WSP06206

• File Number: 8278.200
• Description: Title I - Wellton-Mohawk
• Basin: Colorado Mainstem
• Date: 8/1/1988
• Author: USDOI/SCS
• Title: Wellton-Mohawk ON-Farm Irrigation Improvement Program Post-Evaluation Report
• Water Supply Pro - Doc Type: Publication

II. INTRODUCTION

The la~d around Wellton, Arizona has been an oasis for travelers and
far~ers. Its lifeblood ~as the ~aters of the Gila River. Although
1r.teri..ittC''r'.t ;:in':' ',J.n?redictabl~, ti'.:.:-:. ',.'ater s-ef'..'cd as the foundation upon .....hich
far~ing has developed.

Pima Indians are believed to have irrigated some of the bottomlands as early
as 1538. Father Kino and Father de Anza follo~ed the Gila River in the 17th
and 18th centuries lool:ing for a safe route to California. Wellton ~as the
end of the Camino del Diablo, the Devil's High~ay, for those fortunate enough
to survive this southernmost route to California. But, 'drought, heat, and
Indians discouraged settlement until the 1850's. '

In 1857 the establishment of the Butterfield Stage Line bet~een San Diego and
San Antonio marked the beginning of white settlement. Growth was slow, but by
1875, a numbet of homestead filings had been made. Then, in 1878, the
Souther~ Pacific Railroad was constructed and service at Wellton was begun in
February 1879. Attention was now focused ~ore fully on developing the water
in the Gila River. Between 1860 and 1915 the industrious homesteaders
developed several thousand acres of farmland stretching for 40 miles along the
river. They constructed the llohawk and Antelope canals and diverted the Gila
River. Because of the erratic and silt-laden flows, attention was turned to
punping of groundwater in 1915. This was successful for 15 years. By the
1930's building of da~s upstream on the Gila River and heavy local pumping
caused lo~ering of the watertable. As a result, the groundwater beca~e
increasingly saline. Agricultural activities began to decline and crops were
li~ited to salt tolerant plants.

The proposed solution was to import Colorado River water. The Yuma Area
Project was constructed in 1952 under the direction of the Bureau of
Recla~ation. The l1ellton-:loha~k Irrigation and Drainage District was formed
in 1951. By 1957, crop yields in part of the valley were decreasing because
of high ~atertables. It became necessary to remove the excess groundwater by
punp;ng. This drainage, which was very saline, was discharged into the Gila
River and flowed into the Colorado River. The Colorado was diverted at
~lorelos Dam, just above Yuma, for irrigating extensive farmland in Mexico. As
volume of flo~ in the Colorado River decreased, the salinity of the water
arriving in Mexico increased.

This created an international problem. The Presidents of the United States
and Mexico met in March of 1962. They created the International Boundary and
Water Commission to plan and administer solutions. Between 1963 and 1973 a
series of measures were installed. These included the control of flow volumes
and quality of water. Also, the ,:lain Outlet Drain Extension (~lODE) ~as built
to discharge part of the Wellton-llohawk return flows below Morelos Dam. As
much as 50,000 acre-feet of water per year was released down the Colorado into
the Gulf of Mexico. In the water-short Southwest, this was not considered a
final or satisfactory solution.

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