Oriental OutlookFlood Prevention July 29, 2010The Three Gorges Dam successfully prevented the severest flash flood since 1998 on July 20, showing its significance in floodcontrol. While the dam helped ease the flooding in the Yangtze River area, it has not completely solved the problem. Watercontrol works in the middle and lower reaches still need considerable investment for renovation, said Lu Youmei, from theConstruction Commission for the Three Gorges Dam Project.Future flood control still faces challenges. As the Three Gorges Dam blocks waterborne sand flowing from the upperreaches, erosion has made the riverbed in the middle and lower reaches deeper, increasing the force of water flow. It leads todamage of the embankments along the river.Also, the flood diversion and water storage capacities of tributaries in the downstream areas, an essential flood preventionmeasure, are diminishing. This places a heavier burden on the Three Gorges Dam for flood control, said Zou Chaowang,senior engineer of Hubei Institute of Water Conservation and Hydroelectric Engineering Exploration and Design.