9931 19TH AVE SE 2018-01-02 MF Import

Page 2 wall face should not impact the structural integrity. It is important that a well -graded sand and gravel material (i.e. 5/9-inch crushed rock) be used as backfill behind the block wall. The crushed rock will protect the native silty sand condition expos^d in the glacial till cut, and reduce the amount of migration of fines into the wet cell. We do not expect significant water to seep from the pond through the low permeability glacial soils. We have prepared this letter for ARCO Petroleum Products Company and their agents, for use in planning and design of this project. The data and letter should be provided to contractors for their estimating purposes, but our letter, conclusions and interpretations should not be construed as a warranty of subsurface conditions. We recommend that we he retained to provide construction monitoring services to evaluate conditions encountered in the field with respect to anticipated conditions, to provide recommendations for design changes should the conditions differ from anticipated, and to evaluate whether earthwork activities comply with contract plans and specifications. Within the limitations of scope, schedule and budget for our services, we have strived to take care that our work has been completed in accordance with generally accepted practices followed in this area at the time this letter was prepared. No other conditions, expressed or implied, should be understood. It has been a pleasure to provide service to you on this project. If you have any questions or require further information, please call. Sincerely, NELSON-COUVRETTE & ASSOCIATES, INC. Rick B. Powell, PE Project Engineer RBP:CPC:dfr EXpniES b'1't 7 Charles P. Couvrette, PE Principal Engineer it