Portable water fountain
US D573391 S1
The ornamental design for the portable water fountain, as shown and described.
FIG. 1 is an isometric view of a portable water fountain showing my new design; the broken lines are to show the environment and form no part of the claimed design;
FIG. 2 is a top view of the design shown in FIG. 1; and,
FIG. 3 is a side view of the design shown in FIG. 1.