Download or read book Residence Times and Nitrate Transport in Ground Water Discharging to Streams in the Chesapeake Bay Watershed written by and published by . This book was released on 2003 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Discharge Nitrate Load and Residence Time of Ground Water in the Chesapeake Bay Watershed written by Scott W. Phillips and published by . This book was released on 1999 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Influence of Ground Water on Nitrogen Delivery to the Chesapeake Bay written by Scott W. Phillips and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Estimates of Residence Times and Apparent Ages of Ground Water in the Chesapeake Bay Watershed and Water quality Data from a Survey of Springs written by and published by . This book was released on 1998 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Estimates of Residence Times and Apparent Ages of Ground Water in the Chesapeake Bay Watershed and Water quality Data from a Survey of Springs written by and published by . This book was released on 1998 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chesapeake Bay Groundwater Toxics Loading Workshop Proceedings written by and published by . This book was released on 1993 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Nutrients in the Major Rivers Draining to Chesapeake Bay written by Donna L. Belval and published by . This book was released on 1999 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Quality Functions of Riparian Forest Buffer Systems in the Chesapeake Bay Watershed written by and published by . This book was released on 1995 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chesapeake Wetlands written by and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of Suspended sediment Data for Streams Draining the Chesapeake Bay Watershed Water Years 1952 2002 written by Allen C. Gellis and published by DIANE Publishing. This book was released on 2005 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Spatially Referenced Regression Modeling for the Evaluation of Total Nitrogen Loading in the Chesapeake Bay Watershed written by Stephen D. Preston and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sources Fate and Transport of Nitrogen and Phosphorus in the Chesapeake Bay Watershed written by Scott W. Ator and published by Geological Survey (USGS). This book was released on 2011 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spatially Referenced Regression on Watershed Attributes (SPARROW) was used to provide empirical estimates of the sources, fate, and transport of total nitrogen (TN) and total phosphorus (TP) in the Chesapeake Bay watershed, and the mean annual TN and TP flux to the bay and in each of 80,579 nontidal tributary stream reaches. Restoration efforts in recent decades have been insufficient to meet established standards for water quality and ecological conditions in Chesapeake Bay. The bay watershed includes 166,000 square kilometers of mixed land uses, multiple nutrient sources, and variable hydrogeologic, soil, and weather conditions, and bay restoration is complicated by the multitude of nutrient sources and complex interacting factors affecting the occurrence, fate, and transport of nitrogen and phosphorus from source areas to streams and the estuary. Effective and efficient nutrient management at the regional scale in support of Chesapeake Bay restoration requires a comprehensive understanding of the sources, fate, and transport of nitrogen and phosphorus in the watershed, which is only available through regional models. The current models, Chesapeake Bay nutrient SPARROW models, version 4 (CBTN_v4 and CBTP_v4), were constructed at a finer spatial resolution than previous SPARROW models for the Chesapeake Bay watershed (versions 1, 2, and 3), and include an updated timeframe and modified sources and other explantory terms.
Download or read book Changes in Streamflow and Water Quality in Selected Nontidal Basins in the Chesapeake Bay Watershed 1985 2004 written by Michael J. Langland and published by Government Printing Office. This book was released on 2007-04 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOTE: NO FURTHER DISCOUNT FOR THIS PRODUCT. Significantly reduced price. Overstock List Price Provides an analysis of water quality and streamflow data in nontidal parts of the Chesapeake Bay watershed. CD-ROM included. Related products: Water Management resources collection can be found here: https://bookstore.gpo.gov/catalog/environment-nature/water-management "
Download or read book Impact of Climate Variation and Human Adaptation on the Physical Transport Processes and Water Exchange in Chesapeake Bay written by Jiabi Du and published by . This book was released on 2017 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: The efficiencies of water exchanges in both vertical and horizontal directions reflect the overall impact of various physical processes and serve as important indicators of physical control over a variety of ecological and biogeochemical processes. The vertical exchange between surface layers and bottom layers of a waterbody has proved to exert great control over the hypoxic condition, while the horizontal exchange between an estuary and coastal ocean determines the flushing capacity of the estuary and the retention rate of riverine materials. Various processes, such as tidal flushing, tidal mixing, gravitational circulation, and lateral circulation, can affect water exchange. Therefore, water exchange processes are complex and varying in time and space in estuaries. Besides the impact of numerous forcing variables, large-scale climate oscillation, sea-level rise, and human activities can result in a change of estuarine dynamics. Two biologically relevant timescales, residence time (RT) and vertical exchange time (VET), are used in this study to quantify the overall horizontal and vertical exchange, aiming to understand the physical transport control over the ecosystem functioning in a simpler way. A long-term simulation of VET in the Chesapeake Bay over the period of 1980-2012 revealed a high spatial and seasonal similarity between VET and the dissolved oxygen (DO) level in the mainstem of the Chesapeake Bay, suggesting a major control over the DO condition from the physical transport. Over the past three decades, a VET of about 20 days in the summer usually indicates a hypoxic condition in the mainstem. Strong correlation among southerly wind strength, North Atlantic Oscillation index, and VET demonstrates that the physical condition in the Chesapeake Bay is highly controlled by the large-scale climate variation. The relationship is most significant during the summer, during which time the southerly wind dominates throughout the Chesapeake Bay. By combining the observed DO data with modeled VET, decoupling the physical and biological effect on the DO condition becomes possible. Bottom DO consumption rate was estimated through a conceptual model that links DO with VET. Using observed DO data and modeled VET, the overall biological effect on the DO condition can be quantified. The estimated bottom DO consumption rate shows strong seasonal variation and its interannual variation is highly correlated with the nutrient loading. The response of an estuary ecosystem to a change of nutrient loading depends on the flushing capacity of the estuary, which is related to the horizontal water exchange. The overall flushing capacity can be quantified by resident time, which determines the retention and export rates of materials discharged in the estuary. The horizontal exchange in Chesapeake Bay was investigated over the period of 1980-2012. Quantified by the residence time (RT), the horizontal exchange in Chesapeake Bay exhibits high interannual and spatial variability. The 33-year simulation results show that the mean RT of the entire Chesapeake Bay system ranges from 110 to 264 days, with an average value of 180 days, which is smaller than 7.6 months (approximately 230 days) reported in previous studies. There is significant lateral asymmetry of RT in the mainstem, with a larger RT along the eastern bank than that along the western bank in the lower Bay, which is mainly attributed to the horizontal shearing of estuarine circulation and large freshwater input along the western bank. Because of the persistent stratification and estuarine circulation, the vertical difference between the surface RT and bottom RT is dramatic, with a difference as large as 100 days. Relations among RT, river discharge, and strength of estuarine circulation reveal that the variation of horizontal exchange is mainly controlled by the river discharge and modulated by the estuarine circulation. A strengthened estuarine circulation will enhance the water exchange and reduce the RT. By affecting the estuarine circulation, wind forcing has a great impact on the horizontal exchange. The horizontal and vertical exchanges, together, contribute to the unique pattern of riverine material redistribution in Chesapeake Bay. By conducting long-term numerical simulations using multiple passive tracers that are independently released in the headwater of five main rivers (i.e., Susquehanna, Potomac, Rappahannock, York, and James Rivers), the relative contribution of discharge from each river to the total material in the mainstem can be calculated. The results show that the discharge from Susquehanna River has the dominant control on the riverine material throughout the entire mainstem. Despite the smaller contribution from the lower-middle Bay tributaries to the total materials in the mainstem, materials released from these rivers have a high potential to be transported to the middle-upper Bay through the bottom inflow by the persistent estuarine circulation. Depending on the magnitude of river discharge and the location of the tributary, material released at the headwaters of the main five rivers contributes differently to the riverine material in the mainstem. Material released in the upper estuary tends to have a longer residence time and a larger contribution, while materials released near the mouth are subject to a rapid flushing process, a small retention time, and a strong shelf-current induced dilution. The results reveal three distinct spatial patterns for materials released from the main river, tributary, and coastal oceans. One of the potential factors to change the exchange processes is the degree of human activities, such as construction of large infrastructures. With projected intensified hurricane and an accelerated sea-level rise in the 21st century, building storm surge barriers to mitigate the flooding risk has been considered as feasible climate change adaptation strategies in many coastal areas, which will surely affect the ecosystem functioning by affecting the water exchange. Two types of partially embanked storm surge barriers across the mouth of Chesapeake Bay were examined. Under modeled scenarios, surge barriers exert a significant influence on the tide, salinity, residual current, and transport processes. The vertical exchange is weakened, mainly due to the reduction of tidal range and tidal mixing. Even though the stratification is enhanced, the estuarine circulation is weakened due to accumulation of freshwater in the downstream and a decreased horizontal salinity gradient. The overall horizontal exchange is weakened due to a barrier, but the impact varies spatially.
Download or read book Achieving Nutrient and Sediment Reduction Goals in the Chesapeake Bay written by National Research Council and published by National Academies Press. This book was released on 2011-09-26 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Chesapeake Bay is North America's largest and most biologically diverse estuary, as well as an important commercial and recreational resource. However, excessive amounts of nitrogen, phosphorus, and sediment from human activities and land development have disrupted the ecosystem, causing harmful algae blooms, degraded habitats, and diminished populations of many species of fish and shellfish. In 1983, the Chesapeake Bay Program (CBP) was established, based on a cooperative partnership among the U.S. Environmental Protection Agency (EPA), the state of Maryland, and the commonwealths of Pennsylvania and Virginia, and the District of Columbia, to address the extent, complexity, and sources of pollutants entering the Bay. In 2008, the CBP launched a series of initiatives to increase the transparency of the program and heighten its accountability and in 2009 an executive order injected new energy into the restoration. In addition, as part of the effect to improve the pace of progress and increase accountability in the Bay restoration, a two-year milestone strategy was introduced aimed at reducing overall pollution in the Bay by focusing on incremental, short-term commitments from each of the Bay jurisdictions. The National Research Council (NRC) established the Committee on the Evaluation of Chesapeake Bay Program Implementation for Nutrient Reduction in Improve Water Quality in 2009 in response to a request from the EPA. The committee was charged to assess the framework used by the states and the CBP for tracking nutrient and sediment control practices that are implemented in the Chesapeake Bay watershed and to evaluate the two-year milestone strategy. The committee was also to assess existing adaptive management strategies and to recommend improvements that could help CBP to meet its nutrient and sediment reduction goals. The committee did not attempt to identify every possible strategy that could be implemented but instead focused on approaches that are not being implemented to their full potential or that may have substantial, unrealized potential in the Bay watershed. Because many of these strategies have policy or societal implications that could not be fully evaluated by the committee, the strategies are not prioritized but are offered to encourage further consideration and exploration among the CBP partners and stakeholders.
Download or read book Effect of Residence Time on Net Nitrate Retention in Flow regulated Backwaters of the Upper Mississippi River written by William F. James and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Watershed Hydrology written by Vijay P. Singh and published by Allied Publishers. This book was released on 2003 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
