A Water Balance Budget for Bung Boraphet?A Flood Plain Wetland-Reservoir Complex in Thailand

Resumen

A water balance model was developed for Bung Boraphet reservoir, a large flood plain lake in Thailand, from daily measurements over three inflow outflow cycles between 2003 and 2006. Measurement error was 10% (as one standard deviation) of the total measured volume. The specific yield from the Bung Boraphet catchment was 3.9 m3/ha/yr and surface water inflow from the local catchment was the largest gain term and evaporation was the largest loss term in the water budget. Irrigation was the second largest loss term and dry season demand exceeded the storage supply. Uncontrolled extraction of water for irrigation is regarded as a threat to the reservoir fishery, although the increasing drawdown range may benefit wetland biodiversity. Sustainable management of the Bung Boraphet wetland will depend on careful management based on an informed understanding of the eco-hydrological requirements of all wetland uses. Water balance models like this one are recommended as a tool to allocate water equitably and in ways which can be integrated across the Chao Phraya basin.