Browsing by Subject "Simulation model"

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    Dynamic Lake water quality simulation model "Minlake"
    (1987-08) Riley, Michael J.; Stefan, Heinz G.
    Lakes are in a continuous state of change. Some changes occur over very short periods of time on the order of hours and minutes. Other changes mark long-term trends in the biological and physical condition of a lake. Among the long-term trends in many lakes are a decrease in depth and an increasing productivity in a process called eutrophication. Typically, eutrophication occurs over a time scale of centuries. However, man-made changes to the watershed of a lake may result in a rapid acceleration of eutrophication such that significant changes in the water quality of the lake are noticed in a time span of a few years. Anthropogenic acceleration of eutrophication, known as cultural eutrophication, is due to agricultural, urban, and recreational development in the watershed of a lake which causes an increase in the nutrient loading to a lake. In response to the concern for the water quality of an eutrophic lake, many lake treatment practices have been developed. Treatment processes can be divided into watershed practice methods, inflow-outflow methods, and intake treatment methods. A partial list of these practices is provided in Table I. In some instances, treatment methods have been implemented without significantly improving the quality of a lake. The failure of a treatment method is often a result of a poor understanding of the short term dynamics of a lake which affect the rate and extent of cycling of nutrients within the water column, sediment, and biological components of a lake. To evaluate the effectiveness of lake treatment methods on Minnesota lakes, the Minnesota Lake Model (MINLAKE) has been proposed to model the principal dynamic relationships in a lake on a daily time scale. Treatment methods can then be modeled by modifying those components of the model which will be directly affected by the treatment process. The model can then predict the indirect and direct effects over a period of several months.
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    Erosion Risk Assessment Tool for Construction Sites
    (2006-07-01) Wilson, Bruce N.; Sheshukov, Aleksey; Pulley, Reid
    The impact of erosion and sediment from construction sites can be reduced by using a variety of onsite and offsite practices. The WATER model was developed to be a tool to assess the effectiveness of different sediment control practices. The WATER model evaluates risk by performing many simulations of a construction site response for different weather conditions. A particularly important component of the WATER model is the prediction of daily climate variables and storm characteristics called WINDS. This model uses the statistics for the analyzed data to predict many years of possible weather conditions. Predicted weather and storm characteristics are in very good agreement with those observed. The WATER model simulates surface runoff, plant processes, and erosion and sediment transport as major hillslope processes. Four runoff events (spring dry run, spring wet run, fall dry run, and fall wet run) from artificial rainfall conditions were measured.