Abstract: A mathematical model for seawater intrusion in aquifers is presented; which is capable of handling both confined and phreatic aquifers and mainly contains two partial differential equations. The first equation is used to describe flow of variable-density fluid (mixture of fresh water and seawater), and the second equation is used to describe the transport of dissolved salt. The model is demonstrated by using the three-dimensional observation data of seawater intrusion in Longkou, Shandong Province.
Abstract: In order to solve the shallow water equations accurately, a finite volume MUSCL scheme has been developed on an unstructured mesh consisting of arbitrary triangles. This scheme is a second-order extension of the first-order finite-volume Osher scheme proposed in Ref. 1. Second-order accuracy both In time and space can be achieved by means of an explicit predictor-corrector scheme and slope-limiting within elements. Numerical flux in the direction normal to and across each side of elements is obtained by the flux-vector splitting approach (FVS). Finally, numerical results of tidal flow for the southern branch of the Yangtze estuary and of 1-D instantaneous dam-break-induced flow are presented, to illustrate the merits of this scheme in shallow-water-hydrodynamics and enable us to consider more complex applications.
Abstract: By means of flume experiment and theoretical analysis, the flow depths and ratio of the depths of two-layer parallel stratified flow of non-Newtonian fluid, the stratified mud flow initiated by drag force of the upper layer high speed water flow on the interface, the reciprocal water mud stratified flow resulting frond opening of lock, and the stability of interface for non-Newtonian stratified flows are discussed in this paper.
Abstract: The factor analysis and the orthogonal rotation method under varimax criterion are used to calculate and identify out four high loading regions of precipitation and their factor score coefficients in the flood season (May-Sep.) over middle and lower reaches of the Yangtze river. Their spatial and temporal variations are characterized by the natural synoptic scale precipitations over the reaches. The Eastem Pacific Equatorial SST, the mean SST's for other sea regions and the ENSO events are all associated to a certain with the regional precipitation anomaly in the flood season. The results obtained may be used as reference factors for short-range prediction of flood season's precipitation.
Abstract: The multiobjective optimal operation of a five-reservoir system is studied. according to the characteristics of the reservoirs and the water users, a multiobjective mathematical model by stages of sequential optimization is established. The first priority objective of the model is to optimize water supply for users of two urban and three irrigated areas. The second is to optimize power generation of the hydropower station Al.The results show that satisfied multiobjective benbfits may be gained with the model.
Abstract: Based on some concepts such as risk capacity of water environment etc. proposed in this paper, a model of computing risk capacity and allocating capacity is established to solve problems of total emission control (TEC) of water environment. The concepts and model expand the connotation of TEC and provide a new approach TEC of water environment unaer stocnasnc commons.
Abstract: In view of the characteristics of the Linhuaigang Water Control Project (LWCP), i.e., being rarely in operation and having short storage duration, a method which is simple, rational and visual is presented for an environmental impact comprehensive evaluation if LWCP by using some methods applied in China and abroad.
Abstract: According to the comparative measurement of 8 snowfalls by using the methods of precipitation gages and snow survey on the ground in a small alpine watershed of the Urumqi River Basin during the period between Oct. 1989 to May-1990, it is found that the Chinese standard precipitation gages catch 73% of the relative ground true snowfall. Therefore the snowfall measurement of the gage has a poor representative to the basin-wide snowfall. This systematic error caused by wind effect on the gage should be corrected first for water budget calculation and snowmelt runoff simulation in mountain area.
Abstract: This paper presents an autoregression total linear response modet (ATLIZ) by which the forecast schemes were developed for the Wangjiaba station and the South Canal River system in the Haihe River basin. The proposed model has the same construction as that of the combined model consisting of TLR and error autoregressive real time updating. But,the former is simpler and more accurate than the latter.
Abstract: In the face of the present situation with ever-increasing deterioration of groundwater, geologists have to see far and wide to base themselves upon an everlasting use from the viewpoint of developing environmental strategy. A pressing problem is deeply probed of how keeping groundwater environment good for later existence. Consequently, the inquiry is to conduct intensive researches, in the field of characteristics, evolution, capacity and load of groundwater environment. Furthermore, the degree of weakness about such an environment is expounded and proved in the different natural and economic areas. The divisions of environmental function protection will be brought forward as the scientific basis of groundwater, management, and in accordance with concurrently economic, social and ecological benefits.
Abstract: The influences of urbanization on hydrological regimes in a smarr watershed and their research approaches are reviewed. Based on the data from field observations and laboratorial modelling experiments, an index reflecting hydrologic effects due to urbanization is proposed, that is, the influences of urbanization are considered to be substantial if the impermeable area is over 20% of total catchment area. Also, the estimating method for storm floods in an small watershed due to urbanization is introduced.