The city of Ashland will use a pond and shaded wetlands to cool treated sewage wastewater in response to Oregon Department of Environmental Quality requirements that the city stop emptying overly warm wastewater into a local creek.
Longterm, the city could also plant shade trees along eight miles of waterways in the Bear Creek watershed.
Warm water can be harmful to fish.
The solution to the wastewater temperature issue — which has dogged Ashland for years — is more environmentally friendly than other options and is also cheaper, according to city and DEQ officials.
Ashland City councilors unanimously approved the strategy on Tuesday night.
"For Ashland to be on the leading edge on this is exciting," Councilor Greg Lemhouse said.
Treated sewage wastewater currently empties into Ashland Creek near the city's sewage treatment plant and the Dog Park. Downstream, Ashland Creek soon pours into Bear Creek.
The city plans to reroute the wastewater flow so that it travels into Ashland Pond and wetlands for cooling, and then empties directly into Bear Creek. The pond and wetlands are on Ashland Parks and Recreation Department land. The Parks Commission supports the plan.
Carrying out the plan will cost an estimated $2.9 million.
In contrast, building a cooling tower with added chillers and water storage areas would cost $8.6 million to $11.6 million.
Building facilities to sprinkle warm effluent on hundreds of acres of city land known as the Imperatrice property would cost $5.8 million to $13.4 million, city officials said.
Communities all across Oregon are dealing with the potentially costly mandate to stop emptying warm effluent into creeks and rivers.
Dick Pedersen, statewide director for DEQ, visited Ashland officials in March to tell them that while the pond cooling and tree planting strategy is relatively new, DEQ would support Ashland's decision to take that route.
Pedersen told city officials that the beauty of tree planting is that it costs less than other options, while also improving the health of the watershed in multiple ways. He said many calculations have been done demonstrating the cooling effects of tree shade on water.
Staff reporter Vickie Aldous can be reached at firstname.lastname@example.org or 541-479-8199.