I think I would have started 0n the far side so that I had an intact escape route. Good for you to be out taking part in doing for the environment ... Mikie
If I am not mistaken it looks like the beaver lodge is visible on the right side of the pond. I'd be visiting that to give them something to do before getting back to working on the dam.
unless he digs a narrow deeper trench in a spot, water stops flowing as soon as it hits the highest point. I don't know why people don't dig out a spot lower.
Beaver removal is the only answer to your problem. I don't understand why people are so soft and tender hearted as to not solving the problem. Yes others will move in and you have to take action again but nature isn't nice.
You did it the hard way they will have it plugged up in a week or so. Next time just put a couple lbs of tannerite and shoot it you'll have more views on RU-vid. And the shockwave will scare the beavers off funny how that works.