Researchers report largely clear watershed but warn of microplastic spread after Helene; prescribed burn planned

Dr. Peter Bates and watershed colleague Jerry Miller told the Town of Waynesville council on March 11 that long-term monitoring shows very clear water within the town's watershed but that extreme storms and regional sources are moving sediment and microplastics downstream.

The presentation summarized more than a decade of monitoring at multiple stations in the Richland Creek watershed, ongoing invasive-plant control and forest stewardship work, and regional sampling that found microplastics present in streams, flood deposits and biological samples.

The speakers said routine samples at the "Old Ball 1" monitoring station and most sites show very low suspended-sediment concentrations: more than 90% of samples are under about 10 milligrams per liter, a level the presenters characterized as clear water. But Hurricane Helene produced an extreme flood that briefly pushed turbidity and suspended-sediment values well above typical ranges and delivered large slugs of sediment to the lower Allen Creek channel and the reservoir, they said. The flood also moved substantial quantities of plastic debris downstream into Lake Junaluska and the reservoir area.

Why it matters: Town officials and stewardship partners said the watershed's overall water quality remains good under normal flow conditions, but episodic storm flows can rapidly change conditions and move sediment and contaminants into storage areas downstream. The…