These are the secrets harbored for more than 100 years by a miles-wide reservoir outside of Seattle , Washington . Lake Tapps , which was flooded in 1911 to power a hydro-electric dam , swallowed up four and a half square miles of countryside , including an old railway line and parts of a forest . The images , taken last week by the Seattle Post-Intelligencer , also shows discarded items which have been lost in the lake , which is now used for recreation . Scroll down for video . Revealed : This old wooden railway trestle was unveiled by a draining operation at Lake Tapps , near Seattle , Washington . Emptied out : Local authorities started emptying the lake to enable repairs to be made to a nearby dam . In usual conditions the above homes jut out onto the water . Authorities in the Seattle area drained the lake this winter to relieve pressure on the nearby dam , which had developed a crack . The lake was first formed when the Puget Sound Energy energy company filled the area with water to generate electricity . It stopped producing power in 2009 and has been used for fishing , boating and other waterborne activities since . The maintenance project has now been completed , according to Bonney Lake Courier-Herald , and the lake is being refilled . The process is expected to be finished at the end of May . Abandoned : Bits of junk , and items like this CD , were also uncovered by the lake-emptying project . Underwater forest : These tree trunks have been sitting under the water for the 104 years since the area was flooded . New use : The lake has n't been producing hydro-electric power since 2009 , and is now just for recreation . Normally : Pictured above is Lake Tapps as it looked before the draining operation .
Lake lake , near Seattle , was created by electricity generation in 1911 . Four - and - a - half square miles were submerged to power non - electric dam . Authorities recently flooded lake to repair dam , exposing lake bottom .