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Drought Impacted Summer Water Quality

The water quality assistant above shows the foamy water and the meter confirming a high concentration of dissolved minerals and solids in the Park water on August 20.

The dry conditions over the summer officially landed Pella in the category of severe drought. How did this impact the water quality in Big Rock Park? By the first week in September, much of the creek had dried up and what was left was low on oxygen, high in minerals, and testing positive for harmful bacteria, including E. coli.

You might be curious about how the water is tested.

The high mineral content is detected by a meter which measure conductivity.

Bacteria testing is a little more complicated. The first step is to simply see if harmful bacteria are present using bioactive paper. This paper has been around for about ten years and can give a quick yes or no answer to indicate if harmful bacteria are present. It was developed to meet the immediate need to know if water is contaminated or if it is safe for swimming.

The first area of the park creek to test positive for bacteria was the entrance. By August, the area near the rock was also testing positive using the bioactive paper, as shown below. Similar to a covid home test, two lines are a positive test!

A follow up test, requiring incubation, was done to see if E. coli was present. Coliform bacteria are common in the soil but E. coli comes mostly from fecal matter. (Here's a little more about E. coli.)

Here below are some test results, confirming that E. coli is present. The first photo is the before and the second is after incubation, with the orange color being a positive indicator. The third photo is a second test which was used to determine how high the bacterial count is (before) and the forth shows the color after an incubation period. These water samples were taken from the park entrance area.

The tests confirmed E. coli at a level of around 1 colony forming unit per milliliter. This is slightly higher than what is recommended for swimming but below the danger level for non-swimming. It indicates that the water is vulnerable to contamination to disease causing pathogens. If you visit the park and come into contact with the water, wash your hands before eating or touching your face, especially during the dry summer months. And although no one is sure how the wildlife in the park is affected by E. coli, (they could be the source of it) you shouldn't let your dog drink the water.

We are grateful to the Pella Community Foundation for the funds for the water quality testing. (

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