This report provides a regional overview with the general public in mind: it also contains detailed background that will benefit more technical users The multiyear (2011-2016) project was made possible via several funding sources, including grants from the Colorado Water Conservation Board (CWCB) as well as the Park County Land and Water Trust Fund (LWTF). The CGS — through its Severance Tax Operational Funds, Colorado General Fund, and CUSP — provided matching funds. Digital PDF/GIS/ZIP download. OF-15-11D
An online map — ON-15-11 Geology and Groundwater Resources of Park County, Colorado — is also available.
Zip file contents
Includes report with text, tables, figures, and appendices
Water quality and type map plates:
GIS Data folder
Contains OF-15-11_ParkCo.mpk map-package file
To view GIS files
GIS map-package (.mpk) files may be viewed using ESRI’s ArcGIS software. The map-package was generated in ArcGIS 10.4.
Disclaimer: These data are intended for use at 1:50,000 scale and are checked for accuracy accordingly. CGS does not assume responsibility for the use of these data.
Park County has experienced considerable population growth in recent decades with development becoming increasingly reliant on local groundwater resources. A diverse geologic setting characterizes the county and groundwater may be found in many of those settings. This product compiles the most recent geologic mapping and interpretations focusing on groundwater occurrences in the various geologic formations found in the area. The revisions in the 2017 update include a discussion of groundwater types and quality, as presented in more detail below.
The county straddles two very different geologic terrains that share a long and complex history. The east side of the county extends into the Precambrian-cored Front Range uplift of the Rocky Mountains. The west side of the county covers the South Park topographic basin, a 35 by 50 mile structural feature shaped by a long and varied history of geologic processes. It contains a wide variety of crystalline igneous and metamorphic rocks, volcanic rocks, and sedimentary units, ranging in age from Precambrian through Cenozoic. Based on differences in hydrologic properties, the aquifers and confining units in Park County can be grouped into three general categories: 1) crystalline-rock aquifers, 2) sedimentary bedrock aquifers and confining units, and 3) unconsolidated Quaternary deposits. Within these categories, there were 19 mapped hydrogeologic units.
More that 7,500 completed water wells are inventoried in Park County as of December 19, 2012 and are available in the Colorado Division of Water Resources (CDWR) database. Permitted uses include: domestic or household use only, livestock, commercial, industrial, municipal, irrigation, monitoring and other (such as evaporative, fire, geothermal, gravel, or unspecified). Wells and springs were assigned a hydrogeologic unit. Due to various sources of uncertainty, hydrogeologic unit designations were assigned a confidence level value of 1, 2, or 3, with 3 representing the least confidence.
A Park County groundwater quality database was compiled from publicly available databases, reports, and samples collected in 2011, 2012, 2014 and 2016 by the Coalition for the Upper South Platte (CUSP) with some assistance by CGS. The primary electronic data source was the Water Quality Portal (WQP) from the National Water Quality Monitoring Council. Groundwater data was also manually compiled from other publicly available publications not in the WQP. A total of 689 sample sites had groundwater quality data through 2016. A limited number of sample locations have data from multiple sampling events at the same well or spring. Data analysis for these locations used the maximum value detected, unless it was identified as an anomalous outlier. Where feasible, dissolved water quality data was used preferentially over total data.