The brown dog is running in the water.
The dog is at the beach.
Water is present in lakes and ponds too, not only on a beach.
exists e1 s1 x1 x2.(n_water(x2) & n_dog(x1) & a_brown(s1) & Theme(s1,x1) & in(e1,x2) & Actor(e1,x1) & v_run(e1))
exists p1 x1 x2.(n_beach(x2) & n_dog(x1) & at(x1,x2))