Salt dissolution in the Salado Formation (Upper Permian) and land subsidence south of Imperial, Pecos County, West Texas
— Kenneth S. Johnson

Natural dissolution of the Upper Permian Salado salt has occurred at many places in west Texas and southeast New Mexico. At three sites just southwest of Imperial, in west Texas, dissolution of Salado salt in old boreholes is causing the land surface to subside. At one site, subsidence resulted in concentric ground ruptures that extend at least 1000 ft (305 m) from the borehole. This subsidence has required regrading the adjacent highway twice, at a cost of more than $1 million, and now the highway will probably be relocated at a cost exceeding $10 million. At the second site, high-salinity brine is emitted from the borehole and is forming a 62-acre (25-hectare) lake in the shallow subsidence depression. More than 750 L of brine is coming to the surface every minute at this site, and the brine, with a salinity of about 100,000 parts per million (ppm), is also releasing potentially lethal amounts of hydrogen sulfide. Wells at these two sites were initially drilled for oil in the early 1950s, but they were repurposed as water wells when no oil was discovered. The third site, an area of about 100 by 200 ft (30 by 61 m), has subsided at a rate of about 4 in./yr (10 cm/yr). At all three sites, the shallowest significant Salado salt bed is probably about 20?40 ft (6?12 m) thick and at a depth of 850?1050 ft (259?320 m).