REPORT ON THE FISHING, HUNTING AND RECREATIONAL ASPECTS OF THE PROPOSED BRIDGE AND MARBLE CANYON COLORADO RIVER PROJECTS ARIZONA GAME AND FISH DEPARTMENT PHOENIX, ARIZONA May, 1960 INTRODUCTION Under the Fish and Wildlife Coordination Act of August 12, 1958, Public Law 85-264, amending the Fish and Wildlife Coordination Act of March 10, 1934, as amended in 1946, it is the responsibility of the Arizona Game and Fish Department to report on the fish and wildlife aspects of any federal water resource development program, or any development by any public or private agency under federal permit or license, and to recommend measures which will prevent loss of and damage to fish and wildlife resources, as well as provide for the improvement of these resources in connection with such water developments. Under the laws of the State of Arizona, Section 17-231 ARS, the Department is charged with the responsibility of managing, maintaining and improving the fish and wildlife resources of the State. As a result of the above responsibilities, the Director and various members of the Arizona Game and Fish Department have visited the proposed Bridge and Marble Canyon sites by air and ground, the Bridge Canyon site by river boat, and made studies of the fish, wildlife and recreational potentials of the two development proposals. These investigations have been closely coordinated with the Arizona Power Authority and its staff members. Personnel . of the U. S. Fish and Wildlife Service have provided valuable information also. The Colorado River and Little Colorado River developments are proposed by the Arizona Power Authority of Phoenix, Arizona under application to the Federal Power Commission, dated July, 1958, and an amendment of the -2- application dated November 1, 1959, for a license under Project No. 2248. The Arizona Power Authority operates as a statewide power agency, marketing power from Hoover and Davis Dams and power purchased from steam generating plants, totalling about one billion kilowatt hours annually. Transmission is over Bureau of Reclamation lines under a contract terminating in 1987. The City of Los Angeles Department of Water and Power has applied for a license to construct a dam at the Bridge Canyon site, and one on the Little Colorado River at what is known as the Coconino site. The proposals, designated as Project No. 2272, are substantially the same as two of the developments proposed by the Arizona Power Authority under Project No. 2248, and the applicati on No. 2272 is in conflict. Several bills have been introduced in Congress to authorize the Bureau of Reclamation to construct a "high dam" at the Bridge Canyon site. This report will refer to the proposed developments of the Arizona Power Authority, but wherein applicable all comments and recommendations are to be considered as relative to the City of Los Angeles application or any other similar developments proposed on the Colorado or L i ttle Colorado River. - 3- PROJECT PROPOSALS The Arizona Power Authority proposes to construct a concrete arch dam at the Bridge Canyon site and another at the Marble Canyon site, each within the inner gorge of the Colorado River, for the purpose of developing hydroelectric power. In addition, two earth fill silt detention dams are proposed on the Little Colorado River drainage, one at the Moenkopi site and the other at the Tolchico site, to prolong the life of the Bridge Canyon project. In that the Bridge and Marble Canyon dams will be operated for hydroelectric power production, the surface elevation of the res.ervoirs behind them will fluctuate very little under normal operation. Construction is expected to begin on the Marble Canyon Dam four years after construction is begun at Bridge. • The location of each dam site and the reservoir areas behind each of the proposed dams will be described briefly, followed by a discussion of the recreational aspects of each. DAM AND RESERVOIR LOCATIONS Bridge Canyon The Bridge Canyon dam site is about 20 airline miles north of Peach Springs, Arizona, approximately 50 miles northeast of Kingman, in unsurveyed Section 22, Township 28 North, Range 12 West, at river mile 237. 5. This is approximately 117 miles above Hoover Dam. The waters of Lake Mead at maximum capacity will reach near the base of Bridge Canyon Dam. -4- The stream bed at the Bridge Canyon site is at Elevation 1200, approximately, and it is proposed to construct the dam to Elevation 1625 with the spillway at Elevation 1610. With the normal tailwater elevation at 1220 the reservoir will be about 390 feet deep at the dam. The lake area will extend approximately 50 miles upstream and to within about five miles of the west boundary of the Grand Canyon National Monument. It will cover approximately 6,400 acres and store about 820, 000 acre feet of water. The south side of the dam and impoundment area falls within the Hualapai Indian Reservation, the north side within the Lake Mead Recreational Area. The lake shoreline will fall well within the inner gorge of the Colorado River. The rim of this inner gorge is at about Elevation 2000 at the dam site and throughout the reservoir area the almost perpendicular walls of this inner gorge varies from 700 to 1,000 feet high. The outer rim of the canyon itself is at about Elevation 4600 to 4800, some 2,600 to 3,000 feet above the rim of the inner gorge. With the dam spillway at Elevation 1610, the reservoir shoreline will be 300 to 600 feet below the rim of the inner gorge and 3,000 to 3,400 feet below the outer rim, and access to the 50 mile long picturesque lake will not be readily available for recreational purposes unless provisions for such access are made. The proposed dam will be a double-curvature arch section 1, 100 feet long, with two gravity sections 17 5 feet long and a gated spillway section 243 feet long. The power houses will be located downstream -5- from the dam. Four turbines will be installed initially with provisions for the addition of four more. The dam will be constructed so that it can be raised 256 feet, to Elevation 1866. This will be comparable to the "high dam" which has been considered by the Bureau of Reclamation. Marble Canyon The Marble Canyon site is located just east of the Grand Canyon National Park boundary, about 85 miles north of Flagstaff, at river mile 39. 5 or about 40 miles below Lee's Ferry, and 55 miles below the Glen Canyon Dam. The area is unsurveyed. At spillway elevation the impounded lake will reach to the Glen Canyon Dam. The stream bed at the Marble site is at about Elevation 2825. The spillway will be at Elevation 3130 with a 290 feet depth above the tailwater. The lake area will extend 55 miles, cover 5300 surface acres and contain 480,000 acre feet of water. The area on the south is all within the Navajo Indian Reservation, on the north, U. S. National Fore st and public domain. For a distance of about ten miles within the forest the north shore rim is on the Game and Fish Commission House Rock Buffalo Range which is also an important winter range of the famous Kaibab deer herds. Here the Department has developed extensive pipe lines from springs,transplanted antelope, constructed an attractive area supervisor's headquarters and generally improved the historical 80, 000 acre deer and buffalo range during the past 20 years. -6- The major portion of this lake area also falls within the almost vertical 700 to 1,000 foot high walls of the inner gorge of the river canyon. This inner rim is at about Elevation 3600 at the dam site, From here the canyon walls slope up precipitously to the plateau at about Elevation 5800. Thus the surface of the lake at the dam will be almost 500 feet below the inner rim, about 2670 feet below the quite accessible plateau, At the upper end of the lake the distance from the plateau to the water surface decreases . There is no known place that existing foot trails reach the proposed lake shore line below Lee's Ferry. The proposed concrete arch dam will be 700 feet long at the crest with spillways at each end. Four power turbines will be installed initially with provisions made to add two more at a later date. Tolchico Dam The earth fill silt detention dam site is 102 miles up the Little Colorado River, six miles upstream from Grand Falls, and•approximately 40 air miles northeast of Flagstaff. It will be 490 feet in length, about 80 feet high and at its 600,000 acre foot capacity will impound a lake with about 28,000 surface acres. Uncontrolled outlets will be provided near the bottom of the dam. The entire development will be on the Navajo Indian Reservation. -7- Moenkopi Dam This earth and rock fill dam site is on Moenkopi Wash about a half mile above its junction with the Little Colorado River, two miles west of Cameron, along Highway 89 and 54 miles from Flagstaff. It will be 1300 feet long at the crest, about 130 feet high, impound about 1,000 surface acres and 50,000 acre feet at the spillway, Elevation 4230. Plans include the possibility of eventually raising the dam and spillway 30 feet. Three uncontrolled outlets will be provided, at Elevations 4150, 4178 and 420 5. The development site is on the Navajo Indian Reservation. It is estimated that the two Little Colorado River developments will impound an average of 9, 000 acre feet of sediment annually, reducing the sediment inflow to the Colorado above Bridge Canyon by 60%.