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<br /> Thb!e 17. Agricultural.damage. by irrigated area ($/year).
<br />0 Salinity Imperial Coachella Palo Verde C.R.1.R. Coastal Yuma C.A.P. Range $/mg/l
<br />Range mg/l Total
<br />0
<br />N 900 . 1,000 1,906,439 277 73,759 17,676 3,746 34,687 368 2,036,952 20,370
<br />-..l 1,000.1,100 795,414 14,332 218,895 9,743 18,430 1,486 1,058,300 10,583
<br />l-' 1,100.1,200 1,592,172 476 177,691 17,433 5,867 15,812 423 1,819,874 18,199
<br />1,200.1,300 3,245,149 10,272 274,423 143,416 309,337 1,560 3,984,157 39,842
<br />-.J 1,300.1,400 6,544,502 11,041 582,141 189,966 59,661 278,641 1,506 7,667,458 76,675
<br /> Total 14,083,676 36,398 1,326,909 378,234 69,274 666,907 5,343 16,566,741
<br /> Range Average 28,167 73 2,654 756 139 1,334 11 33,133
<br /> $ pe, mg/l
<br />
<br />Table 18 indieates the combined damages for all
<br />agricultural areas modeled and the predicted values
<br />using the exponential functional form. The function
<br />appears to provid~a good estimate of the real damage
<br />function as the R equals .99. The data are plotted in
<br />Figure 2. These models will provide, at a low cost,
<br />information relative to the economic impact of any
<br />number of alternative operating, management, and
<br />structural policies which we may wish to evaluate in
<br />order to provide guidance for the "best" solutions to
<br />the salinity problems of the Colorado River.
<br />
<br />AppUeatlon of Resn1t8
<br />
<br />The use of the damage estimates in project
<br />evaluation is summarized in Table 19.
<br />
<br />Suppose project "A," a salinity control project, is
<br />being investigat~d. Studies indicate that with the
<br />project the salinity level will be 885 mg/I, a reduction
<br />of 55 mg/l. Solving the damage equation results in an
<br />annual dollar impact of $501,500. This value becomes a
<br />"benefit" estimate for economic justification of the
<br />proposal. Similarly project "E," an upstream develop.
<br />ment scheme, is found to increase the salinity level
<br />from 1,350 to 1,400 mg/l. Evaluating the 60 mg/I
<br />increas~ results in an annual dollar impact of
<br />$3,322,500 which becomes a cost chargeable to the
<br />proposed development. In like manner, any develop.
<br />ment on the river can be evaluated in dollar terms if
<br />indeed farmers respond to increasing salinity in a
<br />profit maximizing manner. Because of uncertainties
<br />surrounding data available to the farm operator,
<br />adjustments probably would not be as great as
<br />
<br />specified by the model runs. Hence, the estimates
<br />given here should be viewed as biased downward or
<br />on the conservative side. Actual losses in profit
<br />available to farmers are likely to be much greater if
<br />projected salinity levels are reach~d on the Colorado
<br />River in the absence of any mitigation measures.
<br />
<br />Table 18. Total agricultural da_ges.
<br />
<br /> Unit; Dollars Per Year
<br />mg/l Observed Predicteda
<br />At Imperial Dam
<br />700
<br /> 661,138
<br />800
<br /> 1,117,401
<br />900
<br /> 2,036,952 1,888,541
<br />1,000
<br /> 3,096,252 3,191,858
<br />1,100
<br /> 4,915,126 5,394,618
<br />1,200
<br /> 8,899,283 9,117,544
<br />1,300
<br /> 16,566,741 15,409,730
<br />
<br />1,400
<br />
<br />aEstimated by the equation: D = bemx where b ==
<br />12,910, e = 2.71B28, and m = 0.0052; R' = 0.99.
<br />
<br />Thble 19. Application of agricultural damage e.timates to project evaluation.
<br />
<br /> Salinity mg/l Total Annual Average
<br />Project At Imperial Dam Salinity Dollar Impact
<br /> With Without Impact Impact Pe, mg/l
<br />A (Control) 885 950 .65 $ 601,600 $ 9,260
<br />B (Control) 980 1,050 .70 $1,082,800 $15,470
<br />C (Control) 1,050 1,150 .100 $3,035,100 $30,350
<br />D (Control) 1,225 1,250 .25 $1,577,500 $63,100
<br />E (Development) 1,400 1,350 +50 $3,322,500 $66,450
<br />
<br />16
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