Session Lead: Lauren McPhillips
Session Co-lead: Jonathan Duncan
Session format: Oral presentation
Abstract:
Major investments have been made in implementing agricultural and urban best management practices (BMPs) to manage nutrient pollution in the Chesapeake Bay watershed. Traditionally, we represent expected benefits of BMPs as ‘percent efficiencies’ where there is some expected reduction in concentration and loads of nutrients and sediment between where water is entering a BMP and when it is leaving. These expected efficiencies vary by BMP type (e.g. bioretention swale vs vegetated filter strip) and may have other assumed dependencies (e.g. BMP size). There are many factors that are not well-captured in this way of representing expected BMP nutrient performance. Examples include temporal variability due to different size storm events; long-term changes due to lack of maintenance, spatial dependence of performance (ie., certain locations in the landscape are more hydrologically optimal), or critical thresholds of BMP implementation required to detect reductions in nutrient loads at the watershed-scale. All of these factors contribute to a failure to detect reductions in nutrient loads at the watershed-scale that are comparable in magnitude to what watershed models might predict. Here, we intend to convene a series of speakers who have addressed some of these challenges related to actual BMP performance in both urban and agricultural settings. Possible speakers in this session include Kristina Hopkins (USGS), Theodore Lim (Virginia Tech), Heather Gall (PSU), Tom Fisher (UMCES emeritus), and Claire Welty (UMBC).