Integrated water resources assessment and management in a small watershed – a geomorphic approach

Abstract

Depleting water resources and increasing human demands on the available fresh water resources suggest the need and scope for integrated water resources assessment and management. Narava basin, a small watershed spread over 105 km2 with a khondalitic suite of rocks and gneisses of Archaean age in the north coastal region of Andhra Pradesh, India was studied to propose effective water resources assessment and management strategies. The watershed, with an undulating topography and gentle to steep slopes, is drained by a dendritic to sub-dendritic drainage system. The watershed receives an annual average rainfall of 980 mm. With increasing agricultural activity, monsoon failures, and indiscriminate developmental activities, groundwater during the last two decades has become the main trusted source for irrigation and drinking. A hydrogeomorphological approach integrating remote sensing applications, geoelectrical investigations and hydrological studies was proposed to delineate and study the groundwater potential and recharge dynamics in the Narava watershed. Linking the remote sensing data, morphometric characteristics, topographic analysis, land use/cover assessment and groundwater conditions, hydrogeomorphic maps were prepared. Synergizing the lineament densities with layer parameters, aquifer yields, groundwater occurrence and dynamics, groundwater potential zones were demarcated and classified. Merging the characteristics of groundwater potential, hydrogeomorphology and water balance, suitable water harvesting structures and management strategies are suggested.