A hydrometeorological flood forecasting system for the Red and Ca rivers (China, Laos and Vietnam). Part I: investigated areas and model setup

Applications and results of the hydrometeorological flood forecasting chain which has been setup for the Red River and the Ca River basins are briefly presented here. Four major floods occurred in the Red river in the 1971-2002 period and several floods occurred in the Ca river in the 2006-2011 period, including the October 2010 disaster, were simulated with the BOLAM-MOLOCH-DIMOSHONG flood forecasting chain. The use of runoff observations at fourteen hydrometric stations in the Lo river, a major branch of the Red river, enabled the distributed model updating with an Extended Kalman Filtering, showing an improvement of flood forecasts compared to the results obtained with the rainfall-runoff model without using hydrometric observations. Perspectives for improvements of the forecasting chain and implementation for real time operations including surface observations and meteorological corrections using weather-types classification are discussed.