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. '{, .,:) - C\J o o . . Attachment I ,#-, ~ Grand Valley Stage Two Alternatives The most viable alternatives identified for Stage Two are: Lateral Improvement: This plan involves improvement of lateral systems under both the private and Federal canal systems in the Grand Valley area to reduce seepage. Improvements would include concrete lining and/or piping the lat erals. Laterals proposed for improvement include those of the Stub and Price Ditches and of the Orchard Mesa, Grand Valley Irrigation Company, and Govern- ment Highline Canals. Some 700 laterals extending about 500 miles could be part of this plan. Over 10,000 irrigators are currently receiving water from the priva~e laterals under consideration. Laterals under the Redlands Canals would not be part of this alternative, nor would laterals already improved under Department of Agriculture programs. Canal Seepage Reduction: Two canal seepage reduction options have been identified under this alternative--canal lining and a canal seepage barrier. In the canal lining option, seepage would be reduced by either concrete or membrane lining. Some 200 miles of private and Federal canals irrigating approximately 60,000 acres are under consideration for this plan. The barrier option involves the placement of an impermeable material within the downslope canal embankment. The material would function as an underground dam, stopping canal seepage from moving down-gradient toward the Colorado River. The barrier would only be considered for portions of the Government Highline Canal and the Kiefer Extension. Systems Combining: This plan involves the water management and salinity reduction opportunities that would result from combining canal systems in the Grand Valley. By combining two or more canals into one, laterals of the upper canal would be extended and combined with those of the lower system. The new laterals would be concrete and/or pipe. (Note: The three structural plans discussed above would include safety features such as fencing and escape ladders on canals. Measures to offset expected losses to wetlands will also be considered. These measures .could include items such as development of wildlife habitat along the Colorado River or elsewhere in the valley.) No Reclamation Development: To assist in the evaluation and comparison of alternatives, the future as it would occur without Bureau of Reclamation salinity control measures is forecast. Under this condition, if salinity improvement were to be realized, it would involve other structural or nonstructural alternatives.