Prelim Drainage ReportMountain Meadows
Yelm, WA
Preliminary Drainage Report
April 2005
Received
APR 1 S 2005
PRELIMINARY DRAINAGE REPORT
Yelm, Washington
April, 2005
Project Information
Project:
Prepared for:
Contact:
Mountain Meadows
Henrietta Morey
Henrietta Morey
P.O. Box 202
Kapowsin, WA 98344
(360) 507-9300
Reviewing Agency
Jurisdiction:
Project Number:
Project Contact
City of Yelm
Jim Gibson
(360) 468.8438
Project Engineer
Prepared by:
Olympic Engineering
1252 Devon Loop NE
Olympia, WA 98506
(360)870.2561
FAX (360) 706-9361
Contact: Chris M. Merritt, P.E.
OES Project No.: 05002
File Name: 05002~tdr.doc
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PROJECT ENGINEERS CERTIFICATION: I hereby certify that this
Preliminary Drainage Report for the Mountoin Meodoma Platin the City
of Yelm, Washington has been prepared by me or under my supervision
and meets the intent of the the WSDOE 1992 Stormwater Management
Manual, unless noted otherwise, and normal standards of engineering
practice. I understand that the jurisdiction does not and will not aeaume
liability for the euf5mency, emtabWty, or performance of drainage facilities
desigved for this development.
Table of Contents
PART I STORM DRAINAGE REPORT ......................................... ...............2
SECTION 1 -PROPOSED PROJECT DESCRIPTION...._ .......... ...............2
SECTION 2 -EXISTING CONDITIONS....__ ................_............ ............... 3
SECTION 3 -INFILTRATION RATES /SOILS REPORT............__...... ....3
SECTION 4- WELLS AND SEPTIC SYSTEMS .........................._......... ....4
SECTION 5 - FUEL TAMf.S .................................................................... ....4
SECTION 6 - SUB-BASIN DESCRIPTION ................................._......._. ....4
SECTION 7 -ANALYSIS OF 100-YEAR FLOOD .................. _............... ....4
SECTION a -AESTHETIC CONSIDERATIONS FOR FACILITIES..... ....5
SECTION 9 -DOWNSTREAM ANALYSIS ............................................. ....5
SECTION 10-COVENANTS, DEDICATIONS, EASEMENTS ..........._.. ....5
SECTION 11 -ARTICLES OF INCORPORATION.._.._ ...................._..... .._ 5
PART lI EROSION CONTROL REPORT ............................................... .....6
SECTION 1 - CONSTRUCTION SEQUENCE AND PROCEDURE ..... .....6
SECTION 2 -TRAPPING SEDIMENT ................................................... .....6
SECTION 3 -PERMANENT EROSION CONTROL .............................. .....7
SECTION 4 - GEOTECHMCAL ANALYSIS AND REPORT ................ .....7
SECTION 5 -INSPECTION SE@UENCE ......................................_...... .._.7
SECTION 6 -CONTROL OF POLLUTANTS .....................__.........._.... ..._ e
PART III MAINTENANCE PLAN ................................................ ................9
SECTION 1 -REQUIRED MAINTENANCE ........................._.... __....._..... 9
SECTION 2 - RESPONSIBLE ORGAMZATION ........................ .............. 18
SECTION 3- VEGETATION MANAGEMENT PLAN ................ .............. 18
SECTION 4- SOURCE CONTROL ................................._........... .............. 18
APPENDICES
Appendix 1-Preliminary Drainage
Caleulatiove
Appendix 2 - Soda Report
Appendix 3 -Vicinity Map
Appendix 3- Drainage Beein Map
ii
PART I STORM DRAINAGE REPORT
SECTION 1 -PROPOSED PROJECT DESCRIPTION
Prepared for: Henrietta Morey
Contact: Henrietta Morey
P.O. Box 202
Kapowsin, WA 98344
(360) 507-9300
Parcel Number: 21713310400, 21713310401, 21713310402
Total Site Area: 4.58 Acres
Zoned: R-6
Site Address: 8812 Burnett Road SW
Yelm, WA 98597
Required Permits: Grading, Utility, Building, etc.
Section, Township, Range: Section 13
Township 17 North
Range 1 East, W.M.
Project Overview
The project site ie located adjacent to Burnett Road in Yelm. The applicant
proposes to construct a new public roadway through the parcel and connect to the
road stub to the south; improve the Burnett Road frontage with roadway
widening, a sidewalk, and a planter strip; and to install utility services to serve 23
single family lots. Access to the proposed lots will be fmm the new public
roadway.
The development will be constructed in one phase. Construction will include
clearing and grading of the site, storm drainage improvements, underground
utilities, and paving. City of Yelm sanitary sewer and water mains will be
extended into the site to provide services to the residential lots.
Stormwater facilities will be constructed that consist of a proposed biofiltration
Swale and a wetvault for storm water treatment and an infiltration pond for
storage and infiltration of Stormwater runoff created by the new development. For
Stormwater design purposes, the proposed development has been subdivided into
three drainage sub-basins (see preliminary calculations in Appendix).
Stormwater Treatment
A proposed wetvault will provide treatment for atormwater runoff from Basin 'A'
(on-site roadway) and a proposed biofiltration Swale will provide treatment for
Basin 'B'. The proposed biofiltration Swale and wetvault exceeds the minimum
required surface area per the DOE manual. See Preliminary Drainage
Calculations in Appendix.
Stormwater Storage:
All atormwater runoff from the new roadways wdl be collected in a series of catch
basins and conveyed to the biofiltration Swale or wetpond for treatment.
Discharge from the biofiltration Swale and wetpond flaw into an infiltration pond
for atormwater detention and infiltration to groundwater. The proposed
Stormwater pond exceeds the minimum storage requirements per the DOE
manual. See Preliminary Drainage Calculations in Appendix.
Roof Runoff:
Roof runoff from each residential home will be tightlined to individual lot
infiltration drainrock drywells. The drywells shall be sized per Table 8.2 in the
DDECM using a soIl hydrologic Group "A" classification.
SECTION 2 -EXISTING CONDITIONS
The project site contains a duplex residence with a barn. The home will remain
and the barn will be demolished. Site relief is gently sloping 2-3% east to west,
varying from an elevation of 340' at the northeast property corner to 328' at the
southwest comer. Site vegetation consists of low cut pasture grasses. The project
site is bounded by single-family residential property to the east, west, and north,
and a recently approved preliminary plat for a single family development to the
south.
See Section 6 for description of off-site drainage to the property, if any.
There appear to be no creeks, lakes, ravines, gullies, or springs on-site. There
appear to 6e no drains, channels, or swales located within the project site, or
immediately adjacent to the proposed development.
The project site is located in an aquifer sensitive area based on review of Thurston
County Comprehensive Plan Map M-8. This project will comply with the
Stormwater treatment requirements of the DDECM.
SECTION 3 -INFILTRATION RATES /SOILS REPORT
The SoIl Conservation Service (SCS) soil survey of Thurston County classifies the
on-site sods as Spanaway Gravelly Sandy Loam (Hydrologic Group A). Soil
testing conSrmed the Spanaway series classification.
Two test pits were excavated by backhoe to a maximum depth of 144" below
existing grade. Soils were inspected by entering and visually logging each test pit
to a depth of four feet. Soils beyond four feet were inspected by examining
backhoe tailings. One double ring infiltration test was completed with a result of
82"/hr. A 20"/hr rate will be used for design. Test pit soil log data sheets and
infiltration test results are included in the Appendix of this report.
SECTION 4 -WELLS AND SEPTIC SYSTEMS
One on-site well waa found during our site investigation of the proposed plat
development and it will be abandoned during development.
Two wells within 200-feet of the project boundaries were found to the east and
southwest, however, it appears the 100-foot protective radii's fall outside this
project's boundaries.
Water and sanitary sewer services for the proposed project will be provided by the
City of Yelm.
A septic system currently serves the existing home. This will be abandoned per
Department of Health standards during development.
SECTION 5 -FUEL TANKS
No fuel tanks were located during our site inspection or soils work. The latest
"LUST" list (Leaking Underground Storage Tank) was reviewed and no listing for
the subject site was found.
SECTION 6 -SUB-BASIN DESCRIPTION
The project site is located within the Nisqually River Drainage Basin per the
Thurston County Geodata Center. From our site visit there were no signs of
existing drainage swales or channels on the proposed property. There did not
appeaz to be a significant amount of off-site runoff onto the site from the adjacent
north, east, and south properties.
Hazardous material handling or transportation is not expected in the area
tributary to the on-site detention facility.
SECTION 7 -ANALYSIS OF 100-YEAR FLOOD
The proposed site does not lie adjacent to or contain a stream on-site, therefore, it
has not keen identified as a 100-year flood hazard area.
SECTION 8 -AESTHETIC CONSIDERATIONS FOR FACILITIES
All disturbed pervious areas including the storm drainage tract and open space
area will be vegetated and landscaped.
SECTION 9 -DOWNSTREAM ANALYSIS
Preliminary calculations for the project stormwater treatment and storage
systems are included in the Appendix of this report.
All stormwater runoff generated by site development will be treated, stored, and
infiltrated on-site. In the event of a failure, storm water will overflow through the
catch basin rims and temporarily back onto the public roadway. Adjacent
properties should not be affected due to failure of the proposed stormwater system.
SECTION 10 -COVENANTS, DEDICATIONS, EASEMENTS
On-site drainage facilities will require routine maintenance. A maintenance
agreement will be prepared and finalized prior to final project approval.
SECTION 11 -PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION
In light of the residential nature of this project, special covenants covering
landscape, maintenance, signage, stormwater and site maintenance may be put in
place at the time of final platting. The Owner's and/or their representatives will
perform maintenance of these private storm drainage facilities.
PART II EROSION CONTROL REPORT
SECTION 1 -CONSTRUCTION SEQUENCE AND PROCEDURE
Proposed development of the residential property will include site grading and
erosion control measures designed to contain silt and soil within the project
boundaries during construction until permanent erosion control is in place.
Erosion sedimentation control will be achieved by a combination of
structurallvegetative cover measures and construction practices tailored to fit the
Bite.
Best Construction Management Practices (BMP's) will be employed to properly
clear and grade the site and to schedule construction activities. Before any
construction begins on~site, erosion control facilities shall first be installed. The
planned construction sequence is as follows:
1. Install rock construction entrance. Use 4" to S" diameter spans with 12"
minimum depth.
2. Install filter fabric fencing, where appropriate.
3. Construct temporary sedimentation basins, if necessary.
4. Clear site (grubbing and rough grading).
5. During November 1 through March 31, all disturbed areas greater than 5,000
sf that are to be left un-worked for more than twelve (12) hours, shall be
stabilized by one of the following: mulch, sodding, or plastic covering.
6. Install underground utilities (cable, telephone, power, etc.).
7. If applicable, provide catch basin protection by installing filter fabric and hay
bales around all inlets to drainage system.
8. After paving is complete, install landscape, sod and/or seed, and mulch all
disturbed areas.
9. Maintain all erosion control facilities until the entire Bite is stabilized and silt
runoff ceases.
10. Designate an area for washing of equipment and concrete trucks to control the
runoff and eliminate entry into storm drainage systems.
SECTION 2 -TRAPPING SEDIMENT
A stabilized construction entrance shall be installed at the entrance to the
proposed plat to prevent vehicles from tracking soil away from the disturbed
areas. If sediment is tracked onto public roadways, sediment shall, on a daily
basis, be swept or shoveled from paved surfaces and not washed down into the
roadside storm drainage system.
The contractor shall not be allowed to leave disturbed areas greater than 5,000 sf
that are to be left un-worked for more than twelve (12) hours uncovered during the
rainy season from November 1 through March 31. Mulch, sodding or plastic
covering will be used to prevent erosion in these areas.
During construction, the contractor will also be required to install filter fabric
fencing as needed, per the erosion control plan and as directed by the engineer, or
City Inspector
SECTION 3 -PERMANENT EROSION CONTROL & SITE RESTORATION
All disturbed areas will be paved, covered with a building or landscaped with
grass, shrubbery or trees.
SECTION 4 -GEOTECHNICAL ANALYSIS AND REPORT
There are no elopes exceeding 15% on-site, therefore, a geotechnical analysis was
deemed unnecessary.
SECTION 5 -INSPECTION SEQUENCE
In addition to the normal City inspections, the Project Engineer shall inspect the
facilities related to storm water treatment, erosion control, storage and
conveyance during construction. At a minimum, the following items shall be
inspected at the time specified:
1. The erosion control facilities shall be inspected before the start of clearing
and grading to ensure the following structures are in place:
a. Construction Entrance
b. Filter Fabric Fences
2. The conveyance systems will be inspected after construction of the facility,
but before the project is completed to ensure the following are in working
order:
a. Road Drainage Conveyance System
b. Biofdtration Swale
c. Wetvault
d. Infiltration Pond
3. The permanent site restoration measures should be inspected after
landscaping is completed.
A final inspection shall be performed to verify final grades, settings of structures
and all necessary information to complete Engineer's Construction Inspection
Report Form and Residential Agreement to maintain stormwater facilities. These
forma must be completed prior to final public works construction approval.
SECTION 6 -CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS
Washout from a concrete truck shall not be dumped into the storm drain, or onto
soil or pavement, which tames stormwater runoff. It can be dumped into a
designated area to be later backfilled or hardened and broken up for disposal into
a dumpster. The Contractor will be required to designate a wash down area for
equipment and concrete trucks.
PART III MAINTENANCE PLAN
SECTION 1 -REQUIRED MAINTENANCE
The following pages contain maintenance needs for most of the components that are
part of your drainage system, as well as for some components that you may not have.
Let us know if there are any components that are missing from these pages. Ignore
the requirements that do not apply to your system. You should plan to complete a
checklist for all system components on the following schedule:
1.Monthly fom November through April.
2.Once in late summer (preferably September).
3.After any major storm (use 1" in 24 hours as a guideline) items marked "S" only.
Using photocopies of these pages, check off the problems you looked for each time you
did an inspection. Add comments on problems found and actions taken. Keep these
"Checked" sheets in your files, as they wffi be used to write your annual report (due in
May). Some items do not need to be looked at every time an inspection is done. Use
the suggest frequency at the left of each item ae a guideline for your inspection.
You may call the jurisdiction for technical assistance. Please do not hesitate to call,
especially if you are unsure whether a situation you have discovered may be a
problem.
ATTACHMENT `A'
Inspection Period:
Number of Sheets Attached:
Date Inspected:
Inapecto~'s Signature:
MAINTENANCE PROGRAM
COVER SHEET
ATTACHMENT "A": MAINTENANCE PROGRAM
Maintenance Checklist for Conveyance Systems (Pipes, Ditches and Swales)
Frequevry Drainage JRegd Problem Gondi[w~To Check For Conditions That Should Exist
System Feature
M.S. Pipes J Sedimevt& Accumulated sediment that Pipe cleaved of aR sediment and
debrs seeds 20%of the diameter debda.
of the pipe.
M J Vegetation Vegetation that reduces free All vegetation removed so water
went orwater tnrongn rows rreety.
pipes.
p J Damaged Protective coating D Pipe repaired or replaced.
(rusted, bent damaged, rust ie sing
crushed) reihan 50%deteriorativn
to any part of pipe.
M J Any dent that sigvficantjy Pipe repaired or replaced.
impedes Oow (ie., devreases
tfie ewes section area of pipe
by more tMv 20%).
M J Pipe has major masks or Pipe repaired or replaced.
tears allowing groundwater
leakage.
M.S. Swales J Traeh& Dumping of yard wastes such Remove trash and debris and
debris as grass chppinge and dispose ae prescribed by County
branches inro Swale. Waste Mavagemevt 6ectiov.
Unsightly accumulation of
non-degradable materials
such as glass, plastic, metal,
foam and mated paper.
M J Sediment Accumulated sediment chat Swale cleaved of all sediment and
buildup seeds 20%of the design debris so that it matcbes design.
depth.
M J Vegetation Grass rover is spazse and Aerate spJS and reseed and mulch
not growing weedy or areas are bare areas. Maintain grass height
or overgrown vergrown with woody a[ a minimum of 6" for best
vegetation. srormwater treatment. Remove
woody growth, rerenmur and
seed as nereseary.
M J Convemivn Swale has been filled iv or If possible, speak with homeowner
by home- blocked by abed, woodpile, and request that Swale area be
nerm shrvbbery, etc. restored. Contact County to
compatible report problem d not rectified
voWntarily.
A J Swale does Water stands in Swale or A survey may be needed to cbeck
no[ drain Row velocity is very slow. grades. Grades need m be in 1%
Stagnation occurs. range 3 possible. IIgrade is less
than 1%, under dram may need
m be installed.
I[you are unsure whether a problem exists, please contast the dvrisdictiov and ask for teehmwl assistamn.
ATTACHMENT "A" (CONTINUED)
Maintenance Checklist for Catch Basins and Inlets
Frequenry Dcainage J lieq'd Problem Cavditiovs To Check Fo+ Cmditions That 3honld Exist
Byatem Feature
M,S General J Trash, Trash or debris iv front ofthe No trash or debris !orated
debris, end catch basin opening is blacking medistely in front of catch
sediment capacity by more tnan 10%. basin opevivg. Grate ie kept
in or on clean and allows water [o
bas enter.
M J Sediment or debris (in the Na sediment or debris in the
basin) that exceeds 1/3 the eaten basin. Catch basiv is
depth from the bottom of basin dug out avd clean.
to invert of the !awes[ pipe into
out of tM basin.
M,S J Tash or debris in avy inlet or Inlet and outlet pipes free of
pipe blocking more than 1/'d o[ trash or debris.
its height.
M J Structural Corver of frame extends more Frame ie evev with curb.
damage m than &4 inch past curb face
frame info the street (V applicable).
and/or nip
slab
M J Top slab Has Holes larger than 2 Tap slab is free of holes and
square ivchee or cracks aide: cracks.
than ll4 inch (intent is [o make
re ell material ie ruvving
info the basin).
M J Frame not sitting Busn on Wp Frame ie sitting flush on top
slab, i.e., sepazatiov of more slab.
than 3~4 inch of [he frame from
the top slab.
p J Cracks in Cracks wider than ll2 ivch and Basin replaced or repafred [o
basin lavgertnan 3 feet, any evidence design standards. Covtact a
walls! ofeoil particles entering catch Drokssional evgineer 6r
botom basin tluough cracks, or evaluation.
maintenanw pe:eonyudges
tnat atrnrenre is mm~nna.
p J Cracks wider than 1/2 inch and No cracks mare than ll4 inch
longer [Han 1 foot et the joint of wide at the joint of ivleUoutlet
any iNetloutlet pipe or any pipe.
evidence of soil paRir]ea
entering catch basin through
acks.
p J Settlement Basin hoe settled more than I Basin replaced or repaired to
Imisaligrv innor hasrotated more than2 design standardsContacts
men[ ivchee out of aBg~went. professio~ml engineer for
evaluation.
Frequency Drainage
Sye[em Feature J Req'd Problem Conditions To Check For Conditions That Should Exist
M,S J Foe harard Presence of chemicals such No mloq odor, or sludge. basin is
r other naNral gas, ail, and dug out and clean.
pollution gasoline. Obnoxious mlor,
odoq or eWdge voted.
M,S J Outlet pipe is Vegetation or roots growing No ~egeratiov or root growth
clogged with vivletloutlet pipe joints present.
vegetation that is more than six ivchee
taR and less than au inches
apart.
If you are unsure wMther a problem exists, please contact the Jurisdiction and ask for technical assistance.
Comments:
Eev A=Annual (March or April preferred)
M =Monthly (see schedule)
5 = Aker major storms
ATTACHMENT "A" (CONTINUED)
Maintenance Checklist for Grounds (Landscaping)
Fmquewy Drainage J Problem Covditiene [o Check Fox Conditiene Tha[SImWd Exist
Syaram
Pastaza
M General J Weeds Weeds growing in more than Weeds present iv less than 5%o[
(nonpoisovoua) 20%of the landscaped area the Lrvdacaped area.
([roes avd shrubs oily).
M J Safety hazard Any presevice of poivin iry or No poisonous vegetation or
other poisonous vegetation or mast[ nests present in
need vests. landscaped area.
M,S J Trash or litter See Ponds Checklist. See Povds Checklist.
M,S J Erosiov of Noticeable rills are seen in Causes oferoaion are identi5ed
Ground Surface landscaped areas. avd steps takev to slow
dowdspread out the water.
Eroded areas are filled,
mvtoured, and seeded.
A Trees and J Damage Limbs or parts of trees or Trim treedahrvbs to reemre
shrubs shrubs thataresplit o: shace~ Replace treeyshrube
brokev which a8ect more with severe damage.
than 26%of the Vital foliage
of the tree or shrub.
M J Trees or shrubs [hat have Replavt tree, inspecting for
beau blown down or knocked irpury to stem or roots. Replace
over if severely damaged.
q J Trees or shrubs which are Place stakes and mbbercoated
not adequately supported or ties ereund young treea'ahrube
areleaning over, causing for support.
exposure o[the motr-
If you are vnswe whe[be: a problem exists, please contact the Jwisdstion and ask for technical assistance.
Comments
Kev
A= Amual (March or April preferred)
M =Monthly (see schedule)
5 =After major storms
ATTACHMENT "A" (CONTINUED)
Maintenance Checklist for Energy Dissipaters
Freq. Drainage ~ Problcm Conditions to Check For Conditions That Should Exist
System
Feature
A Rock Pad ~ Missing or Only one layer of rock exists Replace rocks m design
moved rock above native soil in area 5 standard.
square feet or larger, or any
exposure of votive soil.
A Rock-Belled Missing or Trevch is not NII of rock. Add large rock (t30 Ib. each) so
trench for moved mck Iha[ rock is visible above edge
discharge from of trench.
pond
M Dispersion Pipe plugged Accumulated sedimrn[lhat Pipe Cleaned/flushed
ttrnch with sediment exceeds 20%of the design
depth.
M Perforations Over U2 of perforations in Clean or replace perforated pipe.
pluggcd pipe are plugged with debris
and sediment.
M,S Nat disoharging Visual evidence of ware[ Trrnch must be redesigned or
water properly discharging at concentrated rebuih m standard. Elevation of
poins along trench (normal lip of lrevoh should be the same
condition is a "shee[flow" of (flat) at all points.
water elovg nevch). Iutrnt
is to prevent erosion
damage.
M,5 Water Flows out Maimm~ance person Facility must be rcbuilt or
top of observes water Flowing out redesigned to standards. Pipe is
"distributor" during any smvn less than probably plugged or damaged
catch basin fie design stove or its and needs replacement.
causing or appears likely to
cause damage.
M,S Receiving azea Water in receiving area is Stabilim slope with grass or
over-saNrated causing or has potential of othtt vege[atioq ar mck if
causing landslide. condition is severe.
If you are unsure whether a problem exists, pleaze contact the Jurisdiction and ask for technical assistance.
Comments:
Key: A =Annual (March or April pmferred)
M =Monthly (see schedule)
S = Afltt major storms
ATTACHMENT "A" (CONTINUED)
Maintenance Checklist for Ponds
Freq. Drainage ~ Problem Conditions to Check For Conditions Thai Should Exist
System
Feature
M.S. Grneral ~ Trash & debris Dumping of yard waztes Remove hash and debris and
buildup in pond such az grazs clippings and dispose as prescribed by County
branches into bazin. Waste Management Section
Unsightly accumulation of
non-degradable materials
such as glass, plastic, rnetel,
foam, and coated paper.
M.S. ~ Trazh rack Bar screen ovtt outlet more Replace screen. Remove trazh
plugged or than 25 % covered by debris and debris and dispose as
missing or missing. prescribed by County Waste
Managemrnl Section.
M ~ Poisonous Any poisonous vegetation Remove poisonous vegetation.
vegetation which may constitute a Do not spray chemicals on
haezrd to the public. vegetation wiNout obtaining
Examples of poisonous guidance from the Cooperative
vegetation include: tansy Extension Service and approval
regwort, poison oak, from the County.
stinging nettles, devilsclub
M.S. ~ Fire hoard or Presence of chemicals such Find sources of pollution and
pollution as natural gas, ail, and eliminate them Water is free
gasoline, obnoxious color, from noticeable color, odor, or
odor, or sludge noted. contantination.
M ~ Vegetation not For grassy ponds, grass For grassy ponds, selectively
growing or is cover is sparse and weedy [hatch, aerate, and reseed ponds.
overgrown or is ovttgrown. For Grass cutting unnecessary unless
wetland ponds, plants are dictated by aesthetics. For
sparse or invasive species wetland ponds, hand-plan[
are presem. nursery-grown wetland plants in
bare areaz. ContaM the
Coopemdve Extension Service
far direction in invazive species
such as purple looseime and reed
canary gross. Pond bottoms
should have uniform dense
coverage of desired plant species.
M ~ Rodent holes Any evidence of rodent Rodrnts deshoyed and dam or
holes if facility is acting as berth repaired. Contact the
a dam or berth, or any Thurston County Health Dep[.
evidence ofwattt piping for guidance.
through dam or berth via
rodrn[holes.
M Insects When insects such az wasps Insects destroyed or removed
and hornets iv[erfere with horn site. Contact Cooperative
maintenance activities, or Extension Service for guidance.
when mosquitoes become a
nuisance.
A ~ Tree Growth Tree growth does not allow Trees dv not hinder mainrnance
maintenance access or activities. Selectively cultivate
interferes with maintenance bees such az alders for firewood.
ectiviry (i.e., slope mowing,
silt removal, or ui men[
Freq. Drainage J Problem Conditions to Check For Conditions That Should Exist
System
Feature
movements). If trees are
not interfering with awess,
leave trees alone.
M Side slopes of J Erosion on Check around inlets and Find causes of erosion and
pond berms or at outlets for signs of erasion. eliminaze chem. Then slopes
entrance/ Check berms for signs of should be stabilized by using
exit sliding or settling. Action appropriate erosion control
is needed where eroded measure(s); e.g., rock
damage over 2 inches deep reivforcemevt, plentivg of Bass,
and where there is potential compaction.
for continued erosion.
M Storagearea J Sediment Accumulated sediment that Sediment cleaned ovt to designed
buildup in pond exceeds 10% of the pond shape and depth; pond
designed pond depth. reseeded if necessazy to conhol
Buried or partially buried erosion.
outlet structure probably
indicates significant
sedimrnt deposits.
A Pond dikes J Settlements Any part of dike which has Dike should be built back to the
settled 4 inches lower than design elevation.
[he design elevation.
A Emer-gency J Rock missing Only one layer of rock Replace rocks to design
overflow/ exists above native soil in standazds.
spillway area 5 square feet or larger,
or any exposure of native
soil.
One time Emer-gency J OverFlow Side of pond has no area Contact County for guidance.
overflow/ missing with large rocks to handle
spillway emergrncy overFlows.
If you are unsure whether a problem ezis[s, please comact the Iurisdiction and ask for technical assistance.
Commrnts:
Key: A=Annual (March or April prekrted)
M =Monthly (see schedule)
S = AFltt major storms
SECTION 2 -RESPONSIBLE ORGANIZATION
The owners or ownei s representative shall be responsible for the operation and
maintenance of all on-site drainage facilities.
SECTION 3 -VEGETATION MANAGEMENT PLAN
All disturbed pervious areas within the site will be landscaped to provide an
aesthetically pleasing environment.
SECTION 4 -SOURCE CONTROL
Warning signs (e.g., "Dump No Waste -Drains to Groundwater) will be embossed
or painted on or adjacent to all storm drain inlets and will be repainted
periodically as necessary.
Appendix I
Preliminary Drainage Calculations
DRAINAGE CALCULATIONS
The following calculations were based on the requirements contained in the WSDOE 1992
Stormwater Management Manual.
DESIGN AND BASIN INFORMATION SUMMARY:
Poet Development Basin Area Summary (Acres}
A B Total
Impervious Roadway 0.50 0.13 0.63
Concrete Sidewalk 0.09 0.02 0.11
Impervious Driveway 0.25 0.05 0.30
Impervious Roof Area 0.82 0.16 0.98
Disturbed Pervious 2.46 0.47 2.93
Total 4.12 0.83 4.96
Roof Area: 2,000 sf/lot
Driveway Area: 600 sf/lot
Soil Classification:
SCS Soil Classification: Spanaway Gravelly Sandy Loam
Hydrologic Group: A
Design Infdtration Rate: 20"/hr
BASIN `A' WATER QUALITY CALCULATIONS
Minimum Stormwater Treatment Area Required:
StormShed software was used to model the mnoff from a portion of the on~site
roadway, sidewalks, and driveway areas. The 6-month storm event resulted in a
peak volume of 3,217 cf.
The DOE manual, section III-4.3.2, requires that "the permanent pool volume
equals the runoff volume from the 6-month, 24-hour design storm. Therefore,
using 360 LF of 4~foot diameter pipe as a wet vault, with a cross sectional area of
10 sf at a 3-foot depth, results in an available pool volume of 3,600 ef, which
exceeds the required volume of 3,217 cf.
See the following StormShed modeling output.
BASIN `B' WATER QUALITY CALCULATIONS
Minimum Stormwater Treatment Area Required:
Formula 6-9 from page III-6.14: b = On - Zy
1.486 yissx aos
Qsmo = 0.05 cfa (see attached StormShed output)
n = 0.07
Z=3
y=2"=0.166T
s = 0.02
b = 0.83'
0.83' x 200' long swale = 166 of
Stormwater Treatment Area Provided:
166 sf / 2' wide =min. 83' long
Total Treatment Area Prouided 2' wide x 380' Long = 760 af> 766 of .: OK
Check Velocity:
V=Q/A = 0.05 cfs /((2)(0.1667) +(3)(0.1667)0 = 0.1 cfs < 1.6 cfs .'. OK
BASINS `A' AND `B' WATER QUANTITY CALCULATIONS
*See attached StormShed software output
3 - 70' long x 6' wide x 4.5' deep infiltration galleries with 3' dia. perf. Pipe
Void ratio = 0.30
3 galleries x[[(70')(6')(4.5'}- (70')(3.14)(3'^2)/4] (0.3) +(70')(3.14)(3'^2)/4]
Total Storage Volume Prouided = P,740 cf
Active Live Volume = 2,379 at Elev. = 325.85' per StormShed modeling
2,379 of < 2,740 cf .: OK
48 Hour Drawdown:
((3)(70' x 6')(20 in/hr)(1'/12")(48 hours) = 700,800 cf > 2,379 cf .: OK
Olympic Engineering Mountain Meatlows StonnShed
M05002 4/1]/2005
Basins 'A' Water Quality
Basin A Event Summary:
BasinlD Peak O Peak T Peak Vol Area Method Raintype
Event
(cfs) (hrs) (ac-ft) ac /Loss
BasinA 0.24 8.00 0.0]82 0.89 SCS/SCS TYPEIA 6mo
Drainage Area: Basin A
Hyd Method: SCS Unit Hyd Loss Method: SC S CN Number
Peak Factor: 484.00 SCS Abs: 0.20
Storm Dur 24.00 hrs
Area CN TC
Pervious 0.0000 ac 78.00 0.02 hrs
Impervious 0.8900 ac 96.00 0.03 hrs
Total 0.8900 ac
Supporting Data:
Impervious CN Data:
road 98.00 0.5800 ac
s/w 98.00 0.2300 ac
d/w 98.00 0.0800 ac
Pervious TC Data:
Flow type: Description: Length: Slope: Coeff: Travel Time
Fixed None Entered 0.00 ft 0.00 % 1.0000 0.00 min
Impervious TC Data:
Flow type: Description: Length: Slope: Coeff: Travel Time
Fixed None Entered 0.00 ft 0.00% 0.0000 0.00 min
Basins 'A' and 'B' Water Quaniti
RLPCOMPUTE [Infiltration Level Pool] SUMMARY
100 yr MatchQ=PeakO= 1.5213 cfs Peak Out O: 0.8975 cfs -Peak Stg: 325.85 ft -
Active Vol: 2379.95 cf
Summary Report of all RLPooI Data
Project Precips
[2 yr] 2.00 in
[5 yr] 2.50 in
[10 yr] 3.00 in
[25 yr] 3.00 in
[100 yr] 4.00 in
[6 mo] 1.28 in
BASLI5T2
[Basin AIB Combined] Using [TYPEIA] As [100 yr]
LSTEND
BasinlD Peak O Peak T Peak Vol Area Method Raintype
Event
------ (cfs) (hrs) (ac-ff) ac /Loss
Basin A/B Combined 1.5213 8.00 0]64] 3.97 SCS/SCS
TVPEtA 100 yr
loft
Olympic Engineering Mountain Meatlovrs StormShetl
#05002 4/17/2005
BASLIST [TYPE1A] AS [100 yr] DETAILED
[Basin A/B Combined]
LSTEND
Drainage Area: Basin A/B Combined
Hyd Method: SCS Unit Hyd
Peak Factor: 484.00
Storm Dur 24.00 hrs
Area CN
Pervious 2.9300 ac 77.00
Impervious 1.0400 ac 98.00
Total 3.9700 ac
Supporting Data:
Pervious CN Data:
Landscaping 77.00
Impervious CN Data:
Roadway 98.00
Driveways 98.00
Sidewalks 98.00
Pervious 7C Data:
Flow type: Description:
Sheet Landscaping
Impervious TC Data:
Flow type: Description:
Shallow Impervious
HYDLIST SUMMARY
[100 yr out]
LSTEND
HydID Peak O Peak T
----- (cfs) (hrs)
100 yr ouI 0.90 9.00
Loss Method: SCS CN Number
SCS Abs: 0.20
TC
0.61 hrs
0.03 hrs
2.9300 ac
0.6300 ac
0.3000 ac
0.1100 ac
Length: Slope: Coeff: Travel Time
445.00 ff 2.60% 0.1500 36.84 min
Length: Slope: Coeff: Travel Time
408.00 ft 2.10 % 27.0000 1.74 min
Peak Vol Cont Area
(ac-ff) (ac)
0.7656 3.9700
STORLIST
[Infltration Gallery]
LSTEND
Node ID: Infiltration Gallery
Desc: Infiltration Gallery
S[art EI: 322.0000 ft
Contrib Basin:
Leng[h Width
70.0000 ft 18.0000 ft
Maz EI: 326.5000 ft
Contrib Hytl:
Void Ratio
49.00
DISCHLIST
[Infltration Gallery]
LSTEND
Control Structure ID: Infiltration Gallery -Infiltration control structure
Descrip: Infiltration Gallery
Start EI Max EI Increment
322.0000 ft 327.5000 ft 0.10
Infil: 20.00 in/hr Multiplier: 1.00
2 oft
Appendix li
Soils Report
SOIL EVALUATION REPORT
FORM 1: GENERAL SITE INFORMATION
PROJECT TITLE: Antush Plat SHEET: 1 OF 1
PROJECT N0.:05105 DATE: 3/22/05
PREPARED BY: William Parnell, P.E.
1. SITE ADDRESS: 8818 Bumett Road SE, Yelm 98597
TPN:21713310400,21713310401,21713310402
2. PROJECT DESCRIPTION: Create a residential plat.
3. SITE DESCRIPTION: The 4.89 acre rectangular shaped project site is cunently occupied by a
single residential dwelling and several outbuildings. Site relief is gently sloping with a 2-3 % east to west
slope, varying from an elevafion of 342 ft. at the northeast properly comer [o an elevation of 328 ft.
along the west properly line. Site vege[afion consists of low cut pasture grasses. The project she is
bounded by Bumett Road [o the west and residential properly to the north, east and south. On-site soils
are swell-drained Spanaway series formed in gravely glacial outwash.
4. SUMMARY OF SOILS WORK PERFORMED: Two test pits were excavated by backhoe to a
maximum depth of 144° below existng grade. Soils were inspected by entering and visualy logging
each test pit [o a depth of four feet. Soils beyond four fee[ were inspected by examining backhoe
tailings. One double ring infiltration test was completed. Test pit soil log data sheets and infiltrafion [es[
results are included in this report.
5. ADDITIONAL SOILS WORK RECOMMENDED: Additlonal soils work should no[ be necessary
unless drainage infiltration facilNes are located outside Me general area encompassed by the soil test
pits.
6. FINDINGS: The Natural Resource Conservafion Service soil survey for Thurston County mapped
the on-she soils as a Spanaway Gravelly Sandy Loam (110). All test pits confirmed the Spanaway
designafion generally profiling a gravely very fine sandy loam surtace soil overlying a very [o extremely
gravelly 8 cobbley coarse-medium sand substratum. The substratum gravels and sands were slightly
loose to Blighty tight. Winter water [able was no[ present and no indicators were visible. A double dng
infiltration test revealed an infiltrafion rate of 80 iNhr at 72" below the existing grade in test plt #1.
7. RECOMMENDATIONS: The Spanaway soil series is a somewhat excessively drained soil that
formed in gravelly glacial outwash. Infiltration rates are generally rapid in Me substratum soils. The
specified substratum C horizon soils should be targeted for all drainage infiltrafion facilifies as noted in
Me attached soil log data sheets. A design infiltrafion rate of 20 iNhr or less would be appropriate for
these targeted soils.
During consWcfion, care must be taken to prevent Me erosion of exposed soils. Drainage facility
infiltrafion surtaces must be propedy protected from contaminafion by the fine-grained upper horizon
soils and from compaction by construc8on she activifies. Soils no[ propedy protected will cause
drainage infiltration facilifies to premalurey fail.
I hereby certify that I prepared this report, and conducted or supervised the performance of related
work. I certify that I am qualified [o do this work. I represent my work to be complete an accurate whhin
the bounds of uncertainly inherent to the practice of soils science, and to be suitable for its intended
use. ti `°~,.
SIGNED: (.Ci~.GI=:_ c._. ....iA ~ OF-l.• s~,,~'A/i~
DATE: 3IZZ ~.s ~ G;,!
F
,v
L~ acy,~ !~f ;.
rN a
8':5't,.,.yA r
Jti SY"
i s>~rtsas 8-a-bs
SOIL EVALUATION REPORT
FORM 2: SOIL LOG INFORMATION
PROJECT TITLE: Anlush Plat SHEET: 1 OF 2
PROJECT NO :05105 DATE: 3/18/05
PREPARED BY: William Parnell, P.E.
SOIL LOG: rYi
LOCATION: 60 ft. east and 20 k. north of the southwest property comer.
1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM:
Double Ring Infilbatlon Spanaway (110) Tertace
4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW:
GROUP:
Glacial Outwash B Unknown
7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS:
DEPTH: LAYER:
Greater than bottom of hole Greater than bottom of hole Level
10. POTENTIAL FOR: EROSION RUNOFF PONDING
Minimal Slow Minimal
1 t. SOIL STRATA DESCRIPTION: See Following chart
12. SITE PERCOLATION RATE: See FSP
13. FINDINGS 8 RECOMMENDATIONS: A double ring infiltration test completed at 72"below the
exisfing grade revealed an infihtraton rate of 80 in/hr. Use a design infifirafion mte of 20 in/hr or less for
drainage infiltrafion facilities located in the C2, C3 and C4 horizon soils.
Soils Strata Description
Horz DeoN Color Tax[ure
At 0"- 24' fOVR212 GNFSaIm
ew 24"- 30' 10VR3/3 GrVF6aLm
C1 30"- 36' 10VR3I8 VGraCOb
LmMSa
C2 36"- ]2' tOVR4/6 ExGraCOb
MSa
C3 ]2'- 96" 10VRS12 ExGraCOb
M-FSa
some stones
C4 9fi"-144" 10VR52 ExGraCOb
C-MSa
some stones
Soil Log #7
%CL %ORG CF STR MOT ING CEM ROO <X> FSP
cis cS <10 15BK - - - H 2b 2
<15 - <25 1SBK - - - (I 243 4
<10 - <40 SG - - - - 6-20 20
<f - 46 SG - - - - >20 20
<1 - QS SG - - - - ~ZO 20
q - <q0 SG
>20 20
SOIL EVALUATION REPORT
FORM 2: SOIL LOG INFORMATION
PROJECT TITLE: Antush Plat SHEET: 2 OF 2
PROJECT N0.:05105 DATE: 3/18/05
PREPARED BV: William Parnell, P.E.
SOIL LOG: #2
LOCATION: 160 ft. east and 20 ft. north of the southwest property comer.
1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM:
Douhle Ring Infiltration Spanaway (110) Terrace
4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW:
GROUP:
Glacial OUlwash B Unknown
7. CURRENT WATER 6. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS:
DEPTH: LAYER:
Greater than bottom of hole Greater than bottom of hole Level
10. POTENTIAL FOR: EROSION RUNOFF RoNDING
Minimal Slow Minimal
11. SOIL STRATA DESCRIPTION: See Following chart
12. SITE PERCOLATION RATE: See FSP
13. FINDINGS 8 RECOMMENDATIONS: Use a design infiltration rate of 20 iNhr or less for drainage
infiltration facilifies located in the C2 and C3 horizon soils.
Soils Strata Description
Soil Log #2
Horz De lli Color TeMUre %CL %ORG CF STR MOT IND CEM ROO <X> FSP
Al 0"- 20" 10VR212 GrBCob <75 c5 <10 16aK - - - R 2-6 2
VFSaLm
some stones
ew 20'- 26' 10VR313 GrVFSaLm <15 - c25 15BK - - - H 2'6 4
C1 26"- 3i" 10VR3Ifi VGBCOb <10 - <40 SG - - - - 6-20 20
LmMSa
C2 31"- 72' 10VR4I6 ExGrBCOb <1 - <66 SG - - - - >20 ZO
C-M6a
some stones
C3 ]2"-144' 2.SVSl2 VGrMSa <7 - cqp SG - - - - >20 20
Abbreviations
Textural Class
(Texture) Structure
(STR) Grades of Structure
Cobble -Cob Granular - Gr Stron - 3
Stone - St Block - Blk Moderate - 2
Gravell - Gr Plat - PI Weak - 1
Sand - Sa Massive - Mas
Loam - Lm Sin le Grained - SG
Silt - Si Sub-An ular Block - SBK
Cla e - CI
Coarse - C
Ve -V
Extreme) - Ex
Fine - F
Medium - M
Induration ti Cementation
(IND) (CEM)
Weak - Wk
Moderate -Mad
Stron - Str
Mottles MOT
1 Letter Abundance 1st Number Size 2nd Letter Contrast
Few - F Fine - 1 Faint - F
Common - C Medium - 2 Distinct - D
Many - M Coarse - 3 Prominent - P
Roots (ROO)
1st Letter Abundance 2nd Letter Size
Few -f Fine -f
Common - c Medium - m
Man - m Coarse - c
<X> -Generalized range of infiltration rates from SCS soil survey (<X>)
FSP -Estimated Field Saturated Percolation rate based on horizon specific
factors.
DOUBLE RING INFILTRATION TEST
Antush Plat
Test Date 3/23/2005
Completed By: William Parnell, P.E.
PE Job :#05105
DOUBLE RING INFILTRATION TEST
Test Hole # 1 (test run @ 72" below existing ground surtace )
Start Sto Ela sed Time Total Dro Infiltration Rate
( Min) (Min) (Min) (Inches) (In/Hr )
0 3' 30" 3' 30" 6
3' 30" 7' 15" 3' 45" 6
7' 15" 11' 30" 4' 15" 6
11' 30" 15' 45" 4' 15" 6
15' 45" 20' 15" 4' 30" 6
20' 15" 24' 45" 4' 30" 6
24' 45" 29' 30" 4' 45" 6
29' 30" 34' 00" 4' 30" 6
34' 00" 36' 30" 4' 30" 6
38' 30" 43' 00" 4' 30" 6
43' 00" 47' 30" 4' 30" 6
47' 30" 52' 00" 4' 30" 6
52' 00" 56' 30" 4' 30" 6
56' 30" 1:00' 30" 4' 30" 6 80
Appendix III
Vicinity Map
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Appendix IV
Drainage Basin Map
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