3400 RIVERFRONT BLVD Geotech Report 2022-10-25 (2)

RESPONSE TO REVIEW COMMENT 12 As stated in our draft Summary of Settlement and Surcharge Analysis letter, we agree that the crest of the surcharge should extend at least 10 feet beyond the limits of the building and pavement areas. REVIEW COMMENT 13 Page 5 of the report states "The soil layer containing organics is located below the groundwater level..." This statement is not accurate as it relates to the fill, as there are abundant organics described in the fill, including a 2-foot thick wood shaving layer in TP-4 at a depth of 6 to 8 feet, which is above the water table. The water table was described on Page 2 as being at a depth of 15 feet. GeoDesign should evaluate the long-term impact of potential degradation of the organic materials in the fill and native soils, and describe the settlement impacts on the site improvements and structures. In addition, potential long-term settlement due to organic decomposition should be discussed as it relates to the 2 inches of long-term settlement expected at the site after the surcharges are removed. RESPONSE TO REVIEW COMMENT 13 We recommend that building footings be supported on soil that has been adequately improved or that additional explorations be performed to confirm that organics are not present in the fill layer beneath footings that could cause long-term settlement. The organics in the underlying silt soil are below the water table and not susceptible to degradation. As a result, we anticipate that the buildings will be minimally impacted by long-term settlement resulting from organic decomposition. REVIEW COMMENT 14 Page 5, Settlement of Existing Utilities. Show the location of all major utilities discussed in the report. Please also show the locations of significant ditches along the roads that will receive significant fill. RESPONSE TO REVIEW COMMENT 14 The locations of the major City utilities and the drainage swale that will be filled are shown on Figure 1. REVIEW COMMENT 15 Page 5 discusses "Settlement of Existing Utilities". We recommend that this discussion reference the URS report, and then address potential impacts of the site development plans on the existing utilities. RESPONSE TO REVIEW COMMENT 15 We will reference the URS report in the settlement section of the comprehensive geotechnical report that we prepare for the project. G EO DESIGN= 7 Polygon-128-01:0811 15