The Rio Grande: Is the Past the Key to the Future?

Abstract

The Rio Grande Valley receives the large majority of its water supply, both surface and ground water, from its headwaters in Colorado and northern New Mexico. This area constitutes a small fraction of the drainage basin. This hydrological reality imposes severe constraints on the potential supply of water for the inhabitants of the Rio Grande Valley. For most of its history, the inhabitants accommodated themselves to the flood-and-drought vagaries of the river, modifying it in only very minor ways. This changed with the incursion of railroads in New Mexico in the 1870's. The effects of access to distant markets and to modern engineering technology resulted in changes to the Rio Grande that, by the middle of the 20th century, made it scarcely recognizable as the same river that had existed 100 years prior. In many cases, the changes were not intentional, but rather arose from unforeseen outcomes of economic activities. We have now reached the point where water utilization is a zero-sum game. If water is to be put to new uses, it has to be taken away from an existing user. Water availability is the constraining limitation on human activity in the Rio Grande Valley. The question for the 21st century is whether the inhabitants of the Valley will continue to reallocate the water to satisfy blindly accepted societal goals, and suffer the inevitable unintended consequences, or whether they will recognize the limiting role of water supply and try to direct water use toward achieving the best quality of life possible within the water limitation.