. Brigham Young University science bulletin. Biology -- Periodicals. Biological Sehies, Vol. 19, No. 3 Meteobolocic Measurements 21 20 10 0 -10 10 1 1 1 1 COMPARISON OF DAILY TEMPERATURES UNDER 222-292 MM SNOW COVER 4-10 JAN 1971, PROVO, UTAH (52)1 5CM UNDER GRASS COVER ^ y ^ SOIL SURFACE UNDER GRASS COVER -^ \ â \ -10 SOIL SURFACE WITHOUT GRASS COVER SAM 6AM SAM SAM SAM BAM SAM MONDAY TUESDAY WEDNESDAY THURSDAY I I I I L FRIDAY SAM SATURDAY SUNDAY J I. SAM SAM SAM SAM SAM SAM SAM SAM MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY SUNDAY ing the irrigation season, such lands can often recei
. Brigham Young University science bulletin. Biology -- Periodicals. Biological Sehies, Vol. 19, No. 3 Meteobolocic Measurements 21 20 10 0 -10 10 1 1 1 1 COMPARISON OF DAILY TEMPERATURES UNDER 222-292 MM SNOW COVER 4-10 JAN 1971, PROVO, UTAH (52)1 5CM UNDER GRASS COVER ^ y ^ SOIL SURFACE UNDER GRASS COVER -^ \ â \ -10 SOIL SURFACE WITHOUT GRASS COVER SAM 6AM SAM SAM SAM BAM SAM MONDAY TUESDAY WEDNESDAY THURSDAY I I I I L FRIDAY SAM SATURDAY SUNDAY J I. SAM SAM SAM SAM SAM SAM SAM SAM MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY SUNDAY ing the irrigation season, such lands can often receive far more water than is optimum. Holmes and Watson (1967) stated that farmers in certain areas of southern Australia customarily use too much water for irrigation and often apph' \va- ter crest depths of about 20 cm in order to cover high spots on lands in that area. As a result, as much as 50 percent of the water applied through irrigation must be pumped back into the river. DeVries and Birch (1961) compared environ- mental riieasuremcnts in Australia on three irri- gation pastures to that of an adjacent dry lot east of Rochester, Victoria, where the frequency of irrigation was approximately once every 15 days, and found that the drainage from irrigation lands in that area varied from 3 to 26 percent of the irrigational inflow. They assumed an average of 10 percent of irrigational water sup- plied would eventually leave as drainage. To our knowledge, the only comparable data for irrigational lands in central Utah is that by Israelsen, et al., who showed that in 1944 the average efficienc)- of flood irrigation was 40 percent for 11 farms they tested in Utah Count)'. Presumably the overall efficiency has improved since then, especially in areas in which sprinkler irrigation is used, but it is not uncommon to find pasture lands continually flooded with flows from drain streams during every day of the sum- mer, and even into winter months in this area. The impact of the precipi
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