Reservoir operation schemes for water pollution accidents in Yangtze River

After the Three Gorges Reservoir starts running, it can not only take into consideration the interest of departments such as flood control, power generation, water supply, and shipping, but also reduce or eliminate the adverse effects of pollutants by discharge regulation. The evolution of pollutant plumes under different operation schemes of the Three Gorges Reservoir and three kinds of pollutant discharge types were calculated with the MIKE 21 AD software. The feasibility and effectiveness of the reservoir emergency operation when pollution accidents occur were investigated. The results indicate that the emergency operation produces significant effects on the instantaneous discharge type with lesser effects on the constant discharge type, the impact time is shortened, and the concentration of pollutant is reduced. Meanwhile, the results show that the larger the discharge is and the shorter the operation duration is, the more favorable the result is.

Experimental study on the flow behaviour of water-sand mixtures in fractured rock specimens

The study of flow behaviour of water-sand mixtures in fractured rocks is of great necessity to understand the producing mechanism and prevention of water inrush and sand gushing accidents.A self-developed seepage test system is used in this paper to conduct laboratory experiments in order to study the influence of the particle size distribution,the void ratio,and the initial mass of Aeolian sand on the flow behavior.It is concluded that the water flow velocity is insensitive to the initial mass of the Aeolian sand but increases with the power exponent in the Talbot formula and the specimen height.The outflow of the Aeolian sand increases with the power exponent in the Talbot formula,the specimen height,and the initial mass of the Aeolian sand.Besides,the outflow of the Aeolian sand changes exponentially with the water flow velocity.Finally,it is found that the fractured specimen has a maximum sand filtration capacity beyond which the outflow of the Aeolian sand significantly increases with the initial mass of the Aeolian sand.

An novel identification method of the environmental risk sources for surfacewater pollution accidents in chemical industrial parks

The chemical industry is a major source of various pollution accidents. Improving the management level of risk sources for pollution accidents has become an urgentdemand for most industrialized countries. In pollution accidents, the released chemicals harm the receptors to some extentdepending on their sensitivity or susceptibility. Therefore, identifying the potential risk sources from such a large number of chemical enterprises has become pressingly urgent. Based on the simulation of thewhole accident process, a novel and expandable identification method for risk sources causingwater pollution accidents is presented. The newlydeveloped approach, by analyzing and stimulating thewhole process of a pollution accident between sources and receptors, can be applied to identify risk sources, especially on the nationwide scale. Three major types of losses, such as social, economic and ecological losses,were normalized, analyzed and used for overall consequence modeling. A specific case study area, located in a chemical industry park （CIP） along the Yangtze River in Jiangsu Province, China,was selected to test the potential of the identification method. The results showed that therewere four risk sources for pollution accidents in this CIP. Aniline leakage in the HS Chemical Plantwould lead to the most serious impact on the surroundingwater environment. This potential accidentwould severelydamage the ecosystem up to3.8 kmdownstream of Yangtze River, and lead to pollution over adistance stretching to 73.7 kmdownstream. The proposed method is easily extended to the nationwide identification of potential risk sources.

Electromagnetic drive system of robotic fish

With the aim to apply the electric fish into practice to assist coal mine water disaster life detection and rescue work, based on the analysis on swing propulsion movements of tail fin, this paper integrates the electromagnet technology with tail fin drive system by analyzing how the fish swims with tail fin under the law of progression. The principle, structure, and drive signals of tail fin electromagnetic drive are researched, the enforced situation of fish under eIectromagnetic driving modes are analyzed, and the experimental plat-form of tail fin electromagnetic drive is established. The best distance between electro- magnet and armature, which can realize the swing of tail fin, was researched in the experiment under water. The robotic fish structure parameters of tail fin electromagnetic drive was finalized by theoretical analysis and experimental measurement.

Total phosphorus accident pollution and emergency response study based on geographic information system in Three Gorges Reservoir area

In recent years,sudden water pollution accidents in China's rivers have become more frequent,resulting in considerable effects on environmental safety.Therefore,it is necessary to simulate and predict pollution accidents.Simulation and prediction provide strong support for emergency disposal and disaster reduction.This paper describes a new two-dimensional water quantity and the quality model that incorporates a digital elevation model into the geographic information system.The model is used to simulate sudden water pollution accidents in the main stream of the Yangtze River and Jialing River in the Chongqing section of the Three Gorges Reservoir area.The sectional velocity distribution and concentration change of total phosphorus are then analyzed under four hydrological situations.The results show that the proposed model accurately simulates and predicts the concentration change and migration process of total phosphorus under sudden water pollution accidents.The speed of migration and diffusion of pollutants is found to be greatest in the flood season,followed by the water storage period,drawdown season,and dry season,in that order.The selection of an appropriate water scheduling scheme can reduce the peak concentration of river pollutants.This study enables the impact of pollutants on the ecological environment of river water to be alleviated,and provides a scientific basis for the emergency response to sudden water pollution accidents in the Three Gorges Reservoir area.