Flood Yield Analysis for Design Small Water Resources Development Projects in Thailand

Abstract

This research has studied about flood peak per every square meter of a catchment area at a variety of return periods to be applied for designing irrigation structures, weirs, reservoirs and dams of small water resources development projects in Thailand. The studied areas being analyzed are divided into 4 parts: northern, southern, northeastern, and central (including western and eastern) regions. Moreover, each region is further divided into 3 subareas according to their topographical characteristics and slopes. In the analysis, 135 gauging stations, each with a catchment area greater than 5 square kilometers, were selected

to analyze flood frequencies and flood yields. These stations were divided into 22 northern stations, 31 southern stations, 53 northeastern stations and 29 central stations (including western and eastern). The study of the flood yields at return periods 2, 5, 10, 25, 50 and 100 years comparing the flood yield at return period of 25 years results with the previous studies in 1981. The result showed that variations of flood peak yields at catchment areas in the southern, northeastern and central (including western and eastern) regions in this study were higher than the variations of flood peak yields found in previously study with an exception of the northern region which gave lower variation.