Arizona republican., 1904-07-10

, tus to the north. it is not likely that an irrigation pumping supply will be found north of the Salt River valley canal.
 From the foregoing a word of eau tion is self suggested. Although the amount of water in the underfiow is exceedingly great. as shown by the amount pumped, it must not. as many assume, be considered an inexhaustible supply. The greater the draft on the underf1ow, the faster must be the per manent depression of the water table. The fact that single wells operated for year or two. do not show any marked depression. is by no means a sign that the underfiow cannot be exhausted. There is abundant evidence in locali- ties similarly supplied, especially in California where pumping is done ex- tensively. that continued pumping per manently exAausts th4. underground waters. The water can only enter this underfow from the river above and from occasional floods on the h;llsides at a certain rate or in certain quan- tity, and as soon as the drain of the pumping plants is greater than this constantly augmented supply, there must Of necessity be a lowering of the ] mainly the accumulation of under ground waters that has been going on for years. IT has been estimated by an authority on such questions to whom specimens of the gravels have been sent by MT. Lee, together with an outline of conditions, that the average speed of the underhow of the valley is about enc quarter of mile per annum r,Io f,, gravels no doubt where iS may travel two or three miles per year or even more. Most of the water now being pumped no doubt entered this under flow many years ago. If the water table be greatly lowered it would be many years before it would be re- placed. if ever. An era of wet years would materially help conditions, but since the water gets in at the upper part and sides of the valley, primarily from the river and travels only a mile or two a year, it might take several years for the water table to be mate-- ialiy affected by wet era. just as the valley is now enjoying the benefits of a former wet era. The water table at Mesa in the last four yeals has been lowered about twelve feet and at the ---N4-eN'4 -Fo-4SN'4 sNSpdt bhtli~S ACcl. AL ile Lount ice works in this city it has heen lowered several feet and is now sinking at the rate of inches per month. The drain of the underhow must be kept near the limit of its na l. tural rep.enishment if the underfiow is to be permanently relied upon.
 And in this connection Prof. Lee speaks word of warning to those who propose the installation of pumping plants. It is Beware of the limit of lift What is meant by that is that the man who installs d pumping plant on the margin of the present pumping area. or elsewhere where the depth to water is the full limit of profitable pumping, may find 70 his chagrin in later years, that the water table will sink so low he cannot reach the water, or that the expense of pumping it so great distance will exceed its value after it has been secured.
 This warning is not intended by Prof Lee, to discourage pumping enterprises or to detract in the slightest from the full value and availability of the un- derground flow, but only to call atten-
 tion to the fact that such projects should be entered upon advisedly that disappointment do not follow, and that too great dependence be got placed upon this undevelcped resource.