Wellton-Mohawk Irrigation and Drainage District


Current & Recent Challenges

Because of its location and size, and the complexity of American society, the District has had its share of political controversy. Highlights of some of the more interesting challenges follow.

Corps of Engineers Gila River Channelization Project

Painted Rock Dam, upstream of the District, was to have had a major channel construction project associated with it. That project, to be constructed by the Corps of Engineers, consisted of levees and incidental works through the Wellton-Mohawk Irrigation and Drainage District from the Gila Canal siphon upstream to Texas Hill. Following the river flow of 1966, there was a concerted effort by this District and the Corps to initiate this channelization project. However, environmental opposition slowed the effort until inflation put the project, as designed, beyond economic justification. It is increasingly unlikely that the work as designed will be constructed in the foreseeable future. Events following the record-breaking flood of 1993 have, however, caused the Corps of Engineers to review the benefit/cost ratio under current conditions.

Colorado River Desalinization Project

The extension of the channel carrying the District’s return flows directly to the Colorado River main-stem resulted in the salinity of that river increasing (below the mouth of the Gila River) to an extent that the Arizona Water Company, which at the time provided domestic and industrial water for the City of Yuma, had to change its diversion from the Colorado River to the Yuma Main Canal. That canal is a branch of the All-American Canal, which has its heading at Imperial Dam, above the confluence of the Gila and Colorado Rivers.

The treaty of 1944 between the United States and Mexico established Mexico’s share of the normal flow of the Colorado River at 1,500,000 acre feet per year. The treaty also stated that the water to be furnished to Mexico “shall be made up of the waters of said river, whatever their origin.” The treaty, as originally drafted and signed, made no mention of water quality.

Minute 218

Seeking a permanent solution to the problem of increased salinity in the water of the Colorado River due to Wellton-Mohawk return flows, Mexico and the United States entered into an agreement for the construction of a 353 cfs concrete-lined channel, 12 miles long, from the confluence of the Gila and Colorado Rivers to Morelos Dam. This channel, carrying Wellton-Mohawk return flows, has a structure permitting all or a part of the flow to be either diverted into the Colorado River at the Northern Boundary above Morelos Dam or passed around that dam. The channel, known as the MODE (Main Outlet Drain Extension), and the agreement, or Minute, went into operation on November 15, 1965, for a planned 5-year trial period. That period ended in November 1970, but at Mexico’s request, the Minute was extended for one year. Another provision of this Minute was a program of selective pumping of the District’s drainage wells. The better quality wells were pumped from February 11 to September 30, when there was sufficient Colorado River water to dilute the return flows, and the lesser quality wells were pumped from October 1 to February 10, when the effluent could be by-passed around Mexico’s point of diversion.

Minute 241

A major canal lining improvement program undertaken by Mexico (1969-74) to minimize waterlogging and salt build-up due to canal seepage was not felt by Mexico to have overcome the results of the increased salinity level of its Colorado River diversions. Mexico’s President Echevveria formally conferred with President Nixon early in 1972, resulting in Minute 241, effective on June 26, 1972, which provided for bypassing most of the District’s return flow for the balance of 1972.

Developments in 1972

President Nixon appointed, in September 1972, Herbert Brownell, Jr., a former United States Attorney General, to propose a solution to the Mexican salt problem by December 31, 1972. Mr. Brownell visited the lower Colorado River basin, including Wellton-Mohawk and the Mexicali Valley in Mexico.

Minute 242

Mr. Brownell authored an agreement (Minute 242) which was approved by the United States and Mexican Sections of the International Boundary and Water Commission (“IBWC”, the agency formed by Mexico and the United States to oversee the administration of waterways and boundaries common to the two nations), on August 30, 1973. This agreement provided for:

  1. lining a portion of the Coachella Branch of the All-American Canal to salvage 130,000 acre feet per year;
  2. construction of a desalination plant on the lower Colorado to process Wellton-Mohawk return flows;
  3. an additional extension to the return flow canal from Morelos Dam to Santa Clara Slough near the Gulf of California, to convey the brine from the desalting plant plus any unused/untreated Wellton-Mohawk return flow to coastal waters;
  4. buying and retiring significant acreage of high-water-use land in Wellton-Mohawk to reduce return flows;
  5. an assurance to Mexico of a quality of water at its point of diversion at a yearly average salinity not greater than 145 ppm higher than Imperial Dam quality;
  6. limiting pumping of groundwater by either nation, within five miles of the border, to 160,000 acre feet per year; and other minor agreements.

Public Law 93-320

Wellton-Mohawk representatives testified at hearings before the congressional committees, leading to the passage of this legislation, which was signed by President Nixon on June 24, 1974. Title I of the act confirmed the recommendations of Minute 242.

All provisions of Minute 242, later authorized by Public Law 93-320, have been carried out. The 37-mile extension to the return flow canal from the international border to Santa Clara Slough and the 16-mile portion between Morelos Dam and the international border at San Luis were completed in early 1977.

The desalinization plant, located west of Yuma and immediately north of the Yucca steam-electric plant, is complete and tested, but will be operated only when Colorado River flows are sufficiently low to justify not bypassing Wellton-Mohawk drainage return flows to Santa Clara Slough.

The Bureau of Reclamation and the United States Section of IBWC have been successful in keeping the quality of water delivered to Mexico at less than 145 ppm higher than Imperial Dam quality.

Mexico installed, in 1972-73, sixty-four wells on the mesa east of San Luis, and a concrete channel to carry the effluent from the wells into the San Luis Valley in Mexico. The wells draw about 5 cfs each (at a static level of approximately 90 feet) from the underground accumulation of groundwater created by the Yuma Mesa Irrigation and Drainage District, south of the City of Yuma.

As a result of that action, and to insure that credit would be received for what was essentially Colorado River water making its way into Mexico, Reclamation installed fourteen wells just north of the border within the five-mile limit. A concrete channel was constructed to take the effluent into Mexico on the discharge side of the Boundary pumping plant owned and operated by Yuma County Water Users Association. This water is considered part of the 1,500,000 acre feet of Mexico’s Colorado River entitlement.

Mexico is still pumping from its San Luis well field, most of which is within five miles of the border. Only the water produced by wells within five-miles of the border, on either side, count toward the 160,000 acre feet limitation for each nation.

Quality Improvement, W-M Return Flows

Wellton-Mohawk return flows improved in quality from 6500 ppm salts in 1961, to 3800 ppm in 1973, to 2800 ppm in 1994, and to about 2650 in 1997. The “flattening out”, or slowing in improvement which was predicted 30 years ago, has occurred. Significant additional improvement in the quality of return flows is unlikely. The program of acreage reduction might even have already adversely affected continued improvement in quality, since less deep percolation would naturally result in less dilution of the ground water.

Quality Changes, Colorado River

Quality generally decreases, with or without use, as river water flows downstream. The salinity of Colorado River water at Imperial Dam increased from 693 ppm in 1945 to 894 in 1970, decreased to 820 in 1977, was near 900 ppm in 1994, and averaged around or below 700 ppm in 1997, with steep downward fluctuations during years of flooding.

Return Flow Reduction

Efforts undertaken within the boundaries of Wellton-Mohawk to reduce return flows and to help achieve the quality guaranteed to Mexico by Minute 242, authorized by Public Law 93-320, have been successful, and include the following.

  1. Acreage Reduction

    The initial step in reducing the return flows from Wellton-Mohawk was the elimination of future or current irrigation of 10,000 acres of undeveloped land, or land with low water-use efficiency. Procurement of high-water-use land by the Bureau of Reclamation was completed by the mid 1970s. The bulk of developed, low efficiency land that was taken out of cultivation was citrus on sandy soils. The land was cleared, and the trees were cut and chipped, or windrowed to provide wildlife cover. In all cases, the purchase of lands by the federal government was negotiated with willing sellers.

    In addition to its primary purpose, there was another benefit to acreage reduction. The District’s original contract with the United States was for sufficient water for use on 75,000 acres, or for 300,000 acre feet per year, diversions less return flows. It has been demonstrated on this project that 300,000 acre feet of water is not sufficient to irrigate 75,000 acres in the southwestern desert, where the year-round growing season makes double cropping the norm. Even with several thousand acres of the original 75,000 not yet developed, the net usage (yearly diversions, less return flows) had exceeded the allowed limit, on occasion. The reduction in total irrigable area from 75,000 to 65,000 acres, and ultimately to 62,750 acres, has made it possible for the District to achieve the present allowable consumptive use of 278,000 acre-ft per year.

  2. Irrigation Scheduling

    A major feature of the return flow reduction effort was the establishment within the District of a prototype irrigation scheduling service. Over the years, this service developed the use of neutron probe moisture meters, infrared gun thermometers, and other sophisticated techniques for determining not only soil moisture content, but also rates of depletion and recommended dates and amounts of soil reservoir refill. The overall purpose and effect of this program was to eliminate the unnecessary application of irrigation water, any excess of which is lost to deep percolation, thus necessitating groundwater pumping. Measuring flumes were also part of each on-farm ditch rehabilitation, to allow the farmer to know exactly how much water was being used in an irrigation. This program led to more efficient water use by the land operators.

    Four Wheel Drive Tractor with Laser Controlled Scraper

  3.  Precision Land-Leveling

    Wellton-Mohawk saw the development and first widespread use of laser land-leveling equipment. In addition to the use of laser equipped tractors in the initial leveling of new ground, operators now use touch-up laser-controlled field finishing as a routine step between crops. Almost all irrigated land in the Wellton-Mohawk consists of dead-level basins. Thus, fields can be irrigated with minimum water application, in some cases more efficiently than with sprinklers (because of the extremely high rate of evaporation experienced with sprinklers).

  4. Improved Farm Ditches and Turnouts

    District-owned distribution laterals were concrete-lined at the time of original construction. However, even by the mid 70s, many of the water users’ on-farm ditches were still unlined, or had very thin, deteriorated concrete linings. Public Law 93-320 made it possible to line those ditches. Because of that program, almost all farm ditches in this project are now concrete lined, with a noticeable increase in farm efficiency. In addition to decreased seepage, the lined ditches have the ability to handle the larger irrigation heads which the enlarged and reconstructed farm structures can handle, and without which the precision leveling would be less effective. The on-farm improvements were provided through the USDA Soil Conservation Service from 1974 through 1986. Farm operations on 48,000 acres benefited from system redesigns and installation of improved facilities.

  5. Soil Swapping

    In extreme cases, where the existence of small areas of non-conforming soil made necessary the over-irrigation of the balance of a field, soil swapping was used. Poorer soil was simply removed and replaced by soil similar to the rest of the field, decreasing average water use. This made it no longer necessary to irrigate as dictated by patches of soil with very poor water holding capacity.

District River Channel Clearing

Beginning in 1955, it was the desire of the Wellton-Mohawk Board of Directors that the District clear and maintain a 100-foot wide swath within the otherwise brush-filled Gila River channel, to pass flood flows. Due to a shortage of manpower and equipment, this was not always possible, and moisture from the adjacent irrigated acreage contributed greatly to the growth of phreatophytes (“water-loving” plants) in the uncultivated, non-maintained river channel.

By the time of the 1973 releases from Painted Rock Dam, years of neglect saw the Gila River channel totally choked with brush. At that time, the Board determined that a major effort was justified, and essential to keep the expected flows confined to the channel, lessen damages to adjacent farmland, and to provide a faster surface flow, thus lessening groundwater build-up. A crash program was initiated at Avenue 41 (roughly the middle of the District), and proceeded downstream to Avenue 16, just ahead of the flow. Clearing could only be accomplished in that portion of the channel that was sufficiently free of standing water to allow heavy equipment to work.

However, the effort brought objections from the Arizona Game and Fish Department, which contended that the District was destroying habitat needed for doves and other wildlife. These objections progressed until Arizona Game and Fish filed a lawsuit in federal court against the District and Yuma County (the agency technically responsible for flood control efforts within the county). The first action by the court was a restraining order against the District and County that immediately halted all significant clearing efforts.

There were two days of trial, November 21, and December 5, 1973. Judge Walter F. Craig required the parties to negotiate a solution with which both could agree. He then lifted portions of the restraining order. In the years following, a definite plan began to develop for a 10,000 cfs channel. This size satisfied (barely!) the minimum requirements of the Corps of Engineers in its expected operation of Painted Rock Dam, and involved only a fraction of the cleared area in the original Corps-proposed channel. Even so, the job of convincing those initially adamantly opposed to ANY channel clearing was a long one.

After years of negotiations and innumerable meetings between the parties, with assistance from the Bureau of Reclamation and many other state and federal agencies, the District in 1986 received from the Corps of Engineers a Section 404 permit, allowing a Gila River channel enhancement project to proceed.

Work began on August 4, 1986, and took the expected 6 full years to complete. Involved was the clearing of all brush along the centerline of the existing rudimentary channel, to a width of 250 feet. Excavation was limited to the construction of a pilot channel, or excavation of sufficient material for the construction of dikes. Dikes were constructed to a height of 10 feet above the bottom of the channel, and only at locations where adjacent irrigated acreage lay at an elevation less than 10 feet above the river bottom.

In order to simplify administration of construction and long term maintenance of the enhanced channel, a decision was made early in the project to construct the channel entirely upon federally owned, Reclamation-withdrawn or Reclamation-acquired land. The great majority of the undeveloped river bottomland was already in federal ownership, or had been acquired by the District in years past as one of the requirements of the Corps of Engineers proposed channel. District and non-federal lands necessary to meet the agreed-to requirement for federal ownership of the channel “right-of-way” for the project were acquired by exchange for federal lands outside the channel project area.

Inasmuch as the less expensive District-constructed channel produced many of the non-reimbursable flood control benefits of the original Corps channel, non-reimbursable funding for the new channel project was made available. Most of the recent bridge-building effort described earlier was made possible by the flood control funds procured as a result of the well-received and convincing proposal for a realistically scaled project with benefits accruing to all parties.

The project was far enough along to handle with ease the approximate 5000 cfs Painted Rock release in early 1992. Construction was essentially complete when flooding began again in January 1993. The 10,000 cfs channel, with constant attention, successfully passed flows up to 12,000 cfs, but no amount of effort could strengthen them enough to resist the 20,000+ cfs at which the flood peaked. Damage to the almost-completed channel project was extensive, including major reaches of totally relocated river channel. Flooding of farmland and destruction of on-farm irrigation systems were widespread, as was damage to District irrigation and drainage facilities. Repairs to District irrigation and drainage facilities took almost two years to complete and cost approximately $15 million.

Sequence of Events Relative to Flood Protection Following 1993 Flood

April 1993 - Wellton-Mohawk began assessing damages to flood control facilities and planning for their restoration.

October 1993 - As the flood flow subsided, Wellton-Mohawk, working under the direction of the Federal Emergency Management Agency (FEMA) contracted for a cost comparison analysis of flood protection alternatives.

November 1993 - At the direction of FEMA, Wellton-Mohawk contracted for environmental compliance and engineering support services necessary to accomplish the restoration of flood protection facilities.

December 1993 - FEMA designated the Corps of Engineers (USACE) as the lead Federal agency for environmental compliance.

January 1994 - Wellton-Mohawk, under the guidance of FEMA and USACE, organized an Interagency Working Group to scope the project and assist with environmental compliance activities.

Compliance activities included:

  • Clean Water Act - Sections 401 and 404 (CWA)
  • National Environmental Policy Act (NEPA)
  • Endangered Species Act (ESA)
  • National Historic Preservation Act (NHPA)
  • Executive Order 11990 - Protection of Wetlands
  • Executive Order 11988 - Floodplain Management

The Interagency Working Group included:

  • U.S. Army Corps of Engineers (USACE)
  • Federal Emergency Management Agency (FEMA)
  • U.S. Fish and Wildlife Service (USFWS)
  • U.S. Bureau of Reclamation (USBR)
  • U.S. Environmental Protection Agency (USEPA)
  • Arizona Department of Environmental Quality (ADEQ)
  • Arizona Game and Fish Department (AGFD)
  • Arizona Division of Emergency Management (ADEM)
  • Bookman-Edmonston Engineering, Inc. (consultant)
  • Resource Management International, Inc. (consultant)
  • WESCO (consultant)

The Interagency Working Group had 12 meetings between January 1994 and February 1995.

May 1995 - With the support of the Interagency Working Group (except USEPA), the Corps of Engineers issued a Clean Water Act Section 404 permit and environmental assessment that led to a fully mitigated project and a finding of no significant impact (FONSI).

The Irrigation Plan Includes:

  • Complete avoidance of all existing wetlands
  • Increasing acreage between the levees by 50%
  • Adding over 1900 acres of the most flood sensitive agricultural land to the permanent floodplain through acquisition and retirement
  • Affording protection for an additional 88 acres of wetlands
  • Creating 9 acres of new permanent wetlands
  • Mitigating impacts to riparian vegetation with 100% replacement in-kind, on site, by acquiring private land and deed-restricting its use for the life of the project
  • Stabilizing the river gradient with grade control structures to minimize sediment transport
  • Reducing the low-flow channel width and raising the invert to increase the probability of more natural overbank flooding between the levees
  • Coordinating channel maintenance activities to maximize valuable interim habitats during sensitive biological periods
  • Constructing gated hydrologic connections to protected oxbow areas to extend the wetted period during flood flows

The U.S. Fish and Wildlife Service and the Arizona Game and Fish Department fully support the mitigation plan.

June 1995 - The Southwest Center for Biological Diversity, Defenders of Wildlife, and the Public Employees for Environmental Responsibility filed suit against the Corps of Engineers seeking to enjoin the project and force preparation of an environmental impact statement.

July 1995 - Wellton-Mohawk filed a motion, in U.S. District Court, to intervene in the lawsuit.

August 1995 - FEMA withdraws from project participation

December 1995 - FEMA decides to do a Cost/Benefit analysis of the project.

January 1996 - U.S. District Court allows Wellton-Mohawk’s intervention in the lawsuit, as a matter of right.

1996 to Present - Court rules in favor of Corps of Engineers and District. Plaintiffs appeal. Lower Court verdict is upheld. FEMA participation is reinstated, and work progresses, and is completed in early 2000.

The Kennedy Bills

In April 1976, Senator Edward M. Kennedy (D-Mass) introduced S-3298 entitled “Central Arizona Indian Tribal Water Rights Settlement Act of 1976.” No hearings were held on the bill and it died with the adjournment of the 94th Congress.

However, the bill was reintroduced as S-905 in the 95th Congress in 1977 by Senator Kennedy and co-sponsored by Senator Lee Metcalf (D-Mont), who had announced that he would not seek re-election in 1978.

The bill would have directed the Secretary of Interior to condemn certain private lands in the State of Arizona, with first priority on Wellton-Mohawk, for the purpose of giving the water rights to the Indian tribes of Central Arizona. It was also argued that the bill would have eliminated the necessity for the by-then-authorized desalination plant. The bill was a legislative attempt to solve the problem of Indian water rights by giving the several tribes water of the Colorado River to which they had no historical claim. The cost for the lands of Wellton-Mohawk including District investments, utilities, and relocation of its citizens was estimated at $266,000,000. As a comparison, the annual production of Wellton-Mohawk in recent years has been well above $100,000,000. The total impact of Wellton-Mohawk production on the state’s economy is considered many times that amount.

Wellton-Mohawk representatives attended the hearings and testified before the Indian Affairs Committee of the Senate in Washington in May 1977. The Bureau of Reclamation testified that, even with the retirement of Wellton-Mohawk, a desalination plant, although smaller than planned, would still be needed. The Secretary of Interior recommended that his department be allowed to redraft the bill, and the hearings ended with that admonition. The legislation, as proposed, never materialized.


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