The major watershed is the expanded area of water flow outside the focus watershed and the surrounding impacting watersheds. Comparing water data with other water bodies in the watershed is perhaps the best measuring stick because of the proximity and similarities. Characteristics of the major watershed that are examined include the following:

4.1 Ecoregion

4.2 Basins and Watersheds

4.3 Demographics

4.4 Land Use

4.5 Soils

4.6 Topography

Fig 4.0 Illustration of a watershed