SCH Number 2024020908

Project Info

Title

Marsh Creek Erosion Repair and Improvement Project

Description

During the 2023 winter storms, the Department of Water Resources (DWR) became aware of a sudden and unexpected channel bank and bed scour and erosion within an approximately 1,000 linear foot (LF) reach of Marsh Creek and the distributary channel within DWR's Dutch Slough Tidal Marsh Restoration Project. Emergency temporary repairs included the placement of 1,740 tons of 18-inch minus rock protection to shore up a near-vertical eroded bank to protect the existing levee on the left (west) bank. The Project proposes improvements to permanently stabilize the eroding creek bed and banks and reduce future erosion under high flow conditions. On the left bank of Marsh Creek, the emergency rock armoring will be replaced with vegetated rock slope protection (RSP) along approximately 1000 linear feet. On the right bank of Marsh Creek, the slope will be graded to remove an existing earthen bench will be removed and the bank will be stabilized with brush matting, a biotechnical bank treatment along approximately 600 feet. The eroded left bank of the of the distributary channel will be rebuilt and stabilized with vegetated RSP along with approximately 200 linear feet. Approximately 850 linear feet of channel bed will be raised to pre-storm elevations using graded rock and native bed material to reduce future erosion potential. Bioengineering methods including vegetated RSP, brush mats, and willow pole plantings will be used as much as possible to provide improved riverine habitat value, aesthetics, and long-term sustainability, as compared to emergency measures.

2 documents in project