CONSERVATION is KEY - and keeping the poolside in good shape is a demanding business. Given time, the destructiveness of mother nature knows no bounds - and will over a fifty year period, gradually ruin any stream-fed fishery, as unchecked plant growth encroaches around the perimeter of the water . Sedges, weeds and reeds, unmanaged - will diminish the surface area year on year. The schematic below, shows the effect of the above process - resulting in a  de-seilting cost in the order of five figures to restore the lake to a serviceable & fishable condition once every decade. This is why regular maintenance is so important.