In the early 2000s, landowners in Johnston County began hearing rumors of a deal being negotiated between a handful of large landowners over the Arbuckle Simpson Aquifer (ASA) and the Central Oklahoma Water Resources Authority (COWRA), which provides municipal water to several cities in central Oklahoma, including Piedmont and Yukon. The agreement contemplated pumping at least 80,000 acre-feet of groundwater from the ASA for transport to COWRA (1 acre-foot is the equivalent of 325,851 gallons, so we’re talking about a LOT of water). Citizens, municipalities, the National Park Service, the US Fish and Wildlife Service, and the Chickasaw Nation were all deeply concerned by the proposed withdrawal because of its likely impact on springs and streams in the area. As a result, in 2003 CPASA worked cooperatively with Senator Gumm, Senator Crutchfield, and Representative Roan to pass legislation (now known as Senate Bill 288 or “SB 288”) to protect springs and streams emanating from the Arbuckle Simpson Aquifer. It was a hard fight, but CPASA commends the Oklahoma Legislature for choosing sustainability, at least when it comes to the Arbuckle Simpson Aquifer.  

 

SB 288 did a number of things. First, it expanded upon the U.S. Environmental Protection Agency’s sole source aquifer designation of a portion of the Aquifer. A sole source aquifer designation means that at least half of the overlying communities/individuals rely upon the aquifer for potable water and, if the aquifer were ever to become contaminated, those communities/individuals would have no feasible alternative water source. SB 288 classified any aquifer that had been designated, in whole or in part, as a sole source aquifer, to be a sensitive sole source groundwater basin. The ASA was, and remains, the only aquifer in Oklahoma to receive a sole source aquifer designation by the EPA; thus, it is the only sensitive sole source groundwater basin in the state.

 

Second, SB 288 recognized (and required) conjunctive management. Conjunctive management is where groundwater and surface water are managed as one (i.e., acknowledging the relationship and interconnectedness between groundwater and surface water). While science has known of the connection between surface water and groundwater for decades, this is the first instance where Oklahoma law recognized such a relationship. Everywhere else in the state, the Oklahoma Water Resources Board (OWRB) is required to treat groundwater and surface water as separate and distinct.

 

Third, SB 288 directed the OWRB to conduct a hydrologic investigation of the ASA and determine a maximum annual yield (MAY) that did not degrade or interfere with the natural flow of springs and streams emanating from the Aquifer. A MAY is that quantity of water that can be withdrawn from an aquifer on an annual basis.  The MAY is then divided equally over each acre overlying the aquifer. For example, if you have an aquifer with a MAY of 500 acre-feet that has 500 acres overlying it, then the equal proportionate share (EPS) would be 1 acre-foot per acre per year (500 MAY/500 acres). 

 

As required by SB 288, the OWRB conducted a multi-year, multi-million dollar hydrologic study of the Aquifer. The OWRB partnered with other technical entities, such as the U.S. Geological Survey, Oklahoma State University, the University of Oklahoma, U.S. Environmental Protection Agency, Oklahoma Geological Survey, the National Park Service, U.S. Fish and Wildlife Service, rural water districts, municipalities, and numerous landowners over the Aquifer. Over 20 reports were published as a result of the hydrologic study, including a digital groundwater model to simulate different maximum annual yield scenarios. Based upon the model and other data collected, the OWRB tentatively determined a maximum annual yield of 78,404 acre-feet per year. Interested parties were then allowed to present evidence in support of or in opposition to the OWRB’s tentative determination. Finally, on October 23, 2013 (a decade after the passage of SB 288) the OWRB approved the Final Order determining the maximum annual yield for the Aquifer to be 78,404 acre-feet per year. This amount equates to 0.2 acre-feet per acre per year. 

 

Certain organizations opposed to the sustainable framework immediately appealed the OWRB’s Final Order. In 2015, the OWRB’s Final Order was upheld by the district court. However, those opposed have now appealed to the Oklahoma Supreme Court.