The beaver is an engineer and architect. He dams up creeks to make ponds. Then come fish, turtles, and birds. Sometimes, man comes, too. He learns that beavers detect flow and continue their damming behavior in the presence of flow. Too keep flooding in check, and preserve serenity of beaver pond, man devises Flow Control Device. This paper describes the device and shows a diagram on the 2nd page:
At Bond Park, the beaver pond has been temporarily drained to install the flow control. Nature incurs a temporary wound but in time, the beaver will fill in the breach. The pond will refill. The fish will return. The birds will come back. The birder will be happy again.