Groundwater vulnerability assessment in agricultural areas using a modified DRASTIC model

Area of Science:

• Environmental Science
• Hydrogeology
• Geographic Information Systems (GIS)

Background:

• Groundwater contamination poses a significant global challenge for resource managers.
• Assessing aquifer vulnerability is crucial for effective groundwater management and pollution control.

Purpose of the Study:

• To enhance the accuracy of groundwater vulnerability mapping using a modified DRASTIC model.
• To optimize the DRASTIC model's rating function with statistical techniques for improved zonation.
• To evaluate the effectiveness of the modified model for non-point source pollution assessment in agricultural regions.

Main Methods:

• A modified Depth to water, Net recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and Hydraulic conductivity (DRASTIC) model was developed.
• Statistical techniques were integrated to optimize DRASTIC parameter ratings based on chloride concentration data.
• Geographic Information System (GIS) was utilized for spatial analysis and vulnerability map generation.
• Sensitivity analyses (single-parameter and parameter removal) were conducted to determine parameter importance.

Main Results:

• The modified DRASTIC model significantly increased the coefficient of determination (R²) from 0.52 to 0.78 compared to point data.
• The modified model provided improved groundwater vulnerability zonation over the original DRASTIC model.
• Sensitivity analyses identified the vadose zone as the most influential parameter affecting aquifer vulnerability.

Conclusions:

• The modified DRASTIC model offers a more accurate and efficient approach to groundwater vulnerability assessment, particularly in agricultural areas.
• Statistical optimization of the DRASTIC model enhances its predictive capability for groundwater pollution potential.
• The proposed methodology is valuable for groundwater resource management and land-use planning in vulnerable regions.