Maps

An effective way to measure the health of freshwater streams and rivers is to study the many tiny critters that live in these waters, called “benthic macro-invertebrates.” The abundance and diversity of snails, mussels, insects and other bottom-dwelling organisms are good indicators of the health of streams because they can’t move very far and they respond to pollution and environmental stresses. Benthic macroinvertebrates are generally harmed by direct and indirect effects of pollutants such as metals, acidity, sediment, pesticides, nitrogen and phosphorus. These pollutants come from sources such as mining, agriculture, urban and suburban runoff, automobile and power plant exhaust, and wastewater treatment facilities. Health of streams was evaluated by the Chesapeake Bay Basin-wide Benthic Index of Biotic Integrity (or “Chessie B-IBI”), which was developed from benthic macroinvertebrate data collected across the entire Chesapeake Bay watershed from over 20 federal, state, local, and river basin commission monitoring programs throughout the Chesapeake Bay basin. Each sampling event is scored on a standardized quantitative scale that allows scoring across jurisdictional boundaries. B-IBI scores were averaged for each site over all years of sampling (2000-2010) and then qualitatively categorized in one of the following categories – very poor, poor, fair, good or excellent for a total of 15,112 scored sites. An analysis was conducted on a subset of the 15,112 sites to investigate regional variation in the B-IBI scores. The subset of sites (8,871) were chosen where a random sampling design was used. By using only randomly selected sites, BIBI scores can be averaged across the smallest feasible watershed size without introducing bias associated with sampling designs that target areas with known degraded or high quality waters. For more information see: Buchanan, C., K. Foreman, J. Johnson, and A. Griggs. 2011. Development of a Basin-wide Benthic Index of Biotic Integrity for Non-Tidal Streams and Wadeable Rivers in the Chesapeake Bay Watershed: Final Report to the Chesapeake Bay Program Non- Tidal Water Quality Workgroup. ICPRB Report 11-1. Report prepared for the US Environmental Protection Agency, Chesapeake Bay Program.

This map is a key to monitoring stations used to depict flow-adjusted concentration data for nitrogen, phosphorus, and sediment.

This map shows long-term flow-adjusted trends for suspended sediment (32 sites in the Chesapeake Bay watershed) from 1985-2009.

Long-Term Flow-Adjusted Trends for Total Phosphorus (32 Sites in the Chesapeake Bay Watershed) 1985-2009

This map shows the long-term flow-adjusted trends for total nitrogen at 32 Sites in the Chesapeake Bay Watershed from 1985-2009.

This is a key to non-tidal monitoring stations used to illustrate trend-yield data for nutrients and sediment.

Over the past 10 years, sediment concentration trends show mixed responses among the monitoring sites with the majority of results being not significant, 5 sites indicate improving conditions while 6 sites indicate degrading conditions. The trend results indicate that in some locations, management actions, such as erosion and runoff controls may have contributed to reducing sediment concentrations in streams. The short-term flow-adjusted trends and yields indicator is calculated, and results and maps are published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed.

Over the past 10 years, phosphorus concentration trends are not significant at more than half (19 of 33) monitoring sites within the Bay watershed. Improving trends were estimated at 10 sites while degrading conditions were reported at 4 sites, indicating that in some locations, management actions, such as improved wastewater treatment and nonpoint-source pollution controls (i.e. urban stormwater runoff and agricultural runoff controls), have reduced phosphorus concentrations in streams. The short-term flow-adjusted trends and yields indicator is calculated, and results and maps are published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed.

Over the past 10 years, nitrogen concentration trends are downward at about half (16 out of 33) monitoring sites within the Bay watershed. The trend results indicate that in many locations, management actions, such as improved wastewater treatment and nonpoint-source pollution controls (i.e. urban stormwater runoff and agricultural runoff controls), have reduced nitrogen concentrations in streams. In addition, in the last 5 years, higher yields indicate a tendency to be located in the northern half of the watershed, conversely. lower yields are more numerous in the lower half of the watershed. The short-term flow-adjusted trends and yields indicator is calculated, and results and maps are published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed.

In 2003, the CBP adopted the Strategy to Accelerate the Protection and Restoration of Submerged Aquatic Vegetation in the Chesapeake Bay including a commitment to plant 1,000 acres by 2008. The program partners have thus far planted 17% of their initial goal. In 2011, 0.02 acres were planted. Both funding for SAV planting, and capacity for doing it, will need to be increased dramatically to meet the goal on time.