The Obvious
It may seem obvious to most people that the amount of water pumped from the ground by an irrigator is related to how much rain fails. However, you will often hear someone complimenting the irrigators for how much they have done to reduce usage, how they are doing their part. They should actually be thanking the good Lord. Farmers pump the water they need, nothing more. It is too expensive to waste water. The amount of water that was pumped in the last three years was down because there was more rain at the time the crop was growing. If there is less rain in future years when the crop is growing, there will be more water pumped and that doesn't mean the farmer is or isn't doing his part to help. The amount of water needed is controlled by the weather.