Use of Nonlinear Membership Functions and the Water Stress Index for the Environmentally Conscious Management of Urban Water Systems: Application to the City of Morelia

Abstract

This article proposes a multiobjective optimization strategy based on a fuzzy formulation for the sustainable design and planning of water supply chains in urban areas that considers simultaneously economic and environmental objectives. Harvested rainwater and reclaimed water are considered as alternative sources to reduce freshwater consumption while maximizing water revenues and minimizing land usage. As opposed to other models that attempt to minimize water consumption, this work seeks to minimize the water stress index, which quantifies the impact of freshwater consumption with respect to the specific location where the withdrawals take place. We illustrate the capabilities of this approach through its application to a real case study based on the city of Morelia in Mexico, in which we show that the use of alternative water sources along with an appropriate water distribution plan can reduce the impact over natural reservoirs.

A graph theory approach for scenario aggregation for stochastic optimisation

“…To describe the uncertain demand for the five-year time horizon a total of 5,000 scenarios with 180 uncertain parameters were generated following a normal distribution and a standard deviation of 30%. The associated MILP problem taken from (Medina-González et al, 2018b) was summarised in the supplementary material file. The results of the MILP problem solved using the reduced set of scenarios for SCAN-CODE, OSCAR and SCENRED are summarised in Table 4.…”