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Cross-Media Models for the Chesapeake Bay Watershed and Airshed

A continuous deterministic environmental model of the Chesapeake Bay Watershed (HSPF), linked to an atmospheric deposition model (RADM) is used to examine nutrient loads to the Chesapeake Bay under different management scenarios. Model structures and calibration are generally described. Averaged over a ten-year simulation, loads under a limit-of-technology setting throughout the watershed are a 50% and 65% reduction from loads reflecting 1985 condition and in total nitrogen and total phosphorus, respectively. Urban loads which include discharges from point sources, on-site wastewater, disposal systems, combined sewer overflows and both pervious and impervious non-point sources, have the highest nutrient fluxes to the Chesapeake Bay among major land uses.

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Innovation in Agricultural Conservation for the Chesapeake Bay: Evaluating Progress and Addressing F

Available in digital format and hardcopy. The Scientific and Technical Advisory Committee (STAC), in cooperation with the USDA and the Mid-Atlantic Water Quality Program, convened a forum on innovation in agricultural conservation in May 2003. Leading experts on various aspects of agricultural nutrient pollution control from the Bay region and beyond discussed current, emerging, and future practices, technologies, and policies that can help to achieve needed nutrient reduction goals within a sustainable agricultural system. Twenty-eight speakers and discussion leaders provided their vision for innovation, while discussion among scientists, engineers, economists, and practitioners broadened and diversified the vision. The forum included factors that influence the adoption of innovation and policies and approaches to implementing innovation. This White Paper identifies emerging science-based practices, programs, and policies that can be implemented within three years as well as developing efforts that will aid nutrient reduction within a 10-year timeframe, including the research and education necessary for that implementation.

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Suspension Feeders: A Workshop to Assess What We Know, Don't Know and Need to Know to Determine thei

Available in digital format and hardcopy. Phytoplankton standing stocks, production, and species composition are potentially influenced by both the supply of nutrients to the bottom of the food web and removal by suspension feeders higher in the food web. Similarly, suspended sediment concentrations are determined by both their loading rates and their removal or settlement from the water column. Most management activities to date in the Chesapeake Bay watershed have addressed the supply end of these relationships by attempting to reduce nutrient and sediment loading to waters within the Chesapeake Bay watershed. However, to predict the relationship between nutrient or sediment loading and water quality, it is also important to understand and predict the potential top-down effect of suspension feeders such as menhaden, zooplankton, bivalves, and other benthic invertebrates on phytoplankton and suspended sediment. The current Chesapeake Bay agreement includes the commitment: By 2004 assess the effects of different population levels of filter feeders such as menhaden, oysters, and clams on Bay water quality and habitat. This workshop, sponsored by the Scientific and Technical Advisory Committee (STAC), was a response to this commitment. The workshop report summarizes discussions and outlines steps recommended to meet the filter feeder commitment.

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The Phosphorus Detergent Ban

The phosphorus detergent ban was implemented in the Bay signatory jurisdictions in the mid to late eighties. After the ban's implementation, it became clear that the ban resulted in a significant reduction of discharge in phosphorus from wastewater treatment plants, the ban did not cost the consumer money, and the ban often resulted in O & M cost savings for the wastewater treatment plants. Phosphorus bans limit, to trace amounts, the amount of phosphorus that can be used in detergents and other cleaning products. The P ban resulted watershed wide in a reduction of influent P concentrations of 25-30% to wastewater treatment plants. Phosphorus loads to the bay declined by 6 million pounds per year between 1985-1996.

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Ammonia and the Chesapeake Bay Airshed

This report is a review and assessment of the existing literature on the following topics: distribution of sources and atmospheric concentrations and deposition of ammonia and watershed cycling of NHx.

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Best Management Practices for Sediment Control and Water Clarity Enhancement

The Chesapeake Bay Program (CBP) hosted a workshop in Annapolis, Maryland on February 24-25, 2003, at which sediment experts shared information related to sediment best management practices (BMPs). The information presented on selected BMPs has been summarized in this document, and is intended to assist the CBPs Sediment Workgroup (SedWG) and others as they move to the next generation of sediment controls and other practices to improve water clarity in riverine, tidal and near shore areas. In order to provide a thorough summary of each BMP to the workgroup, experts from within the CBP community have contributed to the presenters information. Each final BMP summary has received the approval of the expert who presented the information at the workshop.

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