Historical Oil and Gas Infrastructure Density, Ecological Change, and Economic Wellbeing in Coastal Louisiana

Infrastructure Mapping Oil and gas infrastructure was mapped to assess the hazardousness of place associated with extraction and processing activities in coastal Louisiana. Infrastructure locations were compiled from secondary data sources and permit records from the U.S. Environmental Protection Agency (USEPA) and categorized using NAICS codes. Facility locations were verified using U.S. Geological Survey (USGS) Digital Orthophoto Quarter Quads, while infrastructure development dates were established using historical business directories, satellite imagery, historical pipeline maps, historical USGS topographic maps, and web resources. Each infrastructure element was assigned an intensity value, influence distance, and distance decay function based on analysis of USEPA toxic release data and chemical toxicity measures developed by the Indiana Pollution Prevention and Safe Materials Institute. Influence distances were estimated using proximity-based buffers, and worst-case chemical release scenarios were modeled using USEPA Risk Management Program software (RMP*Comp) and U.S. Department of Transportation hazardous release isolation guidelines. Hazard layers were combined using an arithmetic GIS overlay to generate a composite environmental risk surface and classify locations by a weighted hazardousness-of-place rating across decadal time steps. Data Sources: USEPA infrastructure and toxic release data; USGS Digital Orthophoto Quarter Quads; historical business directories; satellite imagery; historical pipeline maps; USGS historical topographic maps; Indiana Relative Chemical Hazard Scores Ecological Analysis Ecological functioning was assessed by examining the ability of coastal marsh habitats to support fish and shellfish species through analysis of marsh fragmentation and land–water ratios. Land and water distributions were derived from 1956 aerial photographs and Landsat imagery from the 1970s through 2010, classified into land and water categories at 30-meter resolution. Additional marsh vegetation classifications were incorporated using historical datasets based on aerial surveys of plant species abundance and composition, covering time periods from 1949 through 2013. Habitat suitability for juvenile fish and shellfish was estimated using a simplified trapezoidal Habitat Suitability Index (HSI) defining landscapes containing 25–80% marsh as optimal habitat. The HSI was scaled from 0 (least suitable) to 1 (most suitable) and adjusted to account for the ecological value of open water habitat. Spatial patterns in habitat quality were evaluated using the Getis-Ord Gi* statistic to identify hot spots and cold spots of habitat suitability relative to coastwide averages. Data Sources: 1956 aerial photographs; Landsat imagery (1970s–2010); marsh vegetation datasets from aerial surveys (1949, 1968, 1978, 1988, 1997, 2001, 2007, 2013); coastal marsh classification maps. Socioeconomic Analysis Economic well-being in coastal Louisiana communities was assessed using profile indicators derived from U.S. Census datasets to construct a community-level index. The analysis included 53 incorporated and unincorporated communities within a 30-minute drive time of the Louisiana coastal zone, representing locations with continuous demographic records from 1960 to 2010. An integrated economic well-being index was developed using four variables reported across census years: poverty, unemployment, home ownership, and educational attainment. These indicators were standardized and combined into an additive index weighted equally across variables, enabling comparison of economic conditions across communities and over time. Relationships between economic well-being, oil and gas development, and habitat suitability were assessed using Pearson product-moment correlation analysis at 10-, 30-, and 90-minute drive-time buffers. Data Sources: U.S. Decennial Census (1960–2010); American Community Survey (ACS); census place-level demographic and economic data