Geostatistical Evaluation for Precision Groundwater Mapping in Rajshahi District of Bangladesh: An Approaches to Sustainable Agricultural Water Resource Management

Abstract

Bangladesh, a predominantly agricultural nation, relies heavily on groundwater for economic growth and food security. In Rajshahi District, which is prone to drought, groundwater resources are depleting due to over-abstraction, limited surface water, low rainfall, high elevation, and thick clay layers. To address this and ensure sustainable groundwater management, an integrated surface water-groundwater model was developed, calibrated, and validated using data from 2005 to 2016. This model provides insights into the region’s hydrological conditions. To predict groundwater conditions up to 2030, four scenarios were analyzed, incorporating factors like rainfall, evaporation, groundwater and surface water levels, and water demand. The study found an average annual groundwater recharge of 1563.47 Mm³. However, most groundwater stations in Rajshahi show ongoing depletion, with maximum and minimum groundwater level declines of 0.12m/year and 0.17m/year, respectively. The drought year of 2010 was selected as the design year for the sustainability assessment. Among the scenarios, ‘Option 4’ represented the most extreme case, with a 1.5% increase in agricultural water demand from 2016 and meteorological data from 2004. The analysis indicates that groundwater levels recover during the monsoon season in most areas, suggesting the aquifer’s capacity to support dry-season irrigation, even with future agricultural expansion and extreme dry conditions, provided water demand remains stable. This model serves as a critical tool for optimizing groundwater abstraction and allocation for irrigation and can be extended as a decision support tool for integrated water resources management in Rajshahi, particularly for agricultural development.