Impacts of Land-Use Changes on Chesapeake Bay Sediment Sources, Sinks and Oxygen

Chesapeake Bay Ecosystem History And Response to Land-Use Change in the Chesapeake Bay Watershed

The Chesapeake Bay Program has identified excess sediment in the bay as a major factor affecting water clarity in the bay. Therefore, sediment reduction strategies are being developed to improve water clarity, habitats for submerged aquatic vegetation, and other living resources. Development of sustainable strategies requires an understanding of patterns of sedimentation in the bay and tributaries over time scales ranging from annual to centennial, as well as the impact of altered sediment patterns on biotic components (benthos, phytoplankton, submerged aquatic vegetation). Sedimentation patterns are affected by changes in land cover and by natural climatic processes (i.e., precipitation, sea-level rise); a comprehensive assessment of sediment flux in the bay and its tributaries should include sites with very high and very low sediment influx. Because the Chesapeake Bay Program is committed to reducing sediment input to the bay, an understanding of the relative influences of land cover change and climate variability on estuarine sedimentation is critical to develop realistic reduction goals.

Task objectives include:

• Evaluate temporal and spatial patterns of sediment accumulation in critical regions of Chesapeake Bay over decadal to centennial time scales.

• Assess the relative roles of land-cover changes and natural climate variability in altering sediment supply, nutrient influx, and other environmental parameters.

For more information:

• Dissolved Oxygen Trends of Last Century

• Sedimentation Trends of Last Three Centuries