Expanding food bank's distribution program during Covid-19 pandemic

Network and suitability analysis to find 10 new sites for food distribution  using ArcGIS

 Capstone Project - GIS  UC Davis-Coursera Specialization 

Project Summary

As a consequence of the COVID-19 pandemic food insecurity has increased worldwide. High unemployment rates have impacted many families and individuals’ access to food. Food banks have been essential to fulfill the needs of a growing hungry population during this crisis providing food to millions of Americans.

This project aims firstly to determine how much of the food insecure population of Santa Clara and San Mateo counties (California, USA) is currently served by the local food bank; then it seeks to identify areas in which 10 additional distribution sites could be created in order to expand the spatial reach of the food distribution program.

Results

In the San Mateo and Santa Clara counties, 194 census tracts qualified as potentially at risk of food insecurity. These included low-income tracts in which the median yearly income was below $82,216; and tracts with high rates of unemployment. Out of the estimated total population of almost 2.7 million people, about 1 million residents (37%) were located in census tracts at-risk of food insecurity. The Food Bank serving the population in need had already established 77 food distribution sites throughout the two counties. Virtually the entire population at risk (99%) resided within a 3-mile radius of an existing distribution site, with only two tracts in San Mateo County outside that coverage.

After the COVID-19 pandemic began, the country had registered an increase in unemployment rate reaching 15% at its peak in April 2020. According to the Congressional Research Report published in January 2021, the population that experienced relatively higher rates of unemployment were part-time workers, workers with low educational attainment, and racial and ethnic minorities. After screening the population using these criteria, 46 new tracts were identified. 

The selection of suitable sites was based on their accessibility, namely vicinity to a bus stop (≤0.5 miles) and walkability score of the area. 673 sites qualified as suitable locations based on these criteria. 

Once the suitable new distribution sites were identified, Network Analysis was used to determine the optimal locations for 10 additional sites. An  impedance distance cut-off of 9 miles was necessary to reach 88% of population miles.

Interactive map in ArcGIS Online

Workflow

Limitations

National unemployment statistics were used here, but it has not been confirmed that the national trends are representative of the area of interest. In addition, it is unknown if site accessibility by individuals without private vehicles is typically considered a significant criterion for the selection of all distribution sites. The use of this criteria may have been too conservative, leading to the underestimation of suitable candidate sites. 

In at least three instances, the tract centroids were located far from inhabited areas. This may have impacted the allocation of the population to the nearest site, overestimating the distance between them and potentially forcing the cut-off to expand behind real needs. In  addition, a 9-mile distance between the tracts and the distribution sites may not actually be acceptable. It might be preferable to instead add more sites to cover the population at risk.

In addition, during the Location-Allocation analysis,  the set number of candidate sites was arbitrarily set at 10 under the assumption that larger number of sites would have meant a significant increase in operation costs and management. However, this assumption may not hold in real life.

Finally, during the analysis it appeared that the network connectivity had to be reestablished for some of the distribution sites and it is reasonable to think that some issues remained undiscovered. Therefore it is plausible to expect that using a different network data set may yield different results. 

 References

Disclaimer

This project was designed and developed as capstone project for the GIS Specialization (UC Davis, Coursera). The only purpose of the study is to showcase skills acquired. It must not be considered for any other use. The analysis is based on data freely available online. The project’s author serves as volunteer at the Second Harvest food bank. However, she has no access to any confidential data or information.