Emergency water distribution systems to improve spatial equality and spatial equity in a heterogeneous community with differing mobility characteristics

Abstract

Our study addresses challenges in emergency water distribution systems by proposing a hybrid method that optimizes points of distribution (PODs) and mobile delivery systems. The goal is to optimally dispense emergency water to disaster-affected populations while enhancing spatial equality and spatial equity. By considering the physiological and socioeconomic status of the disaster-affected population, our hybrid method addresses the needs of a heterogeneous community. The hybrid method consists of two models: The first model seeks to determine the optimal locations of POD for populations who are deemed physiologically able to visit PODs and pick up their emergency water. In this model, socioeconomic status is incorporated to account for different mobility characteristics of these populations. The second model focuses on determining efficient routes for mobile delivery to populations who are more likely to have physiological limitations that interfere with them traveling to PODs and picking up their emergency water. The proposed method is then validated with an application to the Flint, Michigan, water crisis. Our experiments demonstrate that, compared to the actual setup of PODs, our method shows a 69.30 % improvement in objective function value and a 7.05 % reduction in the average travel time for people to reach the PODs. Particularly beneficial for those with the longest travel time to the PODs, the model indicates a significant 25.22 % decrease in travel time, equivalent to 19.49 min. Also, our method suggests the optimal delivery solution involving 20 trucks covering 191.82 km for the target populations. We further conduct a sensitivity analysis to discuss the potential impact of various factors on the operations of the emergency water distribution system. Our results highlight that increasing the number of depots does not necessarily lead to a proportional decrease in vehicle kilometers traveled. We also identify that the most cost-effective vehicle type is a 16-foot truck. These findings provide emergency agencies and policymakers with valuable insights, paving the way for improved guidelines and policies to establish more effective emergency water distribution systems.