I have installed the liner of my 5m x 4m wildlife pond in Wiltshire,
England. I have designed it to have a metre-wide very gently sloping beach
all around and a shelf at about half depth.
Because the pond is quite large, and being a wildlife pond needs to be
copiously stocked, I will need to put in an awful lot of plants. I
therefore, except in the deepest water, will not have time to put each plant
in a basket and so will plant directly onto pebbles on the beach and shelf.
I have been advised that to prevent the pebbles migrating down to the
deepest part of the pond I should mortar them to the butyl liner. Or at
least mortar a dam of them along the lowest edges of the shelves.
As a novice to ponds, I am reluctant to do this which can't be undone if it
is wrong. For instance, once the mortar has set I will never be able to
adjust, move, repair, or whatever I might need to do to the lining.

Anybody any views on this?

many thanks

Davy