Geology topics

Research about Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia

Source-linked reports with geographic coverage including Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia.

25 records · Page 2Linked to original sources

USGS2007

Synthesis of U.S. Geological Survey science for the Chesapeake Bay ecosystem and implications for environmental management

The purpose of this report is to present a synthesis of the USGS Chesapeake Bay science related to the 2001-06 goals and provide implications for environmental management. The report provides USGS findings that address the science needs of the Chesapeake Bay Program (CBP) restoration goals and includes summaries of 1. land-use change; 2. water quality in the watershed, including nutrients, sediment, and contaminants; 3. long-term changes in climate and estuarine water quality; 4. estuary habitats, focusing on submerged aquatic vegetation (SAV) and tidal wetlands; and 5. factors affecting fish and waterbird populations.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2007

Changes in streamflow, concentrations, and loads in selected nontidal basins in the Chesapeake Bay Watershed, 1985-2006

Water-quality and streamflow data from 34 sites in nontidal parts of the Chesapeake Bay watershed are presented to document annual nutrient and sediment loads and trends for 1985 through 2006, as part of an annual evaluation of water-quality conditions by the U.S. EPA Chesapeake Bay Program. This study presents the results of trends analysis for streamflow, loads, and concentrations. Annual mean flow to the bay for 2006 (78,650 cubic feet per second) was approximately 1 percent above the long-term annual mean flow from 1937 to 2005. Total freshwater flow entering the bay for the summer season (July-August-September) was the only season classified as 'wet' in 2006. For the period 1985 through 2006, streamflow was significantly increasing at two of the 34 sites. Observed (bias-corrected) concentration summaries indicate higher ranges in concentrations of total nitrogen in the northern major river basins (Pennsylvania, Maryland, and northern Virginia) than in the southern basins in Virginia. Results indicate almost half of the monitoring sites in the northern basins exhibited significant downward bias-corrected concentration trends in total nitrogen over time; results were similar for total phosphorus and sediment. Generally, loads for all constituents at the nine River Input Monitoring Program (RIM) sites, which comprise 78 percent of the streamflow entering the bay, were lower in 2006 than in 2005. The loads for total nitrogen are below the long-term average loads at eight of the nine RIM sites and total phosphorus and sediment loads are also below the long-term average at seven RIM sites. Combined annual mean total nitrogen flow-weighted concentrations from the nine RIM sites indicated an upward tendency in 2006; in contrast, total phosphorus and sediment indicated a downward tendency. From 1990 to 2006 for the 9 RIM sites, the mean concentrations of total nitrogen, total phosphorus, and sediment were 3.49, 0.195, and 116 milligrams per liter, respectively. Flow-weighted concentrations for phosphorus and sediment were lowest in the Susquehanna River at Conowingo, Md., most likely because of the trapping efficiency of three large reservoirs upstream from the sampling point. For all 34 sites and all constituents, trends in concentrations (not adjusted for flow) showed 12 statistically significant upward trends and 59 statistically significant downward trends for the period 1985 through 2006. When trends in concentrations are adjusted for flow, they can be used as indicators of human activity and effectiveness of management actions. The flow-adjusted trends indicated significant downward trends at approximately 74, 68, and 32 percent of the sites for total nitrogen, total phosphorus, and sediment, respectively. This may indicate that management actions are having some effect in reducing nutrients and sediments.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2006

U.S. Geological Survey Chesapeake Bay Studies: Scientific Solutions for a Healthy Bay and Watershed

The U.S. Geological Survey (USGS), the science agency for the Department of Interior (DOI), has the critical role of providing objective science to document and understand ecosystem change in the Chesapeake Bay and its watershed. The human population in the Bay watershed , which grew from 8.1 million in 1950 to almost 16 million in 2000, has resulted in degraded water quality, loss of habitat, and declines in fish and bird populations. USGS scientists are leaders in understanding cause and effect of human activities and natural changes on water quality and the health of the ecosystem. The USGS interacts with resource managers and policy makers to use the science to adapt approaches for implementation, and assess effectiveness of, management actions for ecosystem conservation, restoration, and sustainability. Since the mid-1980s, the USGS has been an active partner in the Chesapeake Bay Program (CBP) , a multi-agency partnership led by the U.S. Environmental Protection Agency, working to achieve the restoration goals set forth in the Chesapeake 2000 agreement . This agreement established over 100 restoration commitments to be addressed by 2010. In 2005, which was the mid-point of the agreement, there was growing concern at all levels of government and by the public that ecological conditions in the Bay and its watershed had not significantly improved. The slow rate of improvement, coupled with the projected impact of human-population increase in the Bay watershed (fig. 1) , implied that many desired ecological conditions will not be achieved by 2010. To address these challenges, the USGS wrote a new science plan for 2006-2011 , and is synthesizing key findings to highlight the accomplishments from science activities for 2000-2005.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2002

Application of landscape models to alternative futures analyses

Scientists and environmental managers alike are concerned about broadscale changes in land use and landscape pattern and their cumulative impact on environmental and economic end points, such as water quality and quantity, species habitat, productivity, erosion potential, recreational value, and overall ecological health (Rapport et al., 1998). They also are interested in predicting short-and long-term future impacts on ecological goods and services based on current land management policies and decisions (Steinitz, 1996). Because we have the means to adjust land management policies, it is worthwhile to develop approaches that can predict the consequences (alternative futures) of different land management policies for different environmental end points. This type of analysis can, for example, allow decision makers in resource conservation and restoration programs to estimate how they can get the most ecological benefit for the least cost

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2000

Factors affecting nutrient trends in major rivers of the Chesapeake Bay Watershed

Trends in nutrient loads and flow-adjusted concentrations in the major rivers entering Chesapeake Bay were computed on the basis of water-quality data collected between 1985 and 1998 at 29 monitoring stations in the Susquehanna, Potomac, James, Rappahannock, York, Patuxent, and Choptank River Basins. Two computer models-the Chesapeake Bay Watershed Model (WSM) and the U.S. Geological Survey's 'Spatially Referenced Regressions on Watershed attributes' (SPARROW) Model-were used to help explain the major factors affecting the trends. Results from WSM simulations provided information on temporal changes in contributions from major nutrient sources, and results from SPARROW model simulations provided spatial detail on the distribution of nutrient yields in these basins. Additional data on nutrient sources, basin characteristics, implementation of management practices, and ground-water inputs to surface water were analyzed to help explain the trends. The major factors affecting the trends were changes in nutrient sources and natural variations in streamflow. The dominant source of nitrogen and phosphorus from 1985 to 1998 in six of the seven tributary basins to Chesapeake Bay was determined to be agriculture. Because of the predominance of agricultural inputs, changes in agricultural nutrient sources such as manure and fertilizer, combined with decreases in agricultural acreage and implementation of best management practices (BMPs), had the greatest impact on the trends in flow-adjusted nutrient concentrations. Urban acreage and population, however, were noted to be increasing throughout the Chesapeake Bay Watershed, and as a result, delivered loads of nutrients from urban areas increased during the study period. Overall, agricultural nutrient management, in combination with load decreases from point sources due to facility upgrades and the phosphate detergent ban, led to downward trends in flow-adjusted nutrient concentrations atmany of the monitoring stations in the watershed. The loads of nutrients, however, were not reduced significantly at most of the monitoring stations. This is due primarily to higher streamflow in the latter years of the monitoring period, which led to higher loading in those years. Results of this study indicate a need for more detailed information on BMP effectiveness under a full range of hydrologic conditions and in different areas of the watershed; an internally consistent fertilizer data set; greater consideration of the effects of watershed processes on nutrient transport; a refinement of current modeling efforts; and an expansion of the non-tidal monitoring network in the Chesapeake Bay Watershed.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS1997

Climate control

April showers bring May flowers. Well, not always. The climate of the Chesapeake Bay area, as elsewhere, varies from year to year as anyone living in the watershed the last few years can attest. That variability, though, is more than just a conversation ice-breaker. Fluctuations in seasonal rainfall affect river flows into the Bay and can hinder nutrient reduction efforts aimed at restoring the Chesapeake ecosystem because nutrient flows into the Bay are closely tied to river discharge.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS1996

January 1996 floods deliver large loads of nutrients and sediment to the Chesapeake Bay

The Blizzard of 1996 struck the Mid-Atlantic region in January, depositing a record amount of snowfall. Within two weeks of the paralyzing blizzard, warm and extremely humid air entered the region, followed by a major rainstorm. The combination of warm, humid air and heavy rainfall melted the snow at an unprecedented rate. In just over one day, two to five inches of water from snowmelt combined with two to five inches of rainfall, resulting in widespread major flooding throughout the Mid-Atlantic region, including the Chesapeake Bay watershed. The January 1996 storm caused severe flooding on many Chesapeake Bay tributaries. As a result of the flooding, large amounts of nutrients and sediment entered the Bay. The U.S. Geological Survey (USGS) monitored the amount of streamflow, nutrients, and sediment that entered the Chesapeake Bay as a result of the flood. This information is used to evaluate the effect of hydrologic events of this magnitude on the Bay's health and living resources.

Delaware, Maryland, New York, Pennsylvania, Virgin↗