Experimentation And Simulation With Impacts Of Dam Operation On Water Quality And Quantity In Polluted Rivers

Water is essential to humanity, and the efficiency of water resource utilization can be improved by building dams. However, some natural hydrological characteristics are lost and the self-purify ability of water is weaken due to dams' regulate and control. Most dams are closed to store water during the dry season, which is most likely to cause sewage aggregation in the upper reach. When the flood season comes, the concentrated pollution plume is usually caused in the first release. Then, sudden pollution accidents occurred. To solve the problem of unexpected water pollution emergency, which is created by overmuch dams in serious polluted rivers, studies on analyzing the spatial and temporal variation laws of water quality and exploring the influence mechanisms of dams are essential.To solve the above problems, this paper carried out several specific works as follows:(1) Experimental study on the influence of the dam operation on river water quality and quantity:choose the representative dam, Huaidian Dam of Shaying River, to carry out the influence of dam control experiment, analyse the movement and transportation of pollutants in water and sediment of different operation schemes in dry and wet seasons by two systematic experiments.(2) Simulation study on the influence of the dam operation on river water quality and quantity:divide the study section into upstream and downstream with the gate, establish two-dimensional Hydrodynamic model of dam influence based on RMA2 model of SMS and two-dimensional water quality model considering dam operation and sediment pollutants based on RMA4. Parameter of hydraulic force-pollutant transportation model are calibrated by water quality data and hydrological data which are acquired through experiments on the influence of dam operation of various operation situations, and application effect is checked out.(3) The mechanism study of dam influence on water quality and quantity. Based on the experiment and simulation of dam regulation, On the one hand, the paper analyse the complex velocity field formed by existing gate on water quality and quantity. On the other hand, analyse the translocation and transformation of pollutants in gas phase, water phase, solid phase and biological phase caused by chang of flow velocity. Then, discuss the mechanism of dam influence on water quality and quantityThe results indicate that the effect shows a complicated non-linear relationship of dam influence on water quality and quantity. Because the change of flow velocity field caused by regulation changed, dam regulation produce certain influence on water quality and quantity, the scope and size is different in the case of various regulation and gateage. In the area of dam influence, pollutants are mutual transformation between sediment-water interface, the sedimentation dominates when impoundment.This paper is a beneficial exploration of searching for heavily polluted river water quality and quantity optimization operationin. It lays the theoretical foundations of setting the action range of dam operation, provides scientific basis for the implementation of united operation of water quality and quantity.