REPORT BLUE-GREEN ALGAE
In the summer of 2008 an outbreak of toxic cyanobacteria (aka blue-green algae) resulted in a public health advisory on the Tualatin River. The source of the outbreak was traced to a discharge of muddy water from Wapato Lake near Gaston (see article).
Though not expected, there is a possibility of another outbreak this summer. River users are urged to report sightings of floating mats of algae to TRK and to Oregon's Department of Human Services.
Exposure to blue-green algae and cause skin reactions and ingestion of the toxins can result in serious illness or death. In 2009 four dogs were killed by blue-green algae exposure on Elk Creek near its confluence with the Umpqua River.
If floating mats of algae are seen, people are advised to stay out of the water and wash off any exposure. Take special care to keep children, pets, and livestock out of the water. Water contaminated with blue-green algae should not be used for irrigation because crops can be contaminated and spray of the toxins are a serious health hazard.
Photos of blue-green algae from the 2008 outbreak on the Tualatin River are shown here to help you identify any outbreak.
DEQ REPORTS THAT BLUE-GREEN ALGAE THREAT FROM WAPATO LAKE SUBSIDES
Avis Newell, DEQ Tualatin Basin Coordinator reported on July 20 : Data were downloadedfrom the USGS probe located in the Wapato Canal, July 19, 2010. It is clear that the bloom activity indicated by both chlorophyll and cyano-pigments has decreased significantly.
Also, the canal below the pumphouse, and thus directly behind the outlet, is dry. The small pump is turned off. The small pump had been running the last few weeks to get the water level low enough to access stop logs in the canal. The larger, damaged pump is now more accessible, and work is underway to repair the larger pump.
The USGS will be removing the probe this week, as it is needed elsewhere. At this point, the algae blooms and water quality have been reasonable at the canal site for a while, so the threat of a downstream bloom is low, and it appears the threat of a bloom at Wapato is low as well.
Weekly samples will continue to be taken in the canal area, and we will still be watching the water quality probes along the Tualatin for signs of bloom activity.
PRELIMINARY WATER QUALITY DATA FOR WAPATO LAKE DISCHARGE POSTED ONLINE
Pumping this spring to drain Wapato Lake has gone on beyond the April 30 deadline (see story below). As required by the Wapato Lake Water Quality Management Plan, water quality monitoring of this discharge is being done by U.S. Geological Survey and the Joint Water Commission. Data are posted here (link below) from the USGS continuous monitor that
is installed at Gaston Road just downstream from the pumphouse.
However, please be warned that those data have NOT received the
normal amount of quality assurance that even USGS provisional data
on the Internet get. Because those data come straight from the
monitor, USGS has not had a chance to delete obviously bad data or
correct for biofouling effects and instrument drift. Also, the
chlorophyll and blue-green algae probes have not been officially
calibrated to lab-generated comparison data, so those data should
only be used in a relative sense -- trending up or down; do not
use the absolute numbers to make decisions. The data are a step
below provisional, and the values WILL change upon final workup.
Please read USGS provisional data disclaimer.
CLICK HEREto download preliminary water quality data from USGS Gaston Road monitor as an Excel spreadsheet. Please read the USGS provisional data disclaimer.
Further Reading
2008 Water Quality Impact Report
Coordinated Agency Response Avoids Repeat of Cyanobacteria Outbreak
In February 2010, Tualatin Riverkeepers informed water and natural resource managers of a potential threat to river water quality that required a coordinated, collaborative response. The Wapato Improvement District (WID), which manages a large dike and pumping system in the upper portion of the watershed near Gaston, lost their primary pump due to a mechanical failure. Under an agreement with the Oregon DEQ, WID uses the pump to drain the Wapato Lake area prior to April 30 each year in order to protect water quality in the Tualatin River. Given limited access to the pump and high water levels, WID was not able to assess the extent of the mechanical problem and facilitate the timely repair of the facility.
Water managers are working together to assist the WID to protect water quality and reduce the risk of an infrastructure failure similar to what occurred in 2008. In 2008, a WID dike failure released warm, algae-laden water to the Tualatin River during May and June that impacted the downstream drinking water plant, agricultural irrigation system, local industries, water quality and resulted in a State-issued public health warning for the river.
A collaborative solution
At the request of the WID, Clean Water Services is coordinating the response to this water quality issue on behalf of the Joint Water Commission, U.S. Fish and Wildlife Service, Tualatin Valley Irrigation District and the Special Service Districts Association of Oregon.
On March 16, Clean Water Services worked with the U.S. Army Corps of Engineers to secure two, large trailer-mounted pumps to assist with the draining of the Wapato Lake area. The COE pumps began operating 16 hours a day on March 18. In addition, Clean Water Services installed one of the District’s portable pumps on March 16 and secured an additional pump from the City of Portland Bureau of Environmental Services which was installed on March 30. These pumps, together with the existing WID pump, operate 24 hours a day. Clean Water Services is continuing to work with regional partners to secure additional pumps to assist with the project.
The Joint Water Commission is assisting Clean Water Services to monitor water quality in the lake and the upper Tualatin River. Water managers continue to work closely with DEQ to coordinate the project.
Information & photo provided by Clean Water Services