Drought and Water Scarcity

Drought has an immediate and longer-term impact on public health, the environment and water quality. These resources provide for a deeper dive into the science of drought and water scarcity.

• U.S. Drought Monitor. A weekly historical drought index map developed and released by the University of Nebraska–Lincoln, NOAA, and USDA. https://droughtmonitor.unl.edu/CurrentMap.aspx
• National Drought Mitigation Center. The education page for the NDMC highlights basic and in-depth information about the science of drought and drought prediction from the University of Nebraska–Lincoln. https://drought.unl.edu/Education.aspx
• Water Use in the United States. USGS publishes a circular every five years on the estimated water withdrawals in the United States. This webpage provides a means to track historic trends in water withdrawals by sector based on the information in those circulars. https://www.usgs.gov/mission-areas/water-resources/science/water-use-united-states  
• StreamStats. Spatial analytical tools used by water resources managers to evaluate high and low flows at sites on waterways around the country. https://streamstats.usgs.gov/ss/ 
• WaterWatch. Toolkit created by USGS to monitor current and historical streamflow conditions around the country. Explores drought and flood history, as well as Flow-Duration-Curves based on historical data at hundreds of gages sites nationwide. https://waterwatch.usgs.gov/
•  “2017 Potable Reuse Compendium.” USEPA, Washington, D.C., 2017. https://www.epa.gov/sites/default/files/2018-01/documents/potablereusecompendium_3.pdf. A document compiling USEPA guidance for technical and regulatory resources for policymakers and water resources managers interested in considered water reuse as a water resource management alternative.
• GRACE(-FO) Data Analysis Tool. A geospatial toolkit for viewing data on land subsidence, groundwater depletion, and much more from the GRACE-FO satellite missions. https://grace.jpl.nasa.gov/data/data-analysis-tool/
• Dillon, et al. (eds.), 2022, Managed Aquifer Recharge: Overview and Governance. IAH Special Publication. https://recharge.iah.org/ ISBN 978-1-3999-2814-4. A report (available online) that provides an overview of the multiple regulatory and technical challenges facing MAR at an international scale.

Flooding

Flood management is a layered and complex enterprise involving scientific, regulatory, and legal perspectives. These resources provide further understanding of some of the tools, datasets, and methods available to those interested in managing flood risk in the United States.

• Coastal flood exposure mapper. https://coast.noaa.gov/digitalcoast/tools/flood-exposure.html This online visualization tool developed by NOAA supports communities that are assessing their coastal hazard risks and vulnerabilities. The tool creates a collection of user-defined maps that show the people, places, and natural resources exposed to coastal flooding.
• FIRM online map center. https://msc.fema.gov/portal/home The online repository for FEMA’s FIRM maps and FIS studies.
• National Academies of Science, Engineering, and Medicine (2019). Framing the challenge of urban flooding in the United States. https://nap.nationalacademies.org/read/25381/chapter/1 This consensus report summarizes the challenges of urban flooding, using case studies from Baltimore, Chicago, Houston, and Phoenix to highlight the topic’s complexity, multidimensional nature, and scope. 
• National Academies of Science, Engineering, and Medicine (1995). Climate and Floods: The Role of Non-Stationarity [Chapter 4] in Improving American River Flood Frequency Analysis. https://nap.nationalacademies.org/read/6483/chapter/6  A chapter that summarizes some of the challenges associated with using a historic record in flood prediction.
• Hashimoto, T., Stedinger, J., and Loucks, D. (1982). Resiliency, reliability, and vulnerability for water resource system performance evaluation. Water Resources Research, 18(1), 14–20. https://www.researchgate.net/publication/248804973_Reliability_Resiliency_and_Vulnerability_Criteria_For_Water_Resource_System_Performance_Evaluation/link/00b4952fafcd59adf5000000/download One of the first papers to set out the distinctions between reliability and resiliency in the context of water resources management.
• Sea level rise map viewer. https://www.climate.gov/maps-data/dataset/sea-level-rise-map-viewer NOAA’s Sea Level Rise map viewer gives users a way to visualize community-level impacts from coastal flooding or sea level rise (up to ten feet above average high tides). Photo simulations of how future flooding might impact local landmarks are also provided, as well as data related to water depth, connectivity, flood frequency, socio-economic vulnerability, wetland loss and migration, and mapping confidence.
• Great Lakes Coastal Analysis and Mapping. https://www.greatlakescoast.org/great-lakes-coastal-analysis-and-mapping/ An effort by FEMA to map and monitor potential flood risks along the shores of the Great Lakes.
• FEMA (2022). Risk Rating 2.0 Methodology and Data Sources. https://www.fema.gov/sites/default/files/documents/FEMA_Risk-Rating-2.0_Methodology-and-Data-Appendix__01-22.pdf A report providing a comprehensive overview of the methodology behind FEMA’s new Risk Rating 2.0 approach.

Water Quality

Water quality is an integral—and scientifically complex—aspect of environmental law. The following resources provide for a fuller examination into the science of water quality.

• Water quality information by topic. This resource page was developed by USGS and provides a high-level overview of many key topics associated with groundwater science. https://www.usgs.gov/special-topics/water-science-school/science/water-quality-information-topic
• Priority Pollutant List. The complete list of pollutants currently prioritized by USEPA under section 307 of the CWA. https://www.epa.gov/sites/default/files/2015-09/documents/priority-pollutant-list-epa.pdf
• National Aquatic Resources Surveys (NARS). NARS was developed by USEPA as a collaboration between federal, state, and tribal governments to assess the health of the nation’s waters. View indicators, field methods, annual reports, and data portals from this main page (https://www.epa.gov/national-aquatic-resource-surveys/).
  
• Water Quality Watch. https://waterwatch.usgs.gov/wqwatch/. Page created by USGS for real-time monitoring of water quality at hundreds of sites around the country. Data collected include pH, temperature, dissolved oxygen, and nitrates.
• Enviro Wiki. PFAS. An Enviro Wiki page about the family of chemical compounds known as Per-and Poly-Fluoroalkyl Substances (PFAS). This page contains information about PFAS chemical properties, environmental contamination and persistence, regulation, and litigation.
• Harmful Algal Bloom Monitoring System. https://coastalscience.noaa.gov/research/stressor-impacts-mitigation/hab-monitoring-system/ The National Oceanic and Atmospheric Administration (NOAA) uses a combination of satellite imagery and in situ measurements to provide HAB monitoring tools for eight regions around the country, with more to come online soon.
• Green infrastructure. https://www.epa.gov/green-infrastructure/what-green-infrastructure A collection of green infrastructure resources, guidelines, and studies collated by USEPA. This website is a good first point to learn more about the details of urban green infrastructure.
• Treatment wetlands. https://www.epa.gov/wetlands/constructed-wetlands A collection of USEPA resources on the design and construction of treatment wetlands, a form of tertiary wastewater treatment.
• Combined sewer overflows. https://www.epa.gov/npdes/combined-sewer-overflows-csos A compilation of guidance, regulations, and scientific resources on combined sewer overflow management for urban areas.

The Science of Groundwater

Tracking the availability and movement of groundwater is an important aspect of the hydrologic cycle and is vital to understanding the role of groundwater in natural resources law and the CWA. These resources provide a closer analysis into the science of groundwater, as well as data on groundwater levels around the country.

• Groundwater Information by Topic. This resource page was developed by the U.S. Geologic Survey (USGS) and provides a high-level overview of many key topics associated with groundwater science. Groundwater Information by Topic (usgs.gov)
• Groundwater Atlas of the United States. This atlas was developed by USGS to provide a 2D representation of the hydrogeology of major aquifers in all fifty states, Puerto Rico, and the U.S. Virgin Islands. https://pubs.er.usgs.gov/publication/ha730. Further Geographic Information Systems data may be found at https://www.usgs.gov/mission-areas/water-resources/science/principal-aquifers-united-states?qt-science_center_objects=0#qt-science_center_objects
• Konikow, L.F., 2013, Groundwater depletion in the United States (1900−2008): USGS Scientific Investigations Report 2013−5079, 63 p., http://pubs.usgs.gov/sir/2013/5079. (Available only online.) A report detailing the rate and magnitude of groundwater depletion in the United States.
• Winter, T., Harvey, J., Franke, O., and Alley, W., 1998. Groundwater and Surface Water: A Single Resource. USGS Circular 1139. [Chapter: Natural Processes of Groundwater and Surface Water Interaction]. https://pubs.usgs.gov/circ/circ1139/htdocs/natural_processes_of_ground.htm Comprehensive work showcasing common interactions between groundwater and surface water, including how groundwater contours can be used to identify direction of flow.
• Groundwater-Surface Water Exchange. (Woessner, 2020). https://books.gw-project.org/groundwater-surface-water-exchange/ This book is available as part of the online content sponsored by The Groundwater Project. It provides a comprehensive overview of the different forms of surface water-groundwater interactions, as well as a chapter on the most up-to-date methods for testing those interactions.
• Enviro Wiki. Groundwater Flow and Solute Transport—Enviro Wiki Developed by the Strategic Environmental Research and Development Program and the Environmental Security Technology Certification Program, Enviro Wiki aims to make engineering research more accessible to environmental professionals. This particular webpage highlights concepts and equations related to groundwater flow and pollutant transport, including Darcy’s Law and the concepts of advection and dispersion.

Groundwater Pollution

Understanding the types of contaminants that impact groundwater quality, their sources, and how they spread through aquifers, is an important aspect of understanding the role of groundwater in the CWA. These resources provide a high-level overview of the science of groundwater quality, a list of common groundwater contaminants, and tools for modeling and mapping aquifer contamination over time.

• Lapham, W., Wilde, F., and Koterba, M., 1995 (rev. 1996). Ground-Water Data-Collection Protocols and Procedures for the National Water-Quality Assessment Program: Selection, Installation, and Documentation of Wells, and Collection of Related Data. USGS Open-File Report 95-398.https://pubs.er.usgs.gov/publication/ofr95398 This report documents the protocols and procedures for installation of water quality monitoring wells as part of the National Water Quality Assessment (NAWQA) program.
• Lapham, W., Wilde, F., and Koterba, M., 1995. Ground-Water Data-Collection Protocols and Procedures for the National Water-Quality Assessment Program: Collection and Documentation of Water-Quality Samples and Related Data. USGS Open-File Report 95-399. https://pubs.er.usgs.gov/publication/ofr95399 This report documents procedures for groundwater sampling implemented as a part of NAWQA, most of which are still used by the USGS today.
• Contaminants Found in Groundwater. A comprehensive list of groundwater contaminants, their sources, and potential human health impacts. All contaminants have been sorted by chemical type: inorganic, organic, microbial, and physical characteristics. https://www.usgs.gov/special-topic/water-science-school/science/contamination-groundwater?qt-science_center_objects=0#qt-science_center_objects
• Groundwater Quality—Current Conditions and Changes Through Time. The USGS’s National Water Quality Program characterizes water quality in twenty of the United States’ sixty-eight principal aquifers. This webpage provides regional analyses for these twenty aquifers, including an analysis of how their water quality has changed over time. An interactive webtool provides further exploration of temporal changes in water quality. https://www.usgs.gov/mission-areas/water-resources/science/groundwater-quality-current-conditions-and-changes-through?qt-science_center_objects=0#qt-science_center_objects
• Predicting Groundwater Quality in Unmonitored Areas. A comprehensive overview of the modeling and statistical studies used by USGS for contaminant prediction in aquifers, as well as national maps of groundwater quality for arsenic, nitrates, and atrazine. https://www.usgs.gov/mission-areas/water-resources/science/predicting-groundwater-quality-unmonitored-areas?qt-science_center_objects=0#qt-science_center_objects
• Introduction to In Situ Bioremediation of Groundwater. This 2013 report from USEPA’s Office of Solid Waste and Emergency Response explores the fundamentals of how bacteria indigenous to soils can be used to break down harmful pollutants. The report also highlights how these natural processes can be augmented and optimized, and some of the associated costs, as well as strategies for field implementation. https://www.epa.gov/sites/default/files/2015-04/documents/introductiontoinsitubioremediationofgroundwater_dec2013.pdf
• Bacteria and Their Effects on Groundwater Quality. A general overview of the impacts of microbes on groundwater from the Michigan Water Science Center. https://mi.water.usgs.gov/h2oqual/GWBactHOWeb.html
• Groundwater Modeling Research. A comprehensive overview of the range of groundwater models typically used to study the fate and transport of groundwater contaminants collated by USEPA. https://www.epa.gov/land-research/ground-water-modeling-research