Flood Forecasting System for Changjiang River Yan Huang Bureau of Hydrology Changjiang Water Resources Commission China 8 Dec, 2009 Geneva, WMO 长江 Changjiang

Hydro-meteorological monitoring network Hydrological Gauging Site Network CWRC Hydrological stations Water level gauging site Rain gauge - 24 Automatic monitoring stations 118 Over 1000 rainfall stations Real time data acquisition Meteorological & Hydrological data

Information management – Automatic data transferring CWRC From stations to Hankou hydrological sub-center Datong Hank information center Lushui transition center Huangzhuan Shayang Zhekou Yuekou 潜江 Xiantao Hanchuan Hankou Huangshi Wuxue Lushui reservoir Bainiqiao chongyang Hongxia Marian Satellite PSTN Satellite GSM GPRS 681 transition station

Short-term real-time Flood Forecasting System CWRC Quantitative Precipitation Forecasting (QPF) Hydrological & Hydraulic models

Interactive expert FFS platform CWRC Time of forecast

CWRC A comprehensive decision support system – short-term Data Acquisition MM5- QPF Flood Forecasting & Impact analysis Support Decision Support System 【 River Management Bureau 】【 Bureau of Hydrology 】

Accurate Flood forecasting Lead time (Day)123 Accuracy (m 3 /s) %1~5%2~5%5~10% CWRC Largely affected by rainfall forecasting

Three Gorges Multiple reservoir operation require longer time forecasting CWRC Built and in-building reservoirs Need to improve: 1. Meteorological forecasting technology 2.Middle-long term hydrological forecasting technology, approach, model tec.

Three Gorges Reservoir (TGR) operation - river morphological change CWRC Need to keep monitoring the river physics and recalibrate models Need to improve updating procedures for modelling work For flood control, power and navigation Storage capacity 39.3 billion m billion m 3 for flood control Power capacity MW 185 m crest elevation, 2,39.5 m long 145km downstream 56km downstream Morphology change - Erosion at downstream river channels

Unclear Climate change trends & characteristics (unpredictability) CWRC A2: A world of independently operating, self- reliant nations. Continuously increasing population. Regionally oriented economic development. Slower and more fragmented technological changes and improvements to per capita income.

Uncertainties – lack of reservoir operation information CWRC Lack of reservoir operation information – current the national and regional flood management headquarter are promoting coordination (with hydropower firms) and cooperation on such issue; Integrated reservoir operation is important for water resources redistribution and management – which requires longer lead time, thus (1)Middle-long term flood forecasting accuracy needs urgent improvement; (2)Need to improve Quantitative Precipitation Forecasting accuracy;

CWRC Need to adapt integrated risk management concepts  A modern flood protection policy will consider not only safety but also other aspects such as Environment and economy  Need to adapt an integrated approach and sustainable policy – risk management Environmental Aspects Economic Aspects Social Aspects 50Year Risk Map Inundation map

We would like to learn from advanced We are willing to share our experiences and technology Thanks!