Doing more research, I'm changing my answer to both of them being different types of 'long-toed water beetles'. I was watching videos on the click beetles, and they seem to be much larger than the ones in the photo. The first very much looks like a Dryops.
The long-toed water beetles mostly float on the water and feed on aquatic insects.
The top photo is likely of a Metallic Wood Boring Beetle of the family Buprestidae and the bottom photo is likely a Long Horn Beetle, family Chrysomelidae. I Have never heard of Buprestidae emerging from a lake but they are not the best fliers so they could be blown into the water.