Survey Of The Fox Hills Artesian Aquifer

The Richland County Conservation District (RCCD) in cooperation with the Montana Bureau of Mines and Geology (MBMG) will be completing an inventory of wells completed in the Fox Hills – Hell Creek aquifer. Wells in this aquifer were often completed with 2-inch metal casing to depths over 1000 feet and originally flowed Because of the small well diameters, these wells depended on flowing conditions. Water level monitoring has documented declines of 1-4 feet per year over the past 20 years in Richland County. As a result, some of the wells that originally flowed at the surface have stopped flowing. The changes in flow were caused by pressure head declines. These declines in wellhead pressure may be the result of overall pressure head declines in the aquifer or the result of leaks through corroded casing into higher lower pressure head aquifers. Reducing or eliminating uncontrolled discharges from Fox Hills wells will reduce or eliminate water level declines. Depending on the interest from well owners, future work could be proposed to control discharges from flowing wells by lining and winterizing them. Based on previous work controlling flowing wells in central Montana, the potential exists for well head pressures to recover and resume flowing.

The MBMG Groundwater Information Center and DNRC water rights databases were queried to identify flowing wells in Richland County. Currently we have identified about 130 Fox Hills-Hell Creek wells that were reported to have flowed when originally constructed. The proposed inventory will initially focus on these wells, but will expand to include other wells not recorded in the databases. MBMG will work with the RCCD to identify the current well owners to obtain access to the wells. Questionnaires will be sent to well owners and others interested in participating in the project. Information from landowners will help identify the location, depth, aquifer, and other pertinent information about wells to be inventoried.

The Richland County Flowing Well Inventory Project proposes to assess the aquifer and well head conditions. Water levels, shut in pressures, and flow rates will be measured and compared to conditions when the wells were constructed. Field water quality parameters will be measured and compiled. The condition of the well head will be evaluated, noting the diameter and condition of the surface casing. The presence of valves to control production and methods of winterizing the wellhead will be described for flowing wells. The well history will be discussed with owner and summarized. All data will be compiled in a final report summarizing findings of the inventory project.

Funding for this project is provided by the Montana Department of Natural Resources and Conservation (DNRC) through the Montana Renewable Resource Grant and Loan Program for the enhancement of Montana’s renewable resources.

If you have any questions on the survey please contact the Richland County Conservation District at 406-433-2103x101 or [email protected] by email.

 

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