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Benthic Macroinvertebrate Impairments

Each state in the watershed conducts benthic macroinvertebrate assessments as part of its biennial water quality assessment report mandated by the Clean Water Act. Where assessed benthic macroinvertebrate communities are deemed the most degraded, states must designate those stream segments as impaired and add them to the list of impaired waters in need of cleanup. The Bay Program state partners - Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia - used the data and results from their 2006 water quality assessments to prepare summaries of stream conditions in each state. The methodologies for benthic macroinvertebrate assessment vary by state, therefore a synthesis of results across the entire watershed was not attempted at this time The map presents a summary of each state's assessment results within the boundaries of the Chesapeake Bay watershed.

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Delivered Yield of Total Phosphorus - Point Sources

This map shows the Delivered yield (load per area) of Total Phosphorus from point sources. Delivered yield is the amount of nutrient that is generated locally for each stream reach and weighted by the amount of in-stream loss that would occur with transport from the reach to Chesapeake Bay. The cumulative loss of nutrients from generation to delivery to the Bay is dependent on the travel time and instream-loss rate of each individual reach. This map shows estimates of Total Nitrogen based on mean conditions for the late 1990's time period using the SPARROW model from USGS. SPARROW, or SPAtially Referenced Regressions On Watershed (SPARROW) attributes, uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed.

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Delivered Yield of Total Phosphorus - Urban Sources

This map shows the Delivered yield (load per area) of Total Phosphorus from urban sources. Delivered yield is the amount of nutrient that is generated locally for each stream reach and weighted by the amount of in-stream loss that would occur with transport from the reach to Chesapeake Bay. The cumulative loss of nutrients from generation to delivery to the Bay is dependent on the travel time and instream-loss rate of each individual reach. This map shows estimates of Total Nitrogen based on mean conditions for the late 1990's time period using the SPARROW model from USGS. SPARROW, or SPAtially Referenced Regressions On Watershed (SPARROW) attributes, uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed.

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Delivered Yield of Total Phosphorus - Agricultural Sources

This map shows the Delivered yield (load per area) of Total Phosphorus from agricultural sources. Delivered yield is the amount of nutrient that is generated locally for each stream reach and weighted by the amount of in-stream loss that would occur with transport from the reach to Chesapeake Bay. The cumulative loss of nutrients from generation to delivery to the Bay is dependent on the travel time and instream-loss rate of each individual reach. This map shows estimates of Total Nitrogen based on mean conditions for the late 1990's time period using the SPARROW model from USGS. SPARROW, or SPAtially Referenced Regressions On Watershed (SPARROW) attributes, uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed.

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Delivered Yield of Total Phosphorus - All Sources

This map shows the Delivered yield (load per area) of Total Phosphorus from all sources. Delivered yield is the amount of nutrient that is generated locally for each stream reach and weighted by the amount of in-stream loss that would occur with transport from the reach to Chesapeake Bay. The cumulative loss of nutrients from generation to delivery to the Bay is dependent on the travel time and instream-loss rate of each individual reach. This map shows estimates of Total Nitrogen based on mean conditions for the late 1990's time period using the SPARROW model from USGS. SPARROW, or SPAtially Referenced Regressions On Watershed (SPARROW) attributes, uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed.

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