bld20150609_Demo.Addition.Remodel Review II.pdf
City of EdmondsBLD20150609
TH
121 5AVENUE NORTHEDMONDS, WA 98020 • (425) 771-0220 FAX(425) 771-0221
Website: www.edmondswa.gov/
PUBLIC WORK DEPARTMENT
Planning • Building • Engineering
Plan Review Comments
BLD20150609
PermitApplication:Date:
#October 14, 2015
th
-Demo, Addition & Remodel22401 98Ave W
Project Name/Address:
Strayer
tom
@lerendesign.com
Contact Person/Address, Fax or E-mail:
Tom Leren
Reviewer: Chris RiveraDivision:
ENGINEERING
During review of the subject submittal, it was found that the following information, corrections, or
clarifications would need to be addressed. All Handouts referred to in these comments can be accessed at
our website: www.edmondswa.gov/under City Government / Development Services Department /
Engineering Division then scroll down to Handouts:
st
1Review June 25, 2015
nd
2Review October 14, 2015
1)Ok
2)A right of way permit is required for the use of the right of way, attached is a right of way application. Please
fill out and submit with a traffic control plan.
October 14, 2015 –Comment addressed, owner to have contractor submit a right of way application
prior to construction.
3)
Ok
4)Please provide the date of construction forall existing impervious surfaces on the Site Plan.
5)Ok
6)In total, I’ve calculated Non-regulatedimpervious surfaces(existing surfaces to remain) as
approximately 1,920sf and New (Post 1977) impervious surfaces at approximately 2,400sf. For whichall
of the2,400sf ofimpervious surfaces will needto be mitigated by a stormwater management system, i.e.
detention system or infiltration system. Please recalculate the impervious surface numbers and revise
the Impervious Surface Calculations on your site plan.
a)If an infiltration system is proposed,aDrainage Reportis required. Please submit aDrainage Report
by a licensed Geotechnical Engineer.The report should addressthe soil conditions and infiltration
rates. Refer to City handoutE-72B Low Impact Development BMP Simplified Sizingalso the
Stormwater Code Supplement –AppendixC Approved Methods for Obtaining Design Infiltration
Rates.
DATE E-MAILED10/14/2015PAGE(1)
City of EdmondsBLD20150609
TH
121 5AVENUE NORTHEDMONDS, WA 98020 • (425) 771-0220 FAX(425) 771-0221
Website: www.edmondswa.gov/
PUBLIC WORK DEPARTMENT
Planning • Building • Engineering
Plan Review Comments
b)If a stormwater detention system is proposed, please refer to handout E-72A, Stormwater Detention
System Simplified Sizingfor stormwater management requirements. Please show the detention
system on the site plan.
c)June 25, 2015–Please revise theDrainage note within the site plan. The 2000sf referredto, is part of
the 2,400sf of impervious surfaces that will need to be mitigated through an approved stormwater
management system.
October 14, 2015 –The above comment is regarding the Drainage Noteon the Site Plan. Which
oncereferenced the proposed 4’ diameter infiltration pit, now no longer proposed. Please
deletethe commentfrom the site plan.
7)October 14, 2015 –Though impervious surfaces within the right of way do not need to be collected
and directed to the onsitestormwatermanagement system, all new impervious surfacesarea need
to be accounted for within the proposed stormwater management systems.Please provide
stormwater management for the additional 333sf of impervious surface created within the right of
way. Please revise the impervious surface table accordingly.
a)A section of the driveway (261sf) that is currently impervious is proposed to be replaced with
pervious concrete. Therefore, stormwater management will be provided for a section of the
driveway where mitigation is not required by code. For this reason, you can consider this area
an impervious surface area swap with a portion of the 333sf driveway approach that it not
being mitigated. This would leave a balance of 72sfthat would need to be accounted for in the
sizing of the rain garden. Please revise the raingarden notes and the impervious surface
stormwater table.
8)October 14, 2015 –A covenant will need to be recorded for the proposed raingarden. Please
review the attached Covenant for Rain GardenStormwater Systemsand provide the required
information on Exhibits A & B. This will need to be reviewedand approved by the city before
recording with Snohomish County.
9)October 14, 2015–The 239sf of impervious surface to be replaced within the right of way should
becategorized as Replaced Exempt,for a total of 500sf Replaced Exemptand 1440sf Non-
Regulated. Please correct the impervious surface table.
10)October 14, 2015 –Per City of Edmonds standard detail E2.26 The driveway approach within the
right of way shall not exceed 30’ width.
STORMWATER REPORT-
October 14, 2015
The following comments are provided from Jerry Shuster, Stormwater Engineer. Please contact Jerry
directly at 425-771-0220 or by email at jerry.shuster@edmondswa.govwith any specific questions you
may have regarding these comments.
DATE E-MAILED10/14/2015PAGE(2)
City of EdmondsBLD20150609
TH
121 5AVENUE NORTHEDMONDS, WA 98020 • (425) 771-0220 FAX(425) 771-0221
Website: www.edmondswa.gov/
PUBLIC WORK DEPARTMENT
Planning • Building • Engineering
Plan Review Comments
11)The proposed permeable pavement must meet the design requirements in Section 5.3 of the City’s
Permeable Pavement Policy
(http://www.edmondswa.gov/images/COE/Government/Departments/Public_Works/Policies/ENG
R-DEVSTM-2010-01.Permeable_Pavement_rev_1_Final.pdf). Include a detail showing a cross-
section of the pavement system with the appropriate layers of the required aggregates.
12)The geotechnical boring was not placed at the proposed location of the rain garden or the
permeable pavement.Section 5.5.2 of the Edmonds Stormwater Code Supplementstates that “Soil
reports are required where infiltration is proposed and for individual lots, they must include at
least two soil logs for each proposed infiltration location.”An additional hand auger boring
under theproposed rain garden will suffice for this site.
13)The plan sheet states that the rain garden bottom area is calculated using a sizing factor of 5.7%
interpolated from Table 5 in City handout #E72B for 0.25 inches per hour and a 6 inch ponding
depth.Thishandout has an entry for an design infiltration rate of 0.25 inches per hour and a 6
inch ponding depth.The table has a sizing factor of 9.7% not 5.7%, please correct the raingarden
design and notes.
14)The sizing factors used in Table 5 of the City’s Handout assume the runoff enters the rain garden
from a pipe at the top of the raingarden.If the designers chooses to use the design shown in Detail
1 with a beehive inlet for the rain garden, it must be modeled by the designer.
15)The replaced impervious (asphalt) in the right of way should be sloped to the west so the runoff
travels to grass/ gravelly area.
Please resubmit 3 copies of the revised plansand associated documents with a written response to each
item to a Permit Coordinator. Please contactme at 425-771-0220ext 1339or by e-mail at
chris.rivera@edmondswa.govif you have specific questions regarding these plan corrections.
DATE E-MAILED10/14/2015PAGE(3)