WSP12649 - Laserfiche WebLink

Home Browse Search

001533 in Grand Canyon National Park (GCNP) is being investigated by National Park Service (NPS). If non-native removal is successful and suitable, additional translocations can be contemplated. Moving young HBC to other tributaries as in-situ refugia would decrease the risk of catastrophic events to the LCR HBC population and allow opportunities for translocated HBC to grow prior to migrating to the mainstream. ELEMENT 1.B Reclamation shall implement a selective withdrawal program for Lake Powell waters and determine feasibility. PROGRESS ON ELEMENT1.B Reclamation has continued to work on the feasibility assessment since the decision was made to rescind the draft environmental assessment on the proposed temperature control device (TCD) released in January 1999. The TCD is often portrayed by fisheries biologists as likely the most important management tool for endangered fish in the Colorado River below Glen Canyon Dam, but also a tool that could have negative effects if mismanaged (Valdez and others 2003). In 2002, Reclamation conducted a survey of operators of dams having selective withdrawal devices, including TCDs, to determine whether concerns evidenced by scientists and managers for effects of the Glen Canyon Dam TCD have been experienced at other facilities. Results of this survey and other related investigations were presented to the AMWG at their July 2002 meeting and were subsequently published in Vermeyen (2003). No major environmental complications were identified in the survey results. In summer 2002, the AMWG recommended that Reclamation should solicit a risk assessment of the Glen Canyon Dam TCD proposal from the GCDAMP Science Advisors. Subsequently, the Advisors produced a report on their findings of risk assessment (Baron and others 2003) which recommended the installation of a TCD for Glen Canyon Dam as soon as possible and the construction of a pilot TCD in the interim. The Science Advisors further recommended a strong leadership role from AMWG, TWG, and GCMRC related to the installation and operation of a TCD along with a commitment from all parties to incorporating the TCD into the GCDAMP and the research required to evaluate the TCD's effects. At the August 13-14, 2003 meeting, the AMWG recommended to the Secretary of the Interior that Reclamation should initiate environmental compliance associated with the construction of a TCD. Reclamation has moved forward with that action and has concurrently initiated a feasibility-level construction design assessment for the TCD. STATUS OF ELEMENT 1.B Onaoing. Following the results of scientific investigations, expert workshops, and a risk assessment, Reclamation advocates that the feasibility assessment requested by the Service has proceeded to the point where it is justified to develop environmental compliance documents to assess the potential effects of constructing and operating a TCD. If the decision is made to proceed, testing of the TCD would occur under the auspices of the GCDAMP using a science plan developed by GCMRC, cooperating scientists, and the Technical Work Group. Reclamation is proposing that the test of the TCD be accomplished by modifying two penstocks on Glen Canyon Dam and operating the dam for a period of 3-4 years with assessment through the GCDAMP before a subsequent decision is made on further modification. Testing of the TCD would be the next phase in the feasibility assessment called for by the Service. The science plan will 5