2016 NGWA Groundwater Summit

Investigating the Upper Pierre Aquifer through Regional and Site-Specific Data and Data Integration into a GIS

Monday, April 25, 2016: 3:20 p.m.
Confluence Ballroom C (The Westin Denver Downtown)
Theresa Jehn-Dellaport, P.G. , Quantum Water & Environment, Lakewood, CO
Tammi Renninger , Quantum Water & Environment, Lakewood, CO

The Upper Pierre aquifer, an under-studied, mostly undeveloped groundwater aquifer, may provide a much needed resource for ranchers and the oil and gas industry within Northeastern Colorado.  Known to expand at least throughout the Cheyenne Basin, the Upper Pierre aquifer lies within the upper unit of the Upper Cretaceous Pierre Shale, underlying the Laramie-Fox Hills aquifer, where present.  Regional data suggest the aquifer to have a thickness of 800-1000 feet  and recent drilling of production wells into the Upper Pierre aquifer, although limited, have been yielding up to 300 gpm. 

Oil and gas exploration drill-hole geophysical logs have been the primary regional source of data for interpretation of the geometry of the Upper Pierre aquifer.   The geophysical logs display a conspicuous spontaneous potential (SP) and resistivity signature within the aquifer, with a distinct low-amplitude deflection in both the SP and resistivity mid-way through the thickness of the aquifer, indicative of the Pierre Ash.   Site-collected data, such as lithologic logs, sidewall cores, and drill cuttings suggest the aquifer to be composed of grey siltstone/sandstone with a calculated specific yield value of 0.17.

A database of over 400 interpreted oil and gas geophysical logs was integrated into a Geographic Information System (GIS).  The data were processed to geostatistically create continuous surfaces representative of the upper and lower elevations of the aquifer.  Spatial characteristics of the aquifer, such as its relation to other aquifers and areas of subcrop and outcrop, have also been defined using GIS capabilities.  Hydrogeologic cross-sections and three-dimensional renderings are being used as key decision-making tools for interested parties in adjudicating the groundwater of the Upper Pierre aquifer.

Theresa Jehn-Dellaport, P.G., Quantum Water & Environment, Lakewood, CO
Theresa Jehn-Dellaport brings more than 26 years of experience in groundwater and surface water evaluations, feasibility studies, large municipal water well design, aquifer storage and recovery, surface and groundwater rights studies, plans for augmentation, substitute supply plans, surface water hydrology studies, aquifer pump test analysis, monitoring well and water well design, construction and testing, and specification preparation for large municipal and domestic water supply wells. She also has extensive experience in directing large multidisciplinary technical staff, subcontractors, and consultants.

Tammi Renninger, Quantum Water & Environment, Lakewood, CO
Tammi Renninger is a Geographic Information Science professional with emphasis in the geosciences. She is proficient with ESRI’s ArcGIS 10.2 to manage geospatial data analysis, collection, organization, maintenance, quality control, development and display. Her geospatial data analysis has been used extensively for numerical modeling of aquifers and surface water and her maps have been used as essential decision-making tools. Ms. Renninger’s experience in the geosciences includes site assessments, geophysical log interpretation, soil and water quality sampling and reporting, soil classification, and sample database management.