Author: Laura Oleniacz
A new mapping tool will help display water quality sampling findings collected through the Western N.C. Recreational Monitoring Program to help the public identify locations where E. coli levels are above and below recreational guidance values before swimming or boating in certain waterways in western North Carolina.
The interactive mapping tool displays water quality results for locations in three river basins that are sampled by the NCDEQ Division of Water Resources Asheville Regional Office, or by program partners. The online tool is being offered as an additional tool that can be used alongside the Swim Guide, where results will continue to be updated.
“We hope this tool will help users better understand their own risk when recreating in select sites in the French Broad, Little Tennessee and Catawba river basins,” said Rachel Rose, coordinator of the program and an environmental specialist with DWR. “The tool is designed to display multiple water quality sampling results, as well as to display E. coli values through a mapping tool that can help the public to identify locations where sampling results are above the guidance values for swimming and kayaking or tubing.”
E. coli is a diverse species of bacteria found in the environment, food and intestines of animals and humans. The presence of E. coli at elevated levels in streams, lakes and rivers is an indication of the increased presence of disease-causing bacteria and viruses.
E. coli can result from point and nonpoint source pollution. U.S. Environmental Protection Agency’s (U.S. EPA)’s website has more information: nonpoint source pollution. DWR cannot tell users when it is safe to swim. The results posted to the dashboard are considered preliminary, and are intended to help the public make informed decisions about their own risk.
The N.C. Department of Human Health Services (DHHS) is charged with issuing health and (or) recreational advisories in North Carolina. Contact NCDHHS or your local health department to stay up to date on water quality advisories for recreational waters. NCDHHS has recommendations for recreational water safety online. More summer safety tips can be found online. DHHS advises the public to use caution during recreational water activities after Hurricane Helene.
Environmentally Speaking spoke with Rose about the new tool, and the program:
Why did DWR launch the new tool?
This new online mapping tool displays E. coli sampling results not only in relation to the primary recreation guidance value, which is the guidance value for primary recreation such as swimming, but it also shows the values in comparison to the guidance value for secondary recreation, which includes activities such as tubing, rowing and kayaking.
In addition, the new tool also displays additional water quality results we have collected through the program, such as specific conductivity, dissolved oxygen, temperature and turbidity, which is a measure of the cloudiness of the water. These additional parameters help us to evaluate the overall condition of the water at the time the sampling was conducted, and can sometimes be used for DWR staff as indication of potential contaminant sources that we need to investigate further.
How should the public use it?
I would advise the public to look into where you’re recreating and find the closest flagged point or icon, and then look at the most recent sample. You can look for a trend, and use the data to guide your decision about getting into water depending on the type of recreation you’re doing. Water conditions can change rapidly depending on conditions such as precipitation, and other factors, so you want to take the latest date of the sample into account.
What is the estimator, and how should the public use this alongside the other tools?
DWR is continuing to provide the estimator tool on the French Broad River for real-time estimates of E. coli at a location at Pearson Bridge. The E. coli estimator can be found online: French Broad at Pearson Bridge E. coli Estimator.
The estimator is designed as a supplemental tool to help offer data in between sampling periods. It provides a real-time estimate of E. coli, based on a statistical relationship between turbidity, which is a measure of water clarity, and E. coli that was calculated for that location.
It's accurate only for the area at Pearson Bridge. There are a few U.S. Geological Survey gages in the area that have turbidity being constantly read – that’s what we’re using to get the E. coli estimated value is those constant turbidity readings.
One of our partners in this program, Mountain True, helps collect more samples so we can calculate that correlation. Those additional samples give us more data to support a more robust equation that is statistically closer to what’s actually going on.
What goals do you have for this program?
We know that water recreation is an important part of the economy in western North Carolina. By providing this tool, we want to help the public better understand their risk when recreating in our waterways.