Using the gerund two times in a row

Question

When you have this construct:

. . . is a key factor in the making and controlling of the water.

Should you leave only the last verb in the gerund:

. . . is a key factor in the make and controlling of the water.

Answer 1

You need to say "making and controlling".

What you have there is a parallel structure. A parallel structure is basically when you condense multiple sentences varying in only one item down to a single sentence with a list of the varied items:

I entered the marathon. I entered the decathlon. I entered the pole vault.

becomes

I entered the marathon, decathlon, and pole vault.

When you form a parallel structure, all the elements in the parallel MUST be in the same grammatical form: all nouns, all gerunds, all infinitive verbs, all prepositional phrases, etc. No mixing and matching is allowed.

Answer 2

No; the first version is correct.