MODIFICATION OF DWCM-AGWU MODEL APPLIED TO A PADDY-DOMINANT BASIN WITH LARGE DAMS

摘要

The DWCM-AgWU (Distributed Water Circulation Model incorporating Agricultural Water Use)model was modifi ed and applied to assess the water use in the Chao Phraya River basinof the years 2008–2011, which included both droughts and fl oods. A cooperating reservoirmanagement model was introduced to incorporate two large dams, the Bhumibol and SirikitDams with several remote irrigated areas in water allocation/management. Besides, specialtreatment of fl ood peaks was also added to take agricultural practices into consideration.The two large dams are the main sources of irrigation water during dry seasons and they arealso responsible for controlling fl oods in the downstream during rainy seasons. For the lowerreaches of the Basin from Nakhon Sawan to the sea, another special water management inrainy days when the release at the Chao Phraya diversion Dam was controlled at a thresholdwas applied. As a result of the simulation, the average relative error between the calculatedand observed daily fl ow volume was 20.1% at the station of Nakhon Sawan, which is locatedbelow the convergence of the four basins of the main tributaries of the Chao Phraya River and37.1% at the downstream point of the Chao Phraya diversion Dam below intake facilities whichsupply irrigated water to the project. Then, modifi ed model will enable continuous calculationsfor mitigating the impacts of extreme events such as the 2011 fl ood in Thailand, for managingthe use of irrigation water, and for proposing adaptive countermeasures to climate change.