EVALUATION OF WELL ECONOMICS AND EFFICIENCY OF IRRIGATION PUMPSETS IN PARTS OF KARNATAKA

Abstract

Studies of utilisation of groundwater are assuming considerable importance especially in the water scarcity areas. The hard rock regions of India pose special problems of groundwater exploitation and it becomes necessary to evaluate the suitability and economics of different types of. wells and the pumpset installations on them. The present study aims at evaluation of the pumping efficiencies, economics for different groundwater structures in selected parts of Karnataka state. Data of pumping tests on few large diameter wells have also been analysed to compute transmissivity characteristics of the fractured aquifers. By using the Papadopulos and Cooper (1974) method, the analysis of pumping test data for large diameter wells located in Mysore, Mangalore, Chickmagalur and Bangalore districts has yielded relatively low values of Transmiss-ivity (T) for shallow fractured aquifers. A study for ascertaining the suitability of the pumps and their installations on different ground water structures has indicated that out of all, the pumps installed on borewells are more efficient and capable of producing greater discharges at optimum efficiencies than other wells. The study of economics of the wells includes a comparison of different ground water structures on the basis of the cost of groundwater per cubic meter ii versus the total discharge of groundwater and total returns from crops. The study has also included the analysis of the cost benefits ratio of different groundwater structures. The overall study has indicated the borewell as most viable groundwater structures, whereas, dug-cum-borewells are considered important.in case of revitalisation of existing dugwells, especially in areas of declining water table. However, the dugwells cannot be ignored for needs of small discharges.