From the LOC Archives

“Potomac flood, Georgetown, D.C.” [created between 1909 and 1923]

Unfortunately there were multiple floods of the Georgetown waterfront in that time period, but GM is relatively confident this flood was from Feb. 1918. Check out this excerpt from a Washington Post article from 2/19/1918:

30,000 Throng Aqueduct Bridge and Neighboring Roads to Witness Wreckage Left By Weeks’ Flood

Everybody nearly was out on the Aqueduct bridge yesterday…watching the ice in the Potomac go by. There were close to 30,000 of them during the height of the ruch witnessing and commenting on the greatest flood the Capital has seen since 1889…A young woman stood on the bridge. She was filled with poetry by the maelstrom which whirled beneath her feet. She grasped her escort by the arm “Ain’t it wonderful what nature can do?” she breathed.

This appears to match up with the photo because the article describes the destruction of several boathouses near the bridge, including the Analostan Club House (Theodore Roosevelt Island used to be called Analostan Island, as well as Mason’s Island). There are a couple other photographs in the LOC’s collection of the same flood from above that show wreckage to the boathouses, so that’s why it would appear to be the same flood: