The National Network of Reference Watersheds

The National Network of Reference Watersheds is a collaborative and multipurpose network of minimally disturbed watersheds and monitoring sites. The purpose of this website is to allow users to search the NNRW database of reference watersheds, to identify watersheds of interest, and download watershed information and water quality data. The current scope of the network is limited to freshwater streams. Membership in the network is voluntary and open to individuals, agencies, and institutions interested in participating in monitoring and (or) research in minimally disturbed and pristine watersheds.

What is a Reference Watershed?

Example Diagram of sites plotted along a disturbance index continuum The NNRW defines reference watersheds as those minimally disturbed by human activity preferably in an area protected from human-induced changes. References watersheds can be used to measure changes in soil chemistry, vegetation, water quality, and biology through time as well as to compare to disturbed watersheds.

The network is currently composed mainly of U.S. Geological Survey and U.S. Environmental Protection Agency watersheds however, as the network expands watersheds will be added from other Federal, State, tribal, interstate, academic, local and private sector organizations that choose to participate.

The "Watershed Search" section of the website allows users to search the entire network database. The database includes many types of reference watersheds; some are considered reference based on low hydrologic disturbance, others based on land use disturbance, and others based on water quality, stream biology, or some combination of criteria. Results of users searches can placed into context with all watersheds in the database on cumulative frequency diagrams like the one to the right.

The "Core Watersheds" section of the website allows users to search a subset of the NNRW database that contains only the most pristine watersheds based on specific land use criteriaInformationLow hydrologic disturbance (dams, water withdrawal, pollutant discharge, etc.); 0% Row Crops; < 5% Pasture; 0% High Impact Development; 0% Medium Impact Development; < 10% Total Development (High + Medium + Low); Natural vegetation + Barren Land > 75% Core watersheds also have stream discharge data available.

Select the "Core Watersheds" tab to explore the most pristine watersheds in the network or select the "Watershed Search" tab to search the entire NNRW database of reference watersheds and access data available for those sites.
If you would like to submit a watershed or a group of watersheds to be included in the network please contact Mike McHale

Today's Featured Watershed

 Sagehen Creek


The Sagehen Creek Basin is located on the east slope of the northern Sierra Nevada section of the Sierra-Cascade Mountains physiographic province in c...

Watersheds Where I Live

Find a Core Reference Watershed near your location

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Site Last Modified: 27 February 2018
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