Spatial Equality and Equity for Effective Emergency Water Distribution System: Points of Distribution

Abstract

In recent years, there have been multiple incidents of drinking water contamination reported in major US cities. A critical part of the response to such an emergency is the distribution of bottled water to affected residents via points of distribution (PODs). However, in all of these instances the locations of the PODs and the limited transportation options of the residents meant that some residents had less accessibility to the PODs to obtain the clean water they needed. Unfortunately, current policies and regulations fail to consider spatial equity in determining placement of PODs. Thus, this study investigates the effectiveness of POD locations from the perspectives of spatial equality and spatial equity. We present a binary linear programming model that considers travel distance-based and time-based accessibility measurements simultaneously to find the optimal location of capacitated public facilities. The proposed model is applied to the Flint, Michigan, water crisis. Our results show the effects of POD locations and census block groups assigned to PODs on spatial equality and spatial equity, and the model's ability to improve accessibility measurements. In particular, the proposed model is able to decrease travel time-based assessment and distance-based assessment by up to 12.5% and 12.24% respectively. Also, our results demonstrate the combined impact of different levels of capacity and numbers of PODs with different allowable levels of accessibility on an efficient emergency water distribution system. The results of this study offer emergency agencies and policy makers an avenue toward better guidelines and policies for an effective emergency drinking water distribution system.