Correspondence (6) ALASKA
=111 SHANNON CALIFORNIA LSON, INC. COLORADO
FLORIDA
ENV GEOTECHNICAL AND ENVIPONMENTAL CONSULTANTS MISSOURI
OREGON
WASHINGTON
WISCONSIN
March 8, 2019
Jean Von Bargen Root
MWH Architects, Inc.
70 NW Couch Street,#401
Portland, Oregon 97209
RE: DURHAM ADVANCED WASTEWATER TREAT 1.4i ►
CITY OF TIGARD PERMITS
EMERGENCY OPERATIONS T '
TIGARD, OREGON
Dear Ms. Von Bargen Root:
Shannon&Wilson, Inc. (Shannon&Wilson), submits this geotechnical letter of compliance for
the proposed Durham Advanced Wastewater Treatment Facility(AWWTF) Conference Building
(BUP 2017-00174) and Operations and Maintenance(OM)Building(BUP2017-0017)located
south of the intersection of SW Durham Road and SW 85th Avenue in Tigard, Oregon. Shannon
&Wilson previously prepared a geotechnical engineering report' for the project.
Work on the Emergency Operations Center began in December 2015, and our involvement
continued through November 2018. During the construction period,we observed the subgrade
for the foundation subgrade for the new Conference Building. We also observed the subgrade
for the the new footings constructed as part of the Operations and Maintenance Building(OM)
expansion. Our services were provided on an intermittent and on-call basis. Copies of our field
visit reports were sent to you previously and are on file in our office.
Based on our intermittent observations of the above described elements,the observed
construction was completed in general conformance with the project specifications and the intent
of our geotechnical recommendations.
'Shannon&Wilson,Inc.,Durham Advanced Wastewater Treatment Facility Emergency Operations Center,Tigard,Oregon,dated April
2018,Shannon&Wilson Project:24-1-04105-001
3990 COLLINS WAY,SUITE 100
LAKE OSWEGO,OREGON 97035-3480
PHONE:(503)210-4750
FAX (503)210-4890
www.shannonwilson.com 101701
Jean von Bargen Root
MWH Architects, Inc.
70 NW Couch Street,#401
Portland, Oregon 97209
Sincerely,
SHANNON& WILSON,INC.
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Elliott C. Mecham, PE Jerry L.Jacksha, PE, GE
Associate Senior Associate
JJW:ECM:JLJ/amn:aeb:sno
CC: 'Nathan Streib,MWA Architects
Tim Rondeau, Clean Water Services
101701 CWS Durham LOC 101701