What is a Reference Watershed?

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 criteriaLow 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

 Cache Creek

Watersheds Where I Live

Find a Core Reference Watershed near your location

Input either a 5 digit zipcode or latitude and longitude (in decimal degrees).

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