Application of GIS for Evaluation and Design of Watershed Guidelines

Abstract

We analyse the suitability of Government of India’s 2003 and 2008 common guidelines for prioritising micro-watersheds for restoration. These guidelines attempt to balance the need for improved hydraulic function with poverty alleviation and agricultural productivity. To do so, they provide a set of sub-criteria for prioritising micro-watersheds for treatment. We ranked the microwatersheds in the Kalivelli basin in South India based on these sub-criteria. We then compared the 2003 with the 2008 guidelines using GIS and spatial statistics. Visual inspection of the resulting digital maps and spatial autocorrelation analysis showed that individual sub-criteria within a guideline were highly positively auto correlated. Spatial cross-correlations using Mantels test between sub-criteria in the same guidelines produced negative results however. Very different watersheds would have been selected for treatment using the 2003 vs. the 2008 guidelines. While this could have been evidence that the 2008 guidelines were an improvement over the 2003 guidelines, comparing the planning outcomes did not support this conclusion. We conclude that criteria used to select micro-watersheds for hydrologic treatment should be re-formulated emphasizing efffcient resource use and improved hydraulic function prior to social and economic concerns. Finally, we argue that a combined GIS and spatial analysis approach is amenable to quickly evaluating watershed selection criteria as well as assessing post implementation outcomes.