Below the bridge, the Penny River flows in braided channels through a narrow valley. During spring thaws, surging high waters and ice flows flood the valley and damage the tall willows that grow close to the river. But the resilient willows regrow, making good browse for moose. Evidence of beaver feeding, cutting, and building dams and ponds is common in the drainage. Muskox may seek out the river or tall willows on hot summer days. River otter, though rarely seen, may be spotted in early winter eating coho salmon carcasses.
The bridge crossing gives a good view of unusual birdlife and the passage of salmon as they return to spawn each year. Red-breasted merganser and harlequin duck like the swift-flowing water. Arctic tern, mew gull, glaucous gull, semipalmated plover, and spotted sandpiper are seen along the river. Bank swallow excavate burrows in cut banks. American dipper, Arctic warbler, gray-cheeked thrush, and common and hoary redpoll are seen in this area. Pink, chum, and coho salmon; Arctic grayling; and Dolly Varden are found in the river.