bld20100376-Maplewood-E1.pdf
DATE: June 25, 2010
TO: Nick Chou
choun@edmonds.wednet.edu
FROM: Jeanie McConnell, Engineering Program Manager
RE: Application #: bld20100376
Project: Maplewood School Walkway
th
Project Address: 8500-200 St SW
During review of the above noted application, it was found that the following information,
corrections, or clarifications are needed. Please redline plans or submit three (3) sets of revised
plans/documents with a written response to each of the items below to Theresa Umbaugh.
City of Edmonds handouts, standard details and development code can be referenced on the City
website.
STORMWATER MANAGEMENT
Project proposes the use of porous or permeable pavement. 4,688 square feet of permeable asphalt
is proposed.
1.Edmonds Community Development Code Chapter 18.30 revisions became effective June 1,
2010. Included as Exhibit A to the code is the Stormwater Code Supplement. The following
items need to be addressed pursuant to the Supplement:
a.Calculate the amount of land disturbing area - this will help classify the project and
decide which minimum requirements apply.
b.Determine project classification. It appears this project will be classified as a Category 1
Small Site Project but amount of land disturbing activity will confirm this.
c.Discuss the potential applicability of each of the Small Site Minimum Requirements
specific to the project classification.
d.Discuss how the proposed project will comply with the applicable Small Site minimum
Requirements.
2.Porous Pavement Path:
a.Provided that soil infiltration rates for the area under the proposed path have not been
submitted, a credit cannot be given or an exemption allowed from Small Site Minimum
bld20100376-Maplewood-E1 Page 1 of 2
Requirement (SSMR) #7, Flow Control, for the permeable path. However, since the
proposed path slopes towards the vegetated area that is the play field, the proposed
design will get 100% credit from SSMR #7 if a 1 foot wide gravel strip is added to the
down slope side of the path. The aggregate should have the gradation of Permeable
Ballast, in Section 9-03.9(2) of the 2010 WDOT Standard Specifications for Road,
Bridge, and Municipal Construction.
b.If sheet flow dispersion is not used for an exemption from SSMR# 7, soils infiltration
tests (one test per 5,000 square feet of impervious, minimum of 1) can be performed.
Design infiltration rate must be 0.13 inches per hour or greater as measured by methods
in Appendix C of the supplement to be accepted as porous pavement.
GENERAL
1.Please note on the plans:
a.Square footage of land disturbing activity.
b.Credit to impervious area calculation due to porous pavement.
2.Permeable pavement and subgrade installation shall be inspected by a special inspector. Please
contact a permit coordinator to obtain a special inspection agreement form.
3.Please provide a Construction Sequence on the plans similar to the following:
a.Schedule pre-construction meeting with City Engineering Division at 425-771-0220, ext.
1326.
b.Review erosion control notes.
c.Call for utility locates.
d.Install ESC measures and maintain dust control.
e.Install utilities and perform other site improvements
f.Stabilize exposed areas.
g.Remove ESC measures once site has been permanently stabilized.
Please contact me at 425-771-0220 or by e-mail at mcconnell@ci.edmonds.wa.us if you have
specific questions regarding these plan corrections.
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