Coastal Plain Culvert Study

Science Center Objects

Various environmental groups in Alabama are concerned that the use of culverts at highway crossings to convey stream flows has detrimental effects on the natural conditions of streams. Specifically, some groups are concerned that changes in stream geomorphology, sediment concentrations, and associated turbidity adversely impact the benthic macroinvertebrate community when culverts are constructed at highway crossings of streams. The Alabama Department of Transportation (ALDOT) would like to address these concerns with a scientific investigation. The U.S. Geological Survey (USGS), in cooperation with the ALDOT, is conducting a three-phase (before, during, and after installation) scientific assessment of the above mentioned concerns in order to determine the degree of impact of culverts on relatively natural-stream condition. The results of this investigation will serve as a valuable tool to the ALDOT in evaluating culvert impacts on the stream channel geomorphology, sediment concentration, turbidity, and benthic macroinvertebrate communities.

Coastal Plain Culvert Study

Various environmental groups in Alabama are concerned that the use of culverts at highway crossings to convey stream flows has detrimental effects on the natural conditions of streams. Specifically, some groups are concerned that changes in stream geomorphology, sediment concentrations, and associated turbidity adversely impact the benthic macroinvertebrate community when culverts are constructed at highway crossings of streams. The Alabama Department of Transportation (ALDOT) would like to address these concerns with a scientific investigation. The U.S. Geological Survey (USGS), in cooperation with the ALDOT, is conducting a three-phase (before, during, and after installation) scientific assessment of the above mentioned concerns in order to determine the degree of impact of culverts on relatively natural-stream condition. The results of this investigation will serve as a valuable tool to the ALDOT in evaluating culvert impacts on the stream channel geomorphology, sediment concentration, turbidity, and benthic macroinvertebrate communities.

The proposed investigation is a 5-year study that targets 8-10 small streams in the Coastal Plain physiographic province of Alabama, beginning in the Federal Fiscal Year 2010 (October 1, 2009). The study will include 4 years of data collection that encompass pre-construction, construction, first-year post-construction, and second-year post-construction phases of box culvert installation at the selected stream sites. The final year will focus on data analysis and report writing. The objectives of this project are to (1) assess the degree and extent of changes in geomorphic conditions, suspended sediment concentrations, turbidity, and benthic macroinvertebrate populations in selected small streams after box culvert installation and (2) identify any significant relationships between observed changes in geomorphology and benthic macroinvertebrate populations. Baseline conditions will be established for each stream and any observed post-construction physical and ecological impacts of the culvert will be documented.