Returning open tidal exchange to diked lands is a primary goal of Delta restoration, driven by the 2008 Biological Opinion from USFWS. This document requires 8000 acres of tidal and subtidal habitat to be created. California EcoRestore is coordinating with state and federal agencies to restore at least 30,000 acres, much of which will be tidal or subtidal. Evidence from newly created tidal wetlands, however, does not support the basic concept behind these restoration actions: that dikes can be breached and then left alone, to create tidal habitat with high benefits to endangered fishes.