Yuya KASUGAI

Understanding the Realities of Relief Supplies Distribution during the Initial Phase of Disaster Response and Evaluation through Mathematical Optimization Models

Kazushi SANO

In recent years, natural disasters have been increasing and becoming more severe due to climate change such as global warming, and many lives and properties are lost every year. Many people are affected by disasters, and relief supplies need to be delivered to disaster-stricken areas as part of disaster response. In this study, we propose a decision-making method to deliver relief supplies to disaster-stricken areas more quickly by clarifying the roles of each organization and the situation in the disaster-stricken areas. This clarifies the roles of each organization, identifies problems in the current delivery system, and optimizes delivery routes to facilitate delivery during a disaster. In this study, as an example of a medium-scale disaster that occurs frequently, the flow and issues of relief goods delivery from the prefecture to evacuation facilities in the affected area were clarified for the August 2022 torrential rainstorm in northern Niigata Prefecture, and a relief goods delivery model was constructed to suit the actual situation.
First, in order to investigate the actual situation of relief goods delivery, interviews were conducted with supporters and recipients regarding the delivery of relief goods during the August 2022 torrential rainstorm in northern Niigata Prefecture. From these interviews, the flow of goods delivery and issues within the prefecture were identified. Next, we developed a relief goods delivery model based on the actual conditions of relief goods delivery. The model can output delivery routes based on a mixed delivery method of two-stage delivery and direct delivery, and can be configured to set the number of vehicles at each location, the amount of inventory at the primary delivery location, and the maximum delivery time limit for each vehicle. The usefulness of the proposed delivery method in the relief goods delivery model was verified by comparing it with conventional delivery methods in several CASE scenarios. The analysis showed that the proposed delivery method is more advantageous than the conventional delivery method when the characteristics of the delivery destination change depending on the scale of the disaster, when the number of vehicles at each location changes, when the distance between the relief workers and the delivery destination is long, and when a lot of time is required for transshipment. We have confirmed that the proposed delivery is more advantageous than the conventional delivery.