Analysis of dredging engineering impact on flood level and flux of the dongting lake

Influence of the dredging engineering on flood level of the Donting Lake is simulated by the SSARR model and the SMS approach in this study. GIS is utilized for the presentation the change of flood level of the Dongting Lake in typical years (1996, 1998 and 1999, respectively), and the reasons led to such different influence by the dredging engineering are finally analyzed. The simulated results suggest that the implement of dredging engineering: 1) has significant impact in high flood level period; 2) can decrease high flood level by 20-30cm for narrow riverways and 5-20cm for wide lakes; 3) remits impact of flood level on the Dongting Lake induced by inner flow or by the cooperation of inner and outer flow. The results also imply that the dredging engineering acted a positive function in decreasing flood level and increasing flood discharge ability.