20100177 Peer Ltr 2 06282011SHEA - CARR - ~1EWELL
ENGINEERING AND PLANNING SERVICES
June 28, 2011
Mrs. Karen T. Bennett
Administrative Support
City of Yelm Community Development Department
105 Yelm Avenue West
Yelm, WA 98597
Re: 2"d Peer Review -Site Construction Documents
Salmon Run Apartments
SCJ Project #0605-05/25
Dear Karen:
As you requested, Shea Carr Jewell has reviewed the resubmittal of the Salmon Run Apartments which
addressed the comments from our first peer review.
The review documents included:
• Civil engineering plans signed June 17, 2011
• STEP System Report signed June 17, 2011
• Drainage and Erosion Control Plan Report signed June 17, 2011
• SWPPP signed June 17, 2011
• Stormwater O&M Manual signed June 17, 2011
Our comments are as follows:
Storm Drainage Report:
1. The modeling of Basins A, B, and C have all impervious areas and no disturbed pervious areas
modeled. The total site area is 2.52 acres and only 1.44 acres of area has been modeled. What will
happen with the remaining 1.08 acres of disturbed area?
2. The methodology used to approximate the volume provided by the trench and pipe does not allow
for a check that adequate freeboard has been provided for the system. In order to check to see if
the suggested minimum 0.5 feet of freeboard is provided, the overflow would needs to be set at a
depth 0.5 feet below the maximum height of the facility. For instance, you would set a riser at 2.5
feet fora 3 foot deep facility. As long as no flow is within the riser, the minimum freeboard has
been achieved.
2102H Carriage Drive SW -Olympia, WA 98502
Office: 360.352.1465 ~ Fax: 360.3521509 ~ Email: info(a sheacarrjewell.com ~ www sheacarrjewell,com
Mrs. Karen Bennett
.~..
_. "~ June 28, 2011
Page 2 of 3
Using the equivalent depth method that was used does not allow for a check for freeboard. The
model does not identify how high the water reached within the facility so the 100% infiltration
demonstrated may have been achieved with a totally full facility.
Please revise the methodology for approximating the volume provided using accurate depth
information. I have seen other galleries modeled with multiple layers with one layer approximating
the pipe with 100% porosity.
Construction Plans:
Sheet 3 of 27:
3. As the driveways proposed are analogous to road approaches, a minimum 25 foot radius is required.
As an alternative, a concrete approach apron can be used instead (City of Yelm Detail 4-9).
The clear width requested per comment #21 in the first comment review letter does not appear to
be addressed. There should be a minimum of 3 feet between the edge of the detectable warning
strip and the back of the sidewalk to provide adequate turning area. Currently it appears that only 2
feet have been provided.
Sheet 7 of 27:
5. The gallery on the far east side of the site has only 6 inches of cover in a vehicle area. According to
sheet 8 of the set, the paving section is 6 inches and shall have a compacted subgrade. Therefore,
for this area, the gallery is the subgrade for the pavement. Please revise.
Sheet 10 of 27:
6. There is a keynote 35 and the sewer information table stops at keynote 34. Please revise.
Sheets 11 and 12 of 27:
7. The STEP Tank table on sheet 12 shows only one tank for Building E and there are 2 -tank #8 and
tank #9. On this same table, the tank for building F should be tank #10 and not tank #9 as labeled.
The detention volumes provided in the STEP Tank Tables and those listed in the STEP report don't
seem to match. Plus, often the storage volumes provided exceed the total volume of the tanks. For
instance, between tanks 1 and 2 for building A, it is shown that there is 6,950 gallons of detention
volume, 265 gallons of working volume, and 4,665 gallons of storage volume. That is a total of 11,
880 gallons and the two tanks should only have 9,000 gallons of total volume. Please revise or
clarify.
9. The profile ends before the end of the public main line. The public main line ends at the end of line
cleanout. Please include the complete public main in the profile.
w- +
Sheet 15 of 27:
Mrs. Karen Bennett
June 28, 2011
Page 3 of 3
10. The RPBA for the domestic water services is an above ground structure per the City Standard Detail
6-17. It appears that many of these are proposed for installation within the sidewalk. It needs to
be ensured that the RPBA installation does not interfere with sidewalk use.
11. Per the fire code, FDC's shall be located on the street side of buildings. In the case of a parking lot,
they should be on the parking lot side of the building for access. Coordinate with the Fire Marshal,
Gary Carlson on appropriate locations.
12. Typically, all FDC's must be within 30 feet of a fire hydrant. Most of the proposed FDC's do not meet
this requirement.
Should you have any questions or comments, please contact me at (360) 352-1465 at your earliest
convenience.
Sincerely,
SrYS~~ f err ln~Riall
N:\Projects\060s City of Yelm\605-OS Civil Plan Reviews\Phase 25-Salmon Run Apartments\Correspondence\L-2011-0627 2nd peer review
commentltr.doc
Associate Principal