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Where will the watersheds in the Worst Environmental Condition be?
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Just as it was of interest to determine whether any watersheds will be removed from the category of best environmental condition, it is also of interest to determine which watersheds will degrade into the lowest category by 2020. By identifying these watersheds, it may be possible to prevent or slow the degradation by controlling development or taking careful planning measures. The approach will be similar to that used to examine the watersheds in
the best environmental condition.
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The areas in the poorest environmental condition are located near urban areas, such as Pittsburgh in western Pennsylvania. The most of these urban areas are concentrated along the Atlantic seaboard and include Philadelphia, Wilmington, Baltimore, and Washington. Watersheds surrounding the city centers are typically impacted by suburban residential areas.
The lower map shows how the watersheds are like to change by 2020. Watersheds in blue have degraded in quality and those in orange have improved. Only four watersheds will be new members of the lowest three septiles by 2020. Two of the watersheds are in western Pennsylvania (Shenango and Lower Allegheny) and two are in the coastal area in southeastern Virginia and North Carolina (Albemarle and Lower Tar).
The most important factor in degrading the two coastal watersheds appears to be the loss of small forests. Increased nitrate in groundwater and Gypsy Moth invasions also play a role in the Lower Tar watershed. The Pennsylvania watersheds are also impacted by loss of small forests and the invasions of Gypsy Moth and terrestrial exotics. The Lower Allegheny watershed is also affected by a number of other factors including urbanization, loss of forest, and increases in nutrient loadings. As a result of the numerous environmental parameters changing for the worse, the Lower Allegheny watershed appears to suffer the greatest degradation of the four watersheds.
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