Hydrogeologic Characterization and Mining Impact Analysis of a Low-Yield, Fractured Granite

  • Michael DayEmail author
  • Paul Kos
  • Scott Brinton


A hydrogeologic characterization and impact analysis was performed for a proposed quarry at the Hitch Rack Ranch located in the Little Turkey Creek watershed southwest of Colorado Springs, Colorado. Continuous multiple channel tubing, nested piezometers, stream flow measurements, and mapping of known seeps were used to define the three-dimensional potentiometric distribution and areas of groundwater recharge and discharge. Water balance considerations, mass balance calculations, and potentiometric response to earth tides and barometric fluctuations confirmed that the granite fracture system in the ridge area of the proposed quarry has an extremely low bulk hydraulic conductivity resulting in minimal groundwater discharge to sustain the baseflow of Little Turkey Creek. The Little Turkey Creek valley forms the major conduit for groundwater flow exiting from the upper part of watershed underlain by granite. This conclusion has significant implications with respect to mine planning to minimize projected impacts to the hydrologic system and preserve this recharge component to downgradient Denver Basin sedimentary deposits.


Fractured media hydrogeology Earth tides Groundwater recharge/water budget Groundwater/surface-water interaction Water resources impact analysis 



The authors acknowledge Transit Mix Concrete Co. for funding the work that provided the basis for this manuscript.

Compliance with Ethical Standards

Conflict of Interest

The work that provided the basis for this manuscript was performed while the authors were providing consulting services to Transit Mix Concrete Co.


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Copyright information

© Society for Mining, Metallurgy & Exploration Inc. 2020

Authors and Affiliations

  1. 1.Hydro-Logic Solutions, Inc., Denver, CODenverUSA
  2. 2.Stantec, Denver, CODenverUSA

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