WATER LOSSES FROM WET AREAS 



45 



willow and wire rush tanks, the water table was kept 2 feet below the 

 soil surface with sliglit fluctuations. 



San Bernardino Station 



The four tanks used at the Antil Plant of the San Bernardino 

 Water Department were installed for measurement of consumptive use 

 of water by Bermuda grass, of which there was a heavy crop growing 

 in the yard in which the tanks were set. As the tanks were filled with 

 undisturbed soil each had a good stand of grass with root systems fully 

 developed from the beginning of the investigation. At this station 

 tanks were operated in duplicate, one pair having a depth of water 

 table of 3 feet and the other of 2 feet below the soil surface. These 

 depths were unchanged throughout the investigation. Each soil tank 

 was connected to a ^Nlariotte supply tank from which the daily amounts 

 of water used were measured. 



Besides the four soil tanks, one tank of round stem tules was 

 maintained to determine the consumptive use by this growth. This 

 tule tank was coimected with a supply tank through a float valve to 

 supply water as needed and hold the water table at an index point 

 about 2 inches above the soil level. Installation data giving the number 

 of tanks, periods of use, and content of each tank are shown in Table 7. 



TABLE 7 

 INSTALLATION DATA FOR TANKS USED AT SAN BERNARDINO STATION 



Tank 

 number' 



1-2 

 3-4 

 5-- 

 6- 



7-- 



Diameter 

 of tank 

 in inches 



23 1,16 

 23 1/16 

 23 1/16 

 23 1/16 

 4S 



Purpose 

 of tank 



Use of water. 

 Use of water. 

 Evaporation . 

 Use of water. 

 Evaporation _ 



Period of test 



Beginning Ending 



May, 1929 

 May, 1929 

 Mav, 1929 

 April, 1930 

 May, 1929 



Jan., 1932 

 Jan., 1932 

 April, 1932 

 April, 1932 

 April, 1932 



Content of tank 



Bermuda grass 



Bermuda grass 



Free water surface 



Round stem tules in water. 

 Free water surface 



Depth to 



water 



table in 



feet 



' Undisturbed Chino silt loam soil used in Bermuda grass tanks. 

 Prado Station* 



Only one crop tank has been used at the Prado station in deter- 

 mination of consumptive use of water. This tank contains a dense 

 growth of triangular stem tules grown in submerged soil as at the 

 other stations. A supply tank is used in connection with the tule tank, 

 the connection being made through a float valve. Measurement of 

 water withdrawn from the suppl}' tank is shown on recorder charts by 

 means of a water stage recorder, and weekly or semiweekly visits are 

 made to the station to replenish the water supply and renew the charts. 

 This station is still in operation and will be continued. 

 Protection from Rainfall 



During the wet seasons of 1929-30 and 1930-31, covers were pro- 

 vided for all soil tanks to prevent changes in soil moisture content due 

 to rainfall. The covers (Plate IV) were of light metal, circular in 

 design and ^\■^th sloping tops, and Avere set on legs a few inches high to 

 allow full circulation of air over the protected tank surface. While it 

 was impossible to keep all rainfall from the tanks be(!ause of absence 

 from the station at the exact beginning of each storm, they were set as 



* Thf United States Geological Survey, cooperated in maintaining this station 

 through the courtesy of F. C. Ebert. 



