Developing a Water Quality Index (WQI) for an Irrigation Dam

Area of Science:

• Environmental Science
• Water Resource Management
• Analytical Chemistry

Background:

• Rising global pollution impacts water ecosystems.
• A Water Quality Index (WQI) simplifies complex water quality data for decision-makers.
• La Vega dam in Jalisco, Mexico, is crucial for irrigating 5000 ha of agricultural land.

Purpose of the Study:

• To develop a Water Quality Index (WQI) for La Vega dam.
• To assess the suitability of dam water for irrigation purposes.
• To identify seasonal trends in water quality.

Main Methods:

• Water samples collected from seven sites at La Vega dam across five months in 2014.
• Utilized the Mexican National Water Commission (CNA) recommended WQI methodology.
• Analyzed parameters including pH, EC, DO, TDS, TH, Alk, TP, Cl-, NO₃, SO₄, Ca, Mg, K, B, As, Cu, and Zn.

Main Results:

• No significant WQI differences were observed among the seven sampling sites.
• Significant seasonal variations in WQI were detected.
• Water quality was poor in March and June, improving to medium-good by July-September, then declining to medium-poor in December.

Conclusions:

• Water from La Vega dam requires treatment before use for irrigation or other purposes.
• Continuous monitoring of La Vega dam's water quality over several years is recommended.
• Seasonal fluctuations necessitate adaptive water management strategies.