Salinity and microbiological risk assessment in surface runoff and main tributaries to La Vega Dam in Teuchitlán, Jalisco, Mexico.

Abstract

Objective: This research aimed to evaluate the water quality of the main tributaries to the La Vega Dam for irrigation purposes through the physicochemical and microbiological parameters.

Design/methodology/approach: The 10 main tributaries to the La Vega Dam were selected. The variables evaluated were pH, Temperature, Electrical Conductivity, Total Dissolved Solids and Dissolved Oxygen, boron calcium, magnesium, sodium, SAR, and RCS.

Results: 50% of samples presented low sodicity risk, 10% medium risk, 20% and 20% very high risk. In the CSR results, only one site (10%) presented a low risk, and the remaining four tributaries (40%) of this area presented a medium risk. Five sites (50%) located east of the dam presented a high risk. Also, high boron concentration was observed, corresponding to El Salado River. Fecal pollution was detected in 100% of sites, limiting their use as irrigation water.

Limitations on study/implications: Continuous water quality monitoring of the main tributaries to and into La Vega Dam should be followed up.

Findings/conclusions: The most significant contribution of contamination to the dam was observed in the eastern part, with the entrance of El Salado River. High concentrations of boron were also observed. A high concentration of total and fecal coliforms was also found, in addition to the presence of Pseudomonas spp., which indicates fecal contamination. The effluent at the east of La Vega Dam is unsuitable for irrigation.