Seriously? Are you kidding? Are THEY kidding? How can the two of them function in the world of reality? How many insects do they kill driving? Are they completely out of their minds? Or is it a selective thing about what can be allowed to die? They do realize that the herons and egrets feast on those tadpoles, right? as do coons, and the fish, and anything else that can swallow them...DW and DD1 were screaming for me to stop. Said there were tadpoles going down. So I pushed some "stuff" to stem the flow. Put me in the doghouse since apparently I was driving over the tadpoles.
Bruce, I really feel for you and can't imagine how you manage to stay sane and calm dealing with your situation... I think I would become "cidal"... either sui or homi And I believe they are deliberately driving you towards one or the other... Sorry man... I'd laugh but it's so far beyond funny... You must have the patience/heart of a saint.
Aside from the issues that are preventing progress, you seem to be making some. I would recommend taking the banks down some as well so they aren't so vertical. That will help slow their collapse into the pond once it starts filling again. If you have some $$ to spare, you could order a couple truck loads of gravel and cover those banks to help with erosion as well.
If you dig the current puddle down as deep as you can so the water can run down into it to "save the tadpoles", you could then clean out the deep end working back toward that puddle and let it drain back into the deep end while you finish up digging out the in-between area.