Fuzzy Set-Based System Performance Evaluation of an Irrigation Reservoir System

This paper presents the development of fuzzy set-based performance measures for an irrigation reservoir system to answer questions on how likely a system is to fail (fuzzy reliability), how quickly it is likely to recover from failure (fuzzy resiliency), and how severe the consequences of failure are likely to be (fuzzy vulnerability). The failure/success state of the system is defined as a fuzzy event. A fuzzy set with an appropriate membership function is defined to describe both the working and failed states, to account for the system being in partly working and partly failed state. Failure of the irrigation reservoir system is related to the evapotranspiration deficit of the crops in a period. Application of the performance measures is demonstrated with the case study of the Bhadra Reservoir system in Karnataka, India. The reservoir operation is simulated using three different reservoir operating policy models: steady-state policy obtained using a fuzzy stochastic dynamic programming (FSDP) model, steady-state policy obtained using a classical stochastic dynamic programming (SDP) model, and yearly operating policy using a conceptual operating policy (COP) model. All reservoir operating policy models consider the integration of the reservoir operation policy at 10-day time periods with water allocation decisions on a daily basis by maintaining the storage continuity and soil moisture balance. Inclusion of fuzziness in the performance measure gives realistic solutions by capturing uncertainties in the reservoir operating policy models. (C) 2017 American Society of Civil Engineers.