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003337 CHAPTER III POTENTIAL IRRIGATION DEVELOPMENT . lands. 'lhe investigations were therefore directed toward studies of possible offstream storage sites. Of the several offstream sites con- Sidered, only two proved to be sui table and worthy of serious considera- tion for project storage, 'Ihese, the O'Neal Park and Perry Draw sites, are discussed in the ""llowing paragraphs. 'lhe O'Neal Park site is located about 2 miles southwest of the Perry Draw site. It is not shown on the frontispiece map because it overlaps a substantial portion of the largest single body of land that would be irri- gated by the O'Neal Park project. Conveyance of water to the O'Neal Park s1 te would require a long siphon across 0 'Neal and Gordon Creeks in addi- tion to several miles of unlined canal. A reservoir at this site would have the disadvantage of inundating some of the better arable lands in the area and of being at a low elevation in :relation to the remaining lands. Some difficulties would be involved in distributing water from the reservoir to the lands. ~ . The Perry Draw site is located in better relation to the project lands than the 0 'Neal Park site. It is approximately 150 feet higher in elevation than the O'Neal Park site and would not inundate any of the arable lands considered for irrigation. The inlet canal from Piedra River to the Perry Draw site would include a siphon crossing Gordon Creek but would not be so long as in the case of O'Neal Park Reservoir. The inlet canal would also include several miles of unlined canal, some of which would be on fairly steep, possibly shale side slopes. Costs per acre-foot of active storage capacity at the Perry Draw Reservoir site would be about twice the costs at the O'Neal Park site. TIle Perry Draw site was selected for inclusion in the adopted plan of development, however, because of its location with respect to the project lands and its better economy in the overall plan of development. Alternative Plans The alternative irrigation plans considered are described in the following paragraphs. From the descriptions and the frontispiece map the relative locations of the features of the various plans can be detennined. The same general criteria were used in the appraisals of alternative plans sS were used in the appraisal of the plan discussed previously in this chapter. Plan A.--Plan A is the 0' Neal Park project plan previously described and evaluated in this chapter. It would serve an area of 3,600 acres. The main project works would be a diversion dam on Piedra River, an inlet canal to Perry Draw Reservoir, Perry Draw Reservoir and rem, outlet canals, laterals, and drains. Plan A would have a higher benefit-cost ratio . (0.91 to 1) than any of the other plans considered. PlaIl A-l.--Plan A-l is essentially the same as Plan A except that it provides for a larger scale of development. It would serve 5,000 acres com- pared with 3,600 acres served by Plan A. The additional lands are located 33