A hydrologic study of the Bear Creek watershed using GIS and the HEC-Hydrologic modeling system
HEC-GeoHMS was used as a precursor for preprocessing data before input into HEC-HMS. A GIS soil's layer containing Iowa Soil Properties and Interpretations Database (ISPAID) was analyzed for this project. The analysis included a query within GIS of the flood frequency code to identify soil polygons that were labeled PONDED. These soil polygons were then displayed as an image within the boundaries of the Bear Creek watershed. GIS was used to calculate the amount of water (volume) that each of these soil polygons can hold. Changes in discharge under different storm events were calculated and displayed based on discharges from HEC-Hydrologic Modeling System. This research provides information for landowners about flooding and its potential damaging impacts on the landscape. Using this hydrologic assessment, alternative strategies can be developed to minimize the impacts of flooding within the Bear Creek watershed. Those strategies include taking some areas out of production in order to construct wetlands. The wetlands will serve as a sink to hold the water, hopefully minimizing the impacts of floodwater.Floods are an increasingly significant hazard in the United States because of the major changes to the hydrology of the landscape. Floods cause financially greater loss and more loss of life per year than any other natural hazard. In order to best assess floods and their effects on landscape most effectively, hydrologic modeling was conducted on the Bear Creek watershed in central Iowa, which extends over portions of three counties, Hamilton, Hardin and Story. Geographic Information System (GIS) was used to obtain the necessary data for completion of this project. A Digital Elevation Model (DEM) was the primary data set used for the hydrologic modeling. The DEM was used to model hydrologic processes due to the changes in elevation. A triangulated irregular network (TIN) was created from the DEM to see these changes in another dimension. The Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) was used to assess the landscape characteristics of the Bear Creek watershed. HEC-HMS is a modeling system designed to simulate the precipitation-runoff in watersheds.