Historical and projected climate (1901–2050) and hydrologic response of karst aquifers, and species vulnerability in south-central Texas and western South Dakota

Scientific Investigations Report 2014-5089
Prepared in cooperation with the Department of Interior South-Central Climate Science Center
By: , and 



Two karst aquifers, the Edwards aquifer in the Balcones Escarpment region of south-central Texas and the Madison aquifer in the Black Hills of western South Dakota, were evaluated for hydrologic response to projected climate change through 2050. Edwards aquifer sites include Barton Springs, the Bexar County Index Well, and Comal Springs. Madison aquifer sites include Spearfish Creek and Rhoads Fork Spring. Climate projections at sites were based on output from the Community Climate System Model of global climate, linked to the Weather Research and Forecasting (WRF) model of regional climate. The WRF model output was bias adjusted to match means for 1981–2010 from records at weather stations near Madison and Edwards aquifer sites, including Boerne, Texas, and Custer and Lead, South Dakota. Hydrologic response at spring and well sites was based on the Rainfall-Response Aquifer and Watershed Flow (RRAWFLOW) model. The WRF model climate projections for 2011–50 indicate a significant upward trend in annual air temperature for all three weather stations and a significant downward trend in annual precipitation for the Boerne weather station. Annual springflow simulated by the RRAWFLOW model had a significant downward trend for Edwards aquifer sites and no trend for Madison aquifer sites.

Flora and fauna that rely on springflow from Edwards and Madison aquifer sites were assessed for vulnerability to projected climate change on the basis of the Climate Change Vulnerability Index (CCVI). The CCVI is determined by the exposure of a species to climate, the sensitivity of the species, and the ability of the species to cope with climate change. Sixteen species associated with springs and groundwater were assessed in the Balcones Escarpment region. The Barton Springs salamander (Eurycea sosorum) was scored as highly vulnerable with moderate confidence. Nine species—three salamanders, a fountain darter (Etheostoma fonticola), three insects, and two amphipods—were scored as moderately vulnerable. The remaining six species—four vascular plants, the Barton cavesnail (Stygopyrgus bartonensis), and a cave shrimp—were scored as not vulnerable/presumed stable (not vulnerable and evidence does not support change in abundance or range of the species). Vulnerability of eight species associated with streams that receive springflow from the Madison aquifer in the Black Hills was assessed. Of these, the American dipper (Cinclus mexicanus) and the lesser yellow lady’s slipper (Cypripedium parviflorum) were scored as moderately vulernable with high confidence. The dwarf scouringrush (Equisetum scirpoides) and autumn willow (Salix serissima) were also scored as moderately vulnerable with moderate to low confidence, respectively. Other species were assessed as not vulnerable/presumed stable or not vulnerable/increase likely (not vulnerable and evidence supporting an increase in abundance or range of the species). Lower vulnerability scores for the Black Hills species in comparison to the Balcones Escarpment species reflect lower endemicity, higher projected springflow than in the historical period, and high thermal tolerance of many of the species for the Black Hills. Importantly, climate change vulnerability scores differed substantially for Edwards aquifer species when RRAWFLOW model projections were included, resulting in increased vulnerability scores for 12 of the 16 species.

Suggested Citation

Stamm, J.F., Poteet, M.F., Symstad, A.J., Musgrove, MaryLynn, Long, A.J., Mahler, B.J., and Norton, P.A., 2015, Historical and projected climate (1901–2050) and hydrologic response of karst aquifers, and species vulnerability in south-central Texas and western South Dakota: U.S. Geological Survey Scientific Investigations Report 2014–5089, 59 p., plus supplements, http://dx.doi.org/10.3133/sir20145089.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Methods and Models
  • Historical and Projected Climate and Hydrologic Response
  • Species Vulnerability to Projected Climate and Hydrologic Response
  • Summary
  • References Cited
  • Supplement 1. Data Tables for Species Vulnerability Assessment
  • Supplement 2. Paleoclimate Inventory
  • Supplement 3. Weather Research and Forecasting Model Namelist Files and Bias
Publication type Report
Publication Subtype USGS Numbered Series
Title Historical and projected climate (1901–2050) and hydrologic response of karst aquifers, and species vulnerability in south-central Texas and western South Dakota
Series title Scientific Investigations Report
Series number 2014-5089
DOI 10.3133/sir20145089
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Northern Prairie Wildlife Research Center, South Dakota Water Science Center, Dakota Water Science Center
Description Report: viii, 61 p.; 3 Supplements
Country United States
State South Dakota, Texas
Other Geospatial Barton Springs, Bexar County Index Well, Comal Springs, Rhoads Fork Spring, Spearfish Creek
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details