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<br />Table 8-116. SMdow price. of land by class and level of TDS, Roo.evelt Irrigation District. <br /> <br />tv 775 900 1000 1100 1200 1300 1400 <br />00 mg/l mg/l mg/l mg/1 mg/l mg/1 mg/1 <br />c.::J (Dollars) (Dollars) (Dollars) (Dollars) (Dollars) (Dollars) (Dollars) <br />C.V Lan.d 1 88 88 88 88 88 88 88 <br /> Land 2 88 88 88 88 88 88 88 <br /> Land 3 70 69 68 68 66 65 65 <br /> Double Cropped 1 88 88 88 88 88 88 88 <br /> Double Cropped 2 88 88 88 88 88 88 88 <br /> <br />Table 8-116. Ratio of amount of water used to land <br />and profit alJ by level of TDS, Roo.evelt <br />Irrigation District. <br /> <br />TDS <br />(mg/l) <br /> <br />Ratio of Net <br />Dollar Return <br />Pe'r Acre Foot <br /> <br />Acre Feet <br /> <br />Acre Feet <br />Per Acre <br /> <br />775 <br />900 <br />1000 <br />1100 <br />1200 <br />1300 <br />1400 <br /> <br />153,030 <br />153.028 <br />153.oz3 <br />153,017 <br />153,013 <br />153,005 <br />152,998 <br /> <br />4.879 <br />4.878 <br />4.878 <br />4.878 <br />4.878 <br />4.878 <br />4.878 <br /> <br />24.96 <br />24.96 <br />24.95 <br />24.95 <br />24.94 <br />24.93 <br />24.93 <br /> <br />Table 8-117. Total and per acre net profit by TDS <br />leve~ Roo.evelt Irrigatitm District. <br /> <br /> <br />TDS Profit Per Acre <br />(mg/l) (Dollars) (Dollars) <br />775 3,819,047 121.75 <br />900 3,818,861 121.74 <br />1000 3,818,493 121.73 <br />1100 3,817,075 121.69 <br />1200 3,816,704 121.68 <br />1300 3,815,144 121.63 <br />1400 3,813,638 12 1.5 8 <br /> <br />Table 8-118. Sum17ltYr/l.tatiBtics, Roosevelt Irigation <br />District. <br /> <br />Total Acres <br />Double Cropped Acres <br />Annual Total Damages <br />Annual Per Acre Damages <br />Annual Damage Per rng/l <br />Annual Damage Per mg/I Per Acre <br /> <br />31,368 <br />839 <br />$ 5,409 <br />$ 0.1724 <br />$ 8.654 <br />$0.00028 <br /> <br />TDS and 190,000 ac ft of surface water with 755 mg/l <br />TDS the projected water would have an average <br />salinity of around 910 mg/l TDS before addition of <br />Colorado River water. This can be expected to remain <br />fairly constant except for the possibly small effect of <br />changes in groundwater salinity due to continued <br />lowering of the water table. However, groundwater <br />quality has little effect due to the proportion involved. <br />As the CAP water increases in salinity, the <br />proportionate increase in the project water would be <br />as shown in Table 8-120. . <br /> <br />The canals and laterals of the project are unlined <br />and losses in the system are estimated to be 80 <br />percent or more (San Carlos Project). This means that <br />the 50,000 acres presently being irrigated are <br />receiving less than 4 ac ft of water per acre. If the <br />losses can be cut to 15 percent by lining the canals and <br />laterals, approximately 880,000 ac ft would be <br />available to irrigate 80,000 acres with a minimum of 4 <br />ac ft per year. Apparently, any crop yield declination <br />due to increasing salinity of the CAP water would be <br />more than offset by the additional acres irrigated. <br />However, since this study is concerned with crop <br />declination due to increasing salinity of CAP water, <br />projections to the year 2000 will be based upon the <br />acreage to be irrigated after the CAP water is brought <br />into the project (80,000 acres assumed). <br /> <br />Acreages of the different soil types or series were <br />estimated from a general soil map of Pinal County <br />prepared in March 1971 by the USDA Soil Conserva. <br />tion Service (Adams, 1972). <br /> <br />Yields and acreages of the major crops in the San <br />Carlos Project were obtained from the annual crop <br />reports published by the project. Since these reports <br />are broken down into "District Part" and "Indian <br />Part," the salinity impact analysis is also treated <br />separately. <br /> <br />San Carlos Irrlgatlon Project, Non.IncU.n <br /> <br />Approximately 55,000 acres are included in the <br />non-Indian part of the San Carlos Project (Map 8-18). <br />Table 8-121 partitions this acreage by land class and <br />use. Presently, only small amounts of land are <br />assumed to be used in a double cropping rotation. <br />About 70 percent of the total project area under <br />cultivation is contained in the non-Indian classifica- <br />tion. . <br /> <br />Alfalfa, cotton, and grains are the major crops in <br />the area with smaller acreages going to sugar beet <br />production. A list of crops selected for the present <br />analysis are shown in Table 8-122. Limited double <br />cropping possibilities exist with maize (sorghum) <br />being the most important. <br /> <br />Average yields were derived from empjtical data <br />presented in Table 8-123. A 95 percent confidence <br />interval was set around the averages as an aid in <br />establishing base yield figures. Once a base yield had <br />been established, Table 8-124 along with Table 8-1 <br /> <br />195 <br />