Project period: 9 1 23-2 28 25PROJECT title: assessing stream health in the chesapeake BAY watershedrecent efforts to synthesize understanding of the state of freshwater health within the chesapeake…

Project period: 9 1 23-2 28 25PROJECT title: assessing stream health in the chesapeake BAY watershedrecent efforts to synthesize understanding of the state of freshwater health within the chesapeake BAY watershed have been hampered by lack of data over large portions of the basin. These data shortcomings make IT difficult to make confident statements about the current state of freshwater health throughout the watershed. BAY program assessments of ecosystem condition use indices of biotic integrity to because biota integrate biotic and abiotic factors over both timeand space. Many states have employed indices to develop probabilistic stressor-response models to guide regulation and rehabilitation efforts. As new monitoring approaches are developed and the list of potential stressors to both tidal and nontidal portions of the BAY watershed grows, there growing interest within state and federal agencies to understand whether current monitoring programs are sufficient for meeting long-term strategic goals of the BAY program. Part 1 of the proposed work will be to host a workshop that will draw regional and national experts tosynthesize relevant issues and make recommendations regarding the adequacy of freshwater assessment and monitoring within the BAY program. Deliverables will include a synthetic report from the workshop that we hope will provide useful guidance for managers as well as in policy and regulatory contexts. In response to calls from the BAY program, a hyper-resolution hydrography has been developed for the watershed. Review of draft linework indicates IT will increase the drainage density of the chesapeake basin by at least two and a half times. Pending release of this dataset has profound implications for strategic goals involving tracking stream health improvements in ten percent of stream miles since IT will shortly be clear to anyone that most stream miles have, until recently, remained unmapped. Given the geomorphic origin of the hyper-resolution flowlines, IT remains uncertain what fraction represents perennial flow capable of supporting aquatic life and thus subject to monitoring and assessment requirements under the same federal statute governing total maximum daily loads (tmdl). Therefore, there is a clear need for cost effective, scalable, and spatially explicit predictions of perennial flow. Two essential components of effective flow mapping include geographic predictions and distributed field observations. To date, much of the understanding of stream flow conditions has come from hydrologic models or statistical extrapolations of stream gauge statistics based on drainage area attributes. What has been lacking in many of these approaches is spatially explicit validation of flow conditions, particularly in headwater channels. Fortunately, recent technological advances have identified new opportunities for enriching geographic understanding of flow permanence. Part 2 of the proposed work will involve assessing the data available for developing geographic predictions of flow permanence and intermittency across the BAY watershed. For several subbasins, will install cameras and temperature sensors as remote detectors of flow in headwater channels mapped by the new linework. The goal is to explore the utility of a broad range of extant and novel geographic approaches to predict stream flow characteristics and to assess the ability, cost-effectiveness, and scalability of remote sensors for validating those predictions. Deliverables include a report on our findings as well as a system for obtaining an extensive yet spatially explicit set of flow observations at scales relevant for widespread flow modeling. Intended beneficiaries include state and federal agencies tasked with managing and monitoring stream flow or aquatic life, as well as the general public.