Scientific and Technical Advisory Committee Publications

“Ecosystem services” are the benefits ecosystems provide to people. These benefits include providing food, clean air, clean water, recreation, and many other explicit or intrinsic values to people and communities. Investments in Chesapeake Bay restoration are typically designed to improve water quality, given the legal requirements of the Clean Water Act. The Chesapeake Bay Watershed Agreement sets goals that encompass a wide range of ecosystem services. A narrow focus on water quality can result in the implementation of practices and policies that maximize nutrient and sediment reductions at the expense of feasible alternatives that offer greater ecosystem services or multiple benefits to living resources and communities.

This workshop was designed to gather input from a diverse array of stakeholders to help shape a coherent framework to identify impactful and durable ways to embed ecosystem services considerations in decision-making. This framework is critical to drive change for both the Chesapeake Bay Total Maximum Daily Load (TMDL) and for multiple lagging outcomes in the 2014 Watershed Agreement that provide ecosystem service benefits beyond water quality. As jurisdictions are doubling down on their efforts to meet the TMDL 2025 target date and large investments are being made in environmental restoration and conservation, there is an opportunity to work strategically to achieve a broader set of goals for ecosystems and communities.

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The workshop, “Using Local Monitoring Results to Inform the Chesapeake Bay Program’s Watershed Model”, was held in March 2023 to provide insight on the scope of local water quality monitoring efforts within and outside of the Bay watershed that could be used to inform the CBWM. Scientists and managers developed recommendations that could be used by modelers for either calibration or knowledge generation to inform the Phase 7 version of the CBWM currently under development for a 2028 decision by the CBP, recommendations for how local monitoring efforts could be designed or altered to better inform the CBWM, and recommendations for how monitored trends could be used in management. The preliminary presentations for the workshop provided essential background information on the CBWM and data used to parameterize it. This information was the foundation for discussions on existing data gaps, the importance of current local monitoring networks, and best practices for developing future monitoring networks.

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As solar energy becomes a lower cost and more efficient source of renewable energy, major utility-scale solar panel installations, or solar farms, are being proposed and installed around the Mid-Atlantic region. These solar farms constitute a major land transformation. This transformation is particularly of interest because there can be substantial alteration of land characteristics in the development process, and solar farms also create a unique land cover with impervious surface over pervious surface, generating potential changes in hydrologic and water quality processes. There is currently wide variability in guidance and understanding of best practices relating to the land development and management of solar farms in the Chesapeake Bay region. Thus, a STAC-led workshop gathered speakers and participants from universities, industry, non-governmental organizations, and multiple levels of government across the Chesapeake Bay watershed to address the following questions in April 2023:

1. What is the state of science on how solar farms impact hydrology and water quality under a range of site and management conditions and project scales?
2. What are current best management practices and policies, and where in our region are there opportunities for improving recommendations and/or policies?
3. What are the key gaps with respect to research needs to better answer understand the implications of utility scale solar development.

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Per- and polyfluoroalkyl substances (PFAS) have been manufactured and used in a variety of industries in the United States since the 1940s. PFAS are ubiquitous and persistent in the environment and have the potential to have adverse human and ecological health effects. There are more than 12,000 unique compounds, making analysis and reporting difficult. A STAC workshop gathered speakers from Chesapeake Bay jurisdictions, federal agencies, and academic institutions, including representatives from across the Nation, to better understand the state of the science, improve science coordination, and propose approaches to improve our knowledge of PFAS. The workshop was designed to (1) summarize current understanding of sources, occurrence, and fate of PFAS, (2) identify current efforts and approaches to inform the potential effects on fish and wildlife, and their consumption by humans, (3) consider study designs, and comparable sampling and analysis methods, for a more coordinated PFAS science effort, (4) determine and prioritize knowledge gaps, and (5) provide actionable scientific recommendations for monitoring and research.

This workshop report summarizes the current understanding of sources, occurrence, and fate of PFAS and identifies on-going efforts and approaches to inform the potential effects on fish and wildlife, and their consumption by humans. The report provides overarching guidance for research and monitoring to address science gaps, foster communication and collaboration, to help stakeholders better coordinate PFAS efforts to ensure data comparability across the entire Chesapeake Bay Watershed. Enhanced coordination among jurisdictions and agencies requires the creation of common study objectives to collect data and information based upon the media being sampled. This strategy could ensure the ability to conduct statistical analysis with “large” pooled data, allowing for a better understanding of PFAS occurrence, fate, transport, and source apportionment within the Bay and across the watershed. With the release of EPA Strategic Roadmap in 2021, the PFAS landscape is rapidly evolving. After the conclusion of the workshop, the EPA released an updated draft Method 1633 for approval and updated interim health advisories (HA’s) for perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorobutane (PFBS) and hexafluoropropylene oxide (HFPO) dimer acid and its ammonium salt (Gen X). Similarly, all guidance and science gaps identified in this report are rapidly evolving and should be reassessed periodically.

Ten science gaps were identified by workshop participants with six overarching actionable recommendations supporting at least one of the science gaps. The science gaps were ranked by need and binned into four categories designed to address data needs on 1) sources, fate, and occurrence more broadly across the watershed, 2) exposure and bioaccumulation across a range of species, 3) fish consumption advisories, and 4) ecological effects across a range of species, PFAS compounds and concentrations.

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As atmospheric temperatures go up, water temperatures have been increasing in the Chesapeake Bay tidal waters and in streams and rivers across the Bay’s watershed. Water temperatures are expected to continue rising, based on climate change projections.

Increases in water temperature have significant ecological implications for Bay and watershed natural resources and could undermine progress toward Chesapeake Bay Program (CBP) partnership goals for fisheries management, habitat restoration, water quality improvements, and protecting healthy watersheds. This STAC workshop examined current information on drivers and effects of rising water temperatures and sought answers to a critical question: what might the CBP partnership do now–within the scope of its current goals, policies and programs–to actively prevent, mitigate or adapt to some of the adverse consequences. Adapting to new water temperature conditions will have effects across the partnership.

Workshop preparation showed, from the outset, that the drivers, effects and likely management implications of water temperature increases are quite different between the Bay and the watershed. Therefore, both workshop days featured concurrent watershed and tidal sessions, and the findings and recommendations in the STAC report are organized in the same way.

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The agricultural sector is a key part of the solution for achieving long-term water quality goals established by the Chesapeake Bay Program (CBP) partnership. Current levels of best management practice (BMP) adoption on agricultural lands are not sufficient to meet pollutant reduction goals across the Chesapeake Bay watershed (CBW). In this workshop, agricultural service providers across public and private sectors were invited to propose and discuss ideas on BMP adoption and implementation garnered from their own experiences.

The main points that emerged from the workshop are: 1) BMP adoption strategies need to be flexible and adaptable to the specific circumstances of individual farm operations (i.e., one size does not fit all), and 2) conservation programs should be designed with outreach needs in mind in order to reach a much broader range of farmers, especially those in critical source areas and those who do not typically seek conservation technical assistance. The recommendations found in this report were formulated by the steering committee based on what was heard over the course of three workshop sessions.

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Improving soil health has gained traction within the farming community because of its importance to long-term crop production and watershed health. To date, management focuses on in-field crop management practices such as reducing tillage, following 4R nutrient stewardship guidelines, and maximizing vegetative cover throughout the year. Guidelines do not address agricultural water management, despite that soil moisture primarily drives underlying soil health processes. In January 2020, STAC partnered with the Foundation for Food and Agriculture Research, West Virginia University’s Institute of Water Security and Science, The Nature Conservancy, and the Transforming Drainage partnership and convened experts to explore the importance of agricultural water management to achieving soil and watershed restoration goals.

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The Chesapeake Bay Program Climate Change Modeling 2.0 workshop was held in late 2018 to give guidance and expert advice on the models and the assessment framework used to assess the effect of climate change on the TMDL. Scientists and managers developed recommendations that could be implemented to support assignment of any additional load reductions in 2021 and made recommendations on longer-term modeling goals for the partnership. Although a full workshop report is only now being published, several recommendations on near-term model revisions have already been implemented and have supported policy decisions made by the CBP Principals Staff Committee. The longer-term model revisions recommended here will be useful in guiding the partnership regarding future projections of climate change impacts on the attainment of the Bay TMDL and water quality standards.

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The workshop convened technical and management personnel to consider pathways to achieve the aforementioned goals. Acquiring CSI at no cost is an option under the NextView License agreement between the National Geospatial-Intelligence Agency (NGA) and Maxar (previously DigitalGlobe, Inc). The NextView License was developed by the NGA to accommodate United States Government (USG) agencies, contractors, partners, and other entities that require CSI to support USG interests. The basic premise of the agreement is that any federal agency that requires satellite imagery from contracted commercial sources can request and obtain said imagery at no cost to the local agency. As 2017 updates to the Water Resource Development Act, which amends Section 117 of the Clean Water Act, called for the U.S. Environmental Protection Agency (EPA) to carry out an annual SAV survey in Chesapeake Bay. This makes it theoretically feasible for the EPA to now request and obtain the high-resolution CSI necessary for the annual SAV assessment.

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Shoreline alterations in the Chesapeake Bay have led to a loss of native tidal and shallow water habitats throughout the waterways of the Bay. Efforts to reduce the proliferation of shoreline hardening through the use of Living Shorelines and similar restoration practices have slowed the loss of native habitats, but do not address areas that have already been hardened. Green Riprap is a low cost, simple restoration technique to improve the water quality, habitat, and aesthetics of shorelines previously hardened with rock revetments by planting marsh vegetation in the voids between riprap rocks. However, Green Riprap techniques are new to the Chesapeake Bay and before widespread use is encouraged, a synthesis of the science and identification of research gaps are needed. This workshop was developed to provide the foundation to evaluate the state of the science on Green Riprap and its potential for providing enhanced water quality, increased near shore biodiversity, and improved aesthetic functions of previously hardened tidal shorelines.

The workshop brought together scientists, practitioners, and NGOs to share aspects of shoreline systems that Green Riprap could contribute to and elucidate the best practices for their construction. The workshop was a single-day online meeting with an optional field trip to example Green Riprap projects. The workshop convened experts from multiple disciplines to evaluate the state of the science for Green Riprap, including estuarine scientists that study tidal wetlands and tidal shorelines, shoreline engineers, physical modelers, and social scientists. Several Green Riprap projects built by the U.S. Fish and Wildlife Service and other groups were shared through talks, a virtual field trip, and an in-person field trip. The talks were followed by discussion on the next steps forward. Results were a prioritized list of research questions related to: site criteria; plant species most effective for Green Riprap use; water quality criteria that could be used to assess project success; ecological benefits, including increased biodiversity; and social benefits, including increased recreational/aesthetic values made possible by Green Riprap habitats.

Key recommendations from the workshop include:

1. Additional research to help understand both the best design of these shorelines and their benefits;
2. Increased visibility of the technique through the creation of public pilot projects; and
3. Additional outreach to all the involved parties, including property owners, contractors, and regulators to ensure clear definitions and that the projects are sited and designed correctly.

Potential partners for addressing these recommendations include the Chesapeake Bay Program’s Wetland and Fish Habitat Workgroups and the U.S. Fish and Wildlife Service.

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