Estimation of Water Loss Due to Evaporation in the El Cazadero Dam, Mexico, during a Drought

In Mexico, large dams have been a critical component of the water supply. However, the places where they can be built are scarcer every day, a situation that adds to the high costs and social conflicts that they cause. Much of the water stored in dams is lost due to evaporation, so technological alternatives are currently being investigated to reduce it. Regarding the determination of evaporated volumes, data obtained with evaporimeters do not represent actual evaporation, being necessary to apply theoretical models in combination with field measurements to reach better approximations. The main objective of this research is to calculate the water evaporation in the El Cazadero dam located in the State of Zacatecas, Mexico, through Penman’s semi-empirical equation using data from the El Cazadero or 32006 weather station. The study area was selected due to its aridity and recurring drought problems that affect water availability. Evaporation results obtained from applying the theoretical model are compared with those reported by the weather station, showing a good correlation. In addition, results of the average daily evaporation are used to determine the approximate volume of water evaporated in the hydrological year between November 2010 and October 2011, when a severe drought occurred, whose magnitude and economic value indicates the necessity to carry out more research on this subject and propose public policies to develop and implement technological alternatives that mitigate this phenomenon.