Characterization of the Surface Lake and Evaluation of Its Benefits on Unconfined Aquifer Interaction—A Study on Coastal Karnataka Lake, India

Abstract

Groundwater recharge is pivotal in addressing diverse water needs in rural India, like water supply, irrigation, and domestic requirements. A significant amount of recharge happens through lakes. However, minimal research has been conducted to evaluate the status of extinct lakes and their potential contributions to nearby unconfined aquifers. This study aims to bridge this gap by assessing critical aspects of groundwater recharge and investigating the role of an extinct lake in this process. Sixteen strategically positioned monitoring wells facilitated data collection, enabling a comprehensive analysis of the groundwater dynamics. The study revealed a substantial increase in built-up areas from 25.66 to 37.59% between 2004 and 2021. The rainfall-runoff relationship was found to be strong, with runoff levels varying from 703.8 to 3426 mm. Using the Korkmaz method, it was determined that around 48% of precipitation naturally replenishes unconfined aquifers. Soil samples near the monitoring wells have varying hydraulic conductivity values of 77.76 to 570.24 m/day, indicating their suitability for water storage. Lake restoration and bund construction emerge as a transformative intervention, positively influencing consistent water levels in wells, redirecting water flow, and enhancing 16.38% increased crop productivity. This emphasizes the lake’s significance in replenishing nearby wells, establishing its crucial role in groundwater recharge. These insights are vital for informed water resource management, particularly in sustaining the region’s water and agricultural needs. Understanding and harnessing the potential of extinct lakes emerge as imperative measures for ensuring long-term water security in rural India. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2024.