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MailTribune.com
  • Treatment plant's impact on Rogue studied

    Fly-fisherman concerned that Medford treatment plant damages river habitat; city official says wait for another study
  • WHITE CITY — John MacDiarmid paws through mats of aquatic plants to pick a slimy rock out of the Rogue River, knowing he won't find a stonefly nymph or other underwater insect beneath it.
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  • WHITE CITY — John MacDiarmid paws through mats of aquatic plants to pick a slimy rock out of the Rogue River, knowing he won't find a stonefly nymph or other underwater insect beneath it.
    The matted algae that shrouds this upper Rogue gravel bar makes it a tough place to live for bugs, the cornerstone to an aquatic environment that makes parts of the Rogue a wild salmon treasure chest.
    "That's what bothers me," says MacDiarmid of the Medford-based Rogue Flyfishers Association. "The bugs are the indicators of (river) health. They're the canaries. But how can you get oxygen down through those rocks to those aquatic insects with this?"
    A study commissioned by the organization last year says the answer is to reduce nutrient levels in water released from Medford's wastewater treatment plant just upstream of this gravel bar.
    MacDiarmid says the study's conclusion — that nutrient levels in the treatment plant's outflow trigger plant growth that causes dissolved oxygen and pH levels to fluctuate dramatically — shows that the city is in violation of its permit to discharge treated water into the Rogue.
    Now the city of Medford will see whether its own studies will agree with that conclusion or point toward another source of nutrients.
    The city has hired a firm to study plant and insect life, as well as the environmental effects of them, so state water-quality managers can determine whether changes are needed in the nutrient levels released from the plant.
    "What it looks like is a nutrient contribution to the river," says Steve Schnurbusch, a DEQ senior water-quality permit analyst in Salem. "The additional monitoring gives us another set of samples.
    "The mantra is that more data is always better," Schnurbusch says.
    If the results mirror the study funded by the Rogue Flyfishers, then the DEQ will look into how best to address the plant's impacts, Schnurbusch says.
    What those changes would be and how much they would cost are unknown so far, he says.
    "We want to make sure we reduce it enough that it won't be an issue," Schnurbusch says. "But we don't want to require more than they need to. We need to figure out what the right numbers are. It's not necessarily going to be an easy exercise."
    Cory Crebbin, the city's public works director, warns against the DEQ and anyone else assuming the plant is to blame for environmental discrepancies found between gravel bars upstream and downstream of the outflow.
    "Until we get the study, there will only be speculation as to what the next step would be," Crebbin says.
    Crebbin says the entire upper Rogue has problems with agricultural runoff that puts enough nitrogen and other nutrients in the river to limit water quality, particularly in low-flow fall periods.
    "We could limit (plant outflows) entirely, and I could speculate that it wouldn't solve the problem," Crebbin says.
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