Just when it seems the Kenai River is on the road to recovery following news that hydrocarbon pollution has been cleaned up in July, results of a new study are stirring up renewed concern over the health of the river.
Robert Ruffner, executive director of the Kenai Watershed Forum, had a good news, bad news presentation for the Kenai Area Fishermen’s Coalition on Thursday.
The good: Test results from this summer show a dramatic reduction in hydrocarbon pollution in the lower reaches of the Kenai River, attributed to a regulation banning two-stroke outboard motors in favor of cleaner-burning, four-stroke models and direct fuel-injection two-strokes.
When the lower Kenai River was placed on the Environmental Protection Agency’s impaired listing due to pollution, tests found hydrocarbon levels at 20 to 25 parts per billion during peak fishing season in July, well over the limit of 10 ppb. In July 2008, those numbers were down to two to five ppb, Ruffner said.
There’s some discrepancy in the numbers, and water-quality testing will continue this summer to nail down the most accurate results possible. Ruffner said water levels and tides were high this summer, which may have aided in the dilution and flushing out of pollutants. And there’s some question over how the lab treated one of the four hydrocarbon compounds it tested for, which may have skewed results slightly higher than they should be.
Then there was the bad news: Turbidity testing from the summer shows significant spikes during late June and especially July, which Ruffner relates to peak boat use on the river.
Turbidity — muddy water — occurs naturally to some extent, but it appears that human activity is causing a literal stir on its own. Sediment in water can impact a fish’s ability to feed and spawn, and certain sizes of particles can lodge in gills and harm organisms. It’s also a sign of bank erosion.
The tricky part comes in determining how much impact is too much, and what should be done about it. The Kenai’s turbidity level can spike up to 40 or 50 NTUs (the measurement for turbidity) due to natural conditions. Human activity seems to be pushing it up significantly higher, to 150 NTUs.
But where’s the line when unnatural becomes unhealthy?
Common sense says there’s an impact from that much sediment being washed into the river, but science has yet to specifically identify the impact and quantify how serious it is.
Then comes the regulatory process to decide whether rules will change to address the issue.
After having just emerged from this process with hydrocarbons, it’d be nice to sit back and relax on the river for a while. But having a resource like the Kenai running through our backyards means we also have the ongoing duty of caring for it.
That duty may be laborious sometimes, but the Kenai River is worth it.