Estimation of Time Variant Water Availability and Irrigation Potential of Small Ponds in a Semi-arid Region of Rajasthan, India

Abstract

A field experiment was conducted to assess water availability and irrigation potential of two small, shallow and Ephemeral ponds located in a small watershed of the semi-arid region of Rajasthan, India. The Holistic Water Depth Simulation (HWDS) model was employed for estimating the pond water availability with 3 years field data (2006–2008). The analysis revealed that the value of depth of water in the selected ponds predicted by the HWDS model had closed match to the field data. The index of agreement between measured and predicted values of depth of water in the selected ponds was found to be ranged from 0.93 to 0.94 for the pool data sets. The F and Student’s T test between measured and predicted values revealed that model estimates were not statistically different from measured values at 0.01 % level of significance. Analysis revealed that mean pond volumetric water availability for the selected ponds ranged from 1448 to 5001 m3 during the study period. During the off monsoon seasons, water availability period was varied between 35 and 78 days with a mean of 61 days. Analyses revealed that water availability in the selected ponds lasted at least 48–61 days. The off monsoon season irrigation potential of ponds with one and two irrigations for the rainfed crops at critical growth stage in the region was estimated to be 12.6 and 6.3 ha, respectively.