Institute for Transportation

About the research

The goal of this project was to assess the potential and develop protocols for the use of high-resolution light detection and ranging (LiDAR) and multispectral imagery to evaluate environmental characteristics of Iowa Department of Transportation (DOT) project areas, with particular attention to identifying federally protected wetland areas that would require mitigation if removed or significantly altered during a road construction project.

Specifically, the research team evaluated how LiDAR and multispectral imagery can support the assessment of design alternatives and whether the data could help DOT staff select alternatives earlier and with less required fieldwork.

During the investigation, which included four objectives, an automated ArcGIS Pro tool that leverages Python and ArcGIS routines to identify potential jurisdictional wetlands based on data derived from LiDAR digital elevation models was developed.

The procedure is a first-pass screening tool that will allow Iowa DOT wetland delineation staff to focus their attention on areas likely to be wetlands, rather than having to scrutinize an entire study area with the same level of attention. The underlying classification model currently over-identifies wetland areas, but much of the overidentification has to do with where exactly the boundaries are mapped.

The final toolboxes and routines required to run the wetland classifying procedures are packaged into shareable toolboxes and have been provided and demonstrated to Iowa DOT staff. Using the automated procedure is expected to save time in wetland delineation by allowing staff to prioritize high-probability areas for further study.

The appendix in the report contains the Wetland Classification Tool User Guide that was developed as part of this project.