Bld20160686_Echelbarger-1.docx
City of Edmonds
TH
121 5 AVENUE NORTH • EDMONDS, WA 98020 • (425) 771-0220 FAX(425) 771-0221
Website: www.ci.edmonds.wa.us
PUBLIC WORKS DEPARTMENT
Engineering Division
Plan Review Corrections
Plan Check : Date:
# BLD20160686 August 3, 2016
Project Name/Address:
Echelbarger Single Family Residence 523 Paradise Lane
Contact Person/Address/Fax:
Todd Echelbarger todd@echelbarger.com
Reviewer: JoAnne ZulaufDivision:Engineering
During review of the subject submittal, it was found that the following information, corrections, or
clarifications would need to be addressed. All Handouts and Standard Details referred to in these
comments can be accessed at our website: www.edmondswa.gov by choosing the “Services” tab and
“Permits and Development”.
Site Plan:
The
1. plot or site plan needs to show the location of all the proposed utilities (i.e. water/sewer) and
stormwater system (infiltration) but does not need to include the details (length, size, etc.).
2.Please note the distance between the property line and the nearest fire hydrant.
3.Add note to plans “Sidewalk is subject to replacement depending on existing condition or damage. To
be determined by Engineering Inspector on site.”
4.Under Impervious surface calcs Proposed Home is noted to have 2394 sf, under Lot Coverage it is also
noted as 2394 sf. Please revise as needed.
5.Label infiltration trench.
6.Remove clean out note regarding cast iron lamphole cover.
7.Please show the sewer easement on the plan and note easement reference number.
Grading and TESC Plan
8.There is a mailbox cluster with three boxes in the property frontage over the water meters. There are no
mailboxes on your plans. Revise with whatever the plan is for them.
9.Temp construction entrance is not shown on the property.
10.Provide top and toe elevation for the northwest end of wall.
11.General Notes: Change 2010 WSDOT to 2016.
Stormwater Report Consultant Review Comments:
The Infiltration Trench Sizing report (5/16/16) is missing the following information:
a.Project category (Category 1 Small Site Project)
b.Drainage basin/Watershed name
c.Narrative describing how each of the Small Site Minimum Requirements will be met.
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2.The applicant has the option to select the City’s Simplified Sizing Approach or perform continuous
modeling. Using the City’s Simplified Sizing Approach, a 1.8% sizing factor would be applied, resulting
in a 60-foot long, 2-foot wide, and 3-foot deep infiltration trench for the 3,356 SF of impervious surface
area. The applicant chose to perform continuous modeling and has proposed a 13.25’ x 13.25’ x 4’
infiltration trench; however, there are several errors and some additional clarification needed regarding
the proposed modeling approach as summarized below:
a.The WWHM output report (5/11/16) included with the 5/16/16 submittal uses the Everett Rain
Gage with a Precip Scale of 0.80. The Edmonds Stormwater Supplement requires the use of the
Puget East 36 rain gage which can be selected by checking “Use WS-DOT data” on the “Map
Information” tab in WWHM.
b.The geotechnical report (5/6/16) lists the soils as hydrologic group B; however, the WWHM
output report (5/11/16) lists the soils as hydrologic group C. The WWHM output report assumes
infiltration through the wetted surface area. Due to the vertical side slopes, infiltration should be
assumed across the trench bottom only (Use wetted surface area = “no”)
c.The porosity in the aggregate layer was assumed to be 0.4 (or 40%). Typical aggregate layer
porosities (and the porosity used in the simplified sizing tool for the City) is 0.3 (or 30%).
d.The proposed infiltration trench does not include an overflow structure. Even though the trench
is designed for 100% infiltration, an overflow structure should still be accounted for in the
modeling approach. Assumptions made for the riser structure to support the simplified sizing tool
for the City included:
i.Riser head = same as height of trench
ii.Riser diameter = 36 inches
iii.Notch height = not applicable
iv.Orifice height/diameter = not applicable
v.Effective total depth = height of trench + 0.1’ freeboard for uncontrolled overflow above
the top of the trench
3.Please indicate an overflow path on Sheet C2 (Stormwater and Utility Plan, 5/25/16)and provide
justification in the report narrative that runoff above the infiltration trench design capacity will not
cause:
a.Flooding of a building or emergency access
b.Erosion or downstream sedimentation
c.Slope failure
4.Note #3 on Sheet C2 (Stormwater and Utility Plan, 5/25/16) should be modified as follows:
“All disturbed pervious surface areas shall be compost amended per BMP T5.13.”
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Stormwater and Utility Plan
12.Add impervious surface calculations to this sheet.
13.Proposed deck is not included in the impervious surface calculations. If pervious with dirt/grass
underneath please add note. If not, add to impervious surface calculations.
14.Footing drains are required by the geotech. On the plans they are shown connecting to the storm system.
Please convey to another system or provide a revision to the storm report showing that the system has
capacity to handle them.
15.Where will retaining wall footings be connecting?
16.How will runoff be collected from the driveway and sidewalk/stairs be collected and directed to the
infiltration system?
17.Add length of storm pipe and an invert at the house and the trench.
18.A 6” grated clean out is called out for the infiltration trench. Is this intentional? Groundwater is not
accounted for in the sizing calculations.
19.Infiltration trench detail 2/C2 has 6” of CSBC label pointing to top of trench. Please clarify the exact
area that the crushed should be and note what the remaining 6” should be (compost amended soil if it is
to be planted with anything.
20.Water meters are shown as existing on this plan. Call out size of water meter and show as proposed if
there is only a meter box and no meter.
21.Add to notes section: Olympic View Water Sewer District is purveyor of water for this site. Water
meter and service location shall be reviewed and approved by OVWSD prior to construction.
22.Add sewer easement on this sheet too.
23.Add 6” clean out at edge of easement. This clean out needs the cast iron lamphole cover.
24.The clean out at the house does not require a cast iron lamphole cover.
25.Call out 6” pipe from main connection to edge of easement. Private service can be 4” or 6”.
26.Add lengths to each section of pipe.
27.Add elevations at main and both the cleanout at the easement edge and at the house to verify 2% slope.
28.Add standard detail for sewer connection.
Please resubmit 3 copies of the revised plans/documents to a Development Services Coordinator. Please
contact me at 425-771-0220 if you have specific questions regarding these plan corrections.
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