Forecast of lake volume and salt concentration in Lake Chapala, Mexico

Abstract

Using historical hydrological information and water quality records, an early warning system was developed to forecast short-and long-term trends in water level changes and volume-dependent major ion concentrations for Lake Chapala, Mexico. The developed tool allows one to forecast yearly minimum lake-water volumes with a 90% probability and less than ±5 % error. The long-term behavior of lake volume and its trend towards a new equilibrium was estimated by a second empirical approach, where water storage variations were calculated by estimating changes in total lake evaporation losses due to variations in lake area. Available historical water quality records were analyzed and, by applying subsequent Aquatic Sciences statistical data filtration, volume and time dependent trends in major ion concentrations were established. Mass and charge balances were applied to complete the datasets with concentrations of ions that are not measured during ordinary monitoring. Concerning water quality regulations, minimum lake volumes were proposed to guarantee the intactness of this important drinking water resource. Despite the uncertainties of these approaches, the early warning system presented provides a useful tool for short and long-term prediction of lake water storage and quality that may support management decisions related to the whole watershed.

Computation of changes in the run‐off regimen of the Lake Santa Ana watershed (Zacatecas, Mexico)

“…in the lake basin, and the strong influence of evaporation in the intermittency of the lake. The lake's estimated evaporation coefficient for March 2006, utilizing an evaporation pan, was C = 0.77, which is in accordance with a typical evaporation coefficient of 0.7 reported for Lake Chapala, the largest natural lake in Mexico, and located immediately south of the study area (Van Afferden & Hansen 2003).…”