Bruce, many of the smaller ponds here are built the way you have described. We have liners available, but the smaller ponds almost always use concrete slabs with block walls. However, almost all are above ground, eliminating the need for excavation. Many build in drain pipe and some use common wall construction and build several ponds.
Here they cover the bottom with a few inches of top soil to get a culture going and stock within a couple of weeks of completion.
