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BUREAU OF RECLAMATION REPORT or land moderately suitable for irrigation farming. Pasture lands are not included as part of the extension and are not considered in the analysis of the extension IS repayment ability. Some pasture lands under the extension works, however, may be furnished a partial irriga- tion supply when the full capacity of the works is not required to sup- ply better lands. All lands in the extension have good natural drainage and with reasonable care in the use of irrigation water they would require no artificial drains. Water Supply The net diversion requirements of extension lands, estimated at 3 oacre-feet an acre annually, could be supplied from natural run-off of Pine River in the spring and from storage releases from Vallecito Reser- voir in the summer. Recent water supply studies show that with holdover storage in Vallecito Reservoir (126,280 acre-foot active capaCity) the Pine River run-off is adequate in nearly all years for full irrigation of the 69,000 acres authorized_Jor.....development. Thus it could readily serve without shortages the(.33,160,hcres now irrigated, the 15,150 acres included in the extension;'and the 3,520 acres included in proj- ects of the Bureau of Indian Affairs and private interests. Until additional land is brought under irrigation, sufficient storage water could be released from Vallecito Reservoir during the nonirrigation sea- son to maintain a minimum stream flow of 45 second-feet for conserva- tion of fish and wildlife. This flow also would meet the domestic requirements of communities and farms along the river. Pine River water is of adequate quality for irrigation and domestic use. The extension would deplete the flow of the Colorado River by . about 28,300 acre-feet annually. About 27,200 acre-feet of the deple- tion would be charged against the water made available to Colorado by the Upper Colorado River Basin Compact and 1,100 acre-feet would be charged against the water apportioned New Mexico by the compact. Ade- quate storage rights for the Pine River project have been acquired and the additional direct flow rights required for extension lands could be obtained under Colorado and New Mexico State laws. > ?: Comparison of Extension Benefits and Costs '- ,.- ;~ ~1 " '.?~ ~., Benefits from the Pine River project extension attributable to Federal expenditures would compare with the attendant Federal costs in a ratio of 1.85 to 1. For the comparison both benefits and costs were considered as average annual equivalents over a lOO-year period begin- ning with the first year of full project operation. The benefits were based on average prices for the period 1939-1944 while the construction costs were based on the higher prices prevailing in December 1949. Future variations in these price levels might result in a different benefit-cost ratio than is presently indicated as the actual ratio 9