<br />Colorado River water, increased by a sufficient incentive.30 Over time, the economic benefit of a
<br />Colorado River water lease may prove sufficiently attractive to WMIDD farmers to overcome
<br />present-day objections.
<br />
<br />An additional cost savings to WMIDD of a water lease would include reduced operation and
<br />maintenance costs associated with retiremeIlt of WMIDD hinds, which could total millions of
<br />dollars annually. Energy required for the pwnp lift stations and maintenance on the 108 miles of
<br />conveyance canals and tunnels is significant. The six pumping plants in the Wellton-Mohawk
<br />Division comprise more than 35,000 horsepower.31 The energy cost to convey irrigation water
<br />uphill and across the entire district for the year 2000 was approximately $1 million.32 A 25%
<br />reduction in water use by WMIDD could result in decreased power costs to WMIDD of up to .
<br />$250,000 annually. .
<br />
<br />One significant consequence of reducing cOIlsumptive use of Colorado River water at WMIDD
<br />will be the reduction of drainwater flowing into the MODE. If water use at WMIDD decreases
<br />by 25%, the bypass flow in the MODE will be reduced by the same percentage, approximately
<br />30,000 acre-feet of water annually.33 As discussed above, MODE water sustains an important
<br />ecosystem in the Cienega de Santa Clara, and its reduction or elimination would cause
<br />unacceptable hann. One way to address this impact to MODE flows is to supplement them with
<br />25,000 acre-feet of water pumped from the Yuma Mesa groundwater mound.
<br />
<br />Securing Federal Credit for Pumped Yumll Mesa Groundwater
<br />In order to sllstain the Cienega de Santa Clara ecosystem, the present-day quaIltity and quality of
<br />flows in the MODE must at minimum be mllintained. It may be acceptable to replace MODE
<br />flows diminished by the lease of water ftom WMIDD with 25,000 acre-feet per year of
<br />groundwater pumped from the Yuma Mesa area.
<br />
<br />Extraordinarily high rates of irrigation in tile Yuma Area Irrigation Districts have created a
<br />mound of groundwater below the Yuma Mesa. Under some 8,700 acres of land the depth to
<br />groundwater is less than 6 feet, despite extensive pumping in the region.34 Groundwater salini~
<br />in the Yuma area averages 1400 ppm.35 The Yuma Area Water Resources Management Group 6
<br />(YAWRMG) has proposed a $2.2 million upgrade of the region's groundwater pumping
<br />infrastructure in order to reduce groundwater levels. under 6,200 acres in the Yuma Valley.
<br />
<br />30 There are various methods of determining this price incentive, This paper refmins from discussing alternatives to
<br />avoid any prem~ture biasing of the pricing process, '
<br />31 See U,S. Bureau of Reclamation, Gila Project, Engineering Data, available at
<br /><hUo:lldataweb usbr,eovlhtml/lceilenedata,html>
<br />)2 Summary of Revenue and Program expense for the parker Davis Project, Schedule No, 26, September 30,2000,
<br />33 Note this assumes a linear relationship between WMIDD diversions and MODE flows.
<br />34 Yuma Area Water Resources Management Group (May 2, 200 I, final dmll prepared for approval). Project
<br />p,ropsal: Improvement of drainage operations in the Yuma Valley,
<br />'US Bureau of Reclamation (1996), Ground Water Status Report, 1994, Yuma Area, AZ and CA, p. A30,
<br />36 The Y A WRMG agencies include the Yuma County Water Users' Association, Unit B Irrigation and Drainage
<br />District, North Gila Irrigation and Drainage District, Cocopah Tribe, City of Yuma, Arizona Department of Water
<br />Resources, Yuma Mesa Irrigation and Drainage District, Wellton-Mohawk Irrigation and Drainage District, Yuma
<br />Irrigation District, Yuma County, U.S. Bureau ofRechunation, and the International Boundary and Water
<br />Commission.
<br />
<br />9
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