstream, the system of roadway ditches and the underground storm culvert system
should be sufficient to handle the proposed project. No net increase in flow is
anticipated.
Element 4:Install Sediment Controls
A silt fence will be set in place along the lower southwesterly boundary of the site prior
to the start of any construction to prevent siltation onto the adjoining property.
Element 5:Stabilize Soils
At the completion of the site grading for the building pads and subgrade for the paving
areas, the areas disturbed by the new construction will be seeded and maintained during
the remainder of the construction period. Upon completion of the residence and
driveway construction,the final landscaping of the site will be installed to stabilize the
soils.
As required by the SMM, from October 1 through April 30, no soils shall remain exposed
and unworked for more than 2 days. From May 1 to September 30, no soils shall remain
exposed and unworked for more than 7 days. The soils will be temporary seeded or
protected with plastic covering,
Element 6:Protect Slopes
No cut slopes are proposed.
Element 7:Protect Drain Inlets
The new catch basin will be protected with hay bales during construction. The driveway
accessing the site will be maintained in as clean as possible state to prevent sediment
tracking onto Parkridge Drive.
Element 8:Stabilize Channels and Outlets
The swales along the gravel driveway will be seeded upon completion of grading and
maintained through out the life of the project. If necessary, hay bales will also be utilized
to control sediment.
Element 9: Control Pollutants
As required by the SMM, all pollutants, including waste materials and demolition debris
5 of 9
that occur on-site during construction shall be handled and disposed of in a manner that
does not cause contamination of storm water.
Maintenance and repair of heavy equipment and vehicles involving oil changes and other
maintenance work shall be conducted using spill prevention measures such as drip pans.
Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment
system.
Element 10: Control De-watering
No de-watering is anticipated with this project.
Element 11:Maintain BMPs
All temporary and permanent erosion and sediment control BMPs shall be maintained
and repaired as needed to assure continued performance of their intended function. All
maintenance and repair shall be conducted in accordance with the Jefferson County
BMPs schedule attached to this plan.
Sediment control BMPs shall be inspected weekly or after a runoff-producing storm
event during the dry season and daily during the wet season.
All temporary erosion and sediment control BMPs shall be removed within 30 days after
final site stabilization is achieved or after temporary BMPs are no longer needed.
Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting
from removal of BMPs or vegetation shall be permanently stabilized.
Element 12:Manage The Project
No work shall commence until an approved site development and building permits have
been issued for the work. All aspects of this Stormwater Control Plan and the
Construction Stormwater Pollution Prevention Plan will be in place in accordance with
the sequencing of the work and will be properly maintained by the contractor during
construction and by the property owner upon completion and occupancy of the residence.
Section 3.1.5 STEP S-Prepare a Permanent Stormwater Control Plan
Existing Site Hydrology(developed area):
Lot 59 Area = 183,631 sft (gross) (4.22 ac.)
Soil type Clallam (CmC) -- Type "C"
Land cover : Forested
2 yr flow 0.01 cfs
100 yr flow : 0.10 cfs
2004
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Proposed Site Hydrology
Impervious areas: Driveway 3060 sft
Roof area 3840 sft
Deck 520 sft
Total 7620 sft 0.18 ac.
The runoff calculations are based on the following 24 hour rainfall parameters as
listed in the DOE Manual; 2 yr 1.00"; 10 yr 1.50"; 100 yr 2.50":
2 yr runoff 0.04 cfs developed
100 yr runoff 0.12 cfs developed
6 mo. runoff= 72% of 2 yr runoff=0.02 cfs
Performance Standards and Goals
The treatment facilities incorporated into this plan provide for a biofiltration swale along
the gravel driveway and capture of the stormwater runoff into an infiltration trench
Flow Control System
The plan provides for directing the stormwater away from the proposed new residence
and existing bluff area, toward the street as recommended in the referenced geologic
report. The infiltration trench is located in the southwest portion of the lot, adjacent to
the street, with an overflow pipe connected to the ditch in Quail Ridge Court. See
attached plan for details of construction. The foundation drains will be directed to the
street.
Water Quality System
The proposed swale along the new gravel driveway should provide treatment for the
minor flows from the driveway. The roof water is considered uncontaminated and
requires no treatment.
Conveyance System Analysis and Design
Capacity of 8"pvc outlet drain = 0.8 cfs
Capacity of biofiltration swale = 2.5 cfs
Section 3.1.6 STEP 6-Prepare a Construction Stormwater Pollution Prevention Plan
I 400'4
7of9
As noted in the SMM,the Construction SWPP must address the elements noted above in
Section 2.5.2 which addressed the 12 elements.
Section 3.1.7 STEP 7- Complete the Stormwater Site Plan
See attached site plan.
Section 3.1.8 STEP 8- Check Compliance with All Applicable Minimum Standards
This report has reviewed all the applicable requirements of the SMM and employed the
appropriate techniques to achieve the goals of the SMM.
SECTION 2.5.3 MINIMUM REQUIREMENT#3:SOURCE CONTROL OF POLLUTION
This report and plan is consistent with the intent of the SMM to prevent stormwater from
coming in contact with pollutants. As discussed above in the Elements, considerations
have been employed with respect to the equipment on the site during construction to
prevent pollutants entering the stormwater system.
SECTION 2.5.4 MINIMUM REQUIREMENT#4:PRESERVATION OF NATURAL
DRAINAGE SYSTEMS AND OUTFALLS
There are no natural drainage systems other than sheet flow across this property. The
stormwater flows will be captured on-site and infiltrated.
SECTION 2.5.5 MINIMUM REQUIREMENT#5: ON-SITE STORMWATER
MANAGEMENT
The SMM principle goal is to infiltrate where possible. This plan has incorporated
infiltration as a part of the storm water system. In addition, the owner will investigate the
possibility of incorporating the captured stormwater into on-site irrigation system thereby
further reducing any potential hydrologic downstream disruption that might accrue to this
proposed development.
SECTION 2.5.6 MINIMUM REQUIREMENT#6:RUNOFF TREATMENT
To mitigate the storm water flow greater than 5000 sf1 , all the roadway ditches on-site
will be planted with a native grass to provide biofiltration of the storm water flow prior to
entering the catch basin and the infiltration trench.
SECTION 2.5.7 MINIMUM REQUIREMENT#7: FLOW CONTROL
The infiltration of the increase in the 100 year flow will provide the flow control required
by the SMM.
EC 81492004
J i
SECTION 2.5.8 MINIMUM REQUIREMENT#8: WETLAND PROTECTION
No wetlands are associated with this project.
SECTION 2.5.9 MINIMUM REQUIREMENT#9:BASIN/WATERSHED PLANNING
There are is no designated basin stormwater plan for this area.
SECTION 2.5.10 MINIMUM REQUIREMENT#10: OPERATION AND MAINTENANCE
An Operation and Maintenance Section has been added below to this plan to provide
guidance to the property owner on their responsibilities with regard to the maintenance of
the grassy swales, the culverts,the catch basins and the infiltration trenches that
constitute the proposed system.
PERMANENT STORMWATER CONTROL PLAN
As noted,this entire report,the attachments and the plan provide for the Permanent
Stormwater Control Plan.
SPECIAL REPORTS AND OTHER PERMITS
There is no current Jefferson County master plan for this area.
O & M MANUAL
The attachments from Volume V,Section 4.6 provide for the Operations and
Maintenance Manual for the project.
BOND QUANTITIES WORKSHEET
As required by the Jefferson County.
ra P fiO4
ATTACHMENT I
SITE PLAN
DEC 1 5 2004
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ATTACHMENT III
HYDROLOGY CALCULATIONS
DEC 200d
Michael J.Anderson
PE&PLS No. 27665
330 Cleveland Street
Port Townsend, WA 908368 SHEET 1 of .44
RYAN RESIDENCE DRAINAGE PLAN
LOT 59, WOODLAND HILLS PHASE 2
IMPERVIOUS AREAS:
New residence 3840 sft
Deck 500
New driveway 3260
Total 7620 Al = 0.18 Ac
Total Lot Area 4.22 Ac
SOIL TYPE: CmC—Clallum Series— TYPE C
TYPE C RUNOFF CRITERIA:
Open 86
Impervious 98
WASHINGTON DOE MANUAL STORM DATA:
2 yr, 24 hour i = 1.00 in/hr
10 yr, 24 hour i = 1.75 in/hr
100 yr, 24 hour I = 2.50 in/hr
2 z
SBUH/SCS METHOD FOR COMPUTING RUNOFF HYDROGRAPH
STORM OPTIONS:
1 - S.C.S . TYPE-lA
2 - 7-DAY DESIGN STORM
3 - STORM DATA FILE
SPECIFY STORM OPTION:
1
S.C.S. TYPE-lA RAINFALL DISTRIBUTION
ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP( INCHES)
2 ,24 , 1 . 00
******************** S.C.S. TYPE-1A DISTRIBUTION ********************
********* 2-YEAR 24-HOUR STORM **** 1 . 00" TOTAL PRECIP. *********
ENTER: A(PERV) , CN(PERV) , A( IMPERV) , CN( IMPERV) , TC FOR BASIN NO. 1
0 . 18 , 86, 0 . 00 , 98 , 5
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A CN A CN
. 2 .2 86 . 0 . 0 98 . 0 5. 0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
. 00 7 . 83 129
ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
c : 2yr .pre
FILE ALREADY EXIST; OVERWRITE (Y or N) ?
Y
SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP
n
STORM OPTIONS :
- S.C.S. TYPE-lA
? - 7-DAY DESIGN STORM
3 - STORM DATA FILE y '
;PECIFY STORM OPTION:
;.C.S . TYPE-lA RAINFALL DISTRIBUTION
LATER: FREQ(YEAR) , DURATION(HOUR) , PRECIP( INCHES)
00 , 24 , 2 . 50
******************* S. C.S. TYPE-lA DISTRIBUTION ********************
******** 100-YEAR 24-HOUR STORM **** 2 . 50" TOTAL PRECIP. *********
NTER: A(PERV) , CN(PERV) , A( IMPERV) , CN( IMPERV) , TC FOR BASIN NO. 1
. 18 , 86 , 0 . 00 , 98 , 5 . 00
ATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) 3/;
A CN A CN
. 2 . 2 86 . 0 . 0 98 . 0 5 . 0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
. 06 7 . 67 812
ENTER Ed: ] [path] filename[ .ext ] FOR STORAGE OF COMPUTED HYDROGRAPH:
c : l00yr.pre
FILE ALREADY EXIST; OVERWRITE (Y or N) ?
y
SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP
n
STORM OPTIONS:
1 - S.C.S. TYPE-1A
2 - 7-DAY DESIGN STORM
3 - STORM DATA FILE
SPECIFY STORM OPTION:
1
S.C.S. TYPE-lA RAINFALL DISTRIBUTION
ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP( INCHES)
2 , 24 , 1 . 00
******************** S .C.S. TYPE-lA DISTRIBUTION ********************
********* 2-YEAR 24-HOUR STORM **** 1 . 00" TOTAL PRECIP. *********
ENTER: A(PERV) , CN(PERV) , A( IMPERV) , CN( IMPERV) , TC FOR BASIN NO. 1
0 . 00, 86 , 0. 18 , 98 , 5 . 00
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
. 2 A CN A CN
. 0 86. 0 . 2 98 . 0 5. 0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
. 04 7. 67 516
ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
2 : 2yr.pst
FILE ALREADY EXIST; OVERWRITE (Y or N) ?
k
SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP
;TORM OPTIONS:
- S.C.S. TYPE-1A
- 7-DAY DESIGN STORM
- STORM DATA FILE
aPECIFY STORM OPTION:
. C. S . TYPE-1A RAINFALL DISTRIBUTION
NTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP( INCHES)
100 , 24 , 2 . 500 ‘ /‘
******************** S .C. S. TYPE-1A DISTRIBUTION----------------------
********* 100-YEAR 24-HOUR STORM **** ********************
2 . 50" TOTAL PRECIP. *********
ENTER: A(PERV) , CN(PERV) , A( IMPERV) , CN( IMPERV) , TC FOR BASIN NO. 1
0. 00 ,86 , 0 . 18 , 98 , 5 . 00
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A CN A CN
. 2 . 0 86 . 0 . 2 98 . 0 5 . 0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
. 12 7. 67 1483
ENTER Ed: ] [path] filename[ . ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
c: 100yr.pst
FILE ALREADY EXIST; OVERWRITE_ (Y or N) ?
y
SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP
s
KING COUNTY DEPARTMENT OF PUBLIC WORKS
Surface Water Management Division
HYDROGRAPH PROGRAMS
Version 4 . 21B
1 - INFO ON THIS PROGRAM
2 - SBUHYD
3 - MODIFIED SBUHYD
4 - ROUTE
5 - ROUTE2
6 - ADDHYD
7 - BASEFLOW
8 - PLOTHYD
9 - DATA
10 - RDFAC
11 - RETURN TO DOS
CNTER OPTION:
0
ID FACILITY DESIGN ROUTINE
PECIFY TYPE OF R/D FACILITY:
- POND 4 - INFILTRATION POND
- TANK 5 - INFILTRATION TANK
- VAULT 6 - GRAVEL TRENCH/BED
VTER: EFFECTIVE STORAGE DEPTH( ft ) BEFORE OVERFLOW
2 . 0
ENTER: VERTICAL PERMEABILITY(min/in)
10 . 0
ENTER Ed: ] [path] filename[ .ext] OF PRIMARY DESIGN INFLOW HYDROGRAPH:
c: 100yr.pst
PRIMARY DESIGN INFLOW PEAK = . 12 CFS
ENTER PRIMARY DESIGN RELEASE RATE(cfs) :
0 . 06
ENTER NUMBER OF INFLOW HYDROGRAPHS TO BE TESTED FOR PERFORMANCE ( 5 MAXIMUM) :
1
ENTER [d : ] [path] filename[ .ext] OF HYDROGRAPH 1 :
c: 100yr.pst
ENTER TARGET RELEASE RATE(cfs) :
0 . 06
ENTER: NUMBER OF ORIFICES, RISER-HEAD( ft) , RISER-DIAMETER( in)
1 , 2 . 0 , 6
RISER OVERFLOW DEPTH FOR PRIMARY PEAK INFLOW = . 08 FT
SPECIFY ITERATION DISPLAY: Y - YES, N - NO
n
SPECIFY: R - REVIEW/REVISE INPUT, C - CONTINUE
c
INITIAL STORAGE VALUE FOR ITERATION PURPOSES: 576 CU-FT
SINGLE ORIFICE RESTRICTOR: DIA= 1 . 25"
PERFORMANCE: INFLOW TARGET-OUTFLOW ACTUAL-OUTFLOW PK-STAGE STORAGE
DESIGN HYD: . 12 . 06 . 06 2. 00
TEST HYD 1 : . 12 . 06 70
. 06 2 . 00 70
SPECIFY: D - DOCUMENT, R - REVISE, A - ADJUST ORIF, E - ENLARGE, S - STOP
3
PERFORMANCE: INFLOW TARGET-OUTFLOW ACTUAL-OUTFLOW PK-STAGE STORAGE
DESIGN HYD: . 12 .06 . 06 2. 00
TEST HYD 1 : . 12 .06 70
. 06 2 . 00 70
;TRUCTURE DATA: GRAVEL TRENCH/BED (30 PERCENT VOID VOLUME)
tISER-HEAD GRAVEL-BED-AREA STOR-DEPTH STORAGE-VOLUME
2. 00 FT 127. 4 SQ-FT 2 . 00 FT 76 CU-FT
;INGLE ORIFICE RESTRICTOR: DIA= 1 . 25"
tOUTING DATA:
TAGE(FT) DISCHARGE(CFS) STORAGE(CU-FT) PERM-AREA(SQ-FT) EC, ' ;V;,;
. 00 . 00 . 0 . 0
. 20 . 02 7. 6 127 . 4
. 40 . 03 15 . 3 127 . 4
. 60 . 03 22 . 9 127 . 4
. 80 . 04 30 . 6 127 . 4
• 1 . 00 . 04
38 . 2 127 .4 S 6/‘,,
1 . 20 . 05 45 . 9 127. 4
1 . 40 . 05 53 . 5 127 . 4
1 . 60 . 05 61 . 2 127.4
1 . 80 . 06 68 . 8 127. 4
2 . 00 . 06 76 . 5 127. 4
2 . 10 . 22 76 . 5 127 . 4
2. 20 . 49 76. 5 127 .4
2 . 30 . 58 76 . 5 127. 4
2 . 40 . 66 76 . 5 127. 4
2 . 50 . 74 76 . 5 127. 4
AVERAGE VERTICAL PERMEABILITY: 10 . 0 MINUTES/INCH
SPECIFY: F - FILE, N - NEWJOB, P - PRINT IF/OF, R - REVISE, S - STOP
s
KING COUNTY DEPARTMENT OF PUBLIC WORKS
Surface Water Management Division
HYDROGRAPH PROGRAMS
Version 4 . 21B
1 - INFO ON THIS PROGRAM
2 - SBUHYD
3 - MODIFIED SBUHYD
4 - ROUTE
5 - ROUTE2
6 - ADDHYD
7 - BASEFLOW
8 - PLOTHYD
9 - DATA
10 - RDFAC
11 - RETURN TO DOS
dh
•
ATTACHMENT IV
OPERATIONS & MAINTENACE
MANUAL INSTRUCTIONS
FOR
PROPOSED FACILITIES
DEC' rt `; 2004
No. 2- Infiltration
• Maintenance Defect Conditions When Maintenance Is Results Expected When
Component Needed Maintenance Is
Performed
General Trash & Debris See"Detention Ponds"(No. 1). See"Detention Ponds"
(No. 1).
Poisonous/Noxious See "Detention Ponds"(No. 1). See"Detention Ponds"
Vegetation (No. 1).
Contaminants and See"Detention Ponds"(No. 1). See"Detention Ponds"
Pollution (No. 1).
Rodent Holes See"Detention Ponds"(No. 1). See"Detention Ponds"
(No. 1)
Storage Area Sediment Water ponding in infiltration pond after Sediment is removed
rainfall ceases and appropriate time and/or facility is cleaned
allowed for infiltration. so that infiltration system
works according to
(A percolation test pit or test of facility design.
indicates facility is only working at 90% of
its designed capabilities. If two inches or
more sediment is present, remove).
Filter Bags(if Filled with Sediment and debris fill bag more than 1/2 Filter bag is replaced or
applicable) Sediment and full. system is redesigned.
Debris
Rock Filters Sediment and By visual inspection,little or no water flows Gravel in rock filter is
Debris through filter during heavy rain storms. replaced.
Side Slopes of Erosion See"Detention Ponds"(No. 1). See"Detention Ponds"
• Pond (No. 1).
Emergency Tree Growth See"Detention Ponds"(No. 1). See"Detention Ponds"
Overflow Spillway (No. 1).
and Berms over 4
feet in height.
Piping See"Detention Ponds"(No. 1). See"Detention Ponds"
(No. 1).
Emergency Rock Missing See"Detention Ponds"(No. 1). See"Detention Ponds"
Overflow Spillway (No. 1).
Erosion See"Detention Ponds"(No. 1). See"Detention Ponds"
(No. 1).
Pre-settling Facility or sump 6"or designed sediment trap depth of Sediment is removed.
Ponds and Vaults filled with Sediment sediment.
and/or debris
•
August 2001 Volume V—Runoff Treatment BMPs 4-33
No. 1 — Detention Ponds
Maintenance Defect Conditions When Maintenance Is Results Expected When
Component Needed Maintenance Is Performed
Beaver Dams Dam results in change or function of Facility is returned to design function.
the facility.
(Coordinate trapping of beavers and
removal of dams with appropriate
permitting agencies)
Insects When insects such as wasps and Insects destroyed or removed from site.
hornets interfere with maintenance
activities. Apply insecticides in compliance with
adopted IPM policies
Tree Growth Tree growth does not allow Trees do not hinder maintenance
and Hazard maintenance access or interferes activities. Harvested trees should be
Trees with maintenance activity(i.e., slope recycled into mulch or other beneficial
mowing, silt removal,vactoring, or uses (e.g., alders for firewood).
equipment movements). If trees are
not interfering with access or Remove hazard Trees
maintenance,do not remove
If dead,diseased,or dying trees are
identified
(Use a certified Arborist to determine
health of tree or removal
requirements)
Side Slopes Erosion Eroded damage over 2 inches deep Slopes should be stabilized using
of Pond where cause of damage is still appropriate erosion control measure(s);
present or where there is potential for e.g., rock reinforcement, planting of
continued erosion. grass,compaction.
• Any erosion observed on a If erosion is occurring on compacted
compacted berm embankment. berms a licensed civil engineer should
be consulted to resolve source of
erosion.
Storage Area Sediment Accumulated sediment that exceeds Sediment cleaned out to designed pond
10% of the designed pond depth shape and depth; pond reseeded if
unless otherwise specified or affects necessary to control erosion.
inletting or outletting condition of the
facility.
Liner(If Liner is visible and has more than Liner repaired or replaced. Liner is fully
Applicable) three 1/4-inch holes in it. covered.
.'1
• Aloe:pFis
August 2001 Volume V—Runoff Treatment BMPs 4-31
No. 8—Typical Biofiltration Swale S
Maintenance Defect or Condition When Recommended Maintenance to Correct
Component Problem Maintenance is Needed Problem
General Sediment Sediment depth exceeds 2 Remove sediment deposits on grass
Accumulation on inches. treatment area of the bio-swale. When
Grass finished,swale should be level from side
to side and drain freely toward outlet.
There should be no areas of standing
water once inflow has ceased.
Standing Water When water stands in the Any of the following may apply: remove
swale between storms and sediment or trash blockages, improve
does not drain freely. grade from head to foot of swale, remove
clogged check dams, add underdrains or
convert to a wet biofiltration swale.
Flow spreader Flow spreader uneven or Level the spreader and clean so that flows
clogged so that flows are not are spread evenly over entire swale width.
uniformly distributed through
entire swale width.
Constant When small quantities of Add a low-flow pea-gravel drain the length
Baseflow water continually flow through of the swale or by-pass the baseflow
the swale, even when it has around the swale.
been dry for weeks,and an
eroded, muddy channel has
formed in the swale bottom.
Poor Vegetation When grass is sparse or bare Determine why grass growth is poor and
Coverage or eroded patches occur in correct that condition. Re-plant with plugs
more than 10% of the swale of grass from the upper slope: plant in the
bottom. swale bottom at 8-inch intervals. Or re-
. seed into loosened,fertile soil.
Vegetation When the grass becomes Mow vegetation or remove nuisance
excessively tall (greater than vegetation so that flow not impeded.
10-inches);when nuisance Grass should be mowed to a height of 3 to
weeds and other vegetation 4 inches. Remove grass clippings.
starts to take over.
Excessive Grass growth is poor because If possible,trim back over-hanging limbs
Shading sunlight does not reach and remove brushy vegetation on
swale. adjacent slopes.
Inlet/Outlet Inlet/outlet areas clogged with Remove material so that there is no
sediment and/or debris. clogging or blockage in the inlet and outlet
area.
Trash and Trash and debris Remove trash and debris from bioswale.
Debris accumulated in the bio-swale.
Accumulation
Erosion/Scouring Eroded or scoured swale For ruts or bare areas less than 12 inches
bottom due to flow wide, repair the damaged area by filling
channelization,or higher with crushed gravel. If bare areas are
flows. large, generally greater than 12 inches
wide,the swale should be re-graded and
re-seeded. For smaller bare areas,
overseed when bare spots are evident, or
take plugs of grass from the upper slope
and plant in the swale bottom at 8-inch
intervals.
•
August 2001 Volume V—Runoff Treatment BMPs 4-39
r
No. 5-Catch Basins
Maintenance Defect Conditions When Maintenance is Needed Results Expected When •
Component Maintenance is
performed
General Trash& Trash or debris which is located immediately No Trash or debris located
Debris in front of the catch basin opening or is immediately in front of
blocking inletting capacity of the basin by catch basin or on grate
more than 10%. opening.
Trash or debris (in the basin)that exceeds 60 No trash or debris in the
percent of the sump depth as measured from catch basin.
the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case
less than a minimum of six inches clearance
from the debris surface to the invert of the
lowest pipe.
Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free
blocking more than 1/3 of its height. of trash or debris.
Dead animals or vegetation that could No dead animals or
generate odors that could cause complaints vegetation present within
or dangerous gases(e.g., methane). the catch basin.
Sediment Sediment(in the basin)that exceeds 60 No sediment in the catch
percent of the sump depth as measured from basin
the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case
less than a minimum of 6 inches clearance
from the sediment surface to the invert of the
lowest pipe.
Structure Top slab has holes larger than 2 square Top slab is free of holes •
Damage to inches or cracks wider than 1/4 inch and cracks.
Frame and/or
Top Slab (Intent is to make sure no material is running
into basin).
Frame not sitting flush on top slab, i.e., Frame is sitting flush on
separation of more than 3/4 inch of the frame the riser rings or top slab
from the top slab. Frame not securely and firmly attached.
attached
Fractures or Maintenance person judges that structure is Basin replaced or repaired
Cracks in unsound. to design standards.
Basin Walls/
Bottom
Grout fillet has separated or cracked wider Pipe is regrouted and
than 1/2 inch and longer than 1 foot at the secure at basin wall.
joint of any inlet/outlet pipe or any evidence of
soil particles entering catch basin through
cracks.
Settlement/ If failure of basin has created a safety, Basin replaced or repaired
Misalignment function, or design problem. to design standards.
Vegetation Vegetation growing across and blocking more No vegetation blocking
than 10% of the basin opening. opening to basin.
Vegetation growing in inlet/outlet pipe joints No vegetation or root
that is more than six inches tall and less than growth present.
six inches apart.
0
,,,,_ ,
4-36 Volume V—Runoff Treatment BMPs '`" August)1001
r •
No. 5— Catch Basins
•
Maintenance Defect Conditions When Maintenance is Needed Results Expected When
Component Maintenance is
performed
Contamination See"Detention Ponds"(No. 1). No pollutionpresent.
resent.
and Pollution
Catch Basin Cover Not in Cover is missing or only partially in place. Catch basin cover is
Cover Place Any open catch basin requires maintenance. closed
Locking Mechanism cannot be opened by one Mechanism opens with
Mechanism maintenance person with proper tools. Bolts proper tools.
Not Working into frame have less than 1/2 inch of thread.
Cover Difficult One maintenance person cannot remove lid Cover can be removed by
to Remove after applying normal lifting pressure. one maintenance person.
(Intent is keep cover from sealing off access
to maintenance.)
Ladder Ladder Rungs Ladder is unsafe due to missing rungs, not Ladder meets design
Unsafe securely attached to basin wall, standards and allows
misalignment, rust, cracks, or sharp edges. maintenance person safe
access.
Metal Grates Grate opening Grate with opening wider than 7/8 inch. Grate opening meets
(If Applicable) Unsafe design standards.
Trash and Trash and debris that is blocking more than Grate free of trash and
Debris 20% of grate surface inletting capacity. debris.
Damaged or Grate missing or broken member(s)of the Grate is in place and
• Missing. grate. meets design standards.
No. 6— Debris Barriers (e.g.,Trash Racks)
Maintenance Defect Condition When Maintenance is Results Expected When
Components Needed Maintenance is Performed
General Trash and Trash or debris that is plugging more Barrier cleared to design flow
Debris than 20% of the openings in the barrier. capacity.
Metal Damaged/ Bars are bent out of shape more than 3 Bars in place with no bends more
Missing inches. than 3/4 inch.
Bars.
Bars are missing or entire barrier Bars in place according to design.
missing.
Bars are loose and rust is causing 50% Barrier replaced or repaired to
deterioration to any part of barrier. design standards.
Inlet/Outlet Debris barrier missing or not attached to Barrier firmly attached to pipe
Pipe pipe
1
III i
DEC
2004
August 2001 Volume V—Runoff Treatment BMPs 4-37