Surface water resources assessment in ungauged upper Don river basin of Karnataka by using Remote Sensing and GIS techniques

The information on spatial and temporal availability of runoff, one day maximum runoff and peak runoff rates is helpful for safe and cost effective planning and design of water harvesting and drainage line treatment structures. The present study was taken up in the upper Don river basin of Karnataka, India. The semi-arid climate prevails in the study area. The water resources of the study area were assessed, using SCS curve number method by analyzing daily rainfall data of ten years (1998–2007). The entire watershed (643.5 km²) was sub-divided into ten sub-watersheds for micro level planning. An attempt was made to use remote sensing (RS) data under the geographic information system (GIS) environment for water resources assessment by adopting lumped curve number technique. Accordingly, loose coupling (linked to GIS) model was used for the assessment of surface water resources. The daily and weekly maximum runoff as well as peak runoff rates were assessed, monthly and annual runoff production at various probability levels were predicted on subwatershed basis. The annual runoff data analysis revealed that runoff as the percentage of annual rainfall varied from 5.08 to 25.66% with an average of 14.38% (81.6 mm). The runoff was also calculated at various probability levels for the daily and monthly rainfall. The sub watershed wise yearly average annual runoff yield ranged from 121.33 to 927.44 ha-m, with an average of 488.88 ha-m. This information on surface water resources would be helpful for computing the water balance of the watershed as well as hydrologic, hydraulic and structural design of water harvesting and artificial recharge structures, proposed to be constructed in the watersheds.