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<br />
<br />
<br />Plan Seven - Improved Irrigation Water Management and Onfarm Ditch Lining -
<br />Mixed Levels - 169,000 Acres
<br />
<br />By combining improved irrigation water management at the minimum
<br />level of implementation with improved irrigation water management and onfarm
<br />ditch lining at the maximum level this is one plan that maximizes salt load
<br />reduction having economic feasibility. This plan includes 109 miles of off-farm
<br />lateral improvements needed to assure proper operation of the improved onfarm
<br />sytems. However, not all watersheds included in this plan have individual
<br />economic feasibility, but all watersheds in the *alley are included because a
<br />greater salt load reduction would be achieved. Watersheds at the respective
<br />level of implementation are tabulated below, except that lining the small
<br />off-farm laterals in Watersheds 2 and 24, and the large off-farm laterals in
<br />Watersheds 5, 7, and 25 is not economically feasible.
<br />
<br />Level of
<br />Implementation
<br />
<br />Scope of
<br />Improvement
<br />
<br />Watersheds Areas
<br />Included in Plan 7
<br />
<br />Improvement
<br />Area II
<br />
<br />2, 5, 6, 10, 12,
<br />13, 14, 15, 16, 18,
<br />23, 24, 25 & 26
<br />
<br />Irrigation Water Management Minimum
<br />
<br />89,400 acres
<br />
<br />Irrigation Water Management
<br />& Onfarm Ditch Lining Minimum
<br />
<br />4, 21
<br />
<br />7,900 acres
<br />
<br />Irrigation Water Management
<br />& Onfarm Ditch Lining Maximum
<br />
<br />I, 3, 7, 8, 9, 11,
<br />17, 19, 20 & 22
<br />
<br />71,700 acres
<br />
<br />!I Proportionally adjusted to exclude 2,000 acres converted to urban use.
<br />
<br />. .
<br />
<br />The onfarm portion of this plan can be implemented at a one-time construction
<br />cost of $115,924,000. Technical assistance and administrative costs, estimated
<br />to be $23,740,000, make a total installation cost of $139,664,000. Including
<br />the 54 miles of off-farm laterals in watersheds 1, 3, and 9 with this plan
<br />will add $10,136,000 to the construction cost and $2,000,000 to the cost of
<br />technical assistance and administration making a total installation cost of
<br />$151,800,000.
<br />
<br />The 300,000 ton reduction in salt loading represents an 68 percent reduction
<br />in total salt load being delivered to the Colorado River. Adding the off-farm
<br />laterals to this plan will increase the potential salt load reduction by 35,~00
<br />tons making a total of 335,000 tons. .
<br />
<br />Implementation of this plan could impact an estimated 3,800 acres, or about 10
<br />percent, of wetlands in the Lower Gunnison Unit. ' Full mitigation for the
<br />impacted habitat, estimated to cost $17,600,000 wopld require upgrading the
<br />habitat value on 8,900 acres of wetlands elsewhere in the valley undisturbed
<br />by implementing this plan. There are 33,600 acres of wetlands avoided in this
<br />alternative.
<br />
<br />IV-16
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