 The saddle dam was built of earthen fill, and reinforced on its lakeside by gravel and riprap.In spite of a four-week work delay caused by flooding, the Douglas Dam was completed and its floodgates were closed on February 19, 1943, 382 days after the construction began; this set a world record for a project of its size.Its first electric generator went on-line on March 21, 1943, and its second one went on-line on January 1, 1944.