05-0770 Review No. 2 012008City of Yelm
Community Development Department
105 Yelm Avenue West
P.O. Box 479
Yelm, WA 98597
January 20, 2008
Jeff McInnis
Petra Engineering
535 Dock Street, Suite 213
Tacoma, WA 98402
RE: Samantha Ridge- City of Yelm Project No. PRD-05-00770-YL
Second Review of Civil Construction Documents
Mr. McInnis:
The City of Yelm has completed the second review of the proposed Planned Residential
Development. Your application included:
• Transmittal
• Comments regarding Initial Review letter from City of Yelm
• Full Size Plans
• Drainage and Erosion Control Report
• Operation and Maintenance Plan
We have reviewed the plans for compliance with the City of Yelm Development Guidelines, the
DOE stormwater Manual and general standards of civil engineering practice. The following
comments need to be addressed before the plans may be approved for construction. I would
recommend we have a meeting to discuss these comments before you revise and
resubmit the plans.
Drainage and Erosion Control Report:
1. The report does not include the correct predevelopment storm event summary. It
appears that the post development summary was included with the wrong header.
2. The stormwater report does not include the disturbed pervious area of the project.
Please include this area in the calculations.
3. The report shows 3 stormwater basins included in the basin map. Please include
information on all stormwater basins. This should include calculations and assumptions
that have been made with these basins.
4. The report should include a level pool routing that includes the routing of the post
developed storms and the predeveloped release rates. It appears that each storm has
been routed in the hydrograph starting at elevation 330.00. Typically the 10 year storm
level should be starting at the top of the 2 year storm.
5. The report should include the orifice sizing calculations.
6. The stormwater design should include an overflow for the pond that has been sized to
accommodate the 100 year design flow.
(360) 458-8438
(360) 458-3144 FAX
www.ci.yelm.wa.us
7. The City of Yelm conditions of approval require you to get a Department of Ecology
Discharge Permit for discharging to Yelm Creek. In the past Department of Ecology has
questioned the Vortechs treatment device. It currently does not meet the DOE
requirements of basic treatment. It is approved for pretreatment only.
8. Please provide conveyance calculations for the level spreader piping.
9. It appears that there are many utilities under the stormwater pond. We can not maintain
these pipes when they are under the pond.
Sewer Plan Review:
10. The number of tanks planned for this project (29) must be reduced. Please use larger
tanks. This same comment was made on the 1St review when only 15 tanks were
planned.
11. The tank sizes need to be shown on the drawings. The step tank sizing must be in
conformance with Department of Ecology Criteria for Sewer Works Design Manual.
12. A 12" sewer main is planned for future capacity (not shown on the drawings). This new
main was to be installed next to the existing main. Please contact City to discuss
installation coordination.
13. Please include all updated sewer details pertaining to this plan.
14. Sta. 4+92.50 needs an end of line clean-out.
15. For clarity, all pressure lines going from the tanks to the main are called "service lines",
not force mains.
16. Please show all gravity side sewers.
17. All Pump Control Panels will need to be mounted on remote posts.
18. Please show the location of all service line valve boxes (Carson boxes).
19. Please show the location of hose bibs to enable servicing of the STEP Tanks. A hose
bib is required to be within 50 feet of a tank.
20. The reclaimed water line is not labeled on the plan. It appears that there is a utility main
running under units 5 and 13 and the stormwater facility. If this is actually the reclaimed
water main then you will not be allowed to construct the buildings on top of the main.
This may also apply to the electrical easement that is along side of the 20' utility
easement.
stormwater and Grading Plan Review:
21. Please revise stormwater table callouts for type 1 and type 2 catch basins.
22. The storm report states that the roof drains are going to be routed to the stormwater
system. Please show the roof drain leaders and connections to the stormwater system.
23. During review of the plans I was not able to find the min 2% call out for the driveways.
Water Plan Review:
24. When a property has a reclaimed water main running through it, all of the water meters
will need a Reduced Pressure Backflow Assembly installed following the water meter.
25. Sta. 2+17.39 -the sewer is too close to the water main. These must have 10 feet of
horizontal separation and 18" of vertical separation.
26. From Sta. 0+54.45, the new water main will need to be run straight to the existing main
under Crystal Springs Road. The connection shall be a hot tap to the existing main.
The project will need to cut and cap or plug the old main at the gate valve under Crystal
Springs Road.
27. The valves shown on the one inch service lines should be Corp Stops, not gate valves.
January 20, 2008 Page 2 of 3
28. The irrigation shows the backflow assembly before the water meter, this needs to be
behind the meter.
29. Please label the water main for removal. I was unable to locate the callout your
response refers too.
Irrigation Plan Review:
30. Irrigation plans have not been included in the construction drawings. Please submit
irrigation plans with the next submittal.
Misc Comments:
31. The City of Yelm no longer allows individual mail boxes clusters. Only metal CBU's are
approved for use in City of Yelm. Please remove the old City of Yelm detail and replace
with CBU detail from manufacture. This location must also be approved by the Yelm
Postmaster. Please submit a signed plan with the Yelm Postmasters' approval on it.
Please review and revise the plans to address the above referenced comments. When the
project is resubmitted you will need to submit 4 sets of plans, 2 stormwater reports. The project
engineer should include a written response with the resubmittal, indicating how all the review
comments above have been addressed or responded to. This will significantly expedite our
review of the project. If you have any additional questions or comments please do not hesitate
to call or contact me at jimg@ci.yelm.wa.us.
Community Development Department
Respectfully,
Jim Gibson P.E.
Development Review Engineer
cc. Jack Long, 115 5th Street NE, Auburn, WA 98002
January 20, 2008 Page 3 of 3