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1-2 . Chapter 1 Box 1-1. Glen Canyon Environmental Studies Glen Canyon Environmental Studies was formed on April 15, 1983 in response to public concern over the effects of Glen Canyon Dam operations on Grand Canyon resources. Reclamation Commissioner, Robert M. Broadbent, instructed Regional Director, Clifford Barrett (letter dated December 6, 1982), to determine the effect of present (1982) flow patterns on the canyon environment. In 1988, GCES submitted a Phase I Report (U.S. Department of Interior 1988), which determined that flood releases and fluctuating flows had substantial adverse effects on downstream resources. A review by the National Research Council (1987) of the National Academy of Sciences recommended further investigations to identify the causes of these effects. On June 19, 1988, the U.S. Department of Interior directed Reclamation to continue GCES with the recognition that sufficient data had not been collected or analyzed under Phase I to make operational decisions on Glen Canyon Dam. The Phase II program was designed to assess the relationship of low and fluctuating flows on specific resources in Grand Canyon and the potential economic impact of operational modification. The Phase II DIRP identified ten primary study components and one monitoring components to assess impacts of operations on specific resources (Fig. 1- 1 ). A series of hypotheses was developed by the GCES Senior Scientific Advisor, GCES researchers, interested groups, and the National Academy of Sciences to address specific questions for each resource (GCES 1990). was to understand the population ecology of the fish and identify responses to the operation of Glen Canyon Dam. These studies were a cooperative effort among Arizona Game and Fish Department (AGF), U.S. Fish and Wildlife Service (Service), National Park Service (NPS), Arizona State Final Report University (ASU), Reclamation, and the Navajo Nation, Hopi Tribe, and Hualapai Tribe. These entities comprised the Aquatic Coordination Team (ACT), a group of researchers that worked jointly and cooperatively to ensure an integrated research approach and. provided guidanc~ to a Senior Scientific Advisor and the GeES Program Manager. The NEF Studies consisted of Native Fish Studies in the mainstem Colorado River, Little Colorado River (LCR), and other tributaries. The Endangered Fish Studies consisted of eight study plans (Fig. 1-2). BIO/WEST was contracted by Reclamation to assist with study plan B-7 ( ecological studies of Gila) by conducting investigations in the mainstem Colorado River. These studies include the elements of early life history, adult movement, adult and juvenile demographics and habitat (Table 1-1). Results of these studies were provided to aid Reclamation in its mandated responsibility under Section 7 (a)( 1) of the Endangered Species Act of 1973, as amended, to .....utilize their authorities in furtherance of the purposes of this Act by carrying out programs for the conservation of endangered species and threatened species...... The Endangered Fish Studies of the Phase II DIRP were formulated in response to a 1978 Biological Opinion (Opinion) which determined that the operation of Glen Canyon Dam "...is likely to jeopardize the continued existence of the humpback chub... .. (U.S. Fish and Wildlife Service 1978). This determination was considered in developing the GCES Phase I Studies and, at their conclusion, the Service reinitiated consultation with the new information collected. The reconsultation resulted in seven conservation measures developed jointly by AGF, NPS, the Service, the Navajo Nation, and Reclamation: Conservation Measure 1: Taxonomic status of the genus Gila. Conservation Measure 2: Maintenance of hatchery stocks of Grand Canyon humpback chub. Conservation Measure 3: Ensure that flood releases from Glen Canyon Dam occur with a frequency of not greater than one in twenty years. Conservation Measure 4: Development of a management plan for the Little Colorado River.