Parks and open space are essential to healthy communities. Studies have shown that living far from parks can be a serious public health issue, while at the same time areas with higher access to parks have higher levels of physical fitness. Likewise, the inequalities of park distribution can have a negative impact on the well-being of our communities. A 2004 study by the Health Research and Policy Centers found that neighborhoods with higher poverty rates and higher proportions of racial minorities have less access to parks and green spaces.

With these findings in mind, the Delaware Department of Natural Resources and Environmental Control, Division of Parks and Recreation (DPR) sought to understand the communities served by parks and plan for future needs of recreational facilities throughout the state. The DPR was interested in calculating travel buffers to measure population served by their parks via walking, driving, or public transit.

After allocating population inside the census geographic areas by using a combination of land use and road density, we used ArcGIS Model Builder to develop a set of processes to allocate population in each census tract based on where the people actually lived. Next, we used ArcGIS Raster Calculator to weight the remaining areas based on road density and allocate the population to raster cells based on that density – under the assumption that areas with a higher road density probably have more houses and thus more people. The output was a raster surface of population with an estimated count for each 30 meter cell. Finally, using the ArcGIS Network Analyst tools, we create service areas for each park based on the time it would take to reach the park using three modes of travel: car, walking and public transit.

The result is a more accurate buffer around each parks based on the ability to reach it. In the final step we used the population map to count the estimated population within the service area of each park.

The complete 2013 Statewide Comprehensive Outdoor Recreation Plan for Delaware is available online.