Earlier this week, I had an interesting assignment from DRBA. Someone who lives downstream from me had
reported occasionally seeing orange water in the creek. Checking a map, I noticed there is another creek
that joins mine, before feeding into the Smith River. I walked a short distance up the road to find
where this other feeder passes under the road. I found
the culvert. There were two feeders, a
wider creek coming from the left and a very narrow, very orange, creek coming
from the right. What!?
I came back the next day wearing my wading boots and carrying
water testing supplies. The water in both creeks was crystal clear, normal pH
and free of E.coli. But, WHY is the creek
on the right orange? I followed the orange
creek upstream. It turned out to be a
spring, appearing from underground about 50 ft from the road. The spring-fed, orange creek was flowing very
slowly. The top surface of the water had
a shiny sheen and was covered in orange slime.
Turns out, the orange slime is from a naturally occurring bacteria that oxidizes iron. There is an abandoned iron mine in Fairystone State Park. We can expect to find a lot of iron in our local soils. Iron-oxidizing bacteria grows in large colonies in shallow, slow-moving creeks. Something must be occasionally washing it downstream. Iron-oxidizing bacteria have been around for millions of years. It is not a threat to aquatic species. Occasionally this type of bacteria can get into wells, where it can clog up plumbing.
If you ever come across an orange creek, don't panic! Investigate and be amazed by the natural world.
- Kathy
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