WHERE IN THE CHESAPEAKE BAY WATERSHED CAN STORMWATER MANAGEMENT PROJECTS HAVE THE HIGHEST IMPACT ON NATURE AND PEOPLE? A PENNSYLVANIA CASE STUDY
The goal of this study is to determine where urban projects should be targeted to have the largest impact on nature and people within the Chesapeake Bay Watershed. The Chesapeake Bay (Bay) is the largest estuary in the United States and home to countless ecosystems and habitats, and nearly 20 million people. Nutrient and sediment pollution are a primary threat to the water quality and health of the Bay, and there are five main sources of this type of pollution: agricultural runoff, air pollution, urban and suburban stormwater runoff, wastewater treatment and factories, and septic systems (CBF 2019). Currently urban and suburban stormwater runoff is the only increasing pollution source. This study utilized ArcGIS Pro, and public GIS data, to conduct a site suitability analysis, and determine where urban/suburban stormwater projects should be focused to curb the increasing source of pollution. I used a fundamental objectives approach to determine which factors should be included in the analysis. A fundamentals objective approach is used to set objectives, which represent “why” the analysis is important. Attributes are then assigned to the objectives to measure them. Two fundamental objectives were used for this analysis. The first was impact to water quality, the second was impact to people. I looked at each objective separately, and then combine them together in the final analysis. To assess water quality impacts, I selected the following metrics: total suspended solids, total phosphorous, total nitrogen, percent impervious area, land use, 303d impaired waters, and already treated land. To assess impact on people, I chose the following metrics: impact of flooding, population density, percent of population below the poverty line, percent of population that is non-white, and if the municipality is covered under an MS4 permit. Due to the size of the Bay watershed the study focused on Southern Pennsylvania. The study found that targeting projects in and around denser urban areas, such as Harrisburg, Lancaster, York, Chambersburg, and Altoona, would have the highest impact on people and nature within the Bay watershed. The results make sense in that these areas have high population density, and land use that would contribute to pollution. However, one surprising result is that most of the target areas are under MS4 permits. The analysis was set-up to target non-MS4 permitted areas. The findings could highlight that the current rate of implementation and treatment is not enough to offset the pollutant load. The next step, and future research, will be to determine which policies and projects would have the most impact in these areas. The study incorporates knowledge gained through the Environmental Science and Policy Master’s program and professional experience. Knowledge from courses such as Environmental Applications of GIS, Strategies in Watershed Management, Sustainable Cities, and Environmental Policymaking and Policy Analysis all provide a base for this study. Professionally, the Chesapeake Bay Program at The Nature Conservancy plans to use this study as the first step in developing an overarching urban/suburban stormwater plan for the Bay. The knowledge gained from this study will help to determine where to prioritize work moving forward.
Stormwater Management, Chesapeake Bay, GIS, Opportunity Mapping, Urban Stormwater