Abstract: Four exceptionally serious r ainstorm events occured in North China and Liaoning Province, namely the "58.7","63.8"."75.8" and "30.8" rains. With a review of their meteorological background and possible causes, this paper points out that the specific disposition of three different synoptic systems of tropical, subtropical and westerly belts causes the meeting of the air current of Warm-wet and cold-dry in this area, and this lend of disposition of the synoptic systems is closely related to the specific superposition of tide-forming force resonance. Especially, if the rainstorm synoptic situation dominates in North China, with a continuously meeting of the superposition of pressure decrease of tide-forming force resonance, it can trigger off an exceptionally serious rainstorm. Concretely, when a typhoon affects this area (assuming that the typhoon intensity is 35m/s at landing the Chinese Continent), the daily maximum rainfall could reached about 500mm if the pressure decrease of one tideforming force resonance occures, and the daily maximum rainfall could reached about 1,000 mm if the superposition of pressure decrease of two tide-forming force resonance occures during the period of a day.
Abstract: In recent years, the first-order finite-volume Osher scheme has been applied with success to a dozen model problems and practical cases involving two-dimensional shallow-water open flows. This paper discusses for the first time relevant techniques in its algorithmic implementation. A kernel lies in the setup of a cell hydraulic model-step flow, which can be described mathematically by a special type of Riemann problem. It can be solved approximately by reducing to a standard Riemann problem in gas dynmaics, and correcting the results accordingly. Based on theoretical analysis and numerical tests, a detailed description is also given about various types of outer, inner and moving boundary treatments, so that a complete and practical algorithm has been formed.
Abstract: Based nn adsorption dynamic equation and mass conservation equation, the variation of sediment adsorption of heavy metal ion with time and that of heavy metal ion concentration with time have been deduced. Furthermore, formulas for calculating the equilibrium sediment adsorption of heavy metal ion and the equilibrium concentration of heavy metal ion in water phase have been established too. And based on proceeding fact the following conclusion is deduced: sediment concentration does not effect sediment adsorption behaviour, namely, saturated adsorption content, coefficient of adsorption rate and coefficient of desorption rate.
Abstract: Based on the flow characteristics of a tidal river, a quasi-dynamic water quality reciprocation model is pressented. The model is solved by using a similar Pearson Type Ⅲ distribution. A method for evaluating the model parameters is given. The model is verified against the amonia-nitrogen concentration data observed in the course of Huangpu River. From the satisfactory results, it appears that the model would be applicable to analysing the distribution and changes of decomposable organic pollutant concentrations.
Abstract: A conceptual flow-sedimentation coupled simulation model for large basins was structured by combining the conceptual equations for interrill and rill-gully soil erosion,and its transport formulations which all described in paper  with, a conceptual flow simulation model for large basins which was proposed in this paper accordirag to characteristics of runoff yields from excess rainfall and processes of snow accumulation and its melt in arid regions of North China. Two difficult problems,lacldng of recorded precipitation data. and too many observed data to treat in simulating flow and sedimentation of a large basin in arid regions, were dealt relatively well with in the model. And the ununiform of some climatic and geomorphologic factors and the different effects of nunoff resulted respectively from rainfall and snow melt on sediment yields were considered. The model was tested with two large basins, and the results were shown that the model structure are resonable,and the simulation of flow and sedimentation were very satisfactory compared to the observed data.
Abstract: Based on the theory of multilevel hierarchical optimal control for large-scale systems, a coordinative management model is presented for analysing the problems concerned with water resources utilization and economic development in the Shijiazhuang region. Some modelling issues including optimal system identification,coordinative management code, and optimization techniques,are discussed.Through digital computer imitation and sensitivity analysis, it confirmed that the results of the model operation are quite reliable and accurate,which will be useful for decision making in water resources managements.
Abstract: Scheduling and determining of irrigation water applications are importart considerations to increase coneern about agriculture productivity in a region of water shortage. In this paper, a two level DP-DP model has been constructed to optimize multicrop allocation of irrigation water in order to increase the benefit of whole region: The first level is to design the optimal irrigation schedule of a single crop;The second is to determine the optimal allocation of irrigation water among crops given limited water resources. A case study example indicates that the model is reasonable and the procedure is feasible. Computer programs utilized in this paper are available from the author.
Abstract: This paper mainly analyses the discharges and critical gate opening regulated by shutting of an emergency gate installed in a hydroelectric, station intake, and the hydraulic forces on the top, bottom and plate of the gate. Biased on observations of a hydrualic model test for the emergency gate shutting in flowing water and unsteady flow theory, a mathematical model has been established for simulating the hydraulic process of gates, draw-in conduits ad turbines. The computational results of some examples showed a satisfactory agreement with the observed ones.
Abstract: Based on sun's activity data, the effect of sunspot and El Niño event on the hydrologic regime and the flood and drought long-term fluctuation of the Songhua River region was analyzed by using statistical method for long-term prediction. The relationship between the El Nino event and 11-year period of sun's activity was revealed through dividing the sun's activity into a strong and a weak section during 1810-1991, a "same year" hydrologic compution formula with sunspot numbers as a parameter was proposed, the fluctuation of the flood and drought influenced by the events in the strong and weak sections was analyzed since 1899, and the periodic change of annual precipitation with the high and low water year was given according to the magnetic cycle.
Abstract: The sciences in the field of water resources came into being and have been developing step by step with the development of water resources and the water related sciences. Since the founding the People's Republic of China, the large scale construction of water works has led to enter a new stage of more comprehensive and integrated approach in the water resources development. The correct handing of the relationships between water resources and socio-economy and eco-environment is becoming an increasingly important subject for the development of water resources, which depends on the advancement of science and technology and the development of management science in water sciences in the future, suggestions in this aspect are put forward in this paper.