Stream Bioregions
In 1992, the U.S. Environmental Protection Agency (EPA) defined ecoregions and subregion as areas "within which there is an apparent homogeneity in a combination of geographic characteristics that are likely to be associated with resource quality, quantity and type of stresses." Regionalization was performed as a collaboration among DEP, water management districts and the U.S. EPA Environmental Research Laboratory in Corvallis, Oregon.