Pond Boss Forums GENERAL QUESTIONS Water chemistry Phosphorus and forest fire?

I am part of an organization that has a series of 6 small ponds on a trout stream that have maintained healthy fish for over 40 years. Our biggest problem has been Eurasian Water Milfoil and filamentous algae but we have been able to keep both under control using a diquat and chelated copper mix. This year a new fish manager decided to bring in a professional pond management company for consideration of taking over management of the lakes. The company requested that the pond water quality be tested and they would do it for a fee. Three lakes were tested, the uppermost, the middle lake and the lowest lake. All looked good on the lower two lakes but The uppermost lake showed an excessive phosphorous level along with out of acceptable range nitrogen-phosphorous ratio. There was a small forest fire immediately above that lake in 2019 which probably produced an increase in runoff silt combined with ash this past spring. Could this explain the high phosphorous unique to this lake. BTW: even with the high phosphorus, fishing was good in the lake this year and they showed no sign of stress. The tests were done in early October of this year.