bld20100784-Clearwater-1.pdf
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:
#BLD20100784 November 16, 2010
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Project Name/Address:
Clearwater SFR 22808 96 Pl W (Lot 6)
Contact Person/Address/Fax:
Tom Berg tomberg58@yahoo.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.ci.edmonds.wa.us by clicking City Government / City
Department / Public Works / Engineering Division:
Please Note: Building Handouts do not include updated Engineering Division Requirements. Refer to
Engineering Handouts for all Engineering Requirements.
Drainage plan will not be reviewed by the Stormwater Engineer as submitted. See comments under
Stormwater Mitigation.
General:
1. Reduced size site plan shall be 1:20 scale.
2. 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.
3. Add note to plans: “Replacement is required of any plat improvements that are damaged
during construction.”
4. Eaves are considered part of a structure, therefore eaves cannot hang over any City of
Edmonds easement. Please provide copy of the easement along the east property line.
5. Show dimensions of structure, deck, driveway length and width at road and property line.
6. Note on plan: “See Grading/TESC and Drainage/Utility Plans for more information.” Add
similar information to the other plans to reference to each other.
7. Please add the identifying plan information shown on the site plan to the grading/erosion plan
and the drainage utility plan (tax id, address etc)
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8. Lot coverage is noted as the same square footage as the impervious surface square footage.
Building footprint square footage is lot coverage (see Planning for specifics) and structure with
eaves is the square footage considered impervious surface. Please correct.
9. Impervious surface breakdown has total of 2130sf. The calculation box has a total of 2720 sf.
Please correct.
10. Patio is shown covered in architectural plans but uncovered on civils. Please clarify.
11. Please add a general notes section to the civils. Please refer to example provided with the
comments for Lot 7.
Grading/TESC
:
1. Please include details of erosion control measures in plans consistant with City of
Edmonds standard details. Also add note to plans “Additional Erosion Control Measures
Consistent With City of Edmonds Standards Provided As Needed”.
2. Please change grading calcs from yards to cubic yards.
3. Grading calcs for this project are estimated as the same amount as the other two lots even
though foundation is already in place. Please revisit grading calculations on all three
submissions and correct to reflect actual amounts.
4. Please review minimum requirements of erosion control for the classification of the project.
Add all minimum requirements to the civil general notes section.
5. Indicate area of disturbance. Outline on grading/tecs plan and label with square footage of
the area.
6. Add note to plans: “All disturbed areas on and off site shall be compost amended to meet
requirements of BMP T5.13 in the Stormwater Manual, Vol V, Chapter 5.
Stormwater Mitigation
:(same comments as provided with Lot 7)
1. 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. 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. Please provide a completed copy of the Worksheet available in Handout E72.
4. 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.
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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.
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 system to meet stormwater
requirements for only the proposed additional impervious surface, 6,945 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. 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 III, 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 only be used for projects that are categorized as
Small Site Category 1 or 2 sites (under 10,000 sf imp surface).
Drainage/Utility Plan:
1. How will the runoff from the driveway be connected to the stormwater system? Show on
plans.
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2. Please note on plans “Required separation of utilities shall be met per City of Edmonds and
industry standards.” on Drainage/Utility plan.
3. Plans indicate utility easement. Why aren’t utilities shown as being installed within the
easement?
4. Show water meter on plans and label as existing or proposed.
5. Note driveway material on plans.
6. Show existing storm line on plans. The plat map shows a storm line along the south property
line with a stub out for connection. It also shows a storm line running on Lot 7 adjacet to the
Lot 6 east property line. Show connection to the storm line. Include rim and invert elevations
at all catch basins.
7. The full extent of all detention or other stormwater mitigation 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.
8. 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. 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. Show 4-6”side sewer clean out at house.
11. Label all pipe with length, material and size.
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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