20100757-EngRevComments.pdfCity of Edmonds
121 5"" AVENUE NORTH ^ EDMONDS, WA 98020 p (425) 771-0220 FAX(425) 771-0221
Website:
PUBLIC WORKS DEPARTMENT
Engineering Division
Plan Review"k-'offections
Plan Check #: BLD20100757-RestibIrI1Date: JanuaKy 26, 2011
Project Name/Address: Cleat -water SFR 22806 96"' P1 W
Contact Person/Address/Tax: Tom Berg tomberg58gcyahoo.com
Reviewer: JoAnne Zulauf Division: En incerin
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 hi these
comments can be accessed at our website: w ' �i,wxied moit(Is '.wqms by clieldng City Government / City
Department / Public Works / Engineering Division:
Please ilfote. fxaiult)�,Us do nox, bieftuie ult-Oated 11), Wi�s ion �,o
.... 1 1. _ , 1111111- U" tl
'11W,11 i,�J lag a
i"or ll
Draipgy,t_plaqMiL1.Liot be review comments under
Stormwater Mit tion.
jgg_
General:
1. 1/26/11 No'? Is a retaining wall planned for this property? If so, please show on plans and
note bottom of wall (bow) and top of wall (tow) elevations at each end and for every two feet of
change.
2. 1/26/11 Add to all plans. Add note to plans: "Replacement is required of any plat
improvements that are damaged during construction,"
3. 1/26/11 Done.
4. 1/26/11 Done.
I`
5. 1/26/11 Done.
6. 1/26/11 Not Done. All civil plans have note "See General Notes". I cannot locate the notes to
which you are referring. Please add a general notes section to the civils. Attached is an
example though may contain more or less requirements than are required for this project as it
is only an example.
DATE FAXED/E-MAILED 1/26/2011 PAGE 1 OF
Grading/TE SC:
1. '1/26/'I'l [)one.,
2. 1/26/11 Done.
3. 1/26/11 Done.
4. 1/26/11 Not Done. Please review minimum requirements of erosion control for the
classification of the project. Add all minimum requirements to the civil general notes
section.
5. 1/26/11 Not Done. Indicate area of disturbance. Outline on grading/tecs plan and label
with square footage of the area.
Storinwater M
1. 1 /26/11 NoA. Done, The information listed below must be presented prior to the City evaluating
the stormwater design for the project. Please review the Stormwater Handout E72 and the
Stormwater Supplement, both available on our website.
2. 1/26/11 Not Done. The project needs to be classified per ECDC 18.30.50. Once classified,
the report should describe how the project plans to comply with applicable minimum
requirements (See Handout E72)
3. '1/26/11 Not Done. Please provide a completed copy of the Worksheet available in Handout
E72.
4. 1/26/11 Per Jeri y Shuster, Storrnwater Engineer, Lot'7 ITILISt provide stormwater mitigation on
site. Developing Lots 6, 7, and 8 as proposed will result in a total of 34,366 sf of impervious
surface. The stormwater system constructed in 2001 was designed for an impervious surface
total of 30,260 sf meeting the design flow rates of that time. The existing construction of the five
lots (17,181 sf) and the cul de sac road and sidewalks (10,240 sf) equals 27,421 sf of impervious
surface that is mitigation by the City approved system meeting the code requirements of 2001.
The mitigation of runoff for the proposed impervious surface, 6945 sf, may be approached in
several ways;
a) Provide engineered calculations that show the existing system has the capacity to
handle the existing and proposed impervious surface runoff (34,366 sf). (includes all 3
proposed lots)
i) Project would be categorized as a Large Site project. See Chapter 4 of the
Stormwater Supplement for requirements.
ii) System sizing would need to meet current stormwater code flow control
requirements. See Chapter 4 of the Stormwater Supplement to find flow control
requirements for runoff In a direct discharge basin, available on the City of
Edmonds website.
DATE FAXED/E-MAILED 1/26/2011 PAC E-2- OF
iii) Soils infiltration testing by an approved method (see Supplement Chapter
4.5.2) is required for any system design using infiltration.
iiii) Physical verification of the current condition and size of the bio Swale
described in the 2001 Stormwater Report for this project is required if intended
for the stormwater mitigation of the proposed construction on lots 6, 7, and 8.
b) Propose an engineered plan adding increasing capacity of the existing system. (same
requirements as 2 a above)
c) Leave existing system untouched and propose a separate systern to meet stormwater
requirements for only the proposed additional impervious surface, 6,94.5 sf.
i) Project would be categorized as a Small Site project Category 2 if the three
lots will use a shared system for mitigation. If the lots are mitigated individually
each would be considered a Small Site Category 1. See Chapter 5 of the
Stormwater Supplement for more information.
5. 1/26/11 Reference. Appendix C of the Supplement provides the acceptable methods for
obtaining a design infiltration rate for infiltration trenches. In addition to the methods in Appendix
C of the Supplement, the City also accepts the "D10 methodology" described in Volume 111,
Section 3.36, number 2 (including Table 3.8) in the 2005 Department of Ecology Stormwater
Management Manual for Western Washington. Once the design infiltration rate is established,
the City has tables for determining the size of the infiltration trench based on the square feet of
impervious area draining to the facility or the sizing can be obtained by the applicant using the
modeling parameters in the Supplement. Attached please find a simplified sizing tool for low
impact development or detention systems. This tool can QLIY be used for projects that are
categorized as Small Site Category 1 or 2 sites (under 10,000 sf imp surface).
D!ainae/Utility Plan:
1 How will the runoff from the driveway be connected to the stormwater system? Show on
plans.
2. 1/26/11 Done.
3. 1/26/11 Done.
4. 1/26/11 Done.
5. 1126/11 Done.
6. 1/26/11 Not Done. Show existing storm line on plans. Include rim and invert elevations, at all
catch basins.
7. 1/26/11 Not Done. All detention etc. systems must be shown on the Drainage Plan. Include
all rim and invert elevations, pipe size material and length, catch basin type, and swale
dimensions.
DATE FAXED/E-MAILED 1/26/2011 PAG 3 OF
8. 1/26/11 Not Done. Show connection of tightline/roof drains to storm system from house to
storm line in easement. A catch basin must be installed at point of connection. Provide rim
and all invert elevations.
9. 1/26/11 Not Done. Water lino frorn rrieter to house is not shown. Show all utilities on
plans (sewer, gas, power, water) from the connection at the property line or easement to the
point of connection to the residence.
'10.1/26/11 Done.
11. 1/26/11 Not Done. Label all pipe with length, material and size.
Please resubmit 3 copies of the revised plans/documents to a Development Services Coordinator. Please
contact ane at 425-771-0220 if you have specific questions regarding these plan corrections.
DATE FAXED/E.-MAILED 1/26/2011 PAGE OF