III-6-Hydrological Assessment for Renovation of tanks using Geo-informatics.

Abstract

Runoff is one of the most important hydrologic variables used in most of the applications of water resources. Reliable prediction of quantity and rate of runoff from land surface into streams / rivers is difficult and time consuming to obtain for un-gauged tank catchments. Space Remote sensing technology in association with geographical information system (GIS) can supplement the conventional methods to an immense amount in hydrological studies. An attempt is made to estimate average monthly/annual run-off from catchment areas of nine tanks in Manjeera river catchment, which is a tributary of Godavari basin covering in Nizambad and Medak districts of Andhra Pradesh. The hydrological assessment for the tanks has been carried out for renovation using Soil Conservation Service (SCS) curve method. Average annual rainfall of the area is 870 mm. Land use / land cover and soils resource information generated from remote sensing data and daily rainfall data of 40 years (1965 to 2005) have been used. The estimated run-off in the area varies from 6.86 mcft to 11.70 mcft per sq.km. Finally, a protocol was developed in a graphical form. It is found that good correlation (RI = 0.97) was observed between the runoff and catchment area. The protocol is useful for assessment of runoff and prioritize the tanks for renovation as well as for optimum utilization of water resources in the Manjeera river catchment.