The study estimates the average soil loss using the Geographic Information Systems (GIS) tool of Integrated Land and Water Information Systems (ILWIS) and the Universal Soil Loss Equation (USLE) methodology for the Hire nadi catchment, in Yelbarga taluk, Koppal district of Karnataka, under different conditions.
Scientific planning for soil conservation and water management requires knowledge of the relations among factors that cause and prevent soil and water loss. Controlled studies on field plots and small watersheds have supplied vital information regarding these complex factors and their interrelations.
Information on sediment yield from a catchment can be modeled using lumped and distributed models. However, for field applications, a reliable and simple method like the USLE is useful for predicting sheet and rill erosion under various conditions of land use and management.
Due to its data handling and analyzing capabilities, GIS is becoming important in natural resources management. The study attempts to test its applicability for the analysis of various components of hydrologic cycle. It uses data pertaining to watershed characteristics and drainage pattern for computing the actual and seasonal soil erosion rates.
In the watershed, the gentle sloping topography and the soil types resulted in very low erosion rates. The results could not be checked due to lack of observed data. Average soil loss for the study area is calculated at 25.98 tons/ ha/ year. Various maps have been prepared showing land use types in the study area, the regions of potential loss, actual annual and seasonal soil loss.
The KCLP (erosion potential) map prepared for the watershed as well as the rainfall station point map can be used for calculating erosion for particular rainfall events. The effectiveness of various types of management and surface practices can be evaluated by changing the K-factor map and the most effective management strategies can be worked out using such a GIS database.
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