Study on the Efficiency of Chantaburi Flood Alleviation Project

Abstract

This research aimed at study the efficiency of flood alleviation project in Chanthaburi by mathematical model analysis. The analysis was carried out in an area of runoff stations Z.13 to Z.14 (Makham district, Chanthaburi province to Chanthaburi river estuary, Mueang district, Chanthaburi province) with calibration of the model with 2 parts: the rainfall-runoff model and the hydrodynamic model. The results for calibration and verification of the rainwater-runoff mathematical model provided values were as follows: The calibration parameter Umax = 10.1-19.1mm., Lmax = 101-104 mm., CQOF = 0.38-0.8hr., CKIF = 213.6-214.9, CK1,2 = 16.4, TOF = 0.42-0.51, TIF = 0.15-0.24, TG = 0.9 and CKBF = 3901 with the index of acceptance (IA) in range of 0.89-0.92. The Manning’s M value, was determined from the hydraulic model, was 20-22 with the index of acceptance (IA) in range of 0.79-0.92. Then, this mathematical model was applied to analyze the efficiency of Chanthaburi flood alleviation project. The flooding data in 1999 and water diversion at the flow rate of 300 m3/s were used for analysis. The amounts of rainfall increasing from the data in 1999 with 25, 50, 75 and 100 % were investigated. The results indicated that Chanthaburi flood alleviation project had been operated efficiently in 1999 and the increment of rainfall with 50 % of data in 1999 would cause flooding in Chanthaburi city.