FROM THE WEST VIRGINIA POTOMAC TRIBUTARY STRATEGY
Selected Graphs of
Chesapeake Bay Watershed
Model Simulations
The Chesapeake Bay Program uses
mathematical models to simulate changes in the Bay ecosystem due to
changes in population, land use, or pollution management. The Chesapeake Bay Watershed
Model (CBWM) simulations are not the same as actual conditions. They
are the best scientific estimate of what average loadings are likely
to be. However, not everyone is willing to accept these as
reasonable estimates. |
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Pennsylvania and Virginia contain the largest percentage of the
Chesapeake Bay watershed, followed by Maryland, New York, West Virginia,
Delaware, and Washington DC. As the watershed areas of each jurisdiction
differ greatly, it is not surprising that their relative contributions
to the Bay’s sediment and nutrient problems differ as well. |
The Chesapeake
Bay Watershed Model is used to estimate past and current water quality conditions, and to predict how changes
in land management will affect future conditions. For example, the model can be
used to estimate the sources of nutrients and sediment to the Bay in any given
year. The following graphs present model estimates of the sources of nitrogen, phosphorus
and sediment in the entire Bay watershed in 2002. |
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The
next three graphs compare nutrient and sediment loads from the seven
political jurisdictions, as estimated by CBWM, for 1985 baseline, 2002 progress,
and 2010 Cap Load Allocations. The jurisdictions with the largest land area
(Pennsylvania, Virginia and Maryland) also contribute the largest nutrient and
sediment loads. Each jurisdiction has a different mix of land uses that produce
their nutrient and sediment loads and require a different mix of remedies. For
example, nitrogen from the highly urbanized Washington DC area comes almost
entirely from point sources, in particular the mammoth wastewater treatment
plant at Blue Plains, while nitrogen from rural Delaware comes mostly from
highly concentrated agriculture. Thus far, CBP signatories Maryland, Virginia,
and Washington DC have made the most progress in reducing their baseline (1985)
nutrient loadings – but all jurisdictions still have a long way to go to meet
the Cap Load Allocations. |
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West Virginia total nitrogen
loads as estimated by the CBWM for 2002. |
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West Virginia total
phosphorus loads as estimated by the CBWM for 2002. |
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West Virginia total sediment
loads as estimated by the CBWM for 2002. |
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