Friday, August 8, 2014
SALEM PUBLIC WORKS STAFF WORK TO ENSURE WATER QUALITY
News Release from City of Salem
Posted on FlashAlert: August 8th, 2014 8:41 AM
Salem Public Works Department staff monitored water contamination developments in Toledo, Ohio, and Lincoln City, Oregon, with interest this week, as a toxic algae bloom restricted use of drinking water in both cities. Algae blooms are also known to occur in Detroit Lake and the North Santiam River, Salem's water source. This toxin is produced by several types of blue-green algae that are typically present in the reservoir.
The Public Works Department has maintained a reservoir and river sampling program for the last four years to monitor for algae blooms and potential toxic blooms. Staff is typically at Detroit Reservoir and on the North Santiam River several times a week during the summer months, when algal blooms are likely to occur. As a result of the monitoring program, staff has identified the presence of frequent, but low levels of algal toxins, in the reservoir this summer. During routine water sampling last week, extremely small amounts of the toxin were found in the North Santiam River for the first time this summer.
The water treatment process was changed to address the issue. Samples of the finished drinking water were taken at the same time and no toxin was found in the water delivered to Salem residents.
Public Works staff developed a different process to address drinking water treatment when substances of this nature are found in the river. The enhanced water treatment process establishes multiple barriers to prevent algae from entering the City's treatment works at Geren Island. Instead of applying river water directly to the main treatment filters, as we typically do, water is instead pumped from wells on the island and is applied to an initial filter that captures any algae that may still be present. This pre filtered water is then applied to the main treatment filters for its normal filtration process. When operating in this mode, water production is limited compared to normal operations; however, no special conservation measures are needed at this time.
There are no federal standards for algal toxins but the Oregon Health Authority follows the World Health Organization limit of six parts per billion as a guideline for recreational health advisories for water bodies and one part per billion for drinking water supplies.
Salem staff share the results of all water sampling with the Oregon Health Authority and the U.S. Forest Service. Oregon Health Authority is the decision making authority for recreational water use advisories. The Oregon Health Authority Drinking Water Program is responsible for public notifications when drinking water supplies are affected.
No sample of Salem's finished drinking water has ever been found to contain any algal toxin based on analytical test results.
Lacey Goeres, Water Quality Supervisor
City of Salem Public Works Department