16 Mar 2017

Pokegama Dam Slurry Trench Project, Grand Rapids, Minn.

Pokegama Dam was constructed in 1884. The main embankment was constructed with a pervious, rock and clay-filled timber structure core and covered with sandy material. In 1941, a sheetpile wall was installed upstream of the timber core to minimize unwanted seepage (flow) through the embankment. The existing sheetpile wall has been effective at controlling seepage, but its overall condition is currently in question. Without an effective seepage barrier, the water levels could rise throughout the embankment causing downstream slope instability, which would threaten the integrity of the dam.