The origin of thousands of playa basins on the Southern High Plains of Texas and New Mexico has been attributed to eolian deflation, evaporite or carbonate dissolution and subsidence, piping, or animal activity. Shallow-seismic data from three ephemeral lake (playa) basins in the Texas Panhandle, collected as part of a hydrogeological study of High Plains playa and interplaya environments, demonstrate that subsidence has figured prominently in the formation of these three basins.

Five coal basins in the Rocky Mountain Foreland of the western United States--San Juan, Greater Green River, Piceance, Powder River, and Raton--contain, by virtue of their tremendous coal tonnage, 522 Tcf (14.7 Tm3) coalbed gas resources, or 77 percent of the nation's total of 675 Tcf (19.1 Tm3), and each is attractive in terms of coalbed methane exploration and development. Only in the San Juan Basin (84 Tcf; 2.38 Tm3), however, are these coalbed resources being extensively exploited to meet the nation's demand for natural gas.

Water produced from oil, gas, and geothermal reservoirs contains natural radioactivity that ranges from background levels to levels found in uranium mill tailings. Radioactivity in fluids and in the scale that forms in oil-producing and gas-processing equipment increases concerns for worker and public safety as well as costs of handling and disposing of naturally occurring radioactive materials (NORM), which include water, sludge, scale, and affected equipment.