Feather River West Levee Rehabilitation
Project Areas A, B, C, & D
Sutter County, California
Project Area A The Feather River West Levee Rehabilitation project consisted of 11 miles of Segment 7 (Project Area A) along the Feather River. The goal of the project is to reduce flood risk and eventually remove more than 34,000 properties from FEMA Special Flood Hazard Areas. Compared historical seepage/slope stability issues, geomorphology, Helicopter Electromagnetic Surveys with new and historical boring logs, lab testing data and cone penetrometer data to provide preliminary and final levee rehabilitation options. Improvement options include installing seepage and stability berms, and soil/bentonite cutoff walls. Performed 2D steady state seepage and slope stability analysis at various cross section locations. Performed rapid drawdown analysis using Duncan, Wright and Wong methodology. Prepared Draft and Final Preliminary Geotechnical Design Recommendation Reports, Draft Geotechnical Recommendations Report, Draft Borrow Site Memo, and helped prepare a Geotechnical Data Report.
Project Area B & D
Crawford oversaw the verification drill logging and sampling program for the deep soil mixing (DSM) portions of the project. Oversaw the trench logging during the traditional slurry wall excavation and installation. Provided Geotechnical consulting during construction including review and summary the historical design boring logs with the new information obtained during construction. The Crawford team reviewed and compared the trench and boring logs with the samples collected in the field to ensure the logs were correct. The project is being completed within the guidelines of FEMA’s Flood Mitigation Assistance Grant Program to provide 200-year level of protection for urban areas in the Sutter basin and 100-year level of protection for non-urban areas.
Project Area C
Crawford was the contracted Geotechnical Engineer for the construction portion of the Project Area C levee rehabilitation project. Oversaw the verification drill logging and sampling program for the deep soil mixing (DSM) and the trench logging during traditional slurry wall excavation and installation. Provided Geotechnical consulting during construction including review and summary the historical design boring logs with the new information obtained during construction. The Crawford team reviewed and compared the trench and boring logs with the samples collected in the field to ensure the logs were correct. The project is being completed within the guidelines of FEMA’s Flood Mitigation Assistance Grant Program to provide 200-year level of protection for urban areas in the Sutter basin and 100-year level of protection for non-urban areas.
