Rusting Rivers B-Roll: Kugururok River, Alaska

This is B-roll video of the Kugururok River, Noatak National Preserve, Alaska from August 30, 2025.

The video follows an orange tributary into the mainstem of the Kugururok River, Noatak National Preserve and observing the precipitation of iron on rocks, rust stained sediment, and impaired water mixing with the mainstem water. Dolly Varden (Salvelinus malma) have been observed spawning in nearby reaches of the Kugururok River.

Rusting rivers are increasingly common in the Brooks Range of northern Alaska. The orange stream color reflects oxidized iron (hence the appearance of rusting), but orange color also indicates elevated heavy metal concentrations and impaired water quality. Our ongoing study aims to document these occurrences, quantify toxic metal concentrations and loads, determine how the interaction of geology, hydrology, and permafrost degradation contributes to the phenomenon, and understand the consequences for stream biota, especially fish.

In 2019, a team of U.S. Geological Survey and Nation Park Service researchers began working on this issue, with the overall goal of defining and understanding changes to Arctic rivers in Alaska to meet conservation goals of the Department of the Interior.

The research team has identified more than 70 locations of rusting rivers throughout the Brooks Range and continue to investigate this phenomenon.