The traditional tank systems in northern Karnataka under varied hydrologic settings, serve as long-term measure for mitigation of droughts and floods apart from serving the community as sources for meeting the irrigation and domestic demands. It was observed that at least an annual rainfall of 645 mm could be expected once in two years with maximum in July (154 mm), followed by September (145 mm), August (143 mm), June (91.2 mm), October (78 mm) and May (34 mm). The rainfall-runoff regression analysis showed that at least 116 mm of runoff could be expected once in two years with the maximum contribution during the period from July to September. A study was carried out on selected cascade system of tanks (four) in Raichur region of northern Karnataka. The Modified Morgan Finney, a lumped sediment yield model under GIS environment, underpredicted the sedimentation rate in the year of average rainfall (2004) by 0.34 to 0.89 kg m-2, whereas it overpredicted during excess rainfall year by 0.43 to 1.17 kg m-2 (2007). Based on the dead storage capacities and  validated sediment inflow rates (0.43 to 1.17 kg m-2) that carried along the annual inflow volume at average probability level (2.3-year return period), the projected  life expectancy of cascade tanks of Devanpalli, Tuntapur, Yergeri and Gunjalli tanks would be 64, 22.2, 34.9 and 10.2 years respectively. Hence, sedimentation preventive measures coupled with desiltation planning are very much needed to improve the performance of these tanks and to prolong their life.