Abstract: A two-dimensional hydrodynamic model is applied to investigation of the effects of variations in Jiaojiang estuarine geography on storm tides. The model was used to reproduce the storm surge generated by Typhoon 9711 and validated against previous measurements of wind fields, tide levels, and storm tide levels. Based on the idea of reclamation planning, astronomical and storm tides were examined under four series of different geographical modifications: north bank extension, south bank extension, two bank extension, and estuarine narrowing. Results show that the different estuarine geography have different effects on water levels in the pattern and degree. And it can be explained by comparison and analysis of the flow fields in the estuary. The results help understand the effects of variations in estuarine geography on the dynamics in tidal estuaries to reduce and prevent hazards.

Key words: Jiaojiang estuary, storm surge, estuarine geometry, high tide level, flow pattern