Throwing shade on a heated issue
The bad news: Ashland’s wastewater treatment plant is releasing effluent into lower Ashland Creek (just before it merges with Bear Creek) at temperatures well above levels the Oregon Department of Environmental Quality finds acceptable.
The good news: Ashland has a brilliant young man, Eugene Weir, who figured out an economical and ecologically sound solution to the problem.
Weir began developing his ingenious program several years ago, after graduating from Southern Oregon University in biology and environmental science. Working through a number of agencies, including the U.S. Forest Service and Rogue Valley Council of Governments, Weir realized that by restoring native vegetation, especially shade trees, to creek banks (called “riparian shading”), one could lower water temperatures to levels comfortable for aquatic wildlife. This model caught the eye of Portland-based The Freshwater Trust, for which Weir now serves as restoration project manager.
Once upon a time, Bear Creek and its tributaries were shaded by pine trees and other native plants. When farmers moved into the valley, many of those trees were cut down for agricultural purposes, leaving sections of the creek exposed to the sun.
As our town paved streets and constructed storm drains, waterways became polluted and overheated from agricultural runoff, as well as rainwater trickling down over hot and dirty sidewalks into local streams (known as “non-point” sources of pollution).
Add to that large amounts of processed effluent, and you’ve created an uncomfortable habitat for native aquatic creatures, especially the endangered coho salmon.
DEQ can do little to mitigate heating from non-point source runoff. However, the agency is responsible for regulating wastewater treatment plants. Municipal sewage treatment facilities must remain in compliance with the pollution and temperature standards set by the state in order to be able to renew their operating permits. Failure to do so can result in fines, even lawsuits.
To stay in compliance, treatment plants can construct any of several types of facilities to reduce the temperature of effluent. These structures are very pricey, require significant land, and create upstream greenhouse gas emissions.
By contrast, Weir’s riparian shading plan lowers temperatures of the waters flowing above the treatment plant, so that when warm effluent enters into chilled waters, the combined temperature remains at levels that are comfortable for salmon. By calculating how much effluent is overheating a creek, doubling that number, then estimating how many miles of upstream waters need to be shaded to reach the desired temperature, Weir can figure out the scope of his project. Sun-exposed banks along upstream tributaries (both publicly and privately owned) are planted with native species, especially shade trees, using the help of local contractors, and the project is monitored for success over a 20-year period.
This natural means of temperature reduction comes with several environmental benefits, among them creating healthy habitats for many aquatic species, and sequestering atmospheric carbon through plant leaves. Best of all, municipalities save costs, using funds rate payers would otherwise have had to spend constructing cooling facilities.
DEQ then reissues operating permits on the basis of TFT’s “water quality offset trading” program (not to be confused with “carbon offset trading,” which is a financial trading vehicle meant to encourage businesses to not emit greenhouse gases). The offset in temperature resulting from riparian shading keeps the treatment plant in compliance with DEQ. As Weir wrote, “TFT created the water quality trading program with a vision for how it could direct compliance dollars toward actions that create the needed results while also building environmental resilience.”
DEQ put it this way: “Trading allows DEQ and stakeholders to look at a watershed holistically, and to ask how efforts to improve water quality can be undertaken to best protect watershed health. This is important, because the best opportunities for improving water quality and watershed health are not always located at point source outfalls. There may also be ancillary benefits to trading, such as the restoration of riparian areas and wildlife habitat and lower costs” (www.oregon.gov/deq/wq/wqpermits/Pages/Trading.aspx).
For the past several years, TFT has been installing and monitoring a riparian shading project for the Regional Water Reclamation Facility in Central Point, which processes waste from Medford, Phoenix, Talent, Jacksonville and Eagle Point, enabling DEQ to reissue that plant’s operating permit. (Note: TFT’s project has nothing to do with mitigating pollutants, which apparently, as some readers may have heard, are present in the Rogue downstream of the plant.)
The city of Ashland is in discussion with DEQ and TFT to develop a similar plan, so that our wastewater facility can also be reissued its operating permit. Once the Ashland plan is finalized, it will be posted for review on the DEQ website. Readers can sign up for the DEQ newsletter at www.oregon.gov/deq/Get-Involved/Pages/default.aspx, enabling the agency to alert them to where the text will be posted online.
Once Ashland signs the contract with TFT, Eugene’s team will be fully engaged, and not have time for private projects. However, property owners who might be interested in implementing riparian shading on their land can contact PlantOregon, 541-535-3531; Rogue Valley Water Council, www.rogueriverwc.org/what-we-do/water-quality-improvement/; Jackson Soil and Water Conservation District, www.jswcd.org/
Weir suggested that residents can reduce erosion by not having bare soil exposed as the rainy season approaches; avoid using pesticides; keep sidewalks clean to mitigate non-source pollution in storm drains; and plant pollinator-friendly shrubs, as well as trees such as cottonwood, alder or ash, which maximize carbon sequestration.
(Thanks to TFT’s David Primozich and Tim Wigington, Fish and Wildlife’s Dan Vandyke, and the DEQ’s Katherine Benenati and Jon Gasik for their helpful explanations.)
Epilogue: I walked along the Greenway, looking for the merger point between Ashland and Bear creeks. I found a group of SOU biology students digging through Ashland Creek’s mud in search of invertebrate lifeforms. Above the treatment plant, the water is cooler, runs more rapidly, but produces fewer critters. Below the plant, temperatures are perceivably warmer, and tiny aquatic beings are abundant.
Still, I have yet to see a salmon or trout.
Ashland resident, author and anthropologist Nina Egert has been a lay environmentalist since the early 1970s.