Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Emergency

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2025. This website is no longer updated and links to external websites and some internal pages may not work. More information »

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Climate Change
    • Emergency Response
    • Environmental Information by Location
    • Environmental Justice
    • Greener Living
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History
    • Staff Directory

Breadcrumb

  1. Home
  2. Water Research
  3. Watersheds Research

Watershed Assessment Research

On this page:
  • National Aquatic Resource Surveys and National Assessment
  • Responses of Aquatic Resources to Stressors
  • Water Quality Benefits and Modeling

The physical, chemical, and biological integrity of aquatic resources across the United States are threatened by multiple stressors, including climate change. To address these stressors and protect and restore aquatic resources, EPA is advancing research to support monitoring and assessment, characterize responses to cumulative impacts of multiple stressors, and estimate economic benefits of water quality improvements.

By improving EPA’s capabilities for economic valuation and the linkages to water quality improvements, research in this area will provide water resource managers with essential science and tools to advance water quality goals.

National Aquatic Resource Surveys and National Assessment

Image of a man standing on a bridge with his back to the camera. He is leaning on the railing looking at the view of the Willamette river surrounded by trees with mountains in the background

EPA’s National Aquatic Resource Surveys (NARS) are designed to assess the quality of coastal waters, lakes and reservoirs, rivers and streams, and wetlands in the United States; track changes over time; and provide critical information for protecting and restoring water quality at national and regional scales. The surveys are designed and implemented as an EPA, state, and tribal partnership. While continuing to assess known stressors to aquatic resources, NARS faces the challenge of developing indicators and approaches for assessing climate change impacts on these waters.

EPA researchers are providing the following science and technical support needed to help implement and improve NARS:

  • Evaluating, improving, and expanding assessment benchmarks and indicators (including assessment thresholds for indicators).
  • Harmonizing datasets and developing national reports.
  • Evaluating survey design frames, target populations, and analysis approaches for ranking single and multiple stressors.
  • Advancing the application of DNA technologies and exploring remote sensing approaches for use in assessments.

Results of this research will make NARS data more broadly accessible to better support policy and management decisions at spatial scales beyond the traditional national and regional NARS focus. The knowledge, tools, and training developed by EPA will help decision makers use NARS data to manage aquatic resources proactively and adaptively.

Additional Information and Resources:

  • National Rivers and Streams Assessment 2018-2019 Report 
  • Environmental Indicators in Aquatic Surveys
  • Modeling Biological Indicators Across Space and Time (webinar recording)
  • NARS Publications in Science Inventory

Stream and Lake Datasets

LakeCat Dataset
LakeCat currently contains over 300 metrics that include local catchment, watershed, and special metrics for over 378,000 lakes.

StreamCat Dataset
StreamCat currently contains over 600 metrics that include local catchment, watershed, and special metrics for approximately 2.65 million stream segments.

Responses of Aquatic Resources to Stressors

Image eelgrass underwater surrounded by rocks

EPA research is addressing the need to characterize the responses of aquatic resources to the cumulative impacts of multiple, interacting stressors across space and time.

Scientists are developing indicators, techniques, and methods to assess stressor-response relationships and impacts of multiple stressors, including climate change impacts. This is being done across a range of aquatic resources, including streams, wetlands, coral reefs, submerged aquatic vegetation, and estuaries. Studies on the development and improvements of biological assessment and monitoring tools, data, and applications continue and include case studies at local levels.

Results of this research will empower communities to make informed decisions on restoration and conservation priorities and promote equitable distribution of the resulting benefits.

Related research: EPA scientists assist with National Coastal Condition Assessment intensification survey in Florida’s Pensacola and Perdido Bays

Water Quality Benefits and Modeling

Bay with blue water and a rocky shore. There is a tall bridge in the background across the bay and there are children fishing from the rocks in the foreground.

Federal, state, Tribal, and local management actions to improve water quality can lead to a broad range of benefits for communities. EPA’s research is increasing the understanding of benefits associated with different waterbody types and our ability to evaluate climate change, environmental justice, and equity issues within a water quality benefits framework.

Gaps being addressed through research:

  • Missing or incomplete categories of water quality benefits.
  • Current measures and models used for economic valuation can be inconsistent and limited in scale.
  • Distributional impacts of water quality benefits, including how water quality changes impact overburdened communities.

Related research: Human Dimensions of Water Quality Research

Water Research

  • Watersheds Research
    • Watershed Assessment Research
    • Ecosystem and Community Resilience Research
    • Advanced Ambient Water Quality Research
  • Nutrients and Harmful Algal Blooms Research
    • Nutrients Research
    • Harmful Algal Blooms Research
  • Water Treatment and Infrastructure Research
    • Drinking Water Research
      • Treatment and Control of Contaminants
      • Infrastructure Resilience and Sustainability
      • Source Water Quality
      • Exposure and Health Risks
      • Models, Tools, and Analytical Methods
      • Technical Assistance in Support of BIL
      • Training, Outreach, and Technical Support
    • PFAS Research
    • Alternative Water Sources Research
    • Stormwater Management Research
    • Wastewater Research
  • Water Research Grants
  • Research Outputs
  • Training, Outreach, and Technical Support
Contact Us about Water Research
Contact Us about Water Research to ask a question, provide feedback, or report a problem.
Last updated on March 26, 2024
  • Assistance
  • Ayuda
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • Aide
  • Asistans
  • Korean
  • Assistência
  • Russian
  • Tulong
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions

Follow.