1500 INDUSTRY ST 2018-01-01 MF Import

:�ent by: Earth Consultants 425 746 08fi0; OG/1g/02 q:57PM;J;IFa: q563;Page 3 � Panattoni Development E-1D134 June 19, 2002 Page 2 Infiltratian Evaluation We understand it is planned 2o infiltrate rooi downspout stormwater from the proposed development at each building location. As part of this evaluation, we conducted an iniiltration evaluation to determine the feasibility of infiltrating stormwater and roof runoff at the site. At the time of our study, we were p�ovided with a general location for the proposed infiltration areas. Our infiliration evaluation consisted of the following: r • Excavating eight test pRs at the proposed infiltration areas; • A textural analysis of representative soils from the infiltration areas; and • Intcrpreting the field data and laboratory analyses in order to �rovide infiltration rates for the proposed iniiltration areas. Textural Analvsis ( Subsurface conditions were evaluated by excavating eight test pits within the proposed infiltration locations. Test pit logs are presented in Appendix A. Grain size � analyses were conducted on representative soils, Based on our grain size analyses, the proposed infiltration areas in ihe vicinity of Test Pits TP-1 througn 7est Pit TP-6 are underlain by coarse sands. 7he proposed infiltration areas in the vicinity of Test Pit TP-7 is underlain by fine sandy loam, and Test Pit TP-8 is underiain by a roximatel five PP Y Seet of coarse sand overlying fine sandy loam. No groundwater ; seepage was encountered at the time of tf�e field work (June, 2UO2). The soil conditions enc�untered at the site are consistent witii geologic maps for this ' I vicinity. Soils in tf�e proposed development are mapped as advance glacial o�twash, consisting primarily of poorly sorted sands with variable gravel content underlying silty sand with gravel glacial till. Infiltration Recommendations E3ased on the results of the field eaploration and textural analyses, ii is ECI's opinion that infiltration of stormwater and roof runoff should be feasible in the proposed development areas in tha �icinity of T its TP-1 through i est Pit TP-6. For design, an ultimate ir,filtration rate of cwenty (2�0 inches per hour can be used. Infiltration in the vicinity of 7est Pit TP-7, below fiv fieet, and Test Pit TP-B will not be feasible. nb ConeultaMe, Inc. � � / �P�✓�(�l� A'1`�v ' 55 � i I