Region 2: The Interior Highlands

Precipitation and the relatively high topographic area associated with the Ozark Uplift provide the region with great potential for hydroelectric power (Figure 7.10), which uses the gravitational force of falling or rushing water to rotate turbines that convert the water’s force into energy. More than 30 small- to medium-sized hydroelectric plants (from less than 2 to almost 400 megawatts) are distributed along the Arkansas, White, and Buffalo rivers in Arkansas, eastern Oklahoma, and southern Missouri (Figure 7.11). Almost all of these power plants are located within the Ozark Plateau. One exception is Arkansas Electric Coop’s 35 MW capacity Dam 2, which sits near the confluence of the Arkansas and Mississippi rivers. There are also three pumped storage facilities within the region, where water is pumped uphill into reservoirs in times of excess production, essentially acting as batteries. These are larger in capacity than most of the power plants, ranging from 186 MW to 440 MW.

Figure 7.10: Hydroelectric power plants in the South Central US.

Figure 7.11: Bull Shoals hydroelectric dam on the White River in Marion and Baxter Counties, Arkansas.

Even though the Interior Highlands produces the most hydroelectricity of all regions in the South Central, the power generated by these plants pales in comparison to that produced by the region’s fossil fuel-powered facilities. For example, Arkansas’ largest power plant is the Union Power Partners natural gas plant, which has a 2020 MW capacity. Overall, coal is the major source of power for the Interior Highlands, providing the region with over ten times more electricity than hydropower.

A minor amount of fossil fuel resources exist within the Arkansas Valley. Natural gas and oil are extracted from sandstones that were deposited in early Pennsylvanian river systems and deltas. An accumulation of plant remains from ancient swamps and forests has also yielded coal resources within the basin. The southern part of the region supports several refineries.