Assessment of Sedimentation Rate in Rain-Fed Irrigation Tank Systems Under Different Agro-Climatic Zones in Karnataka, India

The tank systems spread across Karnataka in southern India serve as traditional but sustainable means of water harvesting and flood control measures and a source of protective irrigation. In recent decades, these are fast losing their storage capacity due to sedimentation. To derive appropriate plans for rate of desiltation and reclamation, ruling rate of sedimentation and life expectancy of these tanks need to be estimated. The present investigation aims at predicting sedimentation rate of 254 tanks spread over different agro-climatic zones of Karnataka to assess the influence of climatic conditions along with topography and soil conditions. The modified Morgan Finney, a lumped sediment yield model, was used which agreed well with the measured sediment yield through capacity-contour and sediment concentration methods. The sediment yield (0.7–1.1 kg m−2) rate does get influenced by climate, the slope and soil characteristics together and would help in evolving desiltation plans. The life expectancy of the sample tanks varied from 2.0 to 85.1 years. © 2016, NAAS (National Academy of Agricultural Sciences).