1902. 



FORESTRY AND IRRIGATION. 



.)>5 



IRRIGATION POSSIBILITIES OF THE LOWER COLO- 

 RADO RIVER/== 



By J. B. LiPPiNCOTT, 

 U. S. Geological Survey. 



ON December 29, 1901, a party con- 

 sisting of Jeremiah Ahern and the 

 writer, hydrographers; W. B. Clapp and 

 F. M. Barnes, field assistants, started 

 on a reconnaissance of the Lower Colo- 

 rado River between the Needles and 

 Yuma. 



A boat was built 20 feet long, 5 feet 

 beam, drawing 8 inches of water, and 

 square cut at each end . The boat might 

 be called a punt. It was, however, 

 rigged with a sail, which 

 was found to be very serv- 

 iceable on the trip, and 

 with two pairs of oars. 

 The prevailing direction 

 of the winds on this river 

 in the wnnter and fall is 

 down stream, while in the 

 summer it is up stream. 

 It is difficult to travel up 

 stream with a small boat, 

 owing to the swift cur- 

 rents. A light-draught 

 boat, particularly in low 

 .stages of the river, is es- 

 sential to the trip, as many 



shoals and sand bars exist 



in the channel . The j our- 

 ney from Needles to Yuma 

 was made in eleven days, 

 or at an average rate of speed of a little 

 less than 27 miles a day. Traveling 

 could only be undertaken during the 

 daytime, and many intermediate stops 

 were made for the purpose of observa- 

 tions, hills and bluffs along the river 

 being climbed for this purpose. The 

 only in.struments used on the trip were 

 four aneroids, field glasses, hand levels, 

 and hand compass. All distances and 

 areas given in this report were estimated. 



The elevation at the Needles railroad 

 depot is 474 feet, the river opposite be- 

 ing probably 450 feet. The elevation 



of the river at Yuma is 107 feet ; it 

 therefore has a fall of 347 feet in an esti- 

 mated distance of 281 miles, or 1.22 feet 

 per mile. It was quickly recognized 

 that aneroid obser\'ations on a stream of 

 such light grade were of small value in 

 comparing relative heights. 



The distance on a straight line from 

 Yuma to the Needles is 147 miles, one- 

 half that by river. This increased river 

 distance is largely' made up by the mean- 



THE BOAT. 



derings of the stream in the alluvial 

 valle3'S which prevail through a large 

 portion of its course; consequently di- 

 version canals having relativeh' straight 

 alignments would have an available fall 

 of about two feet to the mile. 



There is a long river flat, generally 

 known as the Mojave Valley, averaging 

 three miles in width on the Arizona and 

 three-quarters of a mile on the California 

 side, containing 86,000 acres, beginning, 

 it is stated, 10 miles above Ft. Mojave, 

 at a point known as the " Bulls Head," 

 and extending to the Needles, a length of 



* Extract from notes made durinj< a reconnaissance of the Lower Colorado River from the 

 Needles to Yuma. 



