Mark,

Before even putting liner, I'd say put underlayment (felt kind), it will
help reduce any adges of the roots or rocks in the dirt which may puncture
the liner later. Once the water is filled it put a lot of pressure on the
liner.

Also, I've put gravels in my pond and stream. Put it along with the rocks.
I've put mix of one and two head size rocks around the pond on every shelf
and gravel on the bottom and plant shelvs. Except for lillies all my plants
are without pot in the water.

All the best.

- AJ
"mark" wrote in message
om...
I am building a waterfall. Do I cover the hill with liner before
placing rocks? Any tips on how to do this and on placing rocks
appreciated as this is a first time project.