Question

why did the land have to be cleaned before the reservoir could be built?
so the reservoir could hold a lot more water
so the reservoir water could be used in toilets
so the reservoir water would not have germs in it

Explanation:

Cleaning the land removes organic matter, waste, and contaminants that would introduce harmful germs into the reservoir water once it is filled. The other options are incorrect: clearing land does not significantly increase water storage capacity, and toilet water use does not require pre-construction land cleaning as a specific prerequisite.

Answer:

So the reservoir water would not have germs in it