There are some pretty large Eastern Red Cedars there. The dam is rather large I think. It's about 15 to 20 ft wide.

The contractor didn't say anything about it. He also didn't tell me I need to plant grass on the dam, but I guess he figured I should know that because it's pretty much common sense (though it didn't occur to me until reading here).

I highly doubt he'll offer any form of warranty. He got his money so he's done.