Modeling Rainwater Storage in Distributed Reservoir Systems in Humid Subtropical and Tropical Savannah Regions

摘要

Using a hydrologic model this study estimated rainwater storages in field-scale on-farm reservoir (OFR) systems at two locations: (1) Fort Worth, Texas, US; (2) Kharagpur, West Bengal, India. The water storages were estimated for variable OFR sizes: 1%, 5%, 10%, 15%, and 25% of the farm area. Water losses through seepage and evaporation were estimated using variable saturated hydraulic conductivity conditions: 0.33, 0.64,1.3, 5 cm/h, which corresponded to the ranges of hydraulic conductivity of loam, sandy loam, loamy sand, and sandy soils, respectively. Results indicated that the water loss through evaporation was dominant at the first location, while seepage was at the second location. Changing the OFR sizes captured 5 to 28% of the total rainfall received in the farm area of the first location and 20-40% at the second location. Finally, a comparative economic analysis was made between a distributed OFR system and a centralized large reservoir that indicated that the distributed OFR system benefits exceeded the benefits of a large reservoir.