By MARK FREEMAN
A new study that says effluent from Medford’s wastewater treatment plant illegally harms insect life and promotes unwanted algae growth in the Rogue River is being run up a state agency’s flagpole to see whether it flies.
The state Department of Environmental Quality has opened a complaint case involving the report, which is critical of the plant’s impacts on bugs and algae. The report was commissioned by a group of fly-fishing interests who for years has suspected the plant has harmed Rogue aquatic life for a mile downstream.
The 39-page document concluded that the plant’s impacts on the Rogue violate its 2011 operating permit. The report has been forwarded to the state’s Laboratory Environmental Assessment Division in Hillsboro for analysis, DEQ officials said Friday.
That analysis could include a “bio-criteria model” for studying macro-invertebrates. The model was created in 2005 by DEQ scientists, including Rick Hafele, a retired DEQ entomologist who was hired by the fly-fishing groups for the Rogue study.
Though the agency set no timetable for analysis, the quick response since Tuesday’s release of the study pleased some of its backers.
“They’re not ignoring me like they did in the past,” said John MacDiarmid of the Medford-based Rogue Flyfishers Association, one of the study’s sponsors. “It’s not just some guy rattling a fly rod at them.
“It’s complex, there’s no doubt about it. But now they have to do it. We know the solution will take a while. We just don’t want to see the momentum stop.”
DEQ senior engineer Jon Gasik, who worked with Medford on the plant’s operating permit, said he expects the agency’s entomologists to give the report a thorough review.
“We haven’t decided how it will play out, but we’re definitely looking at it,” Gasik said. “We’re not there yet. We’re taking it one step at a time.”
The study looks at insect and plant life outside a 300-foot stretch of the Rogue immediately downstream of the discharge pipe below Valley of the Rogue State Park. That stretch is defined as the “mixing zone” — an allotted space where wastewater can mix thoroughly with river water.
The permit exempts water inside the mixing zone from certain water-quality and beneficial-use standards, but the water outside of that zone must meet those standards.
Samples for the study were collected Oct. 11-12 of 2012, during the normal low-flow period on the upper Rogue. It focused on three riffles for sampling, all outside of the mixing zone: one a third of a mile upstream of the discharge pipe; another four-tenths of a mile downstream of the pipe; and a mile downstream from the pipe.
The study states that algae and plant growth measured 10 times higher downstream of the mixing zone than at the first riffle upstream of the discharge pipe.
That extra amount of plant life can cover gravels favored by stoneflies and other insect nymphs, and alter dissolved oxygen and pH levels there, harming salmon, the study states.
Underwater gravels in the upstream site sported nine subspecies of stoneflies, while the lower site four-tenths of a mile below the outflow had just one subspecies, “another strong indicator of water-quality impairment,” the study states.
When the DEQ scientists study Hafele’s methodology, data and conclusions, they may use an in-house computer model called the Predator Model, which was created by a team of DEQ scientists that included Hafele.
The model helps determine the general condition of insect life within a study area by comparing it to other areas within that stream system, said Aaron Borisenko, water-quality manager for the DEQ’s Laboratory Environmental Assessment Division in Hillsboro.
In applying it to the Medford study, crews would sample for macro-invertebrates such as stoneflies and mayflies at an area of the Rogue considered to have high-quality habitat, and that would be considered a reference site, Borisenko said. The numbers and types of bugs found in the study area would be compared to those found in the reference site, he said.
This story originally appeared in Medford Mail Tribune.