The soil was like powder due to the root system. It took some work to work the roots and walls.
Started toying with a wall for the stream, it didn't pan out - looks wise.
The 4 inch bottom drain was plumbed in to the 275gal settlement tank. 1 1/2 pvc runs out by the shed from the tank to flush the fish poo. Also a 3/4 pvc line was ran for air supply to help draw in crud into the drain.
This is my DIY filters - 55gal drums - sand and gravel filters.
gravity return roughly 18 inches from pond bottom (TPR)
I used some old carpet to protect the liner, I also plumbed in a walmart pool, skimmer. Opposite side of the skimmer you can see a return from the sand and gravel filter.
the lower port under the skimmer is another return (TPR) and above that is a mid level pickup
liner in and getting filled
Within 20 minutes of turning on the pump it poured rain and well the water quailty got nuked. The pump is a es4500 (gph)
worked the wall for a small stream, ran 3in pvc pipe out to the filters min headloss.