Hi,

I have an oval pond (30ft x 50 ft) with island that was put in where there
used to be farm buildings. No liner and seeps away with edge erosion.

Looking at the many web sites, there do not seem to be any solutions along
the lines of my thoughts which are;

Dredge out the silt and get a max depth of about 3 foot. Build inside the
existing edge a low wall using terrmalite blocks on concrete and having a
12-15" shelf. Rounding the edges of the thermalite blocksand then 2" od
builders sand over the whole base. Cover the inside with geotextile material
and then a Firestone liner which would come up over the thermalite edges and
into an anchor trench covered with smooth round stones. Turf over and up to
the pond edge. (maybe more geotextile material over the top edges where the
turf will come? )

It is the use of the thermalite blocks on 4" concrete which I am asking if
it is an acceptable method? I suppose it is a little similar to a concrete
collar but with blocks to extend the depth? Due to the rubble in the first
18" of soil and in the pond, this should get around the issue.

Any other suggestions?

Many thanks,

Stewart