When fecal coliform bacteria show up in a surface water sample, how do analysts know where or even what species it came from? This is a question Pierce County planners and their consultant asked recently as they were updating the 1991 Clear/Clarks Creek basin plan.
The proposed 2005 plan will be presented to the county Planning Commission at a public hearing at 8:30 a.m. Sept. 27 at the Pierce County Public Services Building (Annex), 2401 S. 35th St., Tacoma. The hearing will be preceded by an informational open house Sept. 21 at the Summit Library, 5207 112th St. E. from 4 to 8 p.m.
Among other issues addressed in the plan, such as stream channel erosion and invasive vegetation management, is the question of fecal coliform bacteria levels in Clarks Creek system surface waters and where they’re originating from. Researchers hired by the City of Puyallup used a method called microbial source tracking to identify the sources of fecal coliform. DNA taken from water samples was compared to a library of 50,000 source samples to determine the general category of the source.
It was already known that Swan Creek, Clear Creek, and Clarks Creek are on the state’s list of polluted water bodies due to high levels of fecal coliform bacteria. These bacteria are present in large numbers in the feces and intestinal tracts of humans and other warm-blooded animals and can enter water bodies from human and animal waste. Fecal coliform are also used as an indicator organism to signal that viruses or other pathogens may be present in the water. The microbial source tracking yielded the surprising discovery that humans are not the primary source of fecal contamination in this drainage system.
In samples analyzed from several locations, birds and rodents were often the highest bacterial contributors, followed by dogs and other canines and finally, humans. Bacteria traced to other animals was detected at lower amounts, including cats, deer, raccoons, and cows.
County planners used this data when preparing the updated Clear/Clarks Creek basin plan, which considers bacterial levels and numerous other surface water issues in the basin and proposes projects and programs to alleviate them. “It’s challenging to manage surface water and drainage needs as the surrounding community changes and grows” said Marsha Huebner, Water Programs Division senior planner. “The population in this basin increased by more than 17,000 from 1990 to 2000 and, even more significantly, the amount of pavement and other impervious surfaces is now approaching 25 percent. We develop these plans in order to channel limited resources toward the most urgent needs, in a way that integrates long-term goals.”
The updated plan contains $65 million dollars worth of proposed improvement projects and programs to be implemented by Water Programs over a 10-year period as resources allow. An analytical model was used to identify the most effective water quality improvement actions basin-wide. This led to the development of an all-inclusive approach for addressing basin surface water deficiencies, including programs for flood control, water quality monitoring, invasive vegetation and sediment management, streamside and wetland restoration, and standardized maintenance procedures. Over time, the programs will reduce the need for additional capital projects and maintenance.
Members of the public can learn more about the Clear/Clarks Creek basin plan at the open house or view copies on file at the Summit, Puyallup, Swan Creek, South Hill and South Tacoma libraries. Written or oral comments on the proposed plan may be presented to staff at the Sept. 21 event or to the Planning Commission Sept. 27.
The Clear/Clarks Creek basin plan is one of 10 basin plans for unincorporated Pierce County. Plans for Gig Harbor, Clover Creek and Muck Creek have been adopted previously by the County Council.