Nutrient and Sediment Trends in the Chesapeake Bay Watershed. Prepared by the U.S. Geological Survey, Principals’ Staff Committee Meeting, May 2012 The U.S. Geological Survey (USGS), in partnership with the Chesapeake Bay Issue: Program (CBP), uses the CBP nontidal monitoring network (map 1) to measure changes in nutrients and sediment in the Chesapeake Bay watershed. The data from the network are summarized in an upcoming USGS report about trends of nitrogen, phosphorous, and sediment concentrations in the Bay watershed. The trends are part of the proposed integrated approach to better assess and communicate progress toward attainment of water-quality standards and relation to practices being implemented for the Bay TMDL. Results from Upcoming USGS Report on Trends in Nutrients and Sediment: Watershed trends for nitrogen, phosphorus and sediment are provided for two periods, long-term changes (1985-2010) and over 10 years (2001-2010). Long-term changes are provided for 31 sites while trends for the last 10 year are provided for 33 sites (see table). Nitrogen Trends Since 1985, nitrogen concentrations have improved (decreased) at Long term: about two thirds of the monitoring stations. Two sites showed degrading conditions (see map 2). Over the past 10 years, improvements were observed at just under Short term: half of the monitoring sites, while most sites had no significant change. Phosphorus Trends Since 1985, phosphorus concentrations have improved at 70 Long term: percent of monitoring sites and worsened at 4 sites (see map 3). Over the past 10 years, phosphorus concentrations improved at Short term: 1/3 of the sites, while most sites had no significant change. Sediment Trends Since 1985, sediment has decreased at about 30 percent of the Long term: sites. About 40 percent of the sites showed no significant change (see map 4). Only 3 sites showed improvements, 9 sites showed degrading Short term: conditions with most sites showing no significant trends. Summary of trends for nitrogen, phosphorus, and sediment in the Bay watershed Pollutant Improving Degrading Sites with Trend Period sites sites No Trend Nitrogen Long Term 1985-2010 21 2 8 Recent 2000-2010 14 2 17 Phosphorus Long Term 1985-2010 22 4 5 Recent 2000-2010 12 4 17 Sediment Long Term 1985-2010 10 8 13 Recent 2000-2010 3 9 21
Nutrient and Sediment Trends in the Chesapeake Bay Watershed. Prepared by the U.S. Geological Survey, Principals’ Staff Committee Meeting, May 2012 Issue: The U.S. Geological Survey (USGS), in partnership with the Chesapeake Bay Program (CBP), uses the CBP nontidal monitoring network (map 1) to measure changes in nutrients and sediment in the Chesapeake Bay watershed. The data from the network are summarized in an upcoming USGS report about trends of nitrogen, phosphorous, and sediment concentrations in the Bay watershed. The trends are part of the proposed integrated approach to better assess and communicate progress toward attainment of water-quality standards and relation to practices being implemented for the Bay TMDL. Results from Upcoming USGS Report on Trends in Nutrients and Sediment: Watershed trends for nitrogen, phosphorus and sediment are provided for two periods, long-term changes (1985-2010) and over 10 years (2001-2010). Long-term changes are provided for 31 sites while trends for the last 10 year are provided for 33 sites (see table). Nitrogen Trends Long term: Since 1985, nitrogen concentrations have improved (decreased) at about two thirds of the monitoring stations. Two sites showed degrading conditions (see map 2). Short term: Over the past 10 years, improvements were observed at just under half of the monitoring sites, while most sites had no significant change. Phosphorus Trends Long term: Since 1985, phosphorus concentrations have improved at 70 percent of monitoring sites and worsened at 4 sites (see map 3). Short term: Over the past 10 years, phosphorus concentrations improved at 1/3 of the sites, while most sites had no significant change. Sediment Trends Long term: Since 1985, sediment has decreased at about 30 percent of the sites. About 40 percent of the sites showed no significant change (see map 4). Short term: Only 3 sites showed improvements, 9 sites showed degrading conditions with most sites showing no significant trends. Summary of trends for nitrogen, phosphorus, and sediment in the Bay watershed Pollutant Trend Period Improving sites Degrading sites Sites with No Trend Nitrogen Long Term 1985-2010 21 2 8 Recent 2000-2010 14 2 17 Phosphorus Long Term 1985-2010 22 4 5 Recent 2000-2010 12 4 17 Sediment Long Term 1985-2010 10 8 13 Recent 2000-2010 3 9 21
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