Ecological function evaluation and restoration strategy of rivers in urban built-up areas: a case study of the Dasha River in Shenzhen

Abstract

With the rapid development of urbanization and national economy, the ecological function of rivers has been seriously threatened. In order to evaluate the present situation of ecological function of rivers in urban built-up areas and provide theoretical basis for subsequent river ecological restoration and sponge city planning, we carry out a case study of the Dasha River in Shenzhen city. We construct the ecological function evaluation index system at the reach scale for the Dasha River, in which 10 indicators and 14 indexes of four functions of hydrological support, water environment sustainment, habitat and biodiversity maintenance are evaluated by index evaluation method with aquatic organisms as the core. The index weight is calculated by the analytic hierarchy process method. The results show that the middle reach of the Dasha River is in class Ⅱ level, which is less disturbed by human activities and has relatively integral ecological functions. The upper and middle upper reaches are class Ⅲ areas and some ecological functions are threatened. The lower estuary section is class Ⅳ reach, which is seriously affected by human activities. Combing with the evaluation results of ecological function, we put forward the ecological restoration strategies for each reach, and suggest the daily management measures from the aspects of pollutant, biological species management, ecosystem regulation, and public education. This study provides basis and guidance for the evaluation and restoration of the ecological function and the sponge city construction in urban built-up areas.