There have likely been significant adverse, unintended consequences of breaching levees in the Delta. There is a high probability that site-specific conditions at the breaches have resulted in hazards for juvenile anadromous fish through the creation of favorable predator habitats. The breaches have changed the tidal prisms in the Delta and can change the degree in which juvenile fish are affected back and forth with the tides. Additionally, many of the breaches are narrow which have created deep scour holes favoring predatory fish and high presence of striped bass. These areas are now predation “hot spots”. Sport anglers are often seen fishing for striped bass at these sites during flood or ebb tides. Breaching the levees at Liberty Island is an example. Recent acoustic-tagging of striped bass in this vicinity confirmed this. Many of these levee breaches have been present for numerous years, but nevertheless still pose significant hazards for juvenile anadromous fish.
This project proposes to significantly widen the breaches and feather the edges to eliminate the scouring affect.