GEOINFORMATICS OF AQUIFER RECHARGE IN UPPER KURRAM VALLEY

Abstract

Water is an essential part of life. The exploitation of groundwater is as ancient as civilization itself. Majority of the inhabitants of Upper Kurram valley depend on groundwater for drinking as well as for agriculture needs. Drastic declination in water table has occurred in the recent past due to high runoff and low recharge, overexploitation of available water resources, and urbanization. Through this research, an attempt has made to identify the potential zones for groundwater extraction, demarcation and natural recharge and devising proper artificial recharge mechanism using GIS and RS tools. In order to observe pre- and post-monsoon water table level in the study area, primary and secondary data was used for the year of 2008. Yearly monitoring of water table reveals that 0.5m to 2.8m variation occurred in groundwater table in Upper Kurram valley. The water levels are divided into five arbitrary depth zones, on the basis of water table depth. Water table is deepest in the central part of the study area and shallow along the Kurram, Zeran and Kirman rivers. To identify the potential natural recharge areas, different thematic layers were considered namely, surface slope, landcover, proximity to settlement and road, drainage network, soil and geology. These themes were assigned proper weights and ranked on the basis of their relative contribution to groundwater recharge in the area following the guidelines of ASCE and FAO. Thematic layer were integrated in GIS environment using Overlay analysis. To augment the groundwater, artificial recharge techniques can be used to enhance the groundwater capacity. Three artificial recharge mechanisms namely, small dams, percolation pond and plantation were considered and their suitability analysis was performed using seven parameters namely surface xiv slope, settlement, soil, geology, roads, drainage and landuse. Results reveal that the suitable areas for natural recharge make 14% of the study area, which corresponds to nearly 137 km2. Results reveal that suitable percentage areas for small dams is 3%, for plantation is 9% and 19% is suitable for percolation pond. The study can be helpful for government as well as for private organization to understand the groundwater situation in Upper Kurram valley. This study is also supportive in the selection of potential sites for artificial recharge techniques to enhance the declined groundwater situation. Study can be helpful to increase the groundwater availability for domestic as well for agriculture purposes.