Water
Water is the most important part of Revive & Prosper because revival of nature can happen only with the help of water.
There is usually at least one water source on each map. It looks like a deep hole in the ground from where water flows.
Moisture spreads through the ground from the nearest water source and allows vegetation to grow. Moisture gets higher when rain falls and it gets lower when drought, sand storms, heat bursts, and fire come.
Moisture evaporates from the ground. When there is more vegetation like trees and grass they all slow down the evaporation which means moisture can spread far from the water source.
Water can be distributed by pumps, pipes, and sprinklers throughout an environment.
If you play on higher difficulty it's good to build water cannons that will fight fire coming from heat bursts.