The Hallwood Side Channel and Floodplain Restoration Project

Inside this post, you learned about a local project featured in the ASCE Civil Engineering Magazine by April Sawyer, M.S. from cbec inc., eco engineering

ABOUT THE PRESENTATION:

The Hallwood Side Channel and Floodplain Restoration Project is a multi-benefit project designed to restore and enhance ecosystem processes with a primary objective of enhancing productive juvenile salmonid rearing habitat to increase the natural production of fall‐run and spring‐run Chinook salmon (Oncorhynchus tshawytscha) and Central Valley steelhead (O. mykiss) in the lower Yuba River. Planning, permitting, design, and monitoring were initially funded by Central Valley Project Improvement Act (CVPIA via the United States Bureau of Reclamation) grants through the United States Fish and Wildlife Service’s Anadromous Fish Restoration Program (USFWS AFRP). Yuba Water Agency is providing funding as the Project’s implementation lead with assistance from Proposition 68 and Wildlife Conservation Board (Proposition 1) funding. The Project is intended to directly address the AFRP doubling goal to increase the production of natural anadromous salmonids in the Central Valley. The Project will be implemented over 5 years, divided into four areas/phases, and will rehabilitate or enhance up to 157 acres of seasonally inundated riparian floodplain. Phase 1 was implemented in 2019-2020 and created/enhanced 89 acres of seasonally inundated floodplain, 1.7 miles of perennial channels, and 3.7 miles of seasonal channels.  Phase 2 was completed in November 2021, in which 34 acres of seasonally inundated floodplain habitat and 1.6 miles of seasonal channels were created, and 24 large woody material structures were installed. Across Phases 1 and 2, approximately 44 acres of riparian vegetation were planted across the combined 123 acres.

During Phases 3 and 4, an additional 34 acres of seasonally inundated floodplain habitat will be created. Phase 3 is being implemented in 2022, enhancing 13 areas of seasonally inundated floodplain and creating 0.7 miles of seasonally inundated channels. Phase 4 is funded and is planned to be completed in 2023, enhancing 21 acres of seasonally inundated floodplain and creating 0.9 miles of seasonally inundated channels. An additional 10 acres of riparian planting in Phases 3 and 4 are also planned for 2023. Large woody material will also be installed within the Phase 1, 3, and 4 footprints over the course of the 2022 and 2023 implementation years. Once completed (i.e., Phases 1-4), the Project will result in up to 3 feet of water surface elevation reduction for the 100-year design flow. This water surface elevation reduction is a result of removing 3,200,000 CY of sediment from the floodway, most of which comes from large linear tailings piles that separate the main channel from its floodplain.

What you learned about in this presentation:

• Floodplain Ecosystem Enhancement
• Fish Passage Restoration

ABOUT THE PRESENTER:

April Sawyer, M.S.:

April Sawyer is a Senior Ecohydrologist at cbec inc., eco engineering in West Sacramento, California. April is the project manager for the Hallwood Side Channel and Floodplain Restoration Project and has been involved in the concept development, design, permitting, monitoring, and project implementation since 2012. April has a background in fluvial geomorphology and hydraulic modeling to assess salmonid habitat suitability and restoration design alternatives. She enjoys working on multidisciplinary projects crossing the physical and biological domains. 

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