The Pajaro River Bench Excavation Project is designed to relieve the magnitude and severity of potential future flooding of the Pajaro River levees by “de-stressing” and creating benches along the existing levee system. The California Department of Water Resources awarded approximately $6 million to the local sponsor counties to implement bench excavation within the existing levees as an interim measure until the flood risk management project is finalized and implemented.Bench excavation refers to the excavation of excess sediment from select locations along the upper terrace benches inside the Pajaro River. This process improves the flood carrying capacity of the levee system and helps maintain a shaded low-flow channel for critical fish passage. Bench excavation will eventually become self-maintaining and will help the river regain its natural ability to move sediment through the river channel system by natural geomorphic processes, as it did originally.
Project Limits
Highway 1 to Murphy Road (7.5 miles)
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Project Description
The project construction leaves a 50-foot wide buffer against the levees in both straight reaches and inside meanders, and a 100-foot wide buffer adjacent to outside meanders along the upper 7.5 miles of the Pajaro River.
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At the ordinary high water mark, a 2 year flow event reconnects the river with its floodplain at bank-full capacity. This is a more self-maintaining scenario for the river, restoring the river’s natural ability to effectively move and transport sediment out of the river channel to the ocean by natural geomorphic processes.
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- Bench Excavation will add 10 percent to the carrying capacity of the flood water and reduces the potential water surface elevation flood height by up to 1.2 feet.
- Bench Excavation is a maintenance project, not an element of the USACE flood control project.