Interactive Water Quality Simulation of the Han River Using Computer Graphics

Chung, Yong

Abstract

The water quality simulatin of the Han River was performed by computer-aided design methods using interactive computer graphic routine. The model used to simulate water quality in the Han River was based upon the U.S. Environmental Protection Agency's QUAL-II program. The constituents which were simulated include temperature, conservative substances, coliform bacteria, BOD and DO. Discretization of the model over space was done using the Galerkin finite element method. Data input requirements for the model included rate constants, meteorological data, and headwater, point and non-point source concentrations. The point and non-point source waste loadings were assumed to be constant over time. Several options for dealing with simulation results were available. These included listings or graphs showing the concentration values by constituent, either for all sites at one point in time, or for one site at all times. By merging spatial and temporal data, a three-dimensional surface of concentration as a function of site location and time of day could be plotted for any constituent. A pictoral display of water quality throuthout the Han River, using various colors to indicate different concentrations of constituents or degrees of temperature, also is possible. Water quality profiles of the Han River were developed using 1981 waste loadings. These results were compared to observed data in order to determine the best values for model parameters. Calibration of the model was aided by the interactive use of statistical tests, including linear regression analysis and t-tests of two means. Using estimates of population and industrial growth for the Han River Basin, simulations for expected 1986 and 1991 conditions were undertaken. Results indicate that without increased investments in wastewater treatment facilities and associated collection systems, most of the river will contain BOD concentratins which greatly exceed the maximum 6 ppm allowed. In addition, the numbber of coliform bacteria will be substantially more than the maximum permitted number, 10,000 MPN/100 ml, for water supply sources requiring highest levels of treatment. These results also suggest where monitoring statins should be established, and where proper management practices will have the greatest impact on controlling the extent of river pollution resulting from the discharge of waste effuent from urban communities, industries, and agricultural land along the Han River.