Flexi Says: A reservoir of water, such as a lake, will stay at the same level if the amount of water coming into the reservoir (inputs) is equal to the amount of water leaving the reservoir (outputs). For example, the inputs into a lake include precipitation, runoff, and streams that add water to the lake. Outputs include evaporation and human uses of the water. Conservation of water resources is important because in many areas people are using the water from reservoirs faster than it can be replaced. In such cases, the water level in the reservoir will decrease.
