Multireservoir multiyield model with allowable deficit in annual yield

Yield models produce reasonable reservoir designs with release reliabilities near targets. This paper extends the basic yield model and presents a multiple-yield model for a multiple-reservoir system consisting of single-purpose and multipurpose reservoir. The objective is to achieve prespecified reliabilities for irrigation and energy generation and to incorporate an allowable deficit in the annual irrigation target. A single-reservoir yield model illustrates how a single-yield problem can be converted to a multiple-yield problem that represents the same irrigation deficit criterion while maintaining the desired reliability. The yield model is applied to a system of eight reservoirs in the upper basis of the Narmada River in India. The results are analyzed for four cases. As the desired reliabilities for yields can be prespecified for different purposes by consideration of an allowable deficit in annual yield in a multiple-reservoir system, this model can act as a better screening tool in planning by providing outputs that can be very useful in improving the efficiency and accuracy of detailed analysis methods such as simulation.