Laserfiche WebLink
<br />, <br /> <br />. ' <br /> <br />BIOLOGICAL ASSESSMENT OF A ONE TIME TEST OF <br />BEACH/HABITAT-BUILDING FLOW <br />FROM GLEN CANYON DAM <br />SPRING 1996 <br /> <br />INTRODUCTION <br /> <br />This biological assessment was prepared in compliance with Section 7 of the <br />Endangered Species Act of 1973, as amended. The Bureau of Reclamation <br />proposes to conduct a one time test of a beach/habitat-building flow from Glen <br />Canyon Dam (test flow) in the spring of 1996 to allow for collection of data <br />for use in determining future dam operations. <br /> <br />Six species identified as threatened or endangered are addressed in this <br />assessment: Kanab ambersnail (Oxvloma h~vdeni kanabensis), razorback sucker <br />(Xvrauchen texanua), humpback chub (Gila evohal, bald eagle (Haliaeetus <br />leucocech&lus), peregrine falcon (Falco perearinus), and southwestern willow <br />flycatcher (Emnidonax trailii Axtimus). The list of species is based on <br />discussions with the Fish and wildlife Service (Service) and previous <br />consultations. Impacts of the test flow on endangered species may result <br />from: physical displacement, injury, or death; loss or alteration of habitat; <br />reduction in food availability; or alteration of interactions with other <br />species (Bureau of Reclamation 1995). This biological assessment summarizes <br />the distribution and abundance, life requisites, and potential impacts of the <br />test flow on these species and their habitats. <br /> <br />Background <br /> <br />Glen Canyon Dam is located in north-central Arizona in Coconino County one <br />mile west of Page, Arizona (See Fig. 1). Glen Canyon Dam regulates the <br />Colorado River's flow through lower Glen Canyon and all of Grand Canyon, and <br />is managed in accordance with the Colorado River Compact and the Colorado <br />River Storage Project Act (1956). <br /> <br />In the Colorado River corridor, flow regulation has resulted in erosion and <br />depletion of lateral sand deposits, particularly in narrow reaches of the <br />river, loss of 50% of the native fish species and other changes in the river <br />ecosystem. These impacts focused public and scientific attention on the need <br />for modified operation of Glen Canyon Dam, resulting in a recently completed <br />Environmental Impact Statement (GCD-EIS, Bureau of Reclamation 1995) . <br /> <br />The Grand Canyon Protection Act of 1992 (P.L. 102-575) requires the Secretary <br />of the Interior to operate Glen Canyon Dam ",. .in such a manner as to protect, <br />mitigate adverse impacts to, and improve the values for which Grand Canyon <br />National Park and Glen Canyon National Recreation Area were established, <br />including, but not limited to natural and cultural resources and visitor use." <br /> <br />1 <br />