bld20100999-Read_2.pdf
City of Edmonds
TH
121 5AVENUE NORTH •EDMONDS, WA 98020 • (425) 771-0220 FAX (425) 771-0221
Website: www.ci.edmonds.wa.us
PUBLIC WORKS DEPARTMENT
EngineeringDivision
Plan Review Corrections
Plan Check :Date:
#BLD2010 0999April 5, 2011
Project Name/Address:
Read –9947 Water St
Contact Person/Address/Fax:
W.Glen & Debbie Read –wglenread@gmail.com
Reviewer:Jennifer LambertDivision:Engineering
During review of the subject submittal,it was found that the following information, corrections, or
clarifications wouldneed to be addressed. Our handouts can be found online at the City of
Edmonds web site www.ci.edmonds.wa.usunder City Government/Development
Services/Engineering Division.
st
1Review –February 18, 2011
nd
2Review –April 5, 2011
Grading / Erosion Control Plan
1.
OK
Site Plan
1.4/5/11 –Comment was not addressed.
2/18/11 –Comment: During the short plat improvements, Phase I, a portion of Water St was widened
and a storm line was installed. Please show all improvements on the plan.
2.4/5/11 –Comment was not addressed. There was an error in the comment on 2/18/11. Please
show the outfall pipe on the westsideof the catch basin and the storm line across OceanAve.
2/18/11 –Comment: The catch basin located at the southwest corner of Ocean Ave and Water St has an
outfall pipe on the east side of the catch basin. Please show this storm line and include the invert
elevation for this line.
3.OK
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4.OK
5.4/5/11 –Comment was not addressed.
2/18/11 –Comment: Please show/list the impervious surface calculationsin the tableas shown below.
TypeArea (square Feet)
Line
Exempt
1.
ExemptNon-Exempt
Replaced
2.
New
3.
Total Replaced +New (Non-
4.
Exempt) =
(add numbers in blue boxes)
6.OK
7.OK
8.OK
9.OK
10.4/5/11 –Comment was not addressed.
2/18/11 –Comment: Please clarify what is intended by the note, “All utilities to service proposed lot 1 &
2 will be taken from existing locations within Water St.”.
11.4/5/11 –Comment was not addressed.
2/18/11 –Comment: There appears to be a proposed fence on the landscape plan; however, not shown
on the site plan.
a.Show the fence on the site plan.
b.The gate must be 18’from edge of right-of-way.
c.The gate must open into private property.
d.Fence shall be located entirely on private property.
Sheet 1 of 2 -Site Development (Plot) Plan
1.OK
2.OK
3.OK
4.OK
5.OK
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6.OK
7.OK
8.OK
9.OK
10.OK
Utilities
1.OK
2.OK
3.OK
4.OK
5.OK.
Drainage
1.OK
2.OK
3.OK
4.OK
Sheet 2 of 2 -Site Development (Plot) Plan
1.OK
2.OK
Traffic Impact Analysis:
Per Chapter 18.82 –Traffic Impact Fees of the Edmonds Community Development Code (ECDC), traffic
impact fees shall be required.
1.OK
Drainage/DetentionReviewcomments from Storm Water Engineer,Jerry Shuster:
4/5/11 Comments–Conveyed to Rob Long from Jerry Shuster via phone.
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Comments dated 2/18/11 Below:
For this permit I reviewed the following:
Engineering and Drainage Report for Read Residence, Lot 1 MacDonald Short Plat,9221 Water Street,
Edmonds, Washington, October 2010, LSA.
Plan sheets 1 & 2 for the same.
Engineering and Drainage Report
This short plat is vested under the former drainage code (used prior to the adoption of the new code in
June 2010) and creates 5,000 square feet or more of new impervious surface.The former codestipulates
thata for site of thissize, the drainage report mustinclude a discussion of complying withMinimum
Requirements 2 -10 contained in ECDC 18.30.060.B.This drainage report does not include such a
discussion but should.
The designed infiltration trench for the west basin is less than 50 feet from the toe of the slope.This is
not allowed under the 1992 Ecology Stormwater Manual, even though it has been approved by a
geotechnical engineer.The City will not approve a design that has a potential for destabilizing the slope
over a long period of time that may impact the railroad right of way.It carries toomuch liability for the
City.In addition, the engineering instructions in the approved short plat specifies detentionof
stormwater offfrom thisnew lot not infiltration.Reconfigure the flow control systems so stormwater
management is provided entirely through detention.
The modeling for the design detention system for the east basin useshydrologicGroupC soils when the
geotechnical report confirms the site hasGroup A soils.The report says that theGroup C soils were
used because the underlying soils were dense.This is not acceptable.Group C soils result in more
runoff thanGroup A soils in the predevelopment condition, thus resulting in a smaller detention system.
Since the soils are dense, the City will allow the modeling using GroupB soils.These soils are
described as typically between 10 and 20% clay and 50 to 90% sand (USDA, NRCS, Part 630
Hydrology, National Engineering Handbook, May 2007).This description fits the soilsin by the
geotechnical report.For Group B soils use a CN = 72 for the pre-developed condition and CN = 80 for
grass for the post development condition (CN= 98 for impervious).
The downstream drainage description on page F-1 appears to be incorrect.As described, the current
drainage off the vegetated site diffusely flows to the west into the BNSF ditch on the east side of the
tracks.The ditch drains to the south (not north)to an 18 inch concrete culvert that goes under the tracks
into Puget Sound.Once the site is developed, the flow from the detention system(s) will be concentrated
in the existing outfall intothe railroad ditch from theCity's catch basin onthe SE corner of Water St &
Ocean Ave (CB with rim elevation 32.91 on plan sheet 1).This CB has a 12 inch dia. concrete pipe that
discharges from the hillside ABOVE the railroad ditch (pipe not shown on Plan Sheet 1).Thisdischarge
from the side of the bank appears to cause erosion from the bank under current conditions.Re-assess the
downstream analysis and the potential for erosion in the BNSF right-or-way.
Plan sheets 1 & 2
Review of the storm drainage plan sheets will occur once the commentsfor theDrainage report are addressed.
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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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