In March 2021, multiple Creek Watch volunteers reported a white substance on rocks along the edges of Wissahickon creek. What was it and where did it come from? Pollution? Weird bacteria?
In early March, there was still a lot of snow on the ground, and as days got warmer stream levels were high from lots of snowmelt. During mid to late March when Creek Watchers were visiting their sites, water levels in local streams had dropped and myseterious white deposits were left behind on streamside stones. When water levels drop in streams, it is common for silt, minerals, or even pollen to be deposited on rocks that are newly exposed during low water levels.