Laserfiche WebLink
<br />t.... <br />0Cl <br />C'I'? <br />o <br />C") <br />.:-j <br /> <br />season. Among annual crops, the deep percolation decreased <br />drastically from the first to the second irrigation event <br />and then gradually decreased through the rest of the <br />irrigation season. <br /> <br />7. Several years of monitoring data from improved surface and <br />sprinkler irrigated sites indicate that the overall average <br />deep percolation (surface+sprinkler) for the Grand Valley <br />is 15.9 16 acre inches per acre. When surface and <br />sprinkler irrigated sites are considered separately, deep <br />percolation is about 17.3 inches and 7.1 inches <br />respectively. <br /> <br />8. Deep percolation from surface sites could be reduced by as <br />much as 30 to 50% with use of surge irrigation techniques. <br />When deep percolation data from the 20 surface irrigated <br />sites are separated by conventional (11) and surge (9) <br />systems there is a savings of about 6 inches of deep <br />percolation per acre from surge sites (Table 2). In 1990 <br />and 1991, side-by-side comparison of surge with <br />conventional sites showed that surge could reduce total <br />water application and tailwater runoff by about 20 to 30%. <br /> <br />9. Where improved irrigation systems have been installed, <br />the deep percolation losses can be reduced substantially <br />by proper management of individual irrigation events. <br />Reducing set time (number of hours per set) and waiting <br />longer between irrigations (irrigation scheduling) would <br />reduce deep percolation significantly, and also increase <br />irrigation efficiency. <br /> <br />c. summary Of Water Budget, Deep Percolation And Application <br />Efficiency <br /> <br />Water Budget: The results of the 1991 irrigation monitoring <br />evaluations from the 23 sites are presented in individual site <br />summaries located in Appendix D. Table 2 summarizes the seasonal <br />data obtained from the 23 irrigation monitoring sites and also <br />shows the breakdown of data by crops and irrigation systems. The <br />data on Table 2 represent the total flows on and off the field, <br />total deep percolation and ET for all irrigations during the 1991 <br />irrigation season. The information on Table 2 has been extracted <br />from individual irrigation summaries provided in Appendix D. <br /> <br />During the 1991 irrigation season, all irrigation events, including <br />pre-irrigation events were monitored for all sites with the <br />exception of sites 49 and 50 (comparison sites). At these sites, <br />the first (fall irrigation) was not monitored since it was not <br />known at that time whether the Bureau of Reclamation funding for <br />surge system would be approved. The sites were established in <br />Spring. <br /> <br />13 <br />