The paper explains the 98exceptional large flood situation in Nenjiang and Songhuajiang rivers, analyses the cause of exceptional large flood, The forecast of flood above average is explained from hydrology\,astronomy and meteorological phenomena, explains some ways of looking of forecast study of exceptional large flood.

Regulation indexes of the medium flood in the Lower Yellow River;

Integrated risk assessment of levees under over-level flood condition and a case study;

Prevention countermeasure of excess flood standard in middle and downstream of Liaohe river;