Eng letter for Deten. Footing.pdfRAM
December 9, 2018
City of Edmonds Development Services Department
c/o JoAnne Zulauf, Engineering Technician
121 51h Avenue North
Edmonds, WA 98020
RE: Select Homes: 18807 188th St. SW
Plan Check PLN20170046
Detention Tank Underdrain Field Change
RAM Job No. 17-021
Ms. Zulauf:
Due to field conditions, the contractor has requested an adjustment to the underdrain to the detention
tank system. The detention tank underdrain system has been revised by connecting the underdrain pipe
system into the conveyance pipe between the restrictor CB#1 and the downstream connection CB 5-610
(existing catch basin in 1881h St. SW); the original design showed the underdrain connection directly into
existing CB 5-610. This adjustment does slightly raise the underdrain system elevation from the original
design. The adjustment is acceptable due to the fact the underdrain connection location is downstream
of the systems restrictor and the elevation of the system is still below the permanent ("dead water")
storage elevation within the detention tank system.
If there are any questions regarding the items above, please contact me at your earliest convenience; I
can be reached at (425)678-6960 or RobL@RAMengineeringinc.com.
Thank you,
1219118
Rob Long, PE
Principal