Degradation of water quality as a consequence of use in irrigation in the Lower Rio Grande Valley of New Mexico is a largely unavoidable phenomenon. In this region annual allocations of water to irrigated farms, about 2.5 acre-feet per acre, are little more than enough to produce crops. Evaporation and transpiration, occurring because of irrigation, cause concentrations of salts in return flows to be greatly increased, and the addition of these highly saline return flows to a quite limited flow of water in the Rio Grande causes the quality of the river water to be significantly reduced. It is possible to affect the quantity and quality of return flows by improvement of water transport facilities (canals, laterals and ditches) and by improved management of water on some farms. These two technical improvements can be accomplished by extension of technical assistance through existing federal and state agencies and by cost-sharing programs such as the Agricultural Conservation Program. But it is also possible to achieve improved management of water on farms by facilitating exchanges or sales of allotments among farmers who are members of irrigation districts.

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