Interim Report Finds Cause of Increasing Amount of Algae in Jordan Lake



After a six-year study, an interim report found numerous pollution sources to the contamination of Jordan Lake. This lake serves as a drinking reservoir for over 300,000 people in North Carolina.

The report on nutrient management in Jordan Lake found that among the contaminants are industrial chemicals and agricultural runoff. However, many of the contributors to the reservoir’s problems can be linked back to home septic systems.

Even though one quarter of U.S homes utilize a septic system, the shift from a once-rural watershed to a more urban area has lead to increasing amounts of discharge from these systems that have been feeding the harmful algae in Jordan Lake over the past 20 years.

The report was produced by UNC System scientists who were hired by the NC Collaboratory, a think tank housed at UNC Chapel Hill. After the Collaboratory received $500,000 annually over six years after a 2016 budget bill, they began to investigate pollution sources and to identify potential solutions to the contamination in the Falls Lake and Jordan Lake watersheds.

Mike Piehler, a joint associate professor at UNC’s Institute of Marine Sciences, said the study encompasses “a pretty comprehensive picture of the natural and human system.”

Heavy rainfall can wash contaminants like nitrogen, phosphorous, and debris into the lake in densely developed areas. Nutrients like nitrogen and phosphorous can increase the growth of algae in waterways.

While some types of blue-green algae can be toxic to humans and animals, even more benign versions create problems for municipal water treatment plants. In order to remove the algae from drinking water, additional expensive treatment is required.

The latest proposal to fix Jordan Lake is to spend $1.3 million to have a contractor chemically treat the water. Additionally, there were be up to 350 tons of chemically treated clay dumped into a 300-acre portion of the 14,000-acre lake. However, this plan was rejected by the Army Corps of Engineers due to the fact the chemicals could damage aquatic life and reduce the reservoir’s storage capacity.

The cost to reduce the contaminants entering the lake would be massive.

The report mentioned that local governments, homebuilders, and farmers in the watershed “are not comfortable with the fairness of the rules”.

Because of the disagreement surrounding costs, payment, and treatment methods, appropriate water quality standards will most likely need to be revisited.

“Jordan Lake provides benefits to people, but if the lake degrades, those benefits are lost,” explained Piehler. “We can’t stand on the scientific mountain and say ‘This is how it is.’ There is the question of how it gets paid for.”

Leave a Reply