Prioritization of Micro/Mini Watersheds and Identification of Locations to Construct Rainwater Harvesting Structures using Morphometric Parameters and Geoinformatics

Abstract

Nalluru Amani Kere Watershed (NAKW) is constituent of Caveri river basin, Karnataka state, covering 415.68 km 2 area, representing arid climate. The NAKW has been divided into thirty one micro/mini watersheds (MWS) of 3rd order, designated as MWS-1 to MWS-31, for the purpose of prioritization. For this purpose, morphometric parameters were calculated under linear and shape aspects. Linear aspects such as; drainage density (D d ), bifurcation ratio (Rb), stream frequency (Fu), length of overland flow (Lg), texture ratio (T), and the shape parameter such as; shape factor (B s ), form factor (R f ), compactness constant (C c ), elongation ratio (R e ), and circularity ratio (Rc) are utilized for prioritization of MWS. Above morphometric parameter was determined for each MWS and assigned rank on the basis of value and relationship with erodibility so as to arrive at a compound value for final ranking based on which sub-watersheds were prioritized. Soil map, slope map and land use maps with stream numbers are used in spatial analysis tool of ArcGIS 9.2 platform to identify the best feasible locations to construct different types of engineering structures (water harvesting/soil conservation) in the sub-watersheds. Keywords: Drainage density, Geographic Information System, Rain water harvesting structures, spatial analysis, Slope