A computer simulation of a wetland's hydroperiod : Hult's Environmental Learning Center, Albany, Indiana

This creative project addressed the problem of whether or not it was possible to create a computer simulation (model) that would accurately reflect changes in the volume of a specific wetland as a result of variations in precipitation and evaporation. The model created does not produce any unexpected results and on that basis is a success. However, to determine how accurate the model actually is, further observations of the wetland at Hult's Environmental Learning Center in Albany, Indiana are needed. Because the wetland is held in interest by Ball State University's Department of Natural Resources and Environmental Management, these observations may be carried out by future students as part of their education. The model was created using STELLA® modeling software. STELLA® allows for inputs, outputs, and the initial water volume of the wetland (stock) to be entered. STELLA® also allows for formulas to be entered as converters between inputs, stock, and outputs. Precipitation was used as an input to calculate runoff from the watershed. This runoff from the watershed was the only input used to increase the stock. Therefore, precipitation was the only weather data needed for the inputs. Other data needed here was the area of the watershed and the area of specific surface types within the watershed. The stock (i.e. the volume of water present) was calculated by measuring the depth at several points within the basin as well as the surface area of the water body. The outputs from the stock were 1) runoff over the spillway, 2) drainage, 3) infiltration, and 4) evapotranspiration. Therefore, pan evaporation, to calculate evapotranspiration, was the only weather data needed for the outputs. Other data needed here were the capacity of the wetland, the elevation of a drainage pipe, and the elevation of the spillway. The specific formulas used as converters between the inputs and the stock and between the stock and the outputs are discussed in detail below in the Materials and Methods section.Department of BiologyThesis (M.A.