Improvement and evaluation of hydrodynamic conditions in plain regional drainage systems by artificial lakes: a case study of Xinxiang Economic Development Zone, China.

With the development of the city, people pay more attention to the ecological construction of the city. The objective of this work was to study the effect of artificial lakes on hydrodynamic conditions in urban drainage systems. With Arcgis and the advantage of SWMM in analyzing the impact of the rainfall process on urban runoff, the urban flooding model of "pipe network + river network + artificial lake" was established in the study area. Two scenarios were set up with and without the presence of artificial lakes, and comparative analyses were conducted under the different intensities of rainfall (0.5a, 1a, 2a, 5a, 10a, 20a). The results show that under certain rainfall conditions, the presence of the artificial lake increases the peak flow and rate of upstream streams and decreases the flow and rate of downstream streams in the regional drainage system. The duration of the peak flow rate in the upstream channel increases, and the flow rate curve becomes flat during the confluence; the flow rate in the downstream section decreases, and the magnitude of the peak flow rate change decreases, and a more obvious horizontal section appears. The time of peak occurrence in the downstream river is earlier. The hydrodynamic impact on the downstream channel is more significant. The improvement of hydrodynamic conditions of the drainage system by the artificial lake helps to optimize the layout of low impact development (LID) measures in the study area and also guides ecological construction in other cities.