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<br />('.1 <br />~,~ <br /> <br />The Soil Conservation Service program would <br />cost an estimated $23,620,000 in addition to <br />the Bureau of Reclamation program presented <br />previously. <br /> <br />~'- <br />...~ <br /> <br />The wli t would be developed in stages to allow <br />the Bureau of Reclamation to begin construc- <br />tion in a portion of the valley where plans <br />and designs are complete~ where sufficient <br />data are available to assess the impact of the <br />initial development while investigations and <br />planning continue On the rest of the unitt and <br />where environmental impacts would not be sig- <br />nificant. <br /> <br />(:.. <br /> <br />Stage One would involve the concrete lining and <br />rehabilitation of structures along a 6.7-mile <br />section of the Government Highline Canal in the <br />western end of the valley. Fourteen laterals <br />totalling 34.2 miles that now serve the area <br />under the canal section to be lined would be <br />consolidated into 12 and placed in pipe sec- <br />tions totalling 29.7 miles. About 6.5 miles <br />of interceptor ditch and three small detention <br />ponds would be constructed above the canal sec- <br />tlon to prevent runoff from entering the canal. <br />Some existing cross-drainage features would be <br />enlarged. A field station would be constructed <br />as part of the Stage One development for use as <br />a construction headquarters and permanent oper- <br />ating facilities for the entire unit. To CO~ <br />pensate for wildlife habitat losses and to pro- <br />vide additional hunting opportunities, an area <br />of suitable land would be acquired and initially <br /> <br />Grand Valley Unit <br />Ilay 18, 1979 <br />Page 2 of 2 <br /> <br />developed, and a ~atering pond would be con- <br />structed above the Government Righline Canal. <br /> <br />Data will continue to be gathered to determine <br />the nature and extent of the salt loading to <br />the Colorado River. Such data will include the <br />following: (1) flow measurements and samples <br />from all major washes and drains; (2) samples <br />and water levels from existing observation <br />wells in the Reed Wash Study Area; (3) samples <br />and water levels from an extensive network of <br />wells valleywide; and (4) computation of water <br />and salt budgets for the Grand Valley and for <br />the Reed Wash Study Area. <br /> <br />An extensive drilling program has been co~ <br />pleted 'to obtain subsurface geologic data <br />along all of the major canals in the valley. <br />The core samples obtained will yield informa- <br />tion on the presence and extent of expansive <br />clays, depths to water, and the type of sedi- <br />mentary materials all of which will affect the <br />engineering design of the canals and laterals. <br /> <br />LOCAL INTEREST <br /> <br />Interest in the Grand Valley Systems Improve- <br />ment Program by Federal, State, and local con- <br />cerns is continual.ly growing. In keeping with <br />this interest, the Grand Valley Salinity Con- <br />trol Coordinating Committee meets regularly <br />and 1s open to all persons and agencies inter- <br />ested in attending. The purpose of the co~ <br />mittee is to coord:lnate all salinity s~udies <br />and to disseminate information to the public. <br /> <br />STATISTICS <br />(TAKEN FROIl DRAFT DEFINITE PLAN REPORT FOR STAGE ONE--STILL UNDER REVIEW) <br /> <br />ESTIIlATED COSTS <br /> <br />Overall Unit <br />Water Systems Improvement con- <br />struction costs <br />(January 1978 prices) <br />Canal l1ning <br />Lateral improvement <br />Field Station <br />Less salvage and depreciation <br />Wildlife measures <br />Investigation costs <br />Irrigation Management Services <br />Unit total <br /> <br />$73,200,000 <br />66,000,000 <br />160,000 <br />-75,000 <br />6,515,000 <br />300,000 <br />250,000 <br />$146,350,000 <br /> <br />. <br /> <br />Staa.e One <br />Water Systems Improvement con- <br />struction costs <br />(January 1978 prices) <br />Canal lining <br />Lateral improvement <br />Field Station <br />Less salvage and depreciation <br />Wildlife measures <br />Subtotal <br />Investigation costs <br />Irrigation Management Services <br />Total <br /> <br />$5,450,000 <br />6,450,000 <br />160,000 <br />-20,000 <br />600,000 <br />12,640,000 <br />25,000 <br />25,000 <br />$12,690,000 <br /> <br />EFFECTS ON THE COLORADO R1VER <br /> <br />Overall Unit <br />Reduc tion in sal t loading <br />(tons/year) <br />By Water Systems Improvement <br />By On-farm Improvements and IMS <br />Total <br /> <br />Increase in streamflow <br />(acre-feet/year) <br /> <br />Reduction in salinity concentration <br />at Imperial Dam (mg/L) <br />By Water Systems Improvement <br />By On-farm Improvement ~.nd IMS <br />Total <br /> <br />Stage One (Water Sy"stems <br />Improvement only) <br />Reduction in salt loading <br />( tons/year) <br />Increase in streamflow <br />(acre- fee t/ yea r) <br />Reduction in salinity concentration <br />at Imperial Dam (mg/L) <br /> <br />280,000 <br />130,000 <br />410,000 <br /> <br />4,000 <br /> <br />29 <br />14 <br />43 <br /> <br />24,000 <br /> <br />200 <br /> <br />2.5 <br />