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. I I I I I I I I I I I I I I I I I I Alternatives Evaluated A range of alternatives were considered including 1) don't build the project, 2) repair the structure saving as much of the old structure as possible, 3) completely remove the old structure and replace it with a new structure, and 4) abolish the river diversion structure and replace it with pumped well water. A subjective evaluation of the alternatives follows: L Don't build the project: Shareholders would be unable to irrigate 4,400 acres of cropland. The do nothing alternative is not feasible! 2, Repair the existing structure: Repairing this structure will enable the Company to divert water and operate its recharge project before the irrigation season, This alternative would also be the most economical. This alternative is feasible and is considered the preferred alternative. 3. Completely remove the old structure and replace it with a new structure: This would increase the cost of the project considerably with no added benefits, This alternative is feasible but not very economical. 4, Abolish the use of the river structure and pump well water into the ditch: This alternative would be contingent on the plan being approved by the water court. Considering the time getting court approval and construction time, water would be unavailable for shareholders to irrigate this summer. This alternative is not feasible, The Northern Colorado Water Conservancy District (NCWCD) provided technical engineering assistance in the evaluation of the above alternatives, particularly concerning the type and configuration of gate structures for the headgate and for the river dam. Pneumatic crest gate systems (from Obermeyer Hydro Accessories, Inc.) as well as radial gates, lift gates, and flash boards were considered. The critical design issue was to keep sand from washing into and plugging the ditch. This required that water flow over the top of the ditch headgate (low approach velocity with little sand), and out the bottom of the adjacent river dam sluice gate (where high velocity washes the sand downstream,) 3 ..