Potential flood risk analysis and flood losses assessment in northern Taihu Lake Basin

The heavy floods in the Taihu Basin has showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin is selected for flood risk analysis and potential flood losses assessment. Human activities have strong impact on the studied area′s flood situation (as affected by the polders buildingup, deforestation, population increase, urbanization, etc.),and have made water level higher, flood duration shorter, and flood peaks sharper. Five different flood return periods (2,5,10,20 and 50 years) were used to calculated the potential flood risk area and its losses. The potential flood risk map, economic losses, and floodimpacted population were also calculated with main conclusions that: (1)human activities have strongly changed the natural flood situation in studied area, increasing runoff and flooding;(2)the flood risk area is closely related with the precipitation center;(3)polder construction has successfully protected land from flood, shortened the flood duration, and elevated water level in rivers outside the polders;(4)economic and social development have caused flood losses to increase in recent years.