Marie Vicksta - Cooling down streams

When we think of pollution, a number of offenders quickly come to mind: industrial waste, agricultural chemicals, E. coli, sediment.

One often-forgotten indicator of water quality is its temperature, but all of us can do something about this kind of pollution.

Higher water temperatures can have a negative effect on human health. Increased water temperatures start a cascade beginning with an increase in algae growth and then a mass die-off of algae, which decreases oxygen levels. Algae often creates an anaerobic condition that suffocates ve Marie Vicksta has been a conservation planner with the Yamhill Soil and Water Conservation District since June 2010. She works primarily with private landowners to implement projects that improve water quality, reduce erosion and enhance wildlife habitat. In her free time, she enjoys getting outdoors to hit the trail or kayak on the river. getation and aquatic life.

Elevated water temperatures also can directly harm vegetation and wildlife by disrupting metabolic pathways, causing impairment or death. The result is particularly deadly for sensitive baby salmon headed to the ocean.

The Department of Environmental Quality and Environmental Protection Agency work together to identify streams and lakes exceeding national standards for pollutants. In Yamhill County, 19 streams are listed for too-high temperatures. Temperature listings take into account temperature needs for salmon rearing and spawning. Water temperatures that much exceed 18 degrees Celsius (rearing) and 13 C (spawning) have negative effects on fish survival. Cozine Creek, which runs through McMinnville, has had recorded temperatures as high as 23.1 C in July. Other listed rivers and streams include multiple sections of the north and south forks as well as the main stem of the Yamhill River, three sections of Deer Creek, two sections of Willamina Creek, Baker Creek and 11 other local streams.

Two major driving forces alter water temperature in streams. One factor is warming from direct sunlight or the discharge of warm water from industries. The other is how much water flows in the stream. The more cool water coming down from the mountains, or up out of a spring, the less affected the river will be by warming forces.

 What can we do at home?

Everyone can prevent higher water temperatures in streams and rivers by using less water.

Limiting our own use allows more water to stay in the watershed, reducing the effects from warming forces. In the summer, irrigation accounts for more than 50 percent of the average McMinnville homeowner’s water use.

Fortunately, easy, low-cost methods can dramatically reduce your water use.

A healthy lawn needs only one inch of water a week to stay lush and green. An easy way to get a feel for how much water you’re using is to place rain gauges or shallow cans around the yard and see how much they collect during a typical watering. Then you can customize your watering to get an inch over two or three waterings a week.

An easy way to establish your watering plan is to use timers. Timers prevent accidental over-watering and allow for watering at ideal times of the day.

Watering should be done before 10 a.m. or after 10 p.m. because it allows the water to soak into the soil and avoids unnecessary losses to evaporation. Avoiding mist-style sprinkler heads also helps prevent unnecessary water losses to evaporation.

Garden beds offer other ways to save water.

Shrubs and other groundcovers require even less water than lawns. Shrubs and groundcovers in beds are ideally suited for drip irrigation or soaker hoses that focus the correct amount of water wherever it is needed, whether to a prized rose or your garden vegetables.

Also, thick mulch on beds helps keep water in the soil.

Using native plants also dramatically minimizes the water needs of your yard.

All these measures will help you save on your water bill and permit more water to stay in the river to keep temperatures nice and cool.

 What to do in rural settings

In rural and agricultural settings, plant trees and shrubs along the banks of rivers and streams. These riparian buffers have the greatest long-term impact on water temperature, as they protect water from direct sun exposure. Buffers along the bank of streams and rivers also provide habitat for wildlife and corridors for wildlife to move.

Stream sides with adequate buffers also are more protected from the damage of natural flood events in the winter because the root structure stabilizes the bank.

Riparian areas provide the added benefit of naturally slowing down sediment and nutrients that may enter the stream through runoff. Agricultural water quality rules in Yamhill County require adequate vegetative buffers, appropriate to the site, on agricultural lands to prevent bank degradation and supply shade along streams.

When is a buffer doing its job? The recommendation is to extend riparian buffers 35 feet from the crest of the bank. Buffers consist of trees and shrubs providing adequate shade and preventing runoff of sediment and nutrients into the stream. Native trees and shrubs are often preferred because they are adapted to the climate and pressures of the Willamette Valley, and they provide natural benefits to birds and other wildlife.


Help is available

How can rural residents and agricultural producers improve riparian buffers and help lower water temperatures? The Yamhill Soil and Water Conservation District provides free technical advice on how to establish or enhance riparian habitats.

Also, opportunities exist for sharing project costs through the Conservation Reserve Enhancement Program, a federal program for establishing trees and shrubs along waterways. Oregon’s Watershed Enhancement Board awards grants for enhancement of fish habitat and other projects in riparian areas.

Water temperature is an important factor in the overall health of our environment. It will continue to be a pollutant of interest to people like us, who work to improve water quality in Yamhill County. If you have questions, please contact me at marie@yamhillswcd.org or 503-472-1474, ext. 108. I hope you will take a moment to decide how you will help cool our creeks and rivers.


Guest writer Marie Vicksta has been a conservation planner with the Yamhill Soil and Water Conservation District since June 2010. She works primarily with private landowners to implement projects that improve water quality, reduce erosion and enhance wildlife habitat. In her free time, she enjoys getting outdoors to hit the trail or kayak on the river.


Submitted photos

A stream in Yamhill County, left, could use a cooling buffer. Due to erosion concerns, a landowner installed a riparian forest along the Yamhill River, right, in spring 2000.


A biologist collects a sample. Water temperature, affected by the amount of riparian buffer, gives a critical indication of stream health.

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