Fig. 4: Case Studies.

Selected high-risk counties in A Selected high-risk counties (parishes) in Louisiana are shown in solid green. Yellow patterns are mapped clay-rich bedrock and sediments (Horton, 2017) known or suspected to contain high transition metal contents. Blue polygons or patches are known oil fields and appear green where they coincide with clay-rich material. Large magenta dots are oil refineries, including several in nearby states. B A map of the Colorado River and major tributaries. Municipalities and unincorporated areas using Colorado River water are indicated in blue patterns (website below), along with high-risk counties in red, creating purple regions where they overlap. See text for discussion. https://coloradoriverbasin-lincolninstitute.hub.arcgis.com/. Accessed 22 Jan 2024. Horton JD, San Juan CA, Stoeser DB. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. Data Series 1052. Available from: https://pubs.usgs.gov/publication/ds1052.