Word order is always tricky to explain, but here I don't "feel" what's wrong with "sok allat a vizhez megy" (as opposed to the correct answer : a vizhez sok allat megy". Any clue to "understand" the structure ?
Your version emphasizes the water, as opposed to going to the water. You are saying, many animals go to the water and not to the orange juice, for example.
If you place a location or some similar non-subject word in front of the verb, it usually has a good reason. Emphasis!