Abstract: The aim of this study is to evaluate the eco-hydrological effect of water diversion and dispatching with Dongsha Lake of the Donghu Lakes Network as a typical research object. We selected five key eco-hydrological elements, namely, maximum flow velocity, average flow velocity, water surface ratio of flow velocity exceeding 0.01 m/s, water age, and water exchange rate from the perspective of controlling water eutrophication. By constructing the Dongsha Lake hydrodynamic model, we simulated the spatial distribution of flow velocity and water age under six conditions before and after the diversion and dispatching, and obtained the values of key eco-hydrological elements. Results unveiled that the maximum flow velocity, average flow velocity, water surface ratio of flow velocity exceeding 0.01 m/s and water exchange rate increased remarkably, while water age reduced markedly. Diversion and dispatching effectively affected the eco-hydrological conditions of the Dongsha Lake. The research finding offers a reference for ecological dispatching.

Key words: water diversion and dispatching, eco-hydrological elements, hydrodynamic model, eutrophication, Dongsha Lake