Tidegates and Self-regulating Tidegates
Tidegates are typically one-way culvert placed under a levee or dike that separates freshwater and tidally influenced areas. It is designed to open and allow freshwater to drain to the sea during low tide, but to close at high tide.
Self-regulating Tidegates (SRTs) are a kind of tide gate technology that uses a float or another mechanism to detect water level, and delays closing of the tide gate until flood tide reaches a certain level. Compared to a standard tide gate or flood gate, a SRT maintains connectivity between the Salish Sea and tidal channels, purportedly improving water quality and access for estuarine dependent fish.
- Lyons & Ramsey 2013 provides an analysis of the Tide gate effects analysis work completed by the NWFSC
- The Tidegate Fish Initiative in the Skagit Delta defines a negotiated agreement that balances the diking and drainage district interests in maintaining drainage infrastructure, and the federal interest (as administered by NOAA) in recovery of Chinook salmon under the Endangered Species Act.
- The following restoration efforts have used self-regulating tide gates: