GIS-BASED ASSESSMENT OF AGRICULTURAL CROP WATER REQUIREMENTS FOR DROUGHT MONITORING

Abstract

Global climate change has increased the frequency and severity of drought events, reducing water availability in arid regions. In Uzbekistan, more than 80% of agricultural production depends on irrigation; accurate estimation of crop water demand is therefore critical for food security and sustainable resource management [1, 5]. Crop water consumption was estimated using the Kostyakov empirical formula (E = K·Y) and the bioclimatic Alpatyev equation (E = Kb·Σd) [5, 9]. Seasonal irrigation norms were determined from the Kostyakov water balance equation [5]. Regional bioclimatic coefficients (Kb) were compiled for all provinces of Uzbekistan based on Xamidov et al. [2, 3]. A web-based GIS calculator was built with Leaflet.js and Turf.js. Validation on a 13.75 ha polygon in Khorezm region (cotton + wheat, K = 1.20) yielded an estimated annual demand of 189.8 thousand m³, consistent with normative values [2, 5]. The developed GIS model enables rapid, spatially explicit estimation of irrigation water demand and provides an effective tool for drought monitoring and irrigation planning.