Looks like a beautiful place with a nice dock and LOTS of trees. Although trees on the dam is not recommended. Do you have any vehicle access to the dam?

You said the pipes are galvanized - are they the corrugated "culvert" style tubes? If so they have done well to last 50 years. Perhaps post photos of the water entrance and exit? And measure the height of the vertical pipe - inside and outside.

During a dry spell when there is no water going into the pipe at the surface, there should be none coming out below the pond.

Its good that a dam failure wouldn't be a risk to life/property. Its probably unlikely anyway. More likely to develop holes at the 90 degree joint and leak profusely until the pond is nearly gone. Best start a fund for what could be an expensive repair.

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