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Research Paper | Geology | Nepal | Volume 12 Issue 5, May 2023
The Implication of Hydrogeological Mapping and Recharge Structures to Revive Drying Springs in Hilly Region of Nepal
Ram Singh Thapa | Chitra Bahadur Baniya | Gunanidhi Pokhrel | Krishna Raj Tiwari | Nayan Bista
Abstract: Springs are the primary source of water in the mid - hills and mountainous regions of Nepal. These springs are at risk of drying up or diminishing during the lean season due to climate variability, climate change, and land use modification over the catchment. This study intends to identify the potential recharge area of the Dudhpokhari Springs in the Kathmandu district and determine the impact of constructed water augmentation structures within the identified recharge areas. A hydrogeological conceptual layout was adapted, which involved hydrogeological characterization of the catchment based on available geological maps, topographic maps, land cover maps, and direct field observations. Monthly spring discharge data (248 samples) of three wells and one spring from 14th March 2018 to 14th April 2023 and rainfall data from January 2014 to December 2021 were analyzed to determine the effect of interventions. The study found that the interventions resulted in a significant increase in the discharge of the water supply. In particular, the discharge of all springs under study increased by 32.38 to 67.99% in winter and 28.39 to 55.82% in pre - monsoon. Furthermore, a previously dried well revived with discharge 9.3 liter per minute (lpm) in winter and 6.36 lpm in pre - monsoon. To analyze rainfall and springs?discharge variability and long - term monotonic trends the Mann - Kendall (MK), Sen's Slope estimator test, and Pettitt?s test were utilized. Additionally, an unequal sample variance t - test was used to determine the effectiveness of the interventions in spring discharge. The statistically significant results of the study suggested that the water augmentation structures were effective in increasing the discharge of the springs, and may provide a sustainable solution to address the issue of diminishing spring water supply in the mid - hills and mountainous regions of Nepal.
Keywords: hydrogeological mapping, potential recharge zone, springs, springshed, water augmentation structures
Edition: Volume 12 Issue 5, May 2023,
Pages: 2026 - 2032