Index to Area Offices Brief Description of the FSP	FY1998 Field Services Program Mark Niblack or Joe Espinoza
	Location Water Supply Water Use Statistics Problems and Opportunities * Imperial and Coachella * Drainage in the Yuma Valley Water Conservation Measures FY98 FSP Plan Chart Agreements and Partnerships

Location

The Yuma Area Office administers the lower Colorado River, including all diversions below Davis Dam except the Central Arizona Project and the Colorado River Aqueduct. Davis Dam and the Fort Mohave Indian Reservation mark the northern end of the area; the international border with Mexico establishes the southern boundary.

Water use in the area is predominately agricultural: 920,000 land acres, and well over 1 million crop acres (due to double cropping) are irrigated solely with Colorado River water. A year-round growing season, deep and productive soils, and a dependable water supply make this an important agricultural area.

The Yuma Area is one of the fastest growing regions in the country, and is quickly gaining a significant urban population. Over 345,000 people, residing in all or parts of three counties in Arizona and three counties in California, depend upon Colorado River water. Thousands of visitors increase the population dramatically in the winter months, with some cities doubling or tripling with temporary residents.

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Water Supply

 The Colorado River and its associated groundwater aquifer is, with one significant exception, the sole water supply for the entire area. The Coachella Valley taps an important groundwater aquifer formed initially with inflow from the Whitewater River and side drainage. Nevertheless, the Coachella Valley's water supply must be supplemented with Colorado River water in order maintain the groundwater aquifer.

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Water Use Statistics

The size of districts varies from large organizations with hundreds of employees and hundreds of thousands of acres, to small operations with one employee. There are also big variations in history, infrastructure, and finances from district to district. Consequently, the level of technical and financial assistance needed to apply water conservation measures will also vary.

	Type of District	Number
	Agricultural	11
	Municipal	4
	Combination Ag/Muni	2
	Indian Reservations	5
	Wildlife Refuges	3
	Military	2

Of the 6.6 Million Acre-Feet diverted in 1995, 5.4 Million Acre-Feet were consumed by evapotranspiration or percolation, and 1.2 Million Acre-Feet were credited as return flow.

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Imperial and Coachella Valleys

The Imperial and Coachella valleys reside in a closed basin, where all drainage flows into the Salton Sea. The level of the Salton Sea has risen steadily over the past several years above desired levels, threatening the surrounding landowners. The rise in the Sea is due primarily to tailwater and drainage water flowing in from the surrounding agricultural land. Once drainage or tailwater enters the Salton Sea, it is non-recoverable. Tailwater and drainage water from the Imperial Irrigation District (IID) is the largest source of flow to the Salton Sea.

Water supply issues for California and the lower Colorado River region are also associated with the rise in the Salton Sea. California’s consumptive use exceeds its allotment, and it has been dependent on surplus water to meet its needs from the Colorado River. IID is the largest user of Colorado River water in California, and non-beneficial uses of water are not offset by return flows, as in districts along the river. Irrigation efficiency in the district appears to be declining, or at least not improving, despite conservation efforts by IID. IID is pursuing ways to market conserved water. Reclamation and IID are working on establishing a "partnership agreement" where both parties can promote communication and cooperatively address common concerns. In a proposed partnership agreement, Reclamation and IID would work together to develop a defensible basis for reasonable, beneficial use of water in the district.

A partnership agreement has already been implemented between Reclamation and Coachella Valley Water District (CVWD). This agreement has already led to progress in addressing several issues, including water conservation. The primary concerns in the Coachella valley are the depletion of their groundwater supply, and conservation of a limited Colorado River water supply. CVWD is conducting a water use survey to evaluate their water use and develop a water management and conservation plan which will also be their basis for reasonable, beneficial use of water. Reclamation is working with CVWD to verify and concur with their water use survey.

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Drainage Problems in the Yuma Valley

A high ground water table in the Yuma valley exists, which threatens both agricultural and urban areas, and must be controlled by drainage pumping. The high water table is sustained by deep percolation due to over-irrigation in the surrounding agricultural area. Without other mitigation measures, a significant reduction of ground water levels in the Yuma valley would likely require new, expensive drainage wells and increased drainage pumping.

The deep percolation causing the high water table comes from two irrigated areas: the Yuma-mesa, which is higher in elevation than the Yuma valley; and from the Yuma valley itself. The Yuma-mesa is predominately citrus with very sandy soils. In the Yuma valley there are a variety of crops, but winter vegetable crop acreage has greatly increased in recent years. Winter vegetable production can aggravate the deep percolation problem because irrigation efficiencies with vegetable crops have been generally lower than for other crops.

Studies show that an increase in irrigation efficiency of 17% or better on the Yuma-mesa would eliminate the need for new, costly drainage wells in the Yuma valley. Additionally, any increase in irrigation efficiency in the Yuma valley itself would help with the drainage problem.

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Water Conservation Measures

Priority 1 -Water measurement:

Water measurement is fundamental to successful water conservation efforts. Inaccurate measurement can lead to over-delivery, under-delivery, and unaccounted water. The kind of improvements in water measurement that are needed varies from district to district, but nearly all the districts in the area are striving to improve their water measurement methods. Reclamation is already involved in several water measurement demonstration and improvement projects, and more are planned for 1998.

Priority 2 -Irrigation Water Management:

Most of the farmland in the Yuma area is surface irrigated. It is common for irrigations to be managed well below their practical potential for irrigation efficiency. Improved irrigation water management has the greatest potential for water conservation in the Yuma area. Irrigation water management involves determining how much water to apply, and how to apply irrigation water most effectively. Reclamation is supporting improved irrigation water management through information and education, water management demonstrations, mobile lab programs, and research and demonstration programs.

Priority 3 -Irrigation scheduling:

Use of a reliable, accurate irrigation scheduling service has proven to be a most effective measure for improving water management, thereby reducing diversions while improving farm productivity. Every district would benefit from having irrigation scheduling services available that are adapted to local needs. Growers in the Yuma area irrigate year-round, and have enough water to meet consumptive use requirements even in midsummer. The irrigation water supply system is not stretched to or beyond its limits, as in many places in the Southwest. Therefore, growers in the Yuma area have the flexibility to make irrigation scheduling decisions. Reclamation, Yuma Area Office, proposes to promote and stimulate the use of irrigation scheduling services in this program plan.

Priority 4 -Canal Automation:

The degree to which a farmer can improve his irrigation water management can be limited by the water delivery capability of the District. Fluctuating, inaccurate, or untimely delivery of water can make improvements in water management difficult for an irrigator. Operational spills are necessary to provide reliable service to customers in a canal system, but they can be minimized through improved management. Most Districts are constantly striving to minimize operational spills. Canal automation is a proven and increasingly practical and economical method to improve deliveries to farmers and reduce operational spills. The amount of automation in the Yuma area varies from district to district. Where there is not presently any good experience with canal automation, Reclamation is promoting it through demonstration projects.

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Program Activities

see explanation of headings below

Explanation of headings on plan:

Goals for water conservation, quantified. (Eg.. Save 2% of flows to a district)

Measures to achieve each goal, site-specific

Priority L-Low, M-Medium, or H-High

Target dates to implement each measure

Costs projected for implementing measures and, if applicable, funding sources with percentage share

FTE (Full Time Equivalent) positions within USBR dedicated to do the work.

Results of the effort quantified by estimate or measure

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EXISTING CONSERVATION AGREEMENTS

*CA=cooperative agreement, G=grant, MOA=memorandum of agreement

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