Selenium contamination from the gravel pit operation has persisted through three consecutive quarters, with discharge reaching 335% of permitted limits. The selenium derives from local Cretaceous shale, a common geologic source in this region that mobilizes readily under disturbance. As summer flows drop — the channel now runs at 80 cubic feet per second, down from spring peak of 265 — whatever selenium reaches the water concentrates further downstream.

The harm accumulates invisibly. Trout and waterfowl that feed in contaminated reaches show reproductive failure at concentrations too low to detect by eye or taste. Bioaccumulation means the heaviest burden falls on top predators and breeding females, whose eggs often fail to hatch or produce viable young. The creek has no visible algae die-off or discolored sediment; the real damage is in the tissues of fish and birds that no longer breed there as they once did.