Water supply and demand scenarios in the San Juan watershed

Abstract

Mexico is listed among the countries predicted to have freshwater shortages for the year 2020. The drought spell of the 1990’s has reduced fresh water availability in northern Mexico. Conflicts between users, and political entities have appeared in several watersheds. The río San Juan watershead is a classic example where water resources are of paramount importance for sustainable development. We aimed to predict future water supply and demand along the main of the río San Juan, from El Cuchillo reservoir to the confluence with the Rio Bravo. Monotonic increases in municipal water demand sector in the Monterrey Metropolitan Area and future water supplies predicted under normal and dry conditions were assumed in assessing future water allocation. The results indicate that water allotted for irrigation dramatically decrease under normal and dry conditions, shrinking the size of irrigated lands. We recommend implementation of sustainable management of water resources to buffer the potential contraction of irrigated lands and the disappearance of riparian ecosystems in the lower watershed f the río San Juan.