Drowned Lindsey Lake
The original Lindsey Lake is seen in the foreground of the photo below, though the whole architecture of the river through here has changed since this photo was shot, and the old, natural lake / slough, really, no more, just a small man-made lagoon created by the railroad tracks.
Not exact, but very close to the same location of the real photo postcard by Eddy.
All of the land visible on this map north of the train tracks and highway is now gone. However, it is still there in the Eddy photo above. Lindsey Lake is also, essentially, gone.
The photo below shows that the lake was essentially a slough, and it's size varied greatly with the water levels on the un-dammed river.
Below, piles and the small islands left behind by the flooding of the lake.
The current Lindsey Lake, formed by the railroad tracks, is small compared to its predecessor, which stretched from west of Cabin Creek to Viento Creek (though west of Viento's current confluence with the Columbia).
Looking at the old photos, most of the land around the lake, north of the highway, would be underwater when the river was running high.
Above, a light is out in the river now warning of the sandbars (sometimes quite visible but, to my knowledge, always remaining underwater) that mark the old river bank at Lindsey Lake.
The photo below is very interesting because is captures an interesting moment in time. Obliviously, the dam has been built, which has flooded the original, natural Lindsey Lake, but the railroad tracks have not been relocated yet, creating the new Lindsey Pond. The little tuft of trees on the north side of the highway is the Lindsey Creek delta, and the side road is the same road the HCRH State Trail will follow to the old parking area under Lancaster Falls.
Faint, but present, are some sand bars that used to be the north shore of the lake. I can't tell if they are above the water or not in this image, and I've never seen them above the water...
"Baldock’s faster, straighter version of the Columbia River Highway began to emerge in the 1940s"
#5626 - Columbia River Highway, June 1954Tom Kloster. WyEast Blog: Warren Falls Mystery… Solved! http://wyeastblog.org/2012/01/31/warren-falls-mystery-solved/
"Lindsey Pond is separated from the Columbia by a levee for the Union Pacific Railroad tracks."
Lyn Topinka. The Columbia River: A Photographic Journey. http://columbiariverimages.com/Regions/Places/lindsey_creek.html