Tags: E-Coli | pollution | Thornton Creek Watershed | water quality | WQI

As an urban watershed, Thornton Creek has all the problems caused by being in a population center. Working in teams, volunteers regularly sample creek water in the watershed with the intent to discover levels and locations of pollution. With this information and the help of Seattle Public Utilities, together, we may be able to reduce the levels and make the creek healthier.

E. coli bacteria are present in the creek. These can be a health problem for anyone that encounters creek water. We know that children will play in the creek so it is even more important to understand the levels and locations where higher amounts of E. coli could be present. E. coli can be introduced from human or animal waste. There are several possible sources. A main concern is side sewer incorrect plumbing issues and broken lines. Also human activity around the creek like encampments or RV discharge can cause high levels. Animal waste for example from dogs is also a concern. By analyzing for E. coli at many locations on a frequent basis we will be better able to focus on the problem areas.

We currently have a Community Scientist monitoring group of 30 folks. We also have students involved. We are sampling on a biweekly basis for E. coli at 11 locations along Thornton Creek. These locations were shown to be the higher ones for E. coli based on data obtained from weekly sampling of over 20 locations the previous year. Three schools are monitoring seven locations on a weekly basis when school is in session. We are using a gel scan kit that differentiates between E. coli and other coliform. We are also starting a storm water analysis program to determine metals and anions at PPB levels.

Our initial sampling once a week at over 20 locations has pinpointed 3 areas along the creek or its tributaries that are unusually high for E. coli. We will be focusing on these to determine possible sources. We have also found that when the beaver dams on the south fork are broken that a significant E. coli is released into the creek. We have discussed this with SPU and they are changing their behavior on dam breakage.

We also have found high levels E. coli downstream from encampment areas. Education, waste removal systems and removal of encampments near the creek could reduce this problem.

In some areas we see higher levels of E. coli during rain events. This could be indicative of animal waste washing into the creek. We are starting a program to supply mitts for mutts dispensers in these areas to encourage animal waste removal.

Storm water contamination of the creek is also a significant problem. It has been linked to salmon pre-spawn mortality. These contaminants are at extremely low levels so we will be doing analysis using analytical techniques that are sensitive to the PPB (Parts Per Billion) level. Initially we will focus on Copper, Zinc, Phosphate and Nitrate. We will be sampling the actual storm water coming from the roads before it enters the creek. This work is just beginning.