Multivariate Analysis of Hydrochemical Data for Jewel Cave, Wind Cave, and Surrounding Areas

Authors

Andrew J. Long, United States Geological Survey, Washington Water Science CenterFollow
James B. Paces, United States Geological Survey, Denver Federal Center
William G. Eldridge, United States Geological Survey, Dakotas Water Science Center

Date of this Version

3-2019

Citation

Natural Resource Report NPS/JECA/NRR 2019/1883 / NPS 146/150771, March 2019: ix, 40 pages

Published by the United States Department of the Interior, National Park Service, Natural Resource Stewardship and Science, Fort Collins, Colorado

Also available at: http://www.nature.nps.gov/publications/nrpm/

Please cite this publication as:

Long, A. J., J. B. Paces, and W. G. Eldridge. 2019. Multivariate analysis of hydrochemical data for Jewel Cave, Wind Cave, and surrounding areas. Natural Resource Report NPS/JECA/NRR—2019/1883. National Park Service, Fort Collins, Colorado.

Comments

United States government work. Public domain material.

Abstract

Abstract

Jewel Cave National Monument and Wind Cave National Park in South Dakota contain two of the six longest caves worldwide. These caves contain subterranean lakes that are important points of intersection between the water table of the Madison aquifer and the caves. During 2015 to 2017, several subterranean lakes were discovered in Jewel Cave, which previously was thought to be above the regional water table. The objectives of this study were to better understand the hydrology of the recently discovered subterranean lakes in Jewel Cave and to evaluate their relation or possible connection to similar lakes in Wind Cave. Both objectives align with National Park Service resource management purposes. Multivariate analysis, consisting of principal component analysis (PCA), cluster analysis, and end member mixing, was applied to hydrochemical data for 70 sites within and surrounding Jewel Cave and Wind Cave. Hydrochemical data consisted of the contents of major ions (Ca, Mg, Na, HCO3, Cl, Si, SO₄), arsenic (As), strontium (Sr), uranium (U), stable isotopes of oxygen and hydrogen (δ¹⁸O, δ²H), radiogenic isotope ratios of strontium and uranium (⁸⁷Sr/⁸⁶Sr and ²³⁴U/²³⁸U), pH, and electrical conductivity (EC) in water samples. Five hydrogeologic domains were classified on the basis of PCA and cluster analysis for the area encompassing Jewel Cave and Wind Cave in the southern Black Hills. The Artesian 1 and Artesian 2 domains represent primarily artesian springs and surrounding groundwater, the East and West domains represent areas where Madison and Minnelusa aquifer rocks are at or near the land surface, and the Precambrian domain represents the Precambrian aquifer. Multivariate analysis indicates that the Jewel Cave area is part of the West domain and that Wind Cave is part of the East domain. End member mixing was applied to estimate that groundwater in the Jewel Cave area primarily was derived from the West domain and secondarily from the Precambrian domain. Jewel Cave and Wind Cave contain lakes that are well connected to regional groundwater flow in the Madison aquifer.