Impact of Construction Lands Expansion on Wetlands in Hangzhou

Based on remote sensing images and urban planning data, this paper analyzed the planned conversion of wetlands to urban construction lands from 2005 to 2020 and the potential risk to wetlands using GIS spatial model. The results indicate that: (1) There are many wetlands resources in Hangzhou, most of which are paddy fields with construction land patches enchased at Xiaoshan and Yuhang. (2) According to present planning, construction lands will expand rapidly from 2005 to 2020, especially at Xiaoshan and Yuhang. The occupied wetlands will be paddy fields and aquiculture ponds, and the construction lands mainly converted from paddy fields. (3) On the whole, the potential risk to wetlands is high and the tendency of wetlands occupation by urban construction lands will increase from 2005 to 2020. We can conclude that the increase extent and the layout of construction lands had important effect on the decrease of wetlands and proper layout can reduce the loss of wetlands. Adjustment of urban planning is significant to wetlands protection since the destruction to wetlands by construction is irreversible.