Productivity Improvement of Wasteland in Drought-Prone, Overdrafted and Rocky Terrain Watershed: A Case Study of Upper Thurinjalar Watershed in Ponnaiyar Basin Tamil Nadu, India

Abstract

A great extent of productive land has become wasteland due to climatic change, frequent monsoon failure and inadequate water supply for irrigation. Identification of such lands can be helpful for conversion into productive land. Present study focuses on identification of wasteland in the watershed by utilising land use map of 2018 by interpreting satellite image of IRS-P6 LISS IV over upper Thurinjalar watershed in Thiruvannamalai district of Tamil Nadu. For this purpose, digital image processing software ERDAS IMAGINE 2015 and GIS Software ArcGIS 10.5 version were used. Fifty percentage of the total geographical area of the watershed is reported as wasteland in our study. Favourable wasteland layer was superimposed upon the administrative village boundary map by GIS overlay analysis. Type of wasteland was demarcated using remote sensing and GIS techniques, and thematic layers such as lineament map, geomorphology map and depth to bedrock map were generated. Through GIS overlay analysis, wasteland map of the study area was overlaid on the three thematic layers and favourable artificial recharge sites were identified. In upper Thurinjalar watershed, 61.06 km2 is highly favourable and 214.18 km2 is moderately favourable for recharge, and the sites are recommended for groundwater recharge using structures such as pits, percolation ponds, borewells and check dams. Among wastelands, degraded lands under plantation, lands with scrub and lands without scrub were prioritised for groundwater recharge. Technique adopted in our study can be applied over other watersheds and wasteland to convert them into productive land.