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A well-managed and operational Conservation Gateway is in our future! Marketing, Conservation, and Science have partnered on a plan to rebuild the Gateway into the organization’s enterprise content management system (AEM), with a planned launch of a minimal viable product in early FY26. If you’re interested in learning more about the project, reach out to megan.sheehan@tnc.org for more info!

Photo: Great Basin National Park (L. Provencher)

​​​​​Nevada has many groundwater-dependent ecosystems (GDEs) throughout the state that depend on access to water to sustain them. These include springs, wetlands, phreatophytic communities, riparian zones, rivers, and lakes. These ecosystems are important for wildlife and for humans.

​​​Groundwater provides a buffer to ecosystems during dry periods and critical habitat for rare and endemic species, and the loss of water for natural systems can cause irreversible damage to ecosystems such as the loss of species or habitat. There is a need to quantify groundwater thresholds that can signal what groundwater levels will cause adverse impacts to ecosystems to ensure sustainable groundwater management. To address this need, The Nature Conservancy published Groundwater Thresholds for Ecosystems: A Guide for Practitioners in 2020. This document provides a resource to water managers and conservation practitioners by presenting a five-step process for establishing thresholds with varying levels of data availability, as well as three case studies from Texas (USA). When established, groundwater thresholds can protect ecosystems when evaluating new water development projects, groundwater management planning, or meeting legal requirements such as the Endangered Species Act.

In October 2020, we started a project to quantify vegetation use of and dependence on groundwater.

Stressor and Threat Assessment of Nevada Groundwater Dependent Ecosystems (2022)

For this assessment, we considered "stressors" as things that are currently impacting groundwater dependent ecosystems, and "threats" as things that could potentially impact groundwater dependent ecosystems in the future. We considered five themes of stressors and threats: 1) groundwater withdrawals; 2) climate; 3) ungulates; 4) non-native species and 5) other human activities. Data sources are described in the Report and in metadata for the data. Resources associated with this assessment are as follows:

  • Fact sheet (2 pg)
  • Key findings
  • Executive Summary
  • Report without appendices
  • Appendices A and B
    • Appendix A: Entities who discussed this assessment with TNC staff
    • Appendix B: Examples illustrating complexity of relationship between groundwater withdrawal distance and impact to GDEs
  • Appendix C: Examples of calculations for some stressor and threat risk factors for different GDE types
  • Appendix D: Maps of groundwater level trends in hydrographic areas (HAs)
  • Appendices E and F: Statewide maps of groundwater withdrawal stressors (Appendix E) and threats (Appendix F) by GDE type
  • Appendix G: Equations for calculating climate threat risk factor values
  • Appendices H and I: Statewide maps of climate stressors (Appendix H) and threats (Appendix I) by GDE type
  • Appendices J and K: Statewide maps of ungulate stressors (Appendix J) and threats (Appendix K) by GDE type
  • Appendix L: Non-native plant and animal species considered for non-native species stressor risk factor
  • Appendices M and N: Statewide maps of non-native species stressors (Appendix M) and threats (Appendix N) by GDE type
  • Appendices O and P: Statewide maps of additional impacts of human development stressors (Appendix O) and threats (Appendix P) by GDE type
  • Appendix Q: Statewide maps of overall stressors and threats by GDE type
  • Raw data used to prepare the Stressor and Threat Assessment of Nevada Groundwater Dependent Ecosystems are available here as part of the Nevada Indicators of Groundwater Dependent Ecosystems Database. Please note that the data are current as of March 2022 and will not be updated.
  • A map tool to view groundwater level statistical results for 1984-2021 is available here. 

Estimated groundwater level trends 1985-2021 for GDEs in Nevada (2022) 

Using a machine learning algorithm developed by TNC-CA (see Rohde et al. 2021), we applied the Shallow Groundwater Estimation (SAGE) tool to estimate groundwater level trends for GDEs in Nevada. The tool is applied in Google Earth Engine and uses a Random Forest model that is trained using predictor variables from satellite images and climate data, and observed groundwater table depths.A Mann-Kendall trend test is used to determine significance of groundwater level trends. Results are dependent on the quality of the data input to the model, and choice of appropriate predictor variables. For example, locations with very little vegetation like groundwater-dependent playas or lakes may return erroneous results. Python code to apply the tool along with a methods document is available at https://github.com/tnc-ca-geo/SAGE.

Nevada Indicators of Groundwater Dependent Ecosystems Story Map and Database (2019)

Please visit the Nevada iGDE Story Map to learn more about groundwater dependent ecosystems in Nevada. Raw data used to prepare the Story Map are available here. Please note that the data are current as of June 2019 and will not be updated.

Source documentation for the Nevada Indicators of Groundwater Dependent Ecosystem database are as follows:

Additional resources mentioned on the Nevada iGDE Story Map:

  • Springsnail Conservation Agreement and Strategy: ​​​​​The Nevada Department of Wildlife, Utah Division of Wildlife Resources, The Nature Conservancy, and nine other public partners are working to develop a comprehensive strategy for Nevada and Utah to conserve endemic springsnail species and the spring-dependent ecosystems that support them. A Conservation Agreement committing the partners to this effort was finalized in December 2017, and the partners are now working together to develop the companion Conservation Strategy which identifies the approaches and actions needed to effectively protect and conserve these species on the landscapes of the two states. The strategy focuses on maintaining the function and quality of spring ecosystems to effectively conserve springsnails and other spring-dependent species, while also protecting these important resources for the benefit of other public land users and private landowners.
  • Statewide maps:
    • iGDE Summary Hexagons map (JPG, PDF)
    • iGDE Summary Hydrographic Areas map (JPG, PDF)
    • iGDE Phreatophytes Hexagons map (JPG, PDF)
    • iGDE Phreatophytes Hydrographic Areas map (JPG, PDF)
    • iGDE Wetlands Hexagons map (JPG, PDF)
    • iGDE Wetlands Hydrographic Areas map (JPG, PDF)
    • iGDE Springs Hexagons map (JPG, PDF)
    • iGDE Springs Hydrographic Areas map (JPG, PDF)
    • iGDE Lake&Playas Hexagons map (JPG, PDF)
    • iGDE Lakes&Playas Hydrographic Areas map (JPG, PDF)
    • iGDE Rivers&Streams Hexagons map (JPG, PDF)
    • iGDE Rivers&Streams Hydrographic Areas map (JPG, PDF)

Additional related resources:

Acknowledgements: Funding for this work has been provided in part by the Bureau of Land Management, the US Environmental Protection Agency, the NV Energy Foundation, California-Nevada Clilmate Adaptations Program and The Nature Conservancy in Nevada.

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