An update on my pond digging. 
Now flooding up. I will be able to set the final height of the water, next spring, when I place the culvert. I'll set the height about a foot below the island.  
 
The big pond will flow into another pond , also with an island. 
 
 
 
 
This is the pond where I got stuck, now almost finished. Once again I will control the height of the water with the culvert.