Canyon Lake, Texas
If you are looking for a nice lake with clean, cool water, Canyon Lake is one of a number of places in the Texas hill country that is perfect for cooling off in the heat of summer. There are a number of parks around the lake where you can camp, picnic, hike, and swim. The rocks provide the perfect spots for laying out in the sun, or setting up a picnic lunch.
My family and I went to Canyon Lake this last spring, when the weather was still too cold for a dip. Nevertheless, the lake, and the Guadalupe River it feeds, provided a perfect scene for landscape photography.