ration – n. a specific amount of something, usually food, officially provided during a time of shortage

drought – n. a period with very little or no rain, and extremely dry conditions

vital – adj. extremely important

lean – adj. thin, with little excess

irrigation – n. systems for, or the process of, bringing water to plants for agricultural purposes

reservoir – n. a usually human-made lake that is used to store a large supply of water for use in people's homes, businesses, etc.