8271-030102-groundwaterMarch 1, 2002
Mr. John Knowles
John Knowles and Assoc., Inc.
P.O. Box 1328
Puyallup, Washington 98371-0197
RE: Timbertec – File No. SPR-00-8271-YL
Infiltration Pond Construction
Dear Mr. Knowles:
As you know, the construction of the infiltration pond at the above referenced site has commenced. During the excavation of the infiltration/wetpond facility, groundwater was encountered.
In the stormwater report, you utilized the information from AGI Technology’s soils report and your knowledge of the public work’s yard soil work. In both examples, the ground water
was encountered at approximately 13 feet. The DOE manual requires the infiltration pond bottom to be at least 3’ above groundwater. At this time, the city is not requiring you to redesign
the stormwater facility. The city needs you to inspect the site and respond with a letter stating your findings and conclusions. This letter should clearly state if this groundwater
condition is going to affect your infiltration design. This letter will be added to the stormwater report as supporting information for your design.
If you have any questions or comments please call me at (360) 458-8438 and I will be happy to further assist you.
Respectfully,
City of Yelm Community Development
Jim Gibson
Development Review Engineer
Cc: Tim Peterson
Enc: