Investigating groundwater viability for sustainable agriculture: Introducing the Irrigation Groundwater Viability Index (IGVI)

Groundwater irrigation is essential for enhancing agricultural productivity, with its viability influenced by water quality and depth. Previous studies have often assessed these factors in isolation. This research introduces the Irrigation Groundwater Viability Index (IGVI) as a novel framework for evaluating the financial viability of groundwater resources, integrating both water quality and depth. Two hundred ninety-six groundwater samples were collected and analyzed from an agricultural reclamation project in Minia Governorate, Egypt. The Irrigation Water Quality Index (IWQI) was calculated, and samples were classified into five categories with corresponding weights. Additionally, samples were categorized by water table depth, resulting in five more categories. The IGVI was developed by integrating IWQI weights and depth classifications. Gaussian Process Regression (GPR) models, including Rational Quadratic, Mate<acute accent>rn 5/2, Squared Exponential, and Exponential Rational Quadratic, Mate<acute accent>rn 5/ 2, Squared Exponential, and Exponential, were employed to predict IGVI using measurable parameters, including water depth, distance to the river, electrical conductivity (EC), and total dissolved solids (TDS). Findings reveal that 53 % of agricultural reclamation areas exhibit moderate economic viability, while 30 % are classified as having poor viability and 17 % as good viability. The exponential GPR model showed the best predictive accuracy, with a mean absolute error (MAE) of 0.79 and a root mean square error (RMSE) of 1.14. Practically, the IGVI assists water resource stakeholders in making informed decisions, integrating groundwater chemistry with financial implications. This research supports sustainable agricultural practices, enhancing long-term water resource sustainability and food security by prioritizing groundwater quality preservation and optimizing extraction costs.