An aerial view of the salt scar at Site A, Skiatook Lake, Okla., taken during 2004 data-collection activities. Major oil production activities ceased approximately 65 to 70 years ago; however, a salt scar persists to the right (north) of the road. The salt scar was cased by intentional or accidental releases of produced brine. Photo courtesy of the U.S. Environmental Protection Agency

View from the lower part of Site A's main salt scar looking south uphill toward the beginning of the scar. Seepage of salt water from a shallow sandstone aquifer continues, and active salt scarring persists. This area drains into the Cedar Creek arm of Skiatook Lake, Okla.

The lower part of Site A's main salt scar looking north to Skiatook Lake, Okla. The small white patches in the foreground are salt accumulations. These salt accumulations can wash into the lake in surface runoff during rain events

Salt scar downhill from the remains of two brine pits at Site A by Skiatook Lake, Okla. Grasses and weeds have partly revegetated the area. Grasses are sparse, however, and only grow where the salt content of the soil is not high

Highly saline produced water that was disposed of at Site A by discharging the water on to the ground caused salt scaring and subsequent erosion. Here the maximum depth of erosion is about 2 meters. Saline water seeps to the surface in the middle of the photo and flows to Skiatook Lake, Okla.

The discharge of produced water on the surface caused extensive erosion of the land surface and etching and pitting of sandstone bedrock at Site A, by Skiatook Lake, Okla.

Highly degraded and weathered oil residues from leaks and spills from pipelines and tank batteries are present at Site A, Skiatook Lake, Okla. Microbial action, volatilization, and water washing are most likely responsible for the transformation of spilled oil to the asphaltic and weathered oil observed at the site

Abandoned well at Site A by Skiatook Lake, Okla. Improperly sealed, abandoned wells may act as conduits that allow the flow of high saline water into shallow aquifers and onto the surface

A large band wheel once provided power to pump multiple production wells at Site A, Skiatook Lake, Okla. Attached to the wheel's hub were steel rods connected to outlying pump jacks. The rods ran back and forth through wooden guides mounted in metal posts. Several posts can be seen behind the rim of the wheel