Unfortunately I tossed the drawings a few months back. Regardless I deviated a bit from the design when I started the build.
The external pumps inlet is downflow of both the coarse/fine mechanical filter pads as well as the settling chamber.
Both the Koi pond and the Duck pond are above...
I have an integrated setup where the duck pen, duck pond, koi pond are connected. All are pond lined. Total volume of the whole setup is ~2000g. Water from each flows to a below grade sump and an external 3000gph pumps water back to each separately via a spaghettis nest of valves and pvc pipe...