Gifford monk – not the fat jolly kind with the funny haircut, but the concrete pond outlet kind.
A monk is a very old design for a pond outlet structure. It is believed to be so named because abbeys were the first places to keep fish in ponds for food and they developed the design.
Once the timber boards are put in across the opening the pond will start to fill up. The big advantage is that they don’t block easily and you can lower the water level slowly if you need to, just by taking one board out at a time until the pond is drained again.
This is one we are in the process of building in a pond near Gifford.