LiF has to be the very worst pack of rules ever released for WiF.
One of Rommel's many abilities was to remove all rivers within 5 hexes or so. Very balanced.
I just looked it up - you were playing it wrong. The ability only applies to units in his hex. It is still powerful, but not as uber as you made it out to be - more like a free engineer. He can also convert a 'R' into an 'S' and units advancing with him have an extra movement point if all defenders were disorganized.