Abstract:
In this study, flow-duration curves for a nuinber of selected stream-gauging stations in North-Eastern (Khong, Chi and Mun River Basins), Eastern (Prachinburi, Bangpakong and Tolesap River Basins) and Lower Southern (Peninsula East coast, Mae Nain Tapi, Thale-Sap Songkhla, Mae Na~n Pattani and Peninsula West coast River Basins) kiver Basins of Thailand were prepared from the recorded daily streainflows. These curves would be readily available to engineers for preliiniilary planning of various water resources developinent prqjects in these river basins, which could save coilsiderable time and money. To synthesize a flow-duration curve for any ungauged stream location in these basins, generalized flow-duration curves were developed in the form of a basin-averaged dimensionless curve for each river basin, and a basin-wide parametric curve for the river basins under study. By colnparison with the actual flow-duration curves of solne selected stations within the river basins, it was found that the synthesized curves were reasonably similar to the actual curves. The djscrepailcies wcre believed to be caused by the estiination of parameters froin the iso-parametric maps and the errors of the estiination of Q,,,,, and T,,, froin the regression equations, which was caused by the limitations of the nurnher of exiting stream-gauging stations within the river basins