Wiktionary
n. A dam constructed across a river or stream to raise the water level so that it can turn a millwheel; also, the millpond so created.
Wikipedia
Mill Dam, Shapinsay is a wetland in western Shapinsay, in Orkney, Scotland.
This water body was not shown on the 1840 survey map of the island, since it is a man-made creation from a damming in the 1880s. Mill Dam is fed by a stream flowing from the north that rises on the western lobe of Shapinsay. The pH levels of the outflow stream of Mill Dam are moderately alkaline, in the range of 9.18. The Mill Dam wetland is a significant bird habitat and is owned and managed by the Royal Society for the Protection of Birds.
Usage examples of "mill dam".
But now he was not even at home to do anything before the thousands upon thousands of tons of water from the Minturn reservoir swept through the Red Mill dam.
The Potomac was calm and flat, almost oily, like the pond behind a mill dam.
The river, now within its banks, rushed noisily over the mill dam.
The stream rushed out of the pool below the mill dam, a creaking wheel turning endlessly in its wake.