Water Quality Improvement Projects
Walla Walla Watershed:
The Walla Walla
is located in southeastern Washington State in Walla Walla and Columbia counties, extending into Oregon. This drainage basin covers approximately 1760 square
miles, two-thirds of which are within Washington. The Walla Walla River
starts in Oregon, flows north into Walla Walla County, and drains into the
Columbia River. Major tributaries to the Walla Walla River include the Touchet
River, Dry Creek, Pine Creek, and
(See study area
Water quality issues
early as 1998, the Washington Department of Ecology (Ecology) discovered the water quality data for some streams and
rivers in the watershed did not meet the state's water quality standards. As a
result, these streams and rivers were placed on the 303(d) list. In 2004,
Ecology included additional watershed streams on the list. The streams have low
dissolved oxygen, too many chlorinated pesticides and PCBs, high temperatures,
fecal coliform bacteria, and pH levels.
Why this matters
These pollutants impact everyone. Chlorinated pesticides and PCBs can
make fish unhealthy to eat and can build up in our bodies and lead to health
problems. High levels of bacteria can make us sick. Temperature, pH and
dissolved oxygen can create a difficult or impossible environment for fish to
live in, which can reduce recreational fishing opportunities and further harm
endangered or threatened fish.
What was done
Ecology began a water quality improvement project (also known as a Total
Maximum Daily Load or TMDL) in the watershed to bring watershed streams and
rivers into compliance with state water quality standards. Due to the size and
complexity of the Walla Walla watershed, Ecology developed four different TMDLs
in the watershed:
- Chlorinated pesticides and PCBs: Chlorinated pesticides and PCBs
are chemicals that are recognized as known or possible human carcinogens.
Although these chemicals were banned in the U.S. in the 1970s and 1980s,
they are often called “legacy pollutants” because they persist in the
environment for many years.
- Fecal coliform bacteria: these bacteria are found in the feces of
warm-blooded animals. When found in bodies of water, fecal coliform can
indicate the presence of other disease-carrying organisms called pathogens.
People swimming or playing in water can be exposed to pathogens when they
enter the body through small cuts, abrasions, mucus membranes, or
accidentally swallow water.
- Temperature: When water temperatures are too high, streams can
become uninhabitable for fish and other aquatic animals. Many salmon and
trout species may suffer decreased spawning success and even death when
waters are too warm. In addition, the warmer the water, the less dissolved
oxygen it can hold.
- Dissolved oxygen and pH: Dissolved oxygen (DO) is necessary for
fish and plants to breathe. DO is needed to help decompose organic matter in
the water and bottom sediments. It is also necessary for other biological
and chemical processes. pH is a measure of how acidic or basic the water is.
pH affects the chemistry and chemical reactions that take place in the
water, such as the solubility of nutrients and metal compounds.
Status of the projects
The Environmental Protection Agency (EPA) approved all four TMDLs by August
2007. In addition to working on these TMDLs, Ecology and the Walla Walla
Watershed Planning Unit's Water Quality Subcommittee continued their partnership
to write a water quality implementation plan. The implementation plan guides the
work that is planned to improve water quality. The plan was completed in
December, 2008. Over fourteen organizations committed to help improve water
quality by educating the public, restoring native trees and shrubs along
streams, reducing pollution in stormwater, and installing off-stream water
troughs and fences to control livestock. The Water Quality Subcommittee
prioritized streams in the watershed where work to improve water quality should
begin. Ecology staff are currently providing technical assistance and working
with organizations in these prioritized areas.
The following documents contain more information about the water quality
problems found in the watershed and the activities that will be used to improve
water quality (Note: unless otherwise specified, the following
documents are Ecology publications):
Walla Walla Watershed PCBs, Chlorinated
Pesticides, Fecal Coliform, Temperature, pH & Dissolved Oxygen Total Maximum
Daily Load: Water Quality Implementation Plan.
Chlorinated Pesticides and PCBs:
Fecal Coliform Bacteria:
Dissolved Oxygen and pH:
Walla Walla River Basin Fecal Coliform
Bacteria, pH, and Dissolved Oxygen Total Maximum Daily Load: Supplemental Study
In January 2006 the Washington State Department of Health issued a fish consumption advisory for Northern Pikeminnow and Carp in the Walla Walla watershed.
More information about this fish advisory is available on the
Washington State Department of Health website.
In 2000 and 2002 Oregon DEQ analyzed the entire length of the Walla Walla River. Ecology used Oregon DEQ’s assessment to develop a temperature TMDL for the
Walla Walla River in Washington. For information about that analysis please
Oregon DEQ’s Walla Walla website.
During the summer of 2002, Watershed Science LLC of Corvallis, Oregon used
helicopters mounted with thermal infrared radiometry (TIR) equipment to take a
“picture” of the heat radiating from the water. This data provides an overall
picture of the watershed temperature conditions. To learn more about the
helicopter survey, please see Water Cleanup
Plans: Taking the Temperature of the Walla Walla Watershed.
Walla Walla County
WRIA 32: Walla Walla
Watershed Information (Environmental Assessment
Program web site)
Back to top of page
WRIA: #32 (Walla Walla)
Walla Walla River and Tributaries
Chlorinated Pesticides and PCBs
pH and Dissolved Oxygen
# of TMDLs:
All four TMDL reports approved by EPA.
Has an implementation plan for all parameters
Department of Ecology
4601 N. Monroe
Spokane, WA 99205