Wetlands are constantly affected by human activities such as landscaping, additional abstractions, and changes in catchment imperviousness, resulting in the reduction of wetland area and degeneration of water quality. Modelling of such anthropogenic factors should be explicitly considered, in order to provide better understanding of the hydrological impacts of wetland restoration. In this paper, the wetland module in a distributed hydrological model, SWAT, is modified to simulate the artificial water input to the designated wetlands. The impact and effect of recharging wetlands on local hydrological cycle, sea outflow and estuary ecology is discussed. The Qingdianwa depression, located in the north of Tianjin city, China, is used as a case study to investigate the effect of human activities on the natural eco-hydrological process as well as different restoration schemes.
Water balance analysis shows that there is a significant shortage of water in the drier months, which also indicates that an external water source is required for wetland restoration. The selected restoration scheme of 0·8 m depth is effective in controlling runoff, whereas a depth of 1 m and above is required for maintaining the basic ecological function of the wetland. Such a scheme has an additional effect of increasing the average surface runoff and groundwater recharge during non-flood seasons by 37·65 and 45·4 million m3, respectively, which illustrated the importance of wetland restoration on local runoff, groundwater recharge and local ecology. The proposed method demonstrated that it is possible to select wetland restoration schemes that are beneficial to both hydrology and ecology. Copyright © 2010 John Wiley & Sons, Ltd.