04-0019 Civil Review 2 040104April 1, 2004
Amtech Corp.
C/O Clarke Properties
PO Box 1409
Yelm, Washington 98597
RE: Amtech Parking Lot Expansion – Civil Engineering Review No. 2
City of Yelm Permit Tracking No. CIV-04-0019-YL
Dear Applicant,
I have review the information that was submitted with your application. The application consisted of Grading and Drainage Plans, Landscape and Irrigation plans and Stormwater Report.
The following comments need to be addressed before review can be continued and approval may be granted.
Stormwater Drainage Report:
The calculations for the stormwater treatment swale are not included in the stormwater report. These calculations should support the treatment of the stormwater. See 1992 DOE stormwater
manual for calculations.
How does the stormwater from the corners get treated when it enters the swale at the end of the swale? The design may need to channel the water to the beginning of the swale to achieve
the treatment.
Please include calculations for the existing swale to show that it is still able to treat the proper amount of stormwater.
The stormwater report needs to have a section for the methodology behind the calculations. It is unclear what the calculations are showing. Make sure the basin areas are consistent
sizes. The 2 year and 100 year basins are different sizes, they should be the same.
The bioswale minimum slope is 2%. The slopes shown on the plans are 4% and 7%.
Landscaping and Irrigation Plans:
The landscape plans need to show the proposed driveway location.
The perimeter landscaping will need to continue around the northern property line until even with the new proposed asphalt. See redline markups.
Please review the above referenced comments and revise the plans to address the comments. When resubmitting the plans, submit 2 storm drainage reports and 2 civil engineering plan sets.
If you have any questions or concerns please contact me at 360-458-8438 or email me at jimg@ci.yelm.wa.us.
Community Development Department
Respectfully
Jim Gibson
Development Review Engineer