Hydrological and Economic Viability of Rehabilitated Ponds for Sustainable Irrigation

Depletion of groundwater is mainly due to over-irrigation. Sustainable alternatives were therefore required for the present system. This study assessed the feasibility of supplementary irrigation using rehabilitated ponds in Niamatpur and Atrai Upazilas to minimize groundwater dependency. The region experiences a semi-arid climate, which is associated with erratic rainfall and increased evaporation, making these surface water augmentations necessary. The present research is important because it relates to aquifer depletion: the repurposing of abandoned ponds to enhance storage through arriving rainwater beans as input for agricultural resilience in line with sustainable development goals. Data were collated from the Barind Multipurpose Development Authority (BMDA), satellite imagery, and field measurements. Quantified using hydrological models were catchment areas, runoff, storage capacities, and losses (evaporation, seepage). Economic feasibility was determined through the benefit-cost ratio (BCR), net present value (NPV), and internal rate of return (IRR). The findings revealed that 44 rehabilitated ponds were storing an overall amount of 108605 m³ of water annually and reduced extraction from groundwater by about 4.62%. An economic analysis showed the BCR to be 1.06 with a positive NPV (1.92 million taka) and IRR (7%), confirming the project viability; however, evaporation (63025 m³) and seepage associated with groundwater recharge highlighted new management of such ponds. Rehabilitated ponds will be appropriate for sustainable irrigation as they would relieve groundwater stress and increase agricultural productivity. The study recommends further fostering the rehabilitation of ponds, the application of new technologies of infiltration measurement, and linking with managed aquifer recharge (MAR) systems to optimize water retention measures that can build resilience to climate change in drought-prone areas and serve as an example for similar arid regions around the globe.