Colleen, You are a hard worker and everything looks beautiful! I'm interested in how the top pond flows to the next level? In looking at your pictures, they appear slightly apart from each other. {no, they are side by side}
Did you place the liner over the edge, to the next level? {yes I did}
Also, does some of the water travel from pond to pond, via hoses? {yes, water is pumped from lower level ponds to upper level ponds and then water free flows back down spillway.
In one of your pictures, what was originally your top pond ( now your second pond) looks like it has something on the bottom...is it a bottom drain? {no drain... water just makes it way from top pond to bottom through water drops, water is pumped to top level and reaches the spill way and simply spills down. There is an overflow in bottom pond in case it rains heavy, excess rain seeps to big nearby tree...
I forgot to take a picture of how I framed that one section, where the water flows down to third pond from the top. I did place the liner over and cut away the excess, leaving lots to hang over the edge where I created a spillway. There is a gap in the top wood frame that allows the liner to hang over into next lower pond, creating a spillway, where the water drops down into lower pond.
Hope that helps a bit.