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0:) !.!) ,~, ...-4 l-~) MONITORING AND EVALUATION PROGRAM 1990 ANNUAL REPORT SUMMARY Implementation of the U. S. Department of Agriculture (USDA) Grand Valley Sal inity Project began in 1979. The Soi I Conservation Service (SCS) Monitoring and Evaluation (M&E) Program started in 1984 to determine the long term effects of salinity practices on irrigation, economics, wi Idl ife habitat and soi I sal inity. The M&E program wi II also help direct future salinity program activities. The results of six years of irrigation evaluation indicate that the average deep percolation for the Grand Valley is about 16.1 acre inches per acre. Excess pre-irrigation and/or the first irrigation is the biggest contributor to the seasonal deep percolation losses. Annual crops contribute about 45 to 50% of their total deep percolation losses for the season during the first irrigation, perennials accounted for about 15% of the total. When both annuals and perennials are taken into consideration, the average deep percolation is about 35% of the total during the first irrigation. The 1990 data showed that surge irrigation has a potential to reduce deep percolation and salt load by as much as 50% for the season. Salt savings was about 3.21 tons per acre with surge. Approximately 3 inches of deep percolation could be reduced during the first irrigation with adoption of surge irrigation. Surge has a potential to reduce water appl ication and tai Iwater runoff substantially, especially during pre-irrigation or the first irrigation. Soi I sal inity data since 1984 indicate that sal inity levels are relatively low at most monitoring sites. There has been very little change in sal inity levels at these sites, even on microspray and sprinkler sites. Several years of data wi II be needed to determine if reduced deep perco I at i on has an adverse effect on so i I sa Ii n i ty. The results of 3 years of economic data show that farmers are benefitting from installation of on-farm sal inity practices. It is too soon to quantify the impact on individual farmers. However, results so far indicate that most benefits arise from irrigation labor savings. Publ ic investment in on-farm improvements also seems to be cost effective. The planned monitoring and evaluation of wi Idl ife habitat to determine impacts of improved irrigation practices was completed in 1988. Results indicate that the process of habitat replacement of lost acreages started slow but is now gaining ground. Approximately 66 acres of wi I d life hab i tat need to be app lied annua I I y to meet the SCS goal of 1200 acres.