E. coli Monitoring Results through March, 2019

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FOMR’s E. coli monitoring program is made possible by the following volunteers

Jo-el Nelson and Emma Evans at the Shenandoah Valley Governor’s School

Courtney Hallacher and her students at Riverheads High School

FOMR volunteers Mike Harmon, Justin Fischbach, Joe Thompson, Bobby Whitescarver, Pete Cooper, and Joe McCue.

Here’s how FOMR measures E. coli using the Coliscan process:

1.  take a water sample from the River or stream
2.  mix 3 milliliters (ml) of the water sample with Coliscan
3.  pour the mixture into a special Petri dish
4.  incubate the Petri dish for 24 hours to allow bacteria colonies to grow
read the number of bacteria colonies that have grown in the Petri dish
6.  take the number of colonies counted in the 3 ml mixture and multiply by 33.33 to get the number of colonies that would be in a 100ml water sample

The resulting number of bacteria colonies is represented as “Colony Forming Units” or CFU.  Since it’s based on a 100ml water sample, it’s called “# CFU/100ml”. 

The current Virginia standard for recreational use is 235 CFU/100ml.  Any number greater than that is not safe for swimming, etc., and is highlighted below in red typeface.  The state standard for drinking water is 0 CFU/100ml.

March, 2019, Results

Back Creek 1  – 200
Back Creek 2  –  134
Back Creek 3  –  300 
Back Creek 3.8  – 267
Bells Creek  –  534
Eidson Creek 1  – 100
Eidson Creek 2  – 34
Middle River 1  –  0
Middle River 2  –  167
Middle River 3A  –  34
Middle River 3B  –  100
Middle River 4  –  67
Middle River 4B  –  no sample
Middle River 5  – 134
Middle River 6  – 67

Click here to see a list of where each site above is located and a spreadsheet of all results from July, 2015, through March, 2019.