A watershed, the land area that drains to one stream, lake or river, affects the water quality in the water body that it surrounds. Like water bodies, watersheds differ in many ways. Healthy watersheds not only affect water quality, but also provide greater benefits to the people and wildlife that live there. We all live in a watershed, thus watershed condition is important to everyone.

Comparing watershed differences is one way in which government agencies and citizens learn about their environment, identify water pollution control options and plan for effective restoration and protection. There are literally hundreds of watershed characteristics that may influence water pollution, quality of life and other concerns. These characteristics are mostly environmental traits, sources of stress and environmental damage and community or social factors.

The most relevant characteristics often vary among different purposes for watershed comparison, or from place to place throughout the country. For this reason, a watershed comparison tool must be flexible and offer a broad variety of information to choose from.

The Watershed Index Online (WSIO) is a comparative analysis tool and data library that helps users compare watersheds in a user-defined geographic area, for a purpose of their choice, using the factors most relevant to their comparison.

To enter WSIO and set up your own watershed comparison tool, please click on the link below and follow the directions embedded within the file. After selecting your geographic area of interest and indicators, please save your file for offline use.

• Download WSIO Scoring Spreadsheet (Excel) (2.3 MB)

Users may also download pre-made statewide Recovery Potential Screening (RPS) tools for each of the lower 48 states below. These tools have the geographic area pre-selected (statewide) and the data for 207 watershed indicators pre-loaded.

Download Scoring Spreadsheet per State (Excel):

The WSIO utilizes the spreadsheet tool developed for EPA’s Recovery Potential Screening project along with a watershed indicator data library. The library encompasses several hundred watershed characteristics measured on small-scale watersheds, HUC12, with an average area approximately 35 squares mies across the conterminous US.

After opening the spreadsheet tool, a WSIO user first chooses a geographic area for their project and then selects watershed indicators of interest from a menu. The WSIO creates the user’s own custom tool (an Excel spreadsheet) that is based on the selected geographic area and contains all the data for the selected indicators. The user saves their custom tool copy for use offline on their desktop, where they can use various combinations of the indicators they selected to perform watershed screening-level comparisons.

For each screening run, the tool auto-calculates ecological, stressor and social indicator scores, as well as a combined Watershed Index score to use for comparison and analysis. The tool also creates ranked lists, graphs and maps of the watersheds for use in reports, presentations and informal discussions.

The following links can help users become skilled in using the WSIO:

• WSIO Overview (PDF).(12 pp, 913 K, About PDF)
• WSIO Indicator Descriptions and Metadata.(58 pp, 258 K)
• WSIO User Manual.(27 pp, 2.5 MB)

Other EPA websites with related information on watersheds, indicators and comparison techniques include:

• Recovery Potential Screening Website.
• Healthy Watersheds Website.
• EnviroAtlas Website.