On a Thursday morning in late May, Della Whitlow waded into the Clinch River below a low bridge near Cleveland, Virginia, with a half-meter quadrat and a clipboard wrapped in plastic.
She was conducting the third spring mussel survey of 2026 on behalf of the Upper Clinch Watershed Alliance, a four-person nonprofit she helped found in 2019 and which now operates out of a former insurance office in St. Paul, Virginia.
The Clinch River, which rises in Tazewell County and flows southwest through the coalfields of southwestern Virginia and northeastern Tennessee before joining the Powell to form the Tennessee River, is one of the most biodiverse freshwater systems in North America.
It contains, by recent counts, between forty-four and forty-seven species of native freshwater mussels, including at least eleven species listed as federally endangered, among them the cumberland combshell, the shiny pigtoe, and the slabside pearlymussel.
Mussels are the river's accountants. They live for decades, filter water continuously, and are sensitive to sediment, dissolved metals, and the brief acute pulses of pollution that come from highway accidents, industrial discharges, and the occasional collapsed mine seal.
When the mussels die, the river is in trouble. When they do not die, the river is, in some sense, doing as well as can be expected.
Whitlow's quadrat work is part of a longer-term monitoring program in collaboration with the Virginia Department of Wildlife Resources and with researchers at Virginia Tech. The Alliance contributes the boots-on-the-ground monitoring at twelve fixed sites and the agency biologists do the species identification on collected shells.
The May 2026 count at the Cleveland site found seventeen live mussels of seven species in the half-meter quadrat, which Whitlow described, on the drive back to St. Paul, as a good morning.
The bad mornings are the ones with empty shells. In 2019 and 2020, a series of unexplained mussel die-offs were documented across multiple sites on the upper river. Several thousand mussels of various species died over a roughly six-week window, including a substantial fraction of the cumberland combshell population at one site.
The cause has not been definitively identified. A consortium of researchers, including teams from Virginia Tech, the U.S. Geological Survey, and the U.S. Fish and Wildlife Service, has spent five years investigating possible explanations including pathogens, contaminants, and the synergistic effects of multiple stressors.
The leading hypothesis as of 2025 involved a novel densovirus, possibly endemic, possibly newly introduced, the impact of which may be modulated by background contamination from the watershed's industrial and agricultural history.
The Alliance does not have the laboratory capacity to investigate viruses. What it does have is the time to walk the river and to record what is there.
Whitlow, who is fifty-six, was a high-school biology teacher in Russell County for twenty-three years before she retired and turned to full-time work on the Alliance. Her co-workers are a young aquatic biologist named Janelle Rose, hired in 2023, and two part-time field technicians.
The Alliance's annual budget is approximately 142,000 dollars, funded through state water quality grants, a recurring contribution from the Cabell Brand Foundation, and individual donations from about 380 members, most of them resident in the watershed.
Outside of the formal monitoring, the Alliance runs a citizen-science program in which residents submit water-quality samples and macroinvertebrate counts from creeks and tributaries across the watershed. In 2025 it received 612 sample submissions from 71 volunteers.
The data is not always usable. Many of the samples come from non-standard sites, taken at irregular intervals, with variable methods. Janelle Rose spends a considerable share of her time triaging the submissions and following up by phone or email with individual volunteers.
The value of the program, Whitlow says, is partly the data and partly the network. The 71 volunteers are the people who will report the next chemical spill before it reaches a mussel bed.
What the Alliance cannot do is regulate the watershed. Coal mining continues in the basin at reduced levels, agricultural runoff persists, and the highway that runs along the river will continue to produce occasional spills.
The work, instead, is to document what is happening and to be present when something goes wrong. Whitlow waded out of the river at noon, rinsed her boots, and drove the eleven miles back to St. Paul with the clipboard on the seat beside her.
The numbers from the Cleveland site will be entered into the database on Friday morning. The next survey, at a site twelve miles downstream near the town of Dungannon, is scheduled for June 4.
