Open-File Report 99-219 contents page

INTRODUCTION

The objective of the U.S. Geological Survey's (USGS) Chesapeake Bay Ecosystem Program is to provide information on ecosystem structure responses to changes in water quality , especially nutrients, and to climate variability. This information is used by the broad community of policy makers, resource managers, scientists, and private citizens working on the environmental restoration of the Chesapeake Bay, including the Chesapeake Bay Program (CBP) - which is coordinated by the U.S. Environmental Protection Agency (EPA). During this century, the ecosystem of the Chesapeake Bay, the Nation's largest estuary, has been adversely affected by the loss of submersed aquatic vegetation (SAV) throughout the system. These primary producers form the base of the food chain and provide critical habitat for many of the living resources of the estuary, such as finfish, shellfish, and waterfowl. Decline in SAV has been attributed primarily to decreased water clarity, in response to increases in nutrient and sediment loads that have accompanied regional population growth.

As part of the USGS mission, USGS scientists are collecting and analyzing data related to current and historical nutrient and sediment loads in the drainage basin of the Chesapeake Bay and determining linkages between water quality and the distribution and abundance of SAV in the Potomac River drainage basin. In the tidal Potomac River, since the early 1980's, there has been both a dramatic resurgence as well as a retreat of SAV. The resurgence has been attributed primarily to improved waste-water treatment leading to improved water-column clarity over this time period. (Carter and Rybicki, 1986.) At the same time, there has been a minimal but consistently positive trend in the reemergence of SAV in the Potomac Estuary . This report provides information about the variations in the areal coverage of SAV in the tidal Potomac River and Potomac Estuary in relation to variations in water-quality as defined by CBP criteria for the period 1983 through 1997.

Tidal Potomac River and Potomac Estuary Segmentation and coverage by Submersed Aquatic Vegetation
Abstract
Open-File Report 99-219 contents page