Arizona republican., 1920-02-18

ference in quantities of water applied through irI igation. It must be con- cluded from the above results thal more careful use of water was prac- ticed in 191S-1919 than during the previous year, and attention is called to this as one of the means for reduc- ing the amount of drainage work that will ultimately be needed on the pro- ject. It cannot be stated. and it is not considered safe to assume that areas
 now wet or threatened can be re- claimed and protected without re- sorting to drainage work. By care full use of water, however, drainage can be more easily and economically accomplished.
 Height of Ground Water
 On the project map, drawing No. 2 are shown the areas where ground water was 10 feet or less below the surface, as shown by te4E well re>3' ings taken during October, 1919. These areas. the total of which is estimated roughly at 43,O0O acres within the pro ject boundaries, represent lands that are damaged or threatened, due 10 high ground water. and require drain age for their reclamation and protec tion.
 The height of ground water is not stationary. As heretofore stated, from 1912 to 1918, a period of five years, its average rise was about Is feet per year over the entire project. This rise wa due to the fact that more water found it's way into the subsoil than natural drainage could carry our or II.
 In addition to the average annual rise. seasonal changes also occur, due to the fact that more water reaches the subsoil at one season of the year than at another. The highest water table is usually found during or short It. nf irrir tion.
 During the past two years. read ings of the depth to ground water have been taken in May and October, over the greater portion of the project The results of wells for which continuous record is available is shown by the curves, Drawing No. 2.
 The curve for the north side area represents practically the total area from the western boundary of the project to the Arizona Falls Power House. That for the south side the area east and south of Tempe and extending from the northern to the southern limits of the project. On the Laveen area, records are available only since October. 1918. The average of 16 wells gives the following:
 Oct. 1918 ...S.2 if. to ground water Mas, 1919 9.7 ft. to ground water Oct, 1919 ..... S.S it. to ground water
 Pumping ano ltS EtTect
 On map drawing No. ?, is shown the location of wells that have been con- structed and were available for opera ton during all or a portion of the year 1919. Diagrams. drawing No. 4 show the quantities pumped during that year. For convenience O. discussion, these have been segregated into three SC parate areas. The first includes all of the pumped area of the south side east of the Tempe district. the second, that along the Salt canal and extend .ng northward along the western side ,f the project. and the third. that north of Phoenix and above the Grand canal
 The lowering of ground water on the south side and the area north of Phoe- nix is particularly marked and shows hat the drainage of these areas can De accomplished by pumping. On the lrea west and northwest of Phoenix he amount of pumping has not been sufficient to have any appreciable eff ect over the large tributary area.
 The lowering of the ground water on he south side is shown by the curve. lrawing No. g. The area over which his lowering has been observed j. bout 35,000 acres. Over this area the lowering of the water table, rom May, 1918, to October, 1919. was