534 BuLi^TiN 95 



only 210 feet high would impound 16,000,000 acre- feet of water. 

 The greatest depth to bedrock, a factor of great influence on the cost 

 of a dam, is 121 feet, and the canyon is not narrow. This site should 

 be held available by the Federal Government until it is absolutely 

 certain that the site is not needed in the general scheme for develop- 

 ment of the river. If the site is restored to entry, it will be seized at 

 once by the Denver and Salt Lake Railroad. The railway can be 

 built around the reservoir site. 



A reservoir at the junction of the Green and the Grand has been 

 under consideration for many years. It would regulate partially 

 both streams. A dam 250 feet high would impound 7,450,000 acre- 

 feet. Borings were made to 120 feet without encountering bedrock. 

 It is unfortunate that the borings were not carried somewhat deeper. 



An apparently excellent reservoir site exists on the San Juan 

 near Bluff, Utah, but its feasibility has not been established by test 

 holes to find bedrock. A dam 264 feet high would create a reservoir 

 of 2,600,000 acre-feet capacity. The accumulation of silt in this 

 reservoir would be very rapid. 



The Glen Canyon, or Lee's Ferry, site outclasses all other pro- 

 posed sites in its gigantic possibilities. The maximum development 

 contemplates a dam 700 feet high, 450 feet long at the level of the 

 river, and 1400 feet long on top. The proposed slopes are one to six 

 downstream and one to four upstream, making the length of base up 

 and down stream over a mile. The capacity of the reservoir would 

 be over 50,000,000 acre-feet, and 86 percent of the entire water sup- 

 ply of the Colorado basin would be regulated completely. Over a 

 million continuous horsepower could be developed without sacrifice 

 of irrigation interests. Complete surveys of the reservoir site have 

 been made during the last few months. No test borings have been 

 made, and it is stated that the depth to bedrock is not a crucial matter 

 on account of the radical character of the dam contemplated. Test 

 borings should be made at once. 



Excellent dam sites exist in Cataract Canyon and Marble Canyon. 

 The project for Marble Canyon provides for a power development of 

 1,300,000 horsepower, but the storage possibilities are small. This 

 will be the last of the major projects because of its magnitude and 

 high cost. 



