The Rogue Flyfishers Association has good reason to be concerned about increased nutrient levels in the Rogue River hear Medford's wastewater treatment plant. For that matter, Medford officials and city residents have reason for concern, too, because if the treatment plant is responsible for decreased water quality, the city will be on the hook to fix the problem.
That's all the more reason to wait for the results of a city-commissioned study before jumping to conclusions.
At issue is a study performed last year on behalf of the anglers' group. The study, released in February, found algae and plant growth was 10 times higher downstream of the plant's designated "mixing zone" than above the discharge pipe.
State Department of Environmental Quality rules exempt the mixing zone from some water-quality standards, the standards must be met outside the zone.
Excess algae and plant growth, which can be triggered by high nutrient levels such as those found in treated wastewater, can coat rocks and gravels, blocking the oxygen needed by insect larva such as stonefly and other nymphs. Salmon and steelhead feed on those insects, which are an indicator of the river's overall health.
John MacDiarmid of Rogue Flyfishers says he's convinced his group's study proves the city is in violation of its state permit to discharge treated wastewater.
Cory Crebbin, the city's public works director, is not ready to concede that yet. In fact, he argues, the treatment plant is not the only source of nutrients. He points to agricultural runoff into the upper Rogue that dumps nitrogen from fertilizers as well as other nutrients into the river.
Crebbin suggests that even shutting off the treatment plant entirely wouldn't solve the problem.
So-called non-point source pollution — general runoff from farm fields, roads and other places — has long been a tough problem for environmental regulators. By its very definition, it's hard to pin down where runoff originates and therefore to assign responsibility for reducing or eliminating it.
That's why it's important to collect as much information as possible — as on DEQ analyst put it, "more data is always better" — before pointing the finger at the treatment plant or any other single source.
The Flyfishers' study certainly suggests there is a problem, and if so, it needs to be fixed for the good of the river and everyone who depends on it. But knowing as much as possible about where the problem is coming from is essential, and the city-commissioned study should be complete by the end of the year. The wait is worth it.