Lynette-

From the anterior parts of this mayfly nymph visible in your photo, I believe it to be Drunella doddsii. However, in the future, I would recommend you take along a white jar lid or something similar, so you can photograph aquatic insects fully submerged in water. This will greatly enhance one's ability to identify them, as the body appendages (like gills and tails) will show themselves, as opposed to sticking to their body or the surface on which they rest.

anyway, Ephemerellidae