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I I. I I I I I I I I. I I I I I I I. I I Task 1 Results - Orchard Mesa Power Canal enlargement study 5 Section 11 - Open Earthen Canal 97+71 to 142+50. No plans were found for this section of canal. Upon field inspection, much of ditch had 3 ft of freeboard and would likely convey 860 cfs without any modification. For cost estimation purposes, it was assumed some fill would need to be imported and placed along some sections of the existing canal. A bridge exists along this portion of canal, though it appears clearance is adequate in its existing condition to pass 860 cfs. Section 12 - Watson Creek Siphon 142+50 to 144+00. No plans were found for this structure, however, data on the Bureau of Reclamation website stated that the capacity of this structure was 800 cfs. Modifications required for this inverted siphon will likely be very similar to those made on the Stokes Gulch and Mann Gulch siphons. The overtopping elevations of the inlet works and outlet works will need to be raised by 1.5 ft. Section 13 - Open Earthen Canal 144+00 to 195+00. No plans were found for this portion of the canal. Upon field inspection, some portions of this canal's banks will need filling in order to increase the capacity of the canal. Some portions of the canal are already adequate to handle increased flows. There are two bridge crossings along this portion of canal, and these may require some modifications as they are only 6 inches or so from the water surface, under the 800 cfs discharge condition. Section 14 - Facilities downstream of Power Plant and Pumping Plant. Field inspection determined that the flow channels downstream of the Power Plant and Pumping Station are adequate to convey the increased flow rates back to the Colorado River. Approximate quantities and unit costs were applied to each of these sections. Individual costs estimates for each section can be found in the appendices. Table 2.1 shows a breakdown of approximate cost by section that would be required to upgrade the canal from its current 800 cfs capacity to an 860 cfs capacity. The total cost required to upgrade the canal would be about $1.8 million. 2.2 Benefits of increasing power canal capacity to 860 cfs The purpose of this section is to estimate economic benefits that could be realized by increasing the canal capacity from 800 cfs to 860 cfs. There are two main areas where benefits could be realized: crop production and hydropower generation. In addition to these two main areas of benefits, the water-right maintenance benefit and potential for storing water as a benefit were also evaluated. 2616-R1 Orchard Mesa Irrigation District Water Management Consultants