Supplement to Biological Assessments for Development and Implementation of a Protocol for High-Flow Experimental Releases and Non-native Fish Control Downstream from Glen Canyon Dam, Arizona, 2011 through 2020.

摘要

The Bureau of Reclamation (Reclamation) is in the process of completing NEPA compliance for two separate but related actions: Development and Implementation of a Protocol for High-Flow Experimental Releases (HFEs) from Glen Canyon Dam, Arizona, 2011 through 2020 (HFE Protocol); and Non-native Fish Control Downstream from Glen Canyon Dam, Arizona (Non-native Fish Control). Reclamation completed biological assessments (BAs) on these actions and submitted them to U.S. Fish and Wildlife Service (USFWS) with requests for Endangered Species Act (ESA) section 7 consultation on effects of these actions on listed species. These requests were submitted to USFWS on January 21, 2011 (HFE Protocol) and January 28, 2011 (Non-native Fish Control). A recent finding of HFE analysis is that HFEs, and particularly those conducted in the spring, result in increases in the numbers of rainbow trout (Oncorhynchus mykiss) in the Lees Ferry reach (Korman et al. 2011). These increases, and in particular those resulting from the March 2008 HFE, also result in increases in downstream dispersal of rainbow trout into reaches of the Colorado River that are occupied critical habitat of the humpback chub (Gila cypha), where the trout prey upon and compete with this endangered species. A more detailed description of the relationship of high flows to trout and humpback chub is provided in Appendix A, as well as the Non-native Fish Control and HFE Protocol EAs and BAs (Bureau of Reclamation 2011a, 2011b, 2011c, 2011d).