NATURAL GAS IN GROUNDWATER: THE STORY OF SOUTH DAKOTA'S FLAMING FOUNTAIN

The “Flaming Fountain” is part of a memorial to military veterans in the South Dakota State Capital city of Pierre. The “fountain” consists of a flowing groundwater well drilled in 1910 to a depth of 1280 feet (390 m) and completed in the Lower Cretaceous Inyan Kara Group. These units are known for producing natural gas near Pierre, and gas was expected when the well was drilled. The gas was used for lighting the Capitol building in the days before electricity, and the warm water from the aquifer heated the building. Because of corrosion and other issues, such uses were discontinued in the 1920s, and the well was allowed to flow freely as the water source for Capitol Lake, an impoundment adjacent to the State Capitol Building. Enough methane was entrained in the water to sustain a flame, and this spectacle of a gushing water well surrounded by flaming gas became known as the “Flaming Fountain.” After World War II, it was incorporated into a monument for veterans.

Depletion of natural gas from the aquifer resulted in the flame going out a few years ago. The State Engineer’s office has come under pressure from veterans’ groups to restore the flame, and has tried numerous approaches, including attempts to increase flow from the well, and running a natural gas line to the memorial. None of these have been effective at keeping the flame alight for more than a few hours. A methane sensor developed at the South Dakota School of Mines & Technology to monitor methane in the headspace of groundwater wells near oil and gas production areas was deployed on the Flaming Fountain to assess the levels of methane. Several graduate and undergraduate students were engaged in developing and testing the instrument, and the Flaming Fountain proved to be an excellent field test. Levels of methane were found to be highly variable, and it no longer appears to be a continuously flowing phase. We recommended that the well be plugged and a new fountain built. The sensor will be deployed on a shale gas monitoring site in Canada.