(sorry this post is several years too late) Morton Lake - wow. When I was a kid I had a map of Richmond from the 40's that showed Morton Lake, but the lake itself was long gone. However, the broken concrete dam was located right under the east side of the N. 17th St bridge, between N. J St and New Paris Pike. The middle section of the dam was gone but either side seemed fairly intact. OK, this is how it was when I was in high school in the late 60's. I don't know if any traces of this still exist. There are some little streets called Cherry & Maple north of N. J that fronted the lake. The houses were more like cabins and might be pictured on the postcards.
I once took a drugstore delivery to an old lady who lived on one of these streets and she had a big painting in her living room of the lake in its heyday, with the paddleboat & other little boats and picnickers on the banks. She told me how nice it used to be then. Apparently the lake was hard to maintain and the neighborhood began getting "trashy", so according to her the city solved the problem by breaking the dam. A friend's dad said the dam broke in the '37 flood.
Morrison-Reeves has a picture or two.
Here's a link to the Morton Lake story. Such tragedy! Such gore! such a farce!