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<br />Colorado River Basin Salin/tv Control Program <br /> <br />f\:l <br />t,;,t-' <br /><Jl <br />U <br /> <br />relurn flows pass through highly saline soils and the underlymg ~lancos Shale Fonnation. By <br />reducing lhe amount of groundwater percolating through these saline soils. salt loading to the <br />Colorado River IS bemg reduced by this unit. <br /> <br />Reclamation is conducting a conveyance systems improvement program as a cost-effective method <br />of reducing off-fann seepage and salt loading. Onfann impro.....ements. mcluding upgrading <br />Irrigation systems through cost assistance and imprOVing migation management to reduce deep <br />percolation from fann operations. are bemg implemented by USDA. <br /> <br />Reclamation-Reclamation's program in the Grand Valley has been staged_ Stage One <br />(approx.lmate]y 10 percent of the .....alleyl was used as a test area 10 rerlne analysis and construction <br />techniques used on the balance of the project (Stage Two). After completing environmental studies <br />In 1978. Stage One construcllon t'1egan in October 1980. As part of the development. 6.8 miles of <br />lhe Government Highline Canal were concrete lmed. and 13 unlined laterals were consolidated into <br />12 piped laterals. Construction of Stage One was essentially completed in Apnl 1983. <br /> <br />.\1ol1itoring of the Stage One area began In 1976 and continued through 198..L Under the <br />monitoring program. now and salinity. measurements were taken in the Reed \Vash study area. a <br />hydrologically isolated t'1asm wlthm the Stage One area. The data were used to evaluate the effects <br />(If lhe Slage One improvements on groundwaler. surface flows. and quality. Analysis of the <br />monitorlng data indIcated that canal and lateral seepage was decreased by approx.imatdy <br />5.700 acre-feet and that salt loadmg to the Colorado Ri\'er decreased by appro'\imalely <br />~1.900 IOns. supporting recommendations for initiating construction of Stage Two. <br /> <br />B~gmning in ~o\ember 1981. Stage Two il1\'estigations included re-evaluating various alternatives <br />and analyzing salinity control measures other than concrete Iimng of the canals and lalerals since <br />nonllmng options were mlmmally studied before authorization. The Grand Valley Project. Final <br />Ennronmef/wllmpacf Swument describes alternati\'es for the construction and operation of [he <br />Grand Valley UOlt. The report was filed with EPA on !\.lay 23. 1986. <br /> <br />Stage Two of the Gr3nd Valley Unit covers most of the remaimng canal and 13teral systems in the <br />\"J11e~.. The recommended pl3n included piping and lining selected portions of the private and <br />Federal IrrigatIon systems to reduce seepage into the groundwater system. Construction started in <br />1986 and was essentially completed in 1998. <br /> <br />LSDA- The USDA report. On-fann Program for Salinity Control. w'as published in <br />December 1977. and a supplement 10 the report was prepared in March 1980. The supplement <br />added off-fann laleral improvements which are necessary for proper functioning of the onfann <br />salinity reduction praclices The overall objectIves of the USDA Grand Valley Salinity Control <br />Program are to reduce salt loadmg caused by onfarm irrigation activities and seepage from small <br />group laterals The goal is to reduce salt loading by 132.0c0 tons per year by assisting farmers in <br />applY-lllg salillllY reduction practices and in improving off-farm laterals. Implementation was <br />imuated in 1979 under ongoing USDA programs. Between 1987 and 1996. the program was <br />implemented and funded under the authorities of the USDA Colorado River S31mlty Comrol <br /> <br />45 <br /> <br />