Pond Boss Forums GENERAL QUESTIONS Muddy water Help Please -Our pond keeps turning brown

Hello everyone my name is Tom Ryan,
Very happy to join Pond Boss this looks like the perfect place to learn pond management.

I am hoping for some help with an issue we have been having with our community pond.
Our pond is normally very clear, but for the last 2-3 years it turns brown in the fall and stays brown until late spring plus it also has brown scum or algae floating on the surface during this time.
This issue has never happened before our pond has always maintained good water clarity all year.

Culprit or Coincidence?
On April 4th, 2020 a city water main pipe that runs parallel 20 feet from our south shoreline burst and the treated city water gushed into the pond for about 24 hours before it could be repaired. This actually happened twice when the repair needed to be repaired. lol
The gushing water was brown in color possibly due to soil erosion before it entered our pond; however, it did change a portion of the water to brown.
It appeared to stay contained to a small area of our pond 3-4 acres where it had flowed in and was only visible for a few days then the clarity became normal and remained clear all summer until fall the entire pond changed to brown with a surface scum in areas and has been repeating this cycle for the last 2-3 years. The old sandpits in our area have not been affected.

I am told the water had been tested by a local lab and all is healthy with the exception of some lake turbidity. Can it be rust or something that was in the city water lines that contaminated the whole pond? It is a large horseshoe-shaped pond not sure how it could travel to the other side of the pond. Could this be a winter-long turnover and if so why just the last few years? Should I get it retested?

If this annual issue is due to the city waterline break, without actual proof and the 2-year time that has lapsed It would probably be impossible for me to hold the city responsible.

The pond is a horseshoe shape sandpit of approximately 11 acres with a max depth of 30’
sandy bottom with rip rap rock lining 90% of the shoreline, 25+ years old.
Fishing is average LMB, bluegill, Carp, and a few crappies. We have been trying to add vegetation but with the sandy bottom, the ducks and carp seem to devour or uproot as soon as we get them planted
will take another swing this spring.

I will try to add some photos.

Thanks ahead for any advice,
Tom Ryan