AVSWAT- a spatial decision support system for land and water management and its application for watershed management in Bankura district of West Bengal

The article deals with AVSWAT- A spatial decision support system for land and water management and its application for watershed management in Bankura district of West Bengal. Decision Support Systems (DSS) are defined as computer-based information systems designed to support decision makers interactively in thinking and making decisions about relatively unstructured problems. Spatial Decision Support Systems (SDSS), which are the integration of DSS and GIS was initiated by Densham and Goodchild ( 1988) are emerging as efficient tools for managing natural resources like land and water.

AVSWAT ( Arc View- SWAT) , a user- friendly PC based SDSS tool has been developed at the Black Land Research Center , Temple, Texas, USA integrating Soil and Water Analysis Tool (SWAT) and Arc View GIS version 3.0a software along with Spatial Analyst version 1.1 extension. SWAT is a continuous time river basin or watershed scale model operating on daily time step. In the present study, the tool was applied in digitally delineating watersheds in a block of Bankura district of West Bengal and then it was used for estimating potential water ,silt and crop yield from each of them. This would be helpful in prioritising the watersheds and presenting the results spatially for the district level decision makers. 

In view of the stress on district level planning in the country, watershed based planning of natural resources is becoming increasingly important activity in a district. For watershed management, the foremost application of a SDSS like AVSWAT is in digitally delineating the watersheds and sub-watersheds , at present which is entirely dependent on the experience and skill of the district officials. The initial investment in digital data generation justifies subsequent lesser investment in repeated survey for the purpose and improvement in watershed delineation. 

In a SDSS like AVSWAT, the SWAT model provides the capability of quantitatively simulating land and water related processes important for watershed management like potential water and silt yield. The spatial representation of the results in the form of maps provides added information to the Decision-makers. The silt yield map presents potential silt production rate from different watersheds, thus, depicts the erosion status of them and helps in prioritizing the watersheds for soil and water conservation measures. Similarly, the water yield map presents the amount of water that can be available from each watershed under different management options, thus can help in land use planning, water management planning and in deciding proper land and water management options. A potential crop production map along with the other two maps could be of immense help in crop management and land use planning 

Apart of producing these static spatial representations, the SWAT model helps in generating alternate management scenarios for land and water management by changing the values of input parameters. Thus, providing a dynamic tool to the decision-makers involved in watershed management programmes in a district. 
The SDSS along with the products were demonstrated to the district level decision-makers through a workshop organized at Bankura district. 

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