NEWS RELEASE: WSGS Publishes Report on Groundwater Salinity in the D-J Basin

The Wyoming State Geological Survey (WSGS) recently published a report on groundwater salinity in the Denver-Julesburg (D-J) Basin of southeastern Wyoming. This report examines the salinity of groundwaters that occur at depths of 5000 ft or less in the Denver-Julesburg structural basin where significant oil and gas activity has taken place in recent years. In this report, special emphasis is placed on the location of naturally occurring saline groundwaters with TDS levels greater than 5000 ppm that may be suited to some industrial uses thereby conserving higher quality water for domestic, agricultural and livestock uses.

“Water is an important resource in Wyoming and understanding it’s salinity with depth is helpful to the private and public sector,” says Tom Drean, Director of the Wyoming State Geological Survey, “This information can also be used to help direct future studies regarding valuable groundwater resources in Wyoming.”

Groundwater quality varies widely throughout Wyoming’s geologic basins.  An aquifer may produce high quality groundwater suited for human consumption at a basin’s edge while water pumped from the same aquifer a few miles further into the basin may be unfit for livestock usage. One measure of water quality is its “salinity”, or total dissolved solids (TDS), which is the amount of dissolved material that remains as residue after the liquid portion of a water sample evaporates. Salinity, measured in parts per million (ppm), is one constituent, among others, used by the Wyoming Department of Environmental Quality (WDEQ) to determine if groundwater resources are suited for human consumption, agricultural application or livestock watering. Although salinity provides a general measure of water quality it does not specify the type or amounts of particular chemical compounds present.

“The results of this study show that occurrences of naturally occurring moderately saline groundwaters first appear in scattered locations in the D-J Basin at 3,500 feet below the surface and widen with depth to encompass the northern half of the basin between 4,500-5,000 feet.” says Karl Taboga, WSGS hydrogeologist. “Naturally occurring saline waters can also be found at depths greater than 4,000 feet in a smaller area that stretches across the central basin north of Burns and Pine Bluffs.”

For this report, WSGS geologists examined hundreds of water quality analyses from the U.S. Geologic Survey and geophysical well logs from the Wyoming Oil and Gas Conservation Commission. The 22-page report, “Groundwater Salinity in the Denver-Julesburg Basin, Wyoming: Open File Report 2016-2,” is available as a free download on the WSGS website http://sales.wsgs.wyo.gov/groundwater-salinity-in-the-denver-julesburg-basin-wyoming/. The online report includes an explanation of groundwater salinity and water quality contour maps throughout the Denver-Julesburg Basin.