Geologic Hazards Mapping: Identifying Sinkholes and Karst Susceptible Areas in Worth, Cerro Gordo, Mitchell, and Floyd Counties HR-3018

The original sinkhole map for Iowa was generated based primarily on the Natural Resource Conservation Service (NRCS) county soil surveys. These data sources have proven to vastly underrepresent the number of sinkholes in Iowa. Even if a sinkhole is not readily visible, a region may still be likely to have karst issues. Characteristics of bedrock units and depth to bedrock can be used to determine areas with high karst potential. Previous geologic maps provided the basis for determining areas with bedrock that typically form karst features and sinkholes, but were produced at a state-wide scale (Witzke et al., 2010). By synthesizing more recent geologic mapping data, the previous map resolution can be improved upon to further characterize the bedrock and identify areas with high karst potential. The IGS will map four counties (Worth, Cerro Gordo, Mitchell, and Floyd) in north central Iowa that are known to have a large number of sinkholes (Figure 1) and that may be impacting existing roadways. This area includes several transportation corridors (portions of state highways 9, 27, and 14; US highways 18, 65 and 218; and Interstate 35) and population centers (Mason City and Charles City). These four counties have recently been mapped for surficial and bedrock geology by the United States Geological Survey (USGS) STATEMAP program (Quade et al., 2012; Liu et al., 2012, 2015, 2018; Tassier-Surine et al., 2015, 2018; Clark et al., 2016; Kerr et al., 2018) and a 25 foot bedrock elevation contour map has also been produced from this effort. Depth to bedrock data is further improved for this area as hundreds of GeoSam data points were relocated during recent mapping. The combination of new data sources will provide the opportunity for development of a much more comprehensive sinkhole and karst potential map. The four county area will be surveyed using the methods utilized by the IDNR within the eight county area in 2010. This procedure, coupled with more accurate bedrock subdivisions created during recent STATEMAP mapping and the revised 25 foot bedrock contour maps, will allow for improved identification and characterization of sinkhole and karst prone areas.

    Language

    • English

    Project

    • Status: Active
    • Funding: $135791
    • Contract Numbers:

      HR-3018

    • Sponsor Organizations:

      Iowa Department of Transportation

      800 Lincoln Way
      Ames, IA  United States  50010
    • Managing Organizations:

      University of Iowa, Iowa City

      IIHR- Hydroscience & Engineering
      307 C. Maxwell Stanley Hydraulics Lab
      Iowa City, Iowa  United States  52242
    • Project Managers:

      Goetz, Vanessa

    • Performing Organizations:

      University of Iowa, Iowa City

      IIHR- Hydroscience & Engineering
      307 C. Maxwell Stanley Hydraulics Lab
      Iowa City, Iowa  United States  52242
    • Principal Investigators:

      Tassier-Surine, Stephanie

    • Start Date: 20190501
    • Expected Completion Date: 20201231
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01704370
    • Record Type: Research project
    • Source Agency: Iowa Department of Transportation
    • Contract Numbers: HR-3018
    • Files: RiP, STATEDOT
    • Created Date: May 3 2019 10:06AM