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<br />000061 <br /> <br />. <br /> <br />Operational variables can be evaluated through use of the CRSS model if <br />additional time and manpower are made available. The CRSS is a simulation <br />model that routes monthly flow and salt down through the river system, taking <br />depletions and adding return flow and salt pick-up, and operating the reser- <br />voirs. The major model assumptions include (1) past hydrology and salinity <br />records may be used to estimate the future, (2) monthly complete mixing of <br />the reservoirs is a valid approximation for computing reservoir release <br />concentrations, and (3) there will be no chemical changes in the system <br />that would affect the overall salinity budget. Past studies tend to support <br />these modeling assumptions. <br /> <br />, <br /> <br />WQIP (WATER QUALITY IMPROVEMENT PROGRAM) UNIT APPRAISALS <br /> <br />Las Vegas Wash Unit. - The Wash bypass channel appears viable from an <br />engineering/economics viewpoint. Interaction of these salinity control <br />features with water rights, sewage discharge requirements, and nutrient <br />removal cloud the prospects for local agency approval for construction. In <br />order to satisfy local concerns, additional mitigation features may have to <br />be considered, such as a diffusion outfall pipeline into Lake Mead. The <br />proposed plan would reduce salinity concentrations at Imperial Dam by <br />6 mg/L. <br /> <br />Outlook. - Significant delays in the main bypass canal construction may <br />occur, pending resolution of local issues. <br /> <br />Paradox Valley Unit. - Deep well injection disposal still appears as the most <br />cost-effective solution. Recent findings that the existing Conoco well <br />cannot be rehabilitated will result in additional program delays (6 months) <br />for construction of a new injection well. In addition, there is a 50:50 <br />chance that a second well may be required. The program is expected to reduce <br />the salinity concentrations at Imperial Dam by 18 mg/L. <br /> <br />Outlook. - Cost increases will not be significant in terms of affecting <br />unit cost effectiveness. Some expected contract and construction delays <br />may be offset with incentives for early completion of the well. Other <br />concerns have been effectively addressed; namely, land acquisition, NEPA <br />compliance, and water rights. However, Reclamation's application for <br />water rights and related augmentation plan is still subject to challenge <br />and litigation in water court. There appears to be continued concern or <br />risk in successfully completing one or two injection wells as presently <br />scheduled because of the geologic unknowns. <br /> <br />Grand Valley Unit. - Construction is complete un Stage I canal lining. <br />Construction will be complete prior to the irrigation season on the related <br />laterals. It appears the trashrack and moss screen will be complete prior to <br />the 1983 irrigation season, approximately 1 year ahead of schedule. Work is <br />continuing on preconstruction planning for Stage II with the preferred plan <br />expected to be selected this spring. Salinity reductions expected from the <br />unit are 28 mg/L for Reclamation and 13 mg/L for USDA for a total 41 mg/L <br />reduction at Imperial Dam. <br /> <br />Outlook. - Construction is expected to proceed by 1986 on selected <br />lateral lining throughout the valley. Lateral lining appears very cost <br /> <br />3 <br />