7.7-Reservoir operation using Stretched Thread Rule

Abstract

Reservoir operation forms a very important part of planning and management of water resources development projects. A number of techniques are available for reservoir operation and the two most commonly used techniques now-a-days are linear programming & dynamic programming. Mass curve method has been used since long to estimate required storage capacity. A new idea of stretched thread rule, a variant of the mass curve method, has been in use for quite some time.

According to the stretched thread rule. if an imaginary thread is stretched between a pair of congruent inflow residual mass curves placed parallel keeping a mutual distance equal to the effective reservoir capacity, the stretched thread represents the optimized outflow residual mass curve. The outflow curve so obtained conforms to the commonly accepted reservoir operation policy of flow equalization. The stretched thread method offers a simple, computationally efficient and exact solution to the problem of derivation of reservoir operation rule curves: It has been shown that this method is superior to linear programming & dynamic programming techniques. The stretched thread rule has been applied for operation of Dharoi reservoir in Sabarmati basin in Gujarat. The results are encouraging.