Study On The Interaction Between Runoff And Pipeline, River Water Level And Pump

Municipal sewer system is an important infrastructure of the city. With the increase of urban impervious surfaces and the frequent occurrence of extreme rainfall, rainfall runoff and the waterlogging risk both increase. Waterlogging brings a great loss to our country. It makes the study of urban stormwater runoff and waterlogging problem have important theoretical and practical value.Based on the current research, the model of stormwater runoff, drainage network, river and pump has been established. Then the interactive effects of surface overflow, the drainage network, river water level and pumps under different rainfall intensity and duration were studied. Low-impact development measures were taken in the areas where the ponding is serious. The main conclusions are as follows:(1) When the recurrence interval is 1 a, this three study areas almost don't suffer from ponding and waterlogging. It indicates that the design is roughly consistent with the standard.(2) Under the same rainfall duration, with the increase of the recurrence interval the area of ponding and water depth both increase significantly in area 1. The maximum depth is more than 0.50 m in two places when the recurrence interval is 2 a. There is much more significant pongding area and the ponding mostly will last longer than 1 h when the recurrence interval increases to 5 a or higher. The maximum depth is close to 1.0 m when the recurrence interval is 50 a and it will lead to a serious safety problem.(3) Area 2 and 3 is in urban development stage, so the runoff coefficient is low. There is little ponding area and the maximum depth is 0.15 m and 0.03 m respectively when the recurrence interval is 2 a. There is much ponding area when the recurrence interval is increased to 10 a. As the recurrence interval continues increasing to 50 a, the maximum pongding depth is 0.30 m and 0.14 m respectively in these two study areas, far less than the area 1.(4) The suitable LID measures(green roofs, permeable paving, sunken lawn) are taken in the three study areas and the overflow reduction rate is 12% to 52%, 10% to 100% and 28% to 57%, respectively.(5) The river initial level has a significant effect on the overflow of the drainage network. When the pump flow is small, the overflow is less affected by the open level, but it will improve the drainage capacity significantly to use pumps reducing the river water level before rainfall.