502 



SCIENCE. 



[N. S. V0L.XXIII. No. 587, 



the valley below El Paso for more than three 

 hundred years, but recently, owing to in- 

 creased irrigation on the head-waters of the 

 river, the water supply has materially dimin- 

 ished. Relief is expected from the proposed 

 dam near Engle, New Mexico. 



Supplementing surface water, during the 

 past few years, pumping plants for irrigation 

 have been in successful operation. Water is 

 found in sand about fifteen feet beneath the 

 flood plain of the river and the wells are com- 

 monly sunk to a depth of sixty feet where a 

 bed of gravel is encountered. It has been 

 supposed that the source of the underground 

 water is the underflow of the Rio Grande, but 

 recent tests, made at the narrows above El 

 Paso, have established the fact that the under- 

 flow there is insignificant, amounting only to 

 about fifty gallons a minute, the velocity of 

 the water being less than three feet in twenty- 

 four hours. There is, however, a close rela- 

 tion between the position of the water level 

 in the valley wells and the stage of the river. 

 Instead of the wells tapping a strong under- 

 flow, it appears that the supply is derived 

 from water stored in sand and gravel which 

 are replenished chiefly during periods of 

 floods. At such times the scour of the river 

 is strong and the cover of silt is swept away 

 so that there is direct access of water to the 

 underlying porous material. Except in time 

 of floods the river deposits silt, through which 

 little or no water seeps. 



Until recently the water supply of El 

 Paso has been derived from valley wells, 

 but the quality of the water is poor, and since 

 October, 1905, the city has been supplied from 

 wells on the ' mesa ' six miles northeast. In 

 1903 an experimental hole 2,285 feet deep was 

 drilled there, probably all the way through 

 unconsolidated material, in which little or no 

 water was found below the well-known hori- 

 zon between 200 and 300 feet beneath the 

 surface. At that depth in fine sand and 

 gravel there is an excellent quality of water 

 under a slight artesian head, but whether the 

 supply is equal to the demand remains to be 

 determined. The water company has sunk 

 about a dozen wells of ten- and twelve-inch 

 bore from which the water is raised by com- 



pressed air, petroleum being used for fuel, 

 and the Mty is supplied with about one and 

 a half million gallons a day. Tests are being 

 made of the capacity of the plant. 



Underground Water Conditions along the 



Lower Colorado River and Vicinity: Willis 



T. Lee. 



After outfitting at Kingman on the Santa 

 Ee railroad a trip was made northward 

 through the Hualpai Valley to the Colorado 

 Eiver. Notwithstanding that water often 

 stands for considerable periods in ' Eed Lake ' . 

 in the lowest part of the valley, borings have 

 proved the non-existence of groundwaters 

 down to 700 feet, the greatest depth yet 

 reached, the absence being attributable to 

 leakage into the Colorado Eiver, which cuts 

 the valley to a depth of about 1,400 feet. 

 The conditions are similar in the Detrital- 

 Sacramento valley and in the Cottonwood, 

 Mohave and similar basins through which the 

 river cuts. 



A boat was constructed at the Colorado 

 and towed a few miles up stream to the 

 mouth of the Grand Canyon near the point 

 where the river strikes the Nevada state line, 

 from which point the banks were examined 

 to Yuma near the Mexican boundary. The 

 present position of this part of the river is 

 very clearly due to superimposition, moun- 

 tain ridges and basins being cut indiscrimi- 

 nately. An old valley, which was even deeper 

 than the present canyon, but which was filled 

 before the cutting of the latter, was seen at 

 several points. A number of places were noted 

 where dams might be erected to .furnish power 

 for mining purposes, but the height to which 

 the river water would have to be lifted (500 

 and 2,000 feet) is too great to admit of the 

 economic irrigation of the uplands. Some 

 springs occur, but they are not of economic 

 importance. Below Black Canyon there are 

 considerable flood plains which might be irri- 

 gated from the river, but levees will be neces- 

 sary to protect the land from the river during 

 floods. The silts are so fine that little water 

 can be obtained from them. 



M. L. Fuller, 

 Secretary. 



