State of the River

The present environmental "depauperization" of the Rio Grande between Caballo Reservoir and the confluence of the Rio Conchos may be attributed to 125 years of water development, resulting in full appropriation of the resource (the condition that exists through out the upper basin) and consequent transformation of the river's hydraulic and ecological capacities.
Before the present one million acres of irrigated agriculture were developed in the upper basin, the river flowed through great springtime surges from the melting of mountain snow packs in the headwaters, receded in the hot months of summer, then often filled again during the monsoons of July through October. At approximately 20 year intervals, the moisture from winter storms would fail to come, as it still does, quite often for periods of two to five years.
Zero flows may have occurred prior to irrigation development, but instances were probably quite rare.

Water Availability Baseline

A relatively fixed amount of Rio Grande water is available to supply 200,000 acres of farms and ~1,000,000 human residents, future development and the river dependent environment in the subject region: This amount is 790,000 acre feet (79 kaf), the "firm yield" of the Rio Grande Project.
Project water is regulated (~200 miles upstream of Ft. Quitman) by Elephant Butte and Caballo Reservoirs, which together store about 2,500,000 acre feet (2.5 maf).

Three variables govern the Ft Quitman hydrograph:
-climate (basin wide precipitation as it affects reservoir storage),
-management of water releases from Elephant Butte (particularly control of spills) and
-water use practices (by intervening diverters).

This "water availability white paper" has been prepared to assist in assessing the feasibility of a restoration project for the "Forgotten River", a reach of the Rio Grande from 100 miles south of El Paso to 25 miles north of its confluence with the Rio Conchos (~140 miles).
A prerequisite for any riparian or aquatic restoration project is the availability of an adequate supply of water to support the desired future conditions. It seems clear that since the water management regimes of the past have not satisfied the necessary conditions for maintaining a healthy Rio Grande ecosystem, they will also not suffice for restoring the river's ecosystem.

This paper attempts to:

-Assess the present water supply at Ft. Quitman and
the prospects for protecting it from further depletion.
-Address the political (and logistical) problems of
managing water to achieve restoration goals, including
the prospects for reallocating a potion of existing
supplies to augment streamflows.

Climatic and Development Condition of Basin

The basic, underlying environmental condition of the Rio Grande basin has been accurately described as "a state of drought, occasionally mitigated by abundance". Compared with its westerly-trending sister, the upper Colorado River, the upper Rio Grande produces 10 million acre feet less water or about 3 million acre feet annually (afa).