Well she was located in a "ditch" that runs through a culvert under a trail in the bottomland forest. She was just basking in the dappled sunlight while sitting on a mud bank. She then slithered into the water and swam out of sight (after noticing us). However, on numerous occasions we've seen several cottonmouths at various locations at the nature center (on the board walk, amid fallen branches 2-3ft above the ground, in the water, under logs, etc).
Also there were several raided turtle nest and given the "rough" estimate of the egg remains (12-15 eggs per nest)they were likely from Trachemys scripta.