STORM1_BLD20200017_22810 Edmonds Way_Fill&grade0 E Mr STO RM WATE R REVIEW COMMENTS
U
City of Edmonds
Engineering Division
To: Applicant
Date: March 5, 2020
Project Name: Kisan Fill/Grade
Permit Number: BLD20200017
Address: 22810 Edmonds Way
Review Type: Fill/grade (Construction)
Submittal Date: 1/07/2020
Reviewer: Zack Richardson, PE
City of Edmonds, Stormwater Engineer
Recommendation: I recommend that BLD20200017 be withheld until the comments
below are adequately addressed.
Review Comments:
1. Drainage Report: It is unclear which BMP is being used to mitigate the frontage
sidewalk and which standard is being met to provide mitigation; revise frontage
sidewalk BMP to an appropriate BMPs or provide additional information about
which BMP is proposed and what standard was used to ensure adequate
mitigation.
a. The area appears to lack the necessary vegetated flow path to meet any
dispersion requirements for mitigation; show vegetated flow path area on
the plans along with surfacing/planting requirements in order to qualify as
a vegetated flowpath.
2. Drainage Report: The `mitigated' frontage sidewalk appears to have been fully
omitted form the WWHM model; update WWHM model to include the frontage
sidewalk area.
a. If a BMP is used to mitigate this area, it may be modelled as outlined in
the BMP description (as lawn for sheet flow dispersion), but it is not
removed from the model all together.
3. Drainage Report: Correct the totaled impervious areas on the drainage areas
exhibit; the 0.525 acres does not appear to match model.
4. Drainage Report: Include an exhibit or similar which demonstrates how the
engineer calculated the vault square footage used in the model; ensure square
footage correctly accounts for internal walls and external wall thicknesses.
Page 1 of 2
5. Sheet 2: Identify or callout the size for SDMH-1.
6. Sheet 2: Specify/callout a solid locking lid on SDMH#1, CB #2, and vault access
point.
7. Sheet 2: It appears the proposed storm drain connection (SDMH #1) will conflict
with existing sewer in Edmonds Way; update or address as needed.
8. Sheet 2: It appears the proposed sewer connection will conflict with existing
storm drain in Edmonds Way; update or address as needed.
9. Sheet 2: Correct callout arrow for CB #2 to point to the correct location of CB #2.
10. Sheet 2: Update vault detail to ensure access point are reflected and that all
propose access point are adequately shown.
11. Sheet 2: Provide, show, and detail as needed the 5x10' grate required for vault
over 1250 SF (see SWMMWW section for detention vault -access).
a. If placed in -lieu of a required access point, ensure grate has 3'x3' hinged
one-man access (hinged access not required if placed in addition to the
access points required).
12. Sheet 2: Provide, show, and detail as needed the required vents at the corners of
the vault (see SWMMWW section for detention vault -access).
13. Sheet 2: Update vault detail to show sloping of the vault floor; ensure sloping is
consistent with SWMMWW general design criteria.
14. Sheet 2: Update control structure detail to ensure step/ladder are extended to
within 12" of rim and bottom.
15. Sheet 2: Update control structure detail to remove the shear gate (not permitted
in Edmonds)
16. Sheet 2: It is not clear that the structural plans reflect the sump at the control
structure or all proposed pipe penetrations; update or address as needed.
17. Sheet 2: Correct callout for "phososorb" at CB #3 to ZPG; all media on the site
shall be consistent.
a. It appears a 27" cartridge could be used at CB #5 as well, consider
revising cartridge height to be consistent across site, for ease in
maintenance.
18. Sheet 2: Add to the CB #3 callout, and update the one provided at CB #5, the
correct reference location for the filter detail on sheet 5.
19. Sheet 2: Add callout or notes to this sheet, and details as needed on appropriate
sheet, to address the OSHA confined entry condition and signage for vault
access points.
20. Sheet 2: Correct control structure detail or update WWHM model to ensure
orifice size is consistent.
21. Sheet 3: Review notes that less than only 2.5" are left between CB #3 rim and
the garages of adjacent structures and only 0.6" is left between the garages and
ridge line for spill over to the next basin; reviewer recommends lowering the rim
of CB #3, and/or the valley of the ridge line, to the extent possible.
Page 2 of 2