| Popis: |
For proper management of groundwater resources, estimation of groundwater recharge is crucial. Information on groundwater recharge is particularly important in dry areas where groundwater is continuously depleting. In this study, groundwater recharge was estimated at two locations in the dry, Barind area of Bangladesh using the applied tracer, water balance (WB) and water-table fluctuation (WTF) methods. In the WTF method, considerations for drinking and irrigation withdrawal were taken. For runoff estimation in the WB method, a modified form of the USDA-SCS method was used. The results revealed that the average yearly recharge at the Nachol location varied from 104.9–195.8 mm/year under different methods, having a mean of 136.1 mm/yr over the methods. At Niamatpur location, the recharge rate varied from 125.1 to 210 mm (9.9 – 15.1% of yearly rainfall) under different methods, having a mean of 157.6 mm/yr. On average, the WTF method produced the lowest estimate of recharge followed by WB method. Based on the local geological and hydrological settings and the suitability/limitations of the methods themselves, the tracer technique may be regarded as a reliable method for the study area. The information on recharge will help the ‘water resource agency’ and ‘policymakers’ to adjust pumping/irrigation schemes, avoid over-exploitation of the groundwater resource, and ensure the long-term sustainability of the resource in the area. |
