Spatial and temporal variation of stream chemistry associated with contrasting geology and land-use patterns in the Chesapeake Bay watershed—Summary of results from Smith Creek, Virginia; Upper Chester River, Maryland; Conewago Creek, Pennsylvania; and Difficult Run, Virginia, 2010–2013

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AcknowledgmentsFunding for this study was provided by the U.S. Geological Survey (USGS) Ecosystems Mission Area as part of the Priority Ecosystem Science (PES) Program. Sincere appreciation is extended to the many landowners in all four study watersheds who provided us with access to many of the study sites. Cooperation from the U.S. Department of Agriculture, Natural Resources Conservation Service, as well as the Soil and Water Conservation Service, was instrumental for better understanding each basin and for gaining access to study sites. Additional contributions of data and information were made by the Virginia Department of Environmental Quality, Pennsylvania Department of Environmental Protection, the Maryland Department of Natural Resources, and the U.S. Environmental Protection Agency. Appreciation is extended to the Stormwater Planning Division of the Fairfax County Department of Public Works and Environmental Services for supporting elements of water-quality monitoring in Difficult Run that were incorporated into this report and for providing data on the implementation of best management practices throughout Difficult Run.We are indebted to the many USGS field technicians and hydrologists who have contributed to the collection of field samples and other technical content throughout the report. Technical reviews by Doug Burns of the USGS New York Water Science Center and Angie Crain of the USGS Indiana-Kentucky Water Science Center strengthened this report and are sincerely appreciated. AbstractDespite widespread and ongoing implementation of conservation practices throughout the Chesapeake Bay watershed, water quality continues to be degraded by excess sediment and nutrient inputs. While the Chesapeake Bay Program has developed and maintains a large-scale and long-term monitoring network to detect improvements in water quality throughout the watershed, fewer resources have been allocated for monitoring smaller watersheds, even though water-quality improvements that may result from the implementation of conservation practices are likely to be first detected at smaller watershed scales.In 2010, the U.S. Geological Survey partnered with the U.S. Environmental Protection Agency and the U.S. Department of Agriculture to initiate water-quality monitoring in four selected small watersheds that were targeted for increased implementation of con...

Sediment Fingerprinting to Delineate Sources of Sediment in the Agricultural and Forested Smith Creek Watershed, Virginia, USA

“…The TMDL implementation plan estimated the annual sediment load for Smith Creek as 13,648 Mg/yr, which is 218% higher than the loads reported by the USGS (6,260 Mg/yr; water years 2011–2013) (Hyer et al. ) (Table ). Differences in the reported loads are due to the different time periods examined — 2009 for the implementation plan and 2011–2013 for the USGS data — as well as the different methods used to calculate loads.…”

“…Annual allocation of sediment sources based on weighted‐sediment fingerprinting results at the USGS gage applied to Smith Creek's annual suspended‐sediment load, 2011–2013 (6,260 Mg/yr) (Hyer et al. ).…”

“…Using the weighted‐sediment apportionment results (Table a) and applying it to the average water year suspended‐sediment load for Smith Creek (2011–2013; 6,260 Mg/yr) (Hyer et al. ) shows the following mass contributions by source: streambanks = 4,758 Mg/yr; pasture = 626 Mg/yr; forest = 563 Mg/yr; and cropland = 313 Mg/yr (Figure ).…”

“…The USGS computed suspended‐sediment loads using the relation between discharge, turbidity, and suspended‐sediment concentrations (Hyer et al. ). The Sediment TMDL allocations are based on the Generalized Watershed Loading Functions model, which incorporates the Universal Soil Loss Equation to generate sediment (Haith et al.…”

Floodplain Trapping and Cycling Compared to Streambank Erosion of Sediment and Nutrients in an Agricultural Watershed

“…A large number of confined poultry operations (32 permitted for commercial use), dairy farm operations (18 Grade A), and beef cattle feedlots (30) also occur in the watershed (United States Department of Agriculture, Natural Resources Conservation Service ; Hyer et al. ).…”