RD35 - Annual Report on Environmental Conditions in the Chesapeake Bay and Its Tributaries


Executive Summary:
Introduction

This section presents a very general overview of selected water quality conditions in the tidal portions of the Virginia Chesapeake Bay and its major tributary basins (Potomac, Rappahannock, York, James, and Eastern Shore). Much more comprehensive and detailed analyses are available for each major Bay basin by contacting the Department of Environmental Quality's Chesapeake Bay Program.

Water quality conditions are presented here through a combination of the current status and long-term trends for nutrients (nitrogen and phosphorus), chlorophyll, water clarity, suspended solids, and dissolved oxygen. These are the water quality indicators most directly affected by nutrient and sediment reduction strategies.

The Virginia Chesapeake Bay and its tidal tributaries continue to show environmental trends indicating progress toward restoration to a more balanced and healthy ecosystem. However, the Bay system remains stressed and some areas and indicators show continuing degradation. Progress in reducing nutrient inputs has made demonstrable improvements and it is expected that continued progress toward nutrient reduction goals, along with appropriate fisheries management and chemical contaminant controls, will result in additional improvements to the Bay. Findings from the last 19 years (1985 through 2003) of the monitoring programs are highlighted below and discussed further in the following sections.

• Overall, in Virginia's portion of the Chesapeake Bay drainage area, the 2003 annual nutrient loads discharged by significant point sources were reduced by 53% for phosphorus and 30% for nitrogen, compared to 1985 baseline loads.

• Estimates for the delivered loads of phosphorus, nitrogen and sediment from nonpoint sources, as calculated by the Bay Program Watershed Model, have decreased by 13%, 11%, and 12%, respectively, compared to 1985 levels.

• Phosphorus levels in water entering from the Bay watershed are reflecting both point and nonpoint source nutrient source reductions by showing improving concentration trends in some rivers, while degrading in others. Within the tidal waters themselves there are several areas showing improvement but also some degrading areas. Overall, there were eight areas showing improving trends and ten areas showing degrading trends for phosphorus.

• For nitrogen, the Potomac shows improving trends in water entering from the watershed. Nitrogen levels also showed improving trends in much of the tidal rivers and the Chesapeake Bay. Degrading trends are a concern in the upper Pamunkey River. Overall, there were thirteen areas showing improving trends and only one area showing degrading trends for nitrogen.

• Chlorophyll concentrations (an indicator of algae levels) are relatively poor throughout parts of Virginia's tidal waters. There were widely scattered areas of improving and degrading trends. Overall, five areas showed degrading trends in chlorophyll and five areas showed an improving trend. These results indicate nutrient concentrations are still too high despite relatively widespread improving trends in nitrogen. Initial assessment of recently proposed regulatory criteria (revised tidal water quality standards) indicates fairly widespread areas of non-attainment in the James River.

• Levels of dissolved oxygen are improving in geographically widespread areas of the tidal rivers. However, an assessment of oxygen conditions in relation to recently proposed regulatory criteria shows many areas of impairment. Overall, there were eight areas showing improving trends and one area showing degrading trends for dissolved oxygen conditions.

• Water clarity, a very important environmental parameter for the growth and survival of underwater grasses, was generally fair and degrading trends were detected in many areas. This degradation is probably related to scattered areas of increasing levels of suspended solids. These degrading conditions are a major impediment to restoration of submerged aquatic vegetation (SAV). Overall, there are twelve areas showing degrading trends and no areas showing improving trends in water clarity. An initial assessment of recently proposed regulatory criteria indicates fairly widespread areas of non-attainment.

• The Elizabeth River is showing improving trends in most major water quality parameters.

• Water quality in creeks and inlets of Virginia's Eastern Shore indicates high groundwater nutrient levels, most likely due to agricultural activities.

• In summary, there are generally improving conditions for nitrogen and dissolved oxygen and degrading conditions for water clarity. Other parameters show a roughly equal mix of both improving and degrading trends. These patterns are a combined result of both management controls of nutrient inputs and the natural effects of rainfall (e.g., the drought that ended in 2003).