Paddy field performs important functions in an ecosystem such as maintenance of groundwater supply, water purity, nitrogen cycle control, mitigation of local climate, and so on. In the Dozen plain, the area of paddy field has been decreasing with the urbanization in the recent decades and changing to other land uses such as residential area, roads, etc. To investigate the impact of these land use changes on the groundwater recharge in the coastal plain, a lumped water balance model was developed. The percentage of the paddy field area in the whole Dozen plain was adjusted to simulate the impact of land use change on the groundwater recharge. The results showed that the impact of the land use changes on the groundwater recharge was large, especially in droughty seasons. It demonstrated that the paddy field played a significant role on the hydrological cycle in the coastal plain.
