SPECIAL TO THE LOG CABIN

Concerns over the possible effects of Fayetteville Shale gas development on water resources have prompted the USGS and various agencies and universities to begin or propose monitoring and computer modeling studies.

The first U.S. Geological Survey (USGS) involvement began in July 2009 with water-quality and streamflow monitoring on the South Fork of the Little Red River in north central Arkansas to establish a baseline for determining trends in water quality and quantity. 

The USGS, in cooperation with the U.S. Forest Service, Arkansas Game and Fish Commission, and Arkansas Water Resources Center, University of Arkansas-Division of Agriculture, is measuring temperature, specific conductance, pH, dissolved oxygen, turbidity, stage (water-level), flow, and rainfall at two stations on the South Fork of the Little Red River near the Ozark National Forest and Gulf Mountain Wildlife Management Area in Van Buren County. 

In addition, the USGS has collaborated with Southwestern Energy to develop a computer watershed model of the hydrologic processes within the 24 square-mile upper Cypress Creek Basin, in Conway County north of Morrilton, and is collecting water-quality data during base-flow and storm-flow conditions for use in the model.

The objective of this two-year study is to simulate the hydrologic and sedimentation processes associated with proposed impoundments (used as water-supply ponds for gas extraction operations), proposed well pads, current and proposed gravel roads, and current land use practices occurring in the Cypress Creek Basin.   

The USGS operates eight streamgages to document flow in streams in the counties in the heart of the Fayetteville Shale exploration. In addition, in cooperation with Community Water System, the USGS has been collecting water quality samples since November 2009 at three lake sites on Greers Ferry Lake. 

“Continued collection of water-resources data and analysis of historic data, along with interpretive studies, are especially important to document existing conditions in areas of natural resource development such as the Fayetteville Shale,” said Dave Freiwald, Director of the USGS Arkansas Water Science Center.  “The USGS is one of several agencies, universities, and other entities that continue to study or are beginning to study the natural resources of the area,” he continued. 

“Virtually all of the wastewater produced in the gas drilling and hydrofracking processes contain salts,” explained Tim Kresse, USGS water-quality specialist.  “Change in the electrical conductivity-- affected by salinity — of water sampled from wells and streams is an excellent indicator of potential effects of drilling in an area, but to make this approach more effective, background water-quality sampling is needed before any drilling occurs. If higher concentrations of salts are observed near drilling areas, additional sampling and analyses may be warranted.” 

Other studies in the Fayetteville Shale area are proposed. Kresse is one of several investigators on a study proposed by USGS in conjunction with the University of Arkansas to sample springs and other groundwater sources in the Gulf Mountain Wildlife Management Area. 

Limited amounts of historical USGS groundwater data are available in the shale gas area, primarily from the 1960’s.  The aquifers in the area are not very productive so their use is mostly by rural residences. Concerns about the groundwater in the shale gas area have been on the rise since gas development began. 

Describing the flow of groundwater is a complex task but one that the USGS has conducted in the State for more than 100 years. Innovations in computer models of complex aquifer systems have been provided by the USGS to agencies including the Arkansas Natural Resources Commission, Arkansas Department of Environmental Quality, and the Arkansas Department of Health to help them understand the fate of groundwater. 

“Characterizing groundwater flow and transport is one of several principal activities of the USGS,” said groundwater specialist Dr. John Czarnecki. 

The USGS is proposing to develop a fully three-dimensional description of the hydrogeologic units throughout northern Arkansas and characterize groundwater flow through these units using advanced modeling software and visualization tools. 

These extensive studies would require funding partners, however, Czarnecki said.