bld20130919-Meadowview Estates-E1-storm.pdf
CITY OF EDMONDS
CIVIL PLAN REVIEW COMMENTS
ENGINEERING DIVISION
(425) 771-0220
City Website: www.edmondswa.gov
DATE:
October 30, 2013
TO:
Kent Halvorson
kent@halvorsonconstructiongroup.com
FROM:
Jeanie McConnell, Engineering Program Manager
RE:
Building Permit#: bld20130919
Project: Meadowview Estates –Grading, Driveway & Utilities
nd
Project Address: 15620 72Ave W
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 a Permit Coordinator.
City of Edmonds handouts and standard details can be referenced on the City website under Permit
Assistance.
10/18/2013 –Comments 1
10/30/2013 –Comments 1 revised to include additional storm comments shown in blue
GENERAL
1.Please revise plans to include downstream easement areas that benefit the subject property.
2.Please add a note to plans stating “A separate right-of-way construction permit is required for all
work within the city right-of-way. A ROW permit application with contractor’s signature shall
be provided to the city.
3.Please provide a written response from the geotech that the civil plans are consistent with the
geotech report. In addition, please respond to the following:
a.The geotech report discusses the on-site drainage system that was installed after the slide
of 1997. The plans show these improvements as existing, but it is not clear whether the
stormwater improvements will remain in place with the development of thissite. Please
clarify and if the system is proposed to be removed, please ask the geotech to comment
on this.
b.Will the storm conveyance system located within the 50-foot slope buffer need to be
relocated outside this buffer area?
STORMWATERREPORT
10/30/2013 -Comments from Jerry Shuster, Stormwater Engineer. Please contact Jerry at
425-771-0220 or jerry.shuster@edmondswa.govewith specific questions regarding these
comments:
Introduction:
The Stormwater pollution Prevention Plan prepared for this project (not reviewed by
this reviewer) states that the projectbeing constructed is more than one (1) acre.Based on this
information, the project cannot be classified as a small site project, as described in the drainage
report submitted for the project.Based on Edmonds Community Development Code (ECDC)
Chapter 18.30.050.A.1., this project classifies as a Large site project.Note that ECDC Chapter
18.30.050.A.2 states that Large Site projects also includes:
“If the project disturbs less than one acre of land and it is part of a larger common plan of
development or sale where land-disturbing activity involves one acre or more.”
This code section also applies to Meadowview Estates since the road project included in this permit
application is part of a larger common plan of development. Therefore, the Small Site Drainage
Report for this project does not meet the code requirements for the project.ALarge Project Site
drainage plan meeting all the applicable requirements found in ECDC 18.30.060 must be submitted
for the larger common plan of development.
Section 3 –Offsite Analysis:
This section adequately describes the up and downstream conditions
from a qualitative standpoint. The map on page 3-2 should differentiate between the City-owned
th
system (which begins at the east edge of the 75Pl W. right-of-way line) and the private system
th
(east of the 75Pl. W. ROW). The project is located within a“Puget Sound Piped” drainage basin
that is consider a “Direct Discharge Basin.”According to the Edmonds Stormwater Code
SupplementSection 4.7.1, this Large site project will be exempt from Large Site Minimum
Requirement #7 (Flow Control) if:
A quantitative Offsite Analysis as described in Large Site Minimum Requirement #10 is
performed by the applicant and no unacceptable downstream issues (such as a capacity or
erosion issue), are found.
A quantitative Offsite Analysis as described in Large Site Minimum Requirement #10 is
performed by the applicant, and one or more unacceptable downstream issues are
discovered. A plan is proposed by the applicant to mitigate for the unacceptable downstream
issue and the mitigation plan is approved by the Public Works Director or designee.
Section 4 (Flow Control Analysis) contains this quantitative offsite analysis.
Section 4 –Flow Control Analysis:
It appears that this analysis is done correctly but the following
information is needed verify the work:
Why a flow rate of 1.019 cfs was routed through the system for the project site.
A schematic showing the nodes used in the modeling
The survey and as-built information used to develop the model (pipe sizes, inverts, and
materials)
Page 2of 5
Explain how the WWHM4 land use categories translate into StormShed 2G modeling
(include all modeling input and output)
How was the flow rate of 0.2990 cfs ”from the municipal system” was obtained (show
drainage basin boundary, land use information, and times of concentration calculations,
including flow paths).
All the aforementioned required information can be included in a Large Site stormwater site plan
for the built-out condition for the project. This information will be reviewed by the City along with
the other required components of the plan during the next submittal.
1.Thestormwater report shall reflect the entire phased site development. For this reason, the
project is considered a Large Site Development. Please revise the report as needed to reflect
this.
2.The report states 2400sf impervious surface area for each of the4 proposed residences and
25,000sf for associated driveways, but the proposed driveways are not shown on the plans to
confirm that these areas were included in the calculation.
a.Please revise plans within the stormwater report and provide a breakdown forthe access
road and each single family residence (showing house and drivewayseparate).
b.The surface water runoff form the existing home shall also be collected and connected to
the storm water system and should therefore be included in the calculations.
3.The downstream quantative analysis is currently being reviewed by Jerry Shuster, Stormwater
Engineer. Any comments will follow these plan review comments.
Sheet 1 of 8 –CS-01-COVER SHEET
1.Revise note “Proposed BLA, TYP”to also state “under separate permit application”.
Sheet 2 of 8 –ER-01-TESC PLAN
1.Please revise sheet title to state TESC & demo plan.
2.Clearly indicate removal of all driveway areas –paved and gravel.
3.Revise plan to include temporary measures to control sediment laden runoff duringgrading and
construction efforts –such as swale, check dams, etc.Proposal shall be consistent with methods
allowed by the geotech.
4.Tree protection measures shall be shown on this plan or added to sheet TR-01 and referenced on
this plan sheet.
5.If the existing stormwater system (interceptor) is to be removed, please note as such on this
plan.If not, please indicate protection of this system.
Sheet 4 of 8 –RD-01-GRADING, ROAD & UTILITY PLAN
1.A lot of information is provided on this plan sheet. It would be great to have a separate site
nd
development plan sheet that shows property lines, easement areas, and access to 72Ave W.
2.Impervious Surface Area Chart: Provide a breakdown fortheroad and each single family
residence (showing house and drivewayareas separate).
3.A subdivision application has not been submitted and therefore with this phase of the project the
stormwater stubs provided to the south of CB-1 and to the east of CB-3 shall be eliminated.
You might consider installing a catch basin on the east side of the access road turnaround area
so the storm conveyance pipe under the proposed paved surface can be installed. This would
Page 3of 5
allow for future connection to this CB and conveyance pipe without or with minimal pavement
disruption.
4.Please confirm in the storm analysis that CB-3 will function sufficiently as the only catch basin
collecting runoff from the access drive and the 12” conveyance pipe with almost 90 degree bend
at CB-2 will maintain proper flow and not overflow at CB-2 during largestorm events.
5.Any pipe sections exceeding 20% slope shall be anchored. Please revise plans to show required
anchoring and incorporate associated details.
6.Show easement areas through downstream properties and until the point at which the private
th
system connects with the City storm system on 75.
7.If the existing stormwater system (interceptor) is to be removed, please note as such on this
plan.If not, please indicate protection of this system.
8.Show utilities from the existing home and how they will connect to the proposed utility stubs.
9.Indicate whether the existing home has an interior sewer ejector system or an exterior sewer
grinder pump. Will the existing system be replaced with this project?
10.Indiate RIM and invert elevations at the proposed SSMH-1. Provide a cross-section of this
manhole as well to show connection of the force line and gravity discharge.
nd
11.The existing SSMH in 72Ave W will need to be channeled to accept flows from the new
connection. Clearly show this on the plans and refer to City standard detail E6.1found on sheet
6.
12.Revise plans to show pavement restoration at the sewer connection and water service
connection.
13.Add cross section callout through access drive (showing direction of view) and refer to access
road and driveway cross sections found on sheet DT-01.As noted under DT-01 comments
below, a curb or thickened edge shall be required at the edge of the driveway to direct flows to
appropriate catch basins.
14.Revise water meter & service callout to state 1” water meter with 1” service. That is unless the
existing house does not need a 1” service, in which case standard detail E7.6 on sheet DT-02
should be revised to state ¾” service.In addition, note should be revised to reflect installation
of one meter only.
Sheet 6 of 8 –DT-01–NOTES AND DETAILS
1.Revise the General Notes to reference the current WSDOT standard specs.
2.Revise Driveway section details to include curb or asphalt thickened edge to control stormwater
runoff.
3.Please remove standard detail E5.1.1. Stormwater runoff cannot be directed back into the
ground at the subject site.
Sheet 7 of 8 –DT-02–NOTES AND DETAILS
1.Detail E6.9 is only partially applicable. Provide a detail that represents connectionof the force
main into a sewer manhole.
Sheet 8 of 8 –TR-01–TREE PLAN
1.Tree protection measures shall be shown on this plan or added to sheet ER-01 and referenced on
this plan sheet.
Please contact me at 425-771-0220 or by e-mail at jeanie.mcconnell@edmondswa.govif you have
specific questions regarding these plan corrections.
Page 4of 5
Page 5of 5