Corte Madera Creek Levee Evaluation - Marin County Flood Control District
Key Features
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Comprehensive evaluation of 2.6-nautical-mile-long existing USACE levee system per FEMA and USACE requirements (embankment protection, embankment and foundation stability, seepage, settlement, liquefaction, and interior drainage were evaluated)
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GIS database development, bathymetric surveying, H&H analyses, geotechnical investigations were conducted
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Identified deficiencies in current system and developed conceptual-level designs for remedial improvements
Geotechnical Challenges
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Deep Bay Mud site with ongoing consolidation settlement and intermittent sand layers with increased seepage
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Characterization of an existing levee system constructed with variable fill
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42-inch-diameter sewer force main pipe within the existing left-bank levee
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Constructability issues with many areas accessible only by water at high tide
Innovative Solutions
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Use of the Giken silent hydraulic pile press-in installation system
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Use of tide gates to prevent flooding by automatically closing when water levels reach a set flood level
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Use of passive flood gates and pump stations to protect interior flooding
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Constructing new levees, flood walls, and modifications to existing levees to increase flood protection