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Aerial Imagery, Benthic Macroinvertebrate, Topographic Survey, and Soil Survey datasets collected for a study of Effects of Culverts on the Natural Conditions of Streams in the East Gulf Coastal Plain of Alabama, 2010-2019

September 30, 2021

The Alabama Department of Transportation (ALDOT) and the U.S. Geological Survey (USGS) studied several sites in the northern East Gulf Coastal Plain of Alabama to investigate effects of newly installed box culverts on the natural conditions of the streams they are traversing (Pugh and Gill, 2021). Data collection for the study spanned approximately 10 years and included before-, during-, and after-construction phases of box culvert installations at selected stream sites. The objectives of the project were to (1) assess the degree and extent of changes in geomorphic conditions, suspended-sediment concentrations, turbidity, and benthic macroinvertebrate populations at selected small streams following box culvert installation and (2) identify any substantial relationships between observed changes in geomorphology and benthic macroinvertebrate populations.

Multiple datasets were used in the analysis of culvert effects on the study streams. Suspended sediment and turbidity data are stored in the USGS National Water Information System (NWIS) and are available from U.S. Geological Survey (2021). Topographic survey data and benthic macroinvertebrate identification and enumeration data are provided in this data release because these data types are not able to be stored within the NWIS. Aerial photographs and soil map data for the study sites were used as ancillary information for the interpretations in the main scientific investigations report (Pugh and Gill, 2021) and are included in this data release.

Topographic surveys of stream channel cross-sections, upstream and downstream of the culverts, were conducted both before and approximately 2 years after culvert construction. The cross-sections were evenly distributed along a stream reach length of approximately 20 times the channel width. Twenty-two stream channel cross-sections (11 upstream and 11 downstream of the proposed culvert) were surveyed at each study site to measure the impacts culvert construction may have on the stream channel beds, banks, and slopes. The survey data were used to determine cross-sectional area, top width, mean depth, and thalweg slope for statistical analysis presented in the associated Scientific Investigations Report. Pre- and post-construction channel geometry data for each site are presented in separate comma-separated values (CSV) files. In addition, plan views of before and after construction data points at each site are included in Portable Document Format (PDF) files.

Benthic macroinvertebrate samples to evaluate before- and after-culvert construction phases were collected at seven study sites. Benthic macroinvertebrate results for two sites presented here, Mill Branch and Kanetuche Creek, include data from only the before-culvert construction period. These two sites were initially included in the study, were later dropped due to construction changes, and were not evaluated in the companion report. Samples were collected in two reaches at each site, one upstream and one downstream of the culvert installation. Benthic macroinvertebrate data collected for this project are presented in six comma-separated values (CSV) files in this data release. Sample dates, locations, and identification and enumeration results for all seven sites (14 sample reaches) collected during this project are presented in two files. Two additional files are included which contain sample information for only the samples analyzed and presented in the associated Scientific Investigations Report (Pugh and Gill, 2021). Formatted sample data and processing options used by the Invertebrate Data Analysis System (IDAS; Cuffney and Brightbill, 2010) to calculate metrics evaluated in Pugh and Gill (2021) are contained in two files and could be used with an installation of the IDAS to recreate metrics used in the report.

Aerial imagery taken before, during, and after culvert construction was examined to see if any natural or anthropogenic changes occurred in the areas surrounding the study sites. For example, examination of the High Log Creek imagery from 2013 and 2015 shows the forested area northwest of the study site was clear cut and the start of culvert construction occurred sometime between when the two images were taken. Aerial imagery for each study site, taken before, during and after culvert construction, were downloaded from Google Earth (https://earth.google.com/web/) and are presented as separate PDF files labeled by site name and imagery date.

Soil survey maps were examined to better understand the surficial materials at each study site. Soil maps provide information about soil properties and their behavioral characteristics. Soil survey maps were generated using the United States Department of Agriculture-Natural Resources Conservation Service’s (USDA-NRCS) Web Soil Survey (WSS) tool (http://websoilsurvey.sc.egov.usda.gov/). The USDA-NRCS WSS maps are presented as separate PDF files.

References

Cuffney, T.F., and Brightbill, R.A., 2010, User’s manual for the National Water-Quality Assessment Program Invertebrate Data Analysis System (IDAS) software, version 5: U.S. Geological Survey Techniques and Methods 7–C4, 126 p., accessed February 26, 2019, at https://pubs.usgs.gov/tm/7C4/.

Pugh, Aaron L., and Gill, Amy C., 2021, Effects of culvert construction on streams and macroinvertebrate communities at selected sites in the East Gulf Coastal Plain of Alabama, 2010–19 : U.S. Geological Survey Scientific Investigations Report 2021-XXXX, xx p.

Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey, accessed August 2017 at http://websoilsurvey.sc.egov.usda.gov/.

U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed 30 May 2021 at http://dx.doi.org/10.5066/F7P55KJN.