Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay Watershed, 1985-2004

Michael J. Langland; Jeff P. Raffensperger; Douglas Moyer; Jurate M. Landwehr; Gregory E. Schwarz

doi:10.3133/sir20065178

Home/Archive/USGS

USGS · sir20065178

Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay Watershed, 1985-2004

Michael J. Langland·Jeff P. Raffensperger·Douglas Moyer·Jurate M. Landwehr·Gregory E. Schwarz

View original source ↗Export metadata ↓

Abstract

As part of an annual evaluation of water-quality conditions by the Chesapeake Bay Program, water-quality and streamflow data from 32 sites in nontidal parts of the Chesapeake Bay watershed were analyzed to document annual nutrient and sediment trends for 1985 through 2004. This study also formalized different trend tests and methodologies used in assessing the effectiveness of man-agement actions in reducing nutrients and sediments to the Chesapeake Bay. Trends in streamflow were tested at multiple time scales (daily, seasonal, and annual), resulting in only one significant trend (annual-mean streamflow for the Choptank River near Greensboro, Md.). Total freshwater flow entering the bay for the July-August-September 'summer' season 2004 was the highest ever estimated for that 3-month period (1937-2004). Observed (unbiased) concentration summaries indi-cate higher ranges in total-nitrogen concentrations in the northern major river basins, those in Pennsylvania, Maryland, and northern Virginia, compared to the more southern basins in Virginia. Almost half of the monitoring sites in the northern basins exhibited significant downward trends in total nitrogen with time. Comparisons with total phosphorus and sediment showed similar results to total nitrogen. Monthly and annual loads were available for the River Input Monitoring Program sites from the U.S. Geological Survey. Although loads were significantly reduced from 2003, in 2004, the combined estimated total nitrogen loads were the third highest since 1990, whereas total phosphorus and sediment loads were the fifth highest. A flow-weighted concentration (FWC) is useful in evaluating changes through time. Combined annual mean total nitrogen FWC from the 9 River Input Monitoring Program sites indicated a downward tendency from 1985 through 1998 and an upward tendency since 2001. From 1990 to 2004, the mean concentrations of total nitrogen, total phosphorus, and sediment were 1.58, 0.085, and 51 milligrams per liter, respectively. Flow-weighted concentrations for phosphorus and sediment were lower in the Susquehanna River at Conowingo, Md., most likely due to the trapping efficiency of three large reservoirs upstream from the sampling point. Trends in concentrations, not adjusted for flow, identified 10 statistically significant upward trends, and 50 statistically significant downward trends in concentration for the period 1985 through 2004. Trends in concentrations, when adjusted for flow, can be used as an indicator of human activity and management actions. The flow-adjusted trends indicated significant downward trends at approx-imately 72, 81, and 43 percent of the sites for total nitrogen, total phosphorus, and sediment, respectively. This indicates that management actions are having some effect in reducing nutrients and sediments.

Explore related subjects

Scientific Investigations Report Report

Source-reported bounding extent: 36.48314061639213° to 42.98053954751642° latitude; -80.771484375° to -74.278564453125° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Michael J. Langland, Jeff P. Raffensperger, Douglas Moyer, Jurate M. Landwehr, Gregory E. Schwarz. 2006. Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay Watershed, 1985-2004. https://doi.org/10.3133/sir20065178

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Monitoring recreation on federally managed lands and waters—Aspects of visitor use

Federally managed public lands and waters receive around 1 billion recreational visits each year. Data on these visitors can aid in guiding policy decisions, managing resources effectively, and communicating the economic contributions of lands and waters. This report explores the methods used by agencies to collect data on aspects of recreational visitor use to Federal lands and waters (apart from visitation numbers, which are the focus of a companion publication). Aspects of recreational visitor use include visitor demographics, recreational activity participation, visitor satisfaction, visitor attitudes and experiences, trip characteristics, and economic contributions. We review practices used to understand aspects of visitor use across seven Federal agencies, revealing similarities such as the use of visitor intercept surveys and coverage of similar topic areas, and differences in how survey programs are operationalized and how specific questions on visitor surveys are worded. We also evaluate emerging technologies, such as geolocated social media and mobile device location data, for their potential to aid in understanding aspects of visitor use. This report concludes with potential opportunities to enhance data collection and coordination, ensuring cost-effective data collection and informed decision making.

Scientific Investigations Report↗

USGS2026

Evaluation of best management practices at an edge-of-field site in the Eagle Creek watershed, Ohio, 2012–20

In 2010, the U.S. Geological Survey worked in partnership with the Great Lakes Restoration Initiative and the Natural Resources Conservation Service to identify farm fields in priority watersheds—watersheds critically important to Great Lake health. Intensive best management practices were implemented in five States to test the efficacy of best management practices, also referred to as agricultural conservation practices, to reduce sediment and nutrient runoff on agricultural fields. These fields were chosen as representatives of the priority watersheds because their farming practices and geographical conditions were common among farms in those watersheds. A farm site located near Findlay, Ohio, in the Eagle Creek watershed used two conservation practices, cover crop (Natural Resources Conservation Service practice standard 340) and variable rate technology (VRT; Natural Resources Conservation Service practice standard 590), which represent common practices in the Maumee priority watershed. This study monitored surface runoff and subsurface tile runoff at the Eagle Creek watershed site. The effects of cover crop and VRT nutrient application on sediment and nutrient runoff were assessed from October 2012 to September 2020. Cover crops were applied in fall of 2016, 2017, and 2018, coinciding with VRT applications. The following parameters were analyzed as part of the study: runoff discharge; peak discharge; and concentrations and loads of total phosphorus, particulate phosphorus, dissolved reactive phosphorus, and suspended sediment. High peak runoff events disproportionally affected nutrient concentrations and loads in runoff. A threshold of the 85th percentile of the peak discharge was chosen to assess the effect of cover crop and VRT nutrient application on nutrient mitigation at each gage. Runoff events below the 85th percentile were considered small, and runoff events over the 85th percentile were considered large. Concentrations from collected water-quality samples were used for the analysis; estimated concentrations were excluded from the statistical evaluation. All surface runoff parameters during small runoff events, except surface runoff volume, were significantly lower in the period with cover crops and VRT implementation. Contrarily, subsurface runoff parameters during small events were not statistically different between the periods with and without cover crops and VRT implementation. Surface and subsurface parameters during large events were also not statistically different between the periods with and without cover crops and VRT implementation. These results indicate cover crops and VRT may improve water quality during small runoff events, but additional best management practices that mitigate large runoff events may lead to greater water-quality improvement given the contribution of large events to overall losses.

Ohio↗

USGS2026

Continuous monitoring and temporal variability of fluorescence of dissolved organic matter in karst groundwater of the Edwards aquifer, south-central Texas, 2019–24

Widespread urbanization on the Edwards aquifer recharge zone in south-central Texas has prompted the development of new approaches and tools for evaluating the current and future status of water quality in the San Antonio and Barton Springs segments of the Edwards aquifer. The U.S. Geological Survey, in cooperation with the San Antonio Water System and the City of Austin, applied continuous monitoring of fluorescence of dissolved organic matter (fDOM) to characterize the sources and transport of dissolved organic matter and associated constituents in the Edwards aquifer. Continuous fDOM time-series data were adjusted using empirically derived temperature, turbidity, and inner-filter-effect correction factors prior to analysis and interpretation. Fully corrected fDOM time-series data from the study sites were evaluated for short- and long-term temporal variability in fDOM in the context of the hydrologic and climatic conditions that occurred during the 5-year study period to understand vulnerability of the aquifer to potential contaminants in recharge. Study results indicate that fDOM is an effective proxy for dissolved organic carbon that, in turn, is indicative of the influx of recent surface water and associated contaminants, and thus, aquifer vulnerability to those contaminants. Although other continuously monitored water-quality parameters provide insights into changes in water quality in response to varying hydrologic conditions, the quantitative relation between fDOM and dissolved organic carbon directly indicates the timing and magnitude of pulses of organic constituents derived from the land surface, whereas other water-quality parameters do not.

Texas↗