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<br />"'"'4 <br /> <br />c) <br /> <br />~ <br />o <br />.~ <br />:::.:) <br /> <br />(Figure 2). The monitoring data indicate that for some soils such <br />as Fruita clay loam and Mesa clay loam, the infiltration rate may <br />be higher than current estimates. Monitoring data from 1985 to <br />1989 also indicate this to be true. <br /> <br />4. Salt Budgets <br /> <br />a. Salt Contribution: It is estimated that about 600,000 tons of <br />salt is contributed annually to the Colorado River through deep <br />percolation and seepage. Salt contribution from each of the <br />monitored sites is provided in Table 7. The total amount of salt <br />entering into the Colorado River System from all the monitored <br />sites is estimated at just over 1800 tons for 1991 or about 5.2 <br />tons of salt per acre. Salt factor per acre inch of deep <br />percolation was based on the hydrosalinity model developed for the <br />different canal systems (refer to Appendix F). The amount of deep <br />percolation times the salt factor per acre inch provides salt load <br />per acre. The salt load per acre times the acreage gives the total <br />salt contribution to the Colorado System from the site. <br /> <br />b. Reduction in Deep Percolation and seepage: Deep percolation and <br />seepage could be reduced substantially with installation of <br />improved irrigation systems and better water management. Initial <br />SCS estimates indicate that with on-farm irrigation system <br />improvements about 130,000 tons of salt could be reduced annually <br />by project end. with the installation of improved off-farm lateral <br />systems, the total projected salt load reduction is 163,000 tons. <br /> <br />In 1991, about 58,999 feet of underground pipeline were installed <br />on-farm and 4,458 feet off-farm. Also, about 10,409 feet of <br />concrete ditches and 44,814 feet of gated pipe were installed. <br />Improved surface and sprinkler irrigation systems were also <br />installed (see CRSC project status report section 1.6). <br />Installation of improved systems resulted in reduction of deep <br />percolation, seepage and salt load through FY 91, as follows: <br /> <br />On-farm <br />Off-farm <br /> <br />1991 Cumulative <br />1,095 8,174 <br />53 4,946 <br />1,148 13,120 <br />10,908 31,914 <br />20,783 18,285 <br />31,661 50,199 <br /> <br />Seepage/deep perc. reduction (ac. ft.) <br />On-farm <br />Off-farm <br /> <br />Salt Reduction (tons) <br /> <br />27 <br />