Hydro-ecological impact of water conservancy projects in the Haihe River Basin

Abstract Water conservancy projects are commonly constructed with different purposes. This usually results in improved flooding control, but may lead as well to environmental problems, such as river dry up, river morphology change, and reduction in biodiversity. The present study considers water conservancy projects in the Haihe river basin, following the major flood in 1963. It maps the water projects as well as the surface water bodies in 1964, 1980 and 2004, by using an integrated method of remote sensing and field surveys. The impact of the water conservancy projects on the hydro-ecological processes and the ecological environment is analyzed. Construction of the controlled reservoir resulted in a sharp drop of the river discharge and sediment. It also resulted in a reduction of river infiltration, an increase of evaporation and a change in regional water balance characteristics. Furthermore, the projects separated the hydraulic connection between upstream and downstream areas, weakened the river’s natural connectivity, and changed the dynamic conditions of the river water. On the basis of the study, we propose changing the operation mode of the existing controllable water conservancy projects and removing the projects with degraded and unreasonable functions as two optional ways to resolve the hydro-ecological problems of the basin.