Peer Review letter 1.23.19i
t
SCJ ALLIANCE
CONSULTING SERVICES
January 23, 2019
Tami Merriman, Associate Planner
City of Yelm Community and Economic Development Department
105 Yelm Avenue West
Yelm, WA 98597
Re: 2nd Peer Review —Yelm Auto Recycle (AKA NPR Recycling)
SCJ Project No. 0605.05 Task 41
Dear Tami:
The City has requested SCJ Alliance conduct a second peer review of the construction documents for the
above referenced project. We have performed the review based on the City of Yelm Municipal Code,
Development Guidelines, 2014 DOE Stormwater Management Manual and known City policies. This
review consisted of the following documents:
• Construction Plans — dated 12/17/2018 — Please note that the deferred improvements for the
road frontages, including related drainage improvements, were not reviewed. It is assumed
these will be resubmitted for permit when road frontage construction is required.
• Drainage Report - dated December 2018 — Please note that models and information for Basins 1
and 4 were not reviewed as these will be for deferred improvements. It is assumed these will be
resubmitted for permit when road frontage construction is required.
• O+M Plan
Our comments and observations from the review are:
Construction Documents:
Sheet C1.1
1. The trash enclosure dimensions on the detail provided on Sheet C1.2 do not match what is
shown on Sheet C1.1. Please revise.
2. The concrete for the driveway aprons should extend to the new right -of line. Please revise.
Sheet C3.1
3. Given the high permeability of the site soils and flat ditch slopes, how will infiltration of water
into the v -ditches be prevented? If flows infiltrate within the v -ditches, they will be doing this
prior to treatment which cannot occur. Either provide upstream treatment or provide a method
to prevent infiltration within the ditches.
4. The grading proposed in the areas of drainage Basins #1 and #4 do not appear sufficient to
promote sheet flow towards the drainage facilities. It seems these grades could be tightened up
to provide more defined flow towards these facilities.
8730 Tallon Lane NE, Suite 200 • Lacey, WA 98516 • Office 360.352.1465 0 Fax 360.352.1509 scjalliance.com
January 23, 2019
Page 2
5. How will drainage enter the biofiltration cell for drainage Basin #1? Currently it appears that
flow will just sheet flow to it? How will the side slopes be protected from erosion?
6. Please provide details for catch basins number 13 and 14.
7. The proposed grading contours associated with the v ditches appears to have been turned off or
made too light to see.
Sheet C3.2
8. The proposed grading contours associated with the v ditches appears to have been turned off or
made too light to see.
9. Update the note as indicated on the attached redline.
Sheet C3.3
10. Provide additional requested cross section information on the attached redline.
11. Cross Section 3 has some incorrect elevations referenced per the attached redline.
Sheet C4.1
12. The entire building face is not within 150 feet of a hydrant. Please provide an additional hydrant
to provide sufficient fire protection.
Drainage Report:
13. Please update the section on page 1-2 which describes the conveyance system. Conveyance for
this site also contains V -ditches.
14. For the Basin #3 conveyance calculations in the Appendix, the v -ditch is identified at the top of
page as having a slope of 10.5%, the calculations on the same page used 0.5 % slope and per the
drawings the slope is 1.0%. Based on the drawings, the 1% slope appears to be correct. Please
update the calculations to the correct slope and verify associated velocity. Per the 2014 DOE
Stormwater Management Manual for Western Washington BMP C201, grass -lined channels
have a maximum velocity allowed of 5 feet per second.
15. As the slopes of the v -ditches are variable, individual velocity calcs are needed for each v -ditch
to confirm that the velocity in each ditch is below 5 feet per second.
Should you have any questions or comments, please contact me at (360)352-1465 at your earliest
convenience.
Principal
N:\Projects\0605 City of Yelm\605-05 Civil Plan Reviews\Phase 41- NPR Recycling\Correspondence\To\Yelm\2nd Construction Permit
Review\L-2019-0116 Review Letter.doc