At two in the afternoon of August 25, 1916 the cofferdam that separated the dry ditch of the then recently rendered Montalke cut, was broken and the waters of Portage Bay were released to hasten the work by eroding the dam and filling the cut. Dredging followed here at the west end the cut and then at the east end of the cut Lake Washington was slowly dropped about 9 feet to the level of Lake Union through a dam, which was then removed for some more dredging, this time at the east end. The lowering of the big lake through the temporary dam continued from Aug. 28 into October.