340 
Journal of Agricultural Research 
Vol. XI. No. 7 
and easily excavated. Below the hardpan was found a layer of coarse 
sand i foot in thickness, which contained water. From 9 to 12X feet a 
very dense, brown, iron-cemented hardpan was found, which, although 
somewhat seamy, was excavated with difficulty on accpunt of the water. 
From 12X to 13^ feet a second layer of coarse water-bearing sand was 
found. At 13 % feet a third layer of hardpan was encountered, but its 
nature and thickness were not determined. Later a 4-inch hole was 
bored through this hardpan to the loose material below. 
METHOD OF PROCEDURE 
The sump, which was approximately 6 feet square and feet deep, 
was cribbed with 3 by 6 inch redwood lumber and a yi-mch space was 
Fig. i.—P lan showing location of irrigation canals and test wells with reference to the pumping plant. 
left between planks so that the lateral movement of the water would not 
be retarded. 
The pumping equipment consisted of a 3-inch centrifugal pump of the 
vertical type, having the suction about 13 feet below the surface, and 
operated by a 5-horsepower belt-connected motor controlled by an 
automatic float switch. 
Test wells of 3-inch galvanized-iron pipe, 8 feet deep, were located 
along lines extending in the four cardinal directions from the pump. 
The first wells were 100 feet, the second 300 feet, and the third 600 feet 
distant from the pump. On the diagonals wells were placed 300 feet 
from the pump, thus making eight wells on a radius of 300 feet and four 
at each of the other distances. One test well was located just outside 
