TILLAMOOK, Ore. — Efforts to control manure runoff and to keep dairy cows out of river channels are improving water quality in the Tillamook Bay.
In a report this week to the Oregon Board of Agriculture, researchers and others involved in the Tillamook Estuaries Partnership said water quality readings are improving at nearly half of 42 sites where samples are drawn twice a month.
“We can say definitively for bacteria that we are making a difference,” said York Johnson, a state Department of Environmental Quality employee who coordinates the estuary monitoring program.
Johnson and others said advancing technology will soon provide even more detailed data about contamination levels and sources. A monitoring device developed by a Corvallis company, ZAPS Technologies, automatically tests water samples every two minutes, giving real-time notice of contamination. As part of a research project, one of the devices is installed on a dairy adjacent to the Tillamook River and measures temperature, turbidity, E. coli and nitrate and nitrite levels.
In addition, Oregon State University doctoral student Lauren Brooks is engaged in a microbial source tracking project that uses DNA analysis to identify the source of contamination.
The work is significant because Tillamook Bay is home to some of the state’s best fisheries, ranging from salmon runs to commercial oyster beds. But it’s also the heart of Oregon’s dairy industry, with about 100 dairies, Tillamook Cheese production and associated businesses.
Five rivers — the Tillamook, Trask, Wilson, Kilchis and Miami — drain into Tillamook Bay, and their banks are lined with dairies. With help from the Tillamook County Soil and Water Conservation District and other agencies, many have taken steps to improve water quality. Producers have built fences and provided field watering troughs to keep cows out of streams and riparian areas, installed digesters to break down manure and carefully managed how and when they apply manure to pastures.
Johnson said the Wilson and Kilchis rivers now meet state water quality standards for recreational use; the Wilson since 2005 and the Kilchis since 2009.