Critics at the time and later saw The Flood Gate as a high point in the evolution of Watson’s style. A.Y. Jackson (1882–1974) reportedly told Watson that the canvas belonged in the Louvre, and Jackson’s fellow Group of Seven member Arthur Lismer (1885–1969) characterized it in the 1930s as “an old master” painting: Canada’s finest depiction of a rural landscape.

Its subject and composition—the scene is of a man taking pressure off a dam by opening its floodgate during a storm—underscore Watson’s favourite theme of nature’s power and majesty.