Establishment of a New Wild Population of Kanab Ambersnail in Grand Canyon

Environmental Assessment
June 1998

The 1996 and 1997 U.S. Fish and Wildlife Service Biological Opinions on the operation of Glen Canyon Dam stipulate the need to establish or discover a second population of the endangered Kanab ambersnail (KAS; Succineidae: Oxyloma haydeni kanabensis Pilsbry, 1948) in Arizona before additional Beach/Habitat-Building Flows (BHBF) can occur. BHBFs are controlled floods from Glen Canyon Dam designed to redistribute sediments from the channel bottom to the river banks.

Interagency ecological studies and monitoring of the KAS population at Vaseys Paradise, Grand Canyon were conducted between 1994 and 1997. These studies have documented flood impacts to the KAS population and its habitat during the first BHBF in 1996, and subsequent high flows in 1997. Beginning in 1996, the Arizona Game and Fish Department (AGFD) surveyed and evaluated 74 springs, seeps, and wetlands in Grand Canyon and northern Arizona for suitable KAS habitat; no additional KAS populations were found. Eleven sites in Grand Canyon National Park were identified as optimum or more desirable in biological and environmental conditions for establishing new KAS populations.

Grand Canyon National Park and AGFD jointly submitted this draft environmental assessment in the process of establishing new KAS populations. Public Comment period for the EA ended August 5, 1998.

This Environmental Assessment (EA) is available as a PDF file. PDF files retain the look and feel of the original document (including typography, page layout, and graphics).

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