NATIONAL RECLAMATION OF ARTD LANDS. 475 



IDAHO. 



Minidoka project. — The Minidoka irrigation project is located in 

 Lincoln and Cassia counties, Idaho, and embraces an area of about 

 150,000 acres of sagebrush land on both sides of Snake River. 

 The area to be benefited was all Government land, and was divided 

 in farm units of 40 and 80 acres. Practicall}^ all of the land has 

 been filed upon by bona fide settlers. The average elevation is 

 about 4,200 feet above sea level. The irrigable land is a vast un- 

 broken plain possessing soil of great fertility, a deep sandy loam 

 free from alkali, and covered with a heavy growth of sagebrush. 

 The country is lacking in salient topographic features. Knobs and 

 ridges occur here and there, and near the river there is a belt of low 

 sand dunes which nowhere rise higher than 10 feet above the level 

 of the surrounding country. The land slopes generally southwest- 

 ward rather than toward the river. 



The Minidoka dam. — The location of this dam is about 8 miles 

 southwest of Minidoka, at a point where the channel of the river has 

 been crossed by recurring lava flows of the earlier geological ages. A 

 ridge of lava probably extended at one time entirely across the river 

 channel at this point, and the stream has gradually cut its way 

 through it, j)roducing a comparatively narrow opening and a series 

 of rapids. Above the dam site the valle}^ widens out somewhat, 

 forming a small storage reservoir; below it the valley consists of 

 broad and extensive flats suitable for irrigation. 



The purposes of the dam are mainly control, diversion, and power 

 development. To provide for these purposes and to care for the 

 immense floods to wdiich the river is at times subjected, the dam and 

 appurtenances consist of the following parts : The headworks of the 

 north-side canal; the connecting concrete wall extending from this 

 structure to the sluiceway; the sluiceway, including the controlling 

 works and power-canal penstocks ; the main earth and rock-fill dam ; 

 the spillway; the headworks of the south-side canal, and an earth 

 embankment carried to high ground on the left of the river. 



The headworks of the north-side canal and the controlling works, 

 including the connecting wall located on the right bank of the river, 

 form a continuous concrete structure about 350 feet long, and contain 

 about 8,200 cubic yards of concrete and about 55,000 pounds of 

 reinforcing steel. The headworks of the canal contain nine gates, 

 each 5 feet wide by 7 feet high, and the controlling works contain 

 five Coffin gates, each 8 feet wide by 12 feet high. The controlling 

 works are founded throughout on solid rock. 



The main dam is of the gravity type, and is composed of rock- 

 fill, earth, and gravel, with a concrete masonry core. The height of 

 the dam above bed rock is about 80 feet, and above the original bed of 



