The continuous sea level rise and the increasing frequency of extreme weather events have had significant adverse impacts on coastal areas. Based on existing hydrological data and field investigations, this study analyzes the relationship between water levels in the port channel downstream of Shuangyang Sluice and the land elevation of aquaculture zones during Typhoon Muifa. The results show that the highest tide levels occurred downstream of three sluices north of the Sheyang River estuary during the typhoon, leading to the greatest direct economic losses. The target research area is located outside the standard sea dike and lacks effective storm surge defense structures. A road in the area has nearly half of its elevation lower than the highest tide level observed during Typhoon Muifa, rendering it ineffective for flood protection. If aquaculture or other production activities must be carried out seaward of the primary sea dike, it is recommended to adopt appropriate engineering and non-engineering measures.