Solution:

• Yield is the volume of water which can be withdrawn from a reservoir in a specified period of time.
• Water supply reservoir is designed for drinking water purposes and a higher yield can reduce the time of distribution.
• The yield whose value is smaller than the safe or guaranteed yield is known as design yield.
• In the case of reservoirs used for irrigation purposes, the design yield may be taken slightly more than the safe yield as crops can tolerate some deficiency of water during the dry season.