Hydrological Feasibility of Environmental Flows in the Rio Grande/Bravo Basin

Due to high water demand, the scarcity of water resources, and the complexity of water allocation in the Rio Grande/Bravo basin, environmental flows have not been considered as an integral part of the water management in this basin. Important environmental habitats such as the Big Bend National Park in the US, the Northern Chihuahuan desert, the Maderas del Carmen and the Cañon de Santa Elena natural reserves in Mexico are ecologically threatened because of the lack of environmental water management policies in the basin. Several efforts have been undertaken by government agencies and non-governmental organizations in order to determine the environmental flows requirements for the basin. Even though environmental flows in several locations along the basin have been determined (e.g., the Rio Conchos tributary), the quantification and availability of the water necessary to provide these environmental flows has not been determined. In this paper we evaluate the hydrological feasibility of environmental flows in the Rio Conchos tributary to the Rio Grande. This evaluation is done in a basin model constructed in the Water Evaluation and Planning system (WEAP) software. An analysis of the available water has been defined to determine the amount of water required to provide the environmental flows. The description and evaluation of the environmental flows are presented along with a comparison against the current water management policies.