43-Groundwater Pricing in Over-Exploited Torehalla Watershed (4B4B2), Hassan District, Karnataka - A Scientific Approach

Abstract

Ground water is the most reliable resource to meet domestic and agricultural water needs and for agricultural demands where the surface water is scarce. As a consequence of increased groundwater reliance, the stage of groundwater development in many watersheds in Karnataka state is semi-critical to over-exploited. The cost of ground water extraction in over-exploited areas is high due to the increased cost of drilling and electricity charges. In order to reduce the groundwater extraction, pricing in over-exploited watershed and conservation of watershed should be taken up. The groundwater pricing should be in tandem with the cost involved for construction of Artificial Recharge Structures (ARS). Based on the groundwater resources estimation, in Torehalla watershed covering total geographical area of about 455 sq.km., the net annual groundwater availability is 6277 ha.m., which is 764 ha.m. less than the gross groundwater draft for all uses. An attempt has been made to balance the groundwater availability and draft for all uses in a watershed. Geomorphological, geology and lineament have been interpreted using IRS-ID satellite data and aero-magnetic breaks map prepared based on aero-magnetic contour map. Based on the drainage map of the watershed, sub- watershed has been demarcated and the drainage morphometric characteristic of micro-watershed has been analysed. Geomorphology, geology, lineament, aero-magnetic breaks, landuse/landcover, soil layers and morphometric characteristic have been generated in GIS and integrated using weighted index overlay model to derive feasible artificial recharge structures in micro-watershed. Based on the number of ARS to be constructed in the watershed, groundwater pricing is proposed for future planned development of the watershed.