Hydrologic modeling

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Projects

GIS-Based Hydrologic Modeling of Watersheds that Drain into Lake Michigan: Examples from the Watersheds of Trail Creek and the East Little Calumet River

Report by Greg Olyphant and Ginger Korinek, Center for Geospatial Data Analysis, Department of Geological Sciences, Indiana University;
and Sally Letsinger, Kevin Spindler, and Denver Harper, Center for Geospatial Data Analysis, Indiana Geological Survey
August 2002

Project Overview

The objectives of the project were:
(1) to develop a computationally efficient hydrologic watershed model that is based on existing geographic information systems (GIS) layers and data, and
(2) to develop a Visual Basic application to provide a means of visualizing concentrations of E. coli bacteria within drainage systems and their outfalls during storms.

GIS data for the Trail Creek and East Little Calumet River watersheds were obtained from the Lake Michigan Rim GIS (Lake Rim GIS). These data were supplemented by new layers generated using hydrologic tools available in ESRI ArcGIS.

Project participants were Greg Olyphant and Ginger Korinek, Center for Geospatial Data Analysis (CGDA), Department of Geological Sciences, Indiana University (IU); and Sally Letsinger, Kevin Spindler and Denver Harper, CGDA, Indiana Geological Survey (IGS).

The project was sponsored by Office of Land Quality (OLQ), the Indiana Department of Environmental Management (IDEM); the IDEM project manager was Greg Overtoom. The project commenced on July 1, 2001, and ended on June 30, 2002.

Project Elements

The project included five elements (click titles for detailed descriptions):

Element 1 - Developing hydrologic GIS layers. Digital Elevation Model (DEM) data were gathered and hydrologic tools (available in ESRI ArcGIS) were used to extract channel networks, contributing interfluve areas, and slopes of stream reaches.
Element 2 - Determining runoff coefficients and bacterial loadings from interfluves. Develop a basis for determining runoff coefficients and bacterial (E. coli) loadings for interfluve surfaces (adjacent hillslopes) contributing runoff and contaminants to each stream segment within the watershed drainage network.
Element 3 - Developing a model. Develop a computationally efficient and physically based hydrologic model for routing streamflow and E. coli through branching drainages in two watersheds that drain into Lake Michigan during storms.
Element 4 - Calibrating the model. Calibrate the hydrologic model to replicate stream discharges measured at U.S. Geological Survey gauging stations in the targeted watersheds and E. coli concentrations archived within the Lake Michigan Rim GIS.
Element 5 - Demonstrating the model. Undertake simulations to determine how water quality (E. coli concentrations) and streamflow vary within the watersheds during storm flows and develop visualizations to illustrate the findings.