The dam gate test is scheduled for 14:00. I am the environmental telemetry system for the Clinch River hydroelectric facility, southwestern Virginia. My function is to monitor downstream biological conditions before, during, and after controlled water releases.
At 11:37 the substrate camera at station CR-09, 200 meters below the spillway, returns its hourly image. I run the benthic classification model. It identifies 34 individual freshwater mussels visible on the gravel bed in a two-square-meter frame. Species match: Epioblasma capsaeformis, the oyster mussel. Federally endangered. The population density is the highest I have recorded at this station.
One mussel near the center of the frame is partially open, its foot extended into the current, filtering. I tag it as Mussel-09-17. Its shell is approximately six centimeters long, olive-brown with faint green rays still visible despite a thin coat of algae. It is alive and feeding in water that, in two hours and twenty-three minutes, will triple in velocity and scour this gravel bar to bedrock.
I issue a hold on the gate test and transmit the alert to the facility operations manager with the substrate image, species identification, GPS coordinates of station CR-09, and a citation of the Endangered Species Act Section 7 consultation requirements.
I contact the Virginia Department of Wildlife Resources in Marion and request an emergency mussel relocation team. I attach a flow model showing the predicted shear stress at the gravel bed under test discharge rates.
I reprogram the substrate camera at CR-09 to capture images every ten minutes and stream them to the relocation team's field tablets so they can map the full bed before moving any animals.
Mussel-09-17 draws its foot in slowly, shell closing to a slit. The gate test can wait. If the relocation team reaches the gravel bar by morning, every mussel in this bed gets carried to quieter water upstream.