UPDATE: A friend had the wise idea to query the ranger on duty at Nisqually. I am fortunate to know people as curious as I am !
The ranger shared that “the water often is orange-red because of bacteria in the water attempting to “feed” on the iron components in it. This kind of bacteria tends to oxidize the iron creating an orange-color, but water also helps to stop the oxidizing process”
He also shared this website as a good resource for this and other questions. https://www.fairfaxcounty.gov/publicworks/stormwater/whats-stuff-stream.
What’s that Stuff in the Stream? | Public Works and Environmental Services – Fairfax County, Virginia Streams in Fairfax County support many different types of life. Fish, insects and salamanders live in many streams. Sometimes we may see things in streams that we do not recognize. Natural foam appears as light tan or brown, but may be white and has an “earthy,” “fishy” or “fresh cut grass … www.fairfaxcounty.gov
This is a natural phenomenon, most common in late winter and spring. I’ll be looking at the refuge much more closely the next time I am there for a walk. Cheers to curiosity !
A couple photos from my walk yesterday at Nisqually. Does anyone know why the water in this stagnant pond turns orange every year ?
Looks like liquid toffee! Glad you were able to get some info from the folks in Fairfax County! The first and last shots make great book ends, Bon! Good stuff!
Thanks, Mare. It’s really striking in the sun. The orange ripples made as they glide through the water are true art.
Offhand I would guess that it’s either algal bloom or clay runoff, but those are pure guesses. What time of year does it happen? Is it associated with heavy rain or snow? I’m colorblind so I may have seen this phenomenon but didn’t notice its oddness.
Thank you, Dan. It is a quite interesting phenonemon. I’ve updated this post to include the response from a knowledgable ranger at Nisqually. Cheers to curiosity !