Societal benefits of floodplains in the Chesapeake Bay and Delaware River watersheds: Sediment, nutrient, and flood regulation ecosystem services.

Floodplains provide critical ecosystem services to people by regulating floodwaters and retaining sediments and nutrients. Geospatial analyses, field data collection, and modeling were integrated to quantify a portfolio of services that floodplains provide to downstream communities within the Chesapeake Bay and Delaware River watersheds. The portfolio of services included floodplain sediment and nutrient retention and flood regulation. Sediment and nutrient retention were quantified and valued for all non-tidal wadable streams in the Chesapeake Bay and Delaware River watersheds. Predicted nitrogen fluxes from measurements of streambanks and floodplain geomorphic changes were summarized at various scales (river basin, state, and county) and valued using a benefits transfer approach. Floodplain flood regulation services were assessed through a pilot study focused on the Schuylkill River watershed in the Delaware River watershed. Geospatial analysis and published flood frequency estimates were used to assess baseline and counterfactual (i.e., floodplain storage removed) scenarios. Flood regulation was valued using the Federal Emergency Management Agency's Hazus model to compare differences in structural damage to private residences under baseline and counterfactual scenarios. The estimated value of floodplain sediment and nutrient retention was $223 million United States dollars (USD) per year in the Chesapeake Bay watershed and $38 million USD per year in the Delaware River watershed. Sediment and nutrient retention benefits were offset by a streambank erosion cost of $123 million and $14 million USD annually in the Chesapeake and Delaware watersheds, respectively. In the Schuylkill River watershed floodplain flood regulation was valued at $860,000 USD per year, with an additional $7.2 million USD annually provided through floodplain sediment and nutrient retention. Together this portfolio of floodplain ecosystem services indicates that floodplains provide substantial benefits to people by trapping nutrients and storing floodwaters.

Economic valuation of health benefits from using geologic data to communicate radon risk potential.

BACKGROUND: Radon exposure is the second leading cause of lung cancer worldwide and represents a major health concern within and outside the United States. Mitigating exposure to radon is especially critical in places with high rates of tobacco smoking (e.g., Kentucky, USA), as radon-induced lung cancer is markedly greater among people exposed to tobacco smoke. Despite homes being a common source of radon exposure, convincing homeowners to test and mitigate for radon remains a challenge. A new communication strategy to increase radon testing among Kentucky homeowners utilizes fine-scale geologic map data to create detailed radon risk potential maps. We assessed the health benefits of this strategy via avoided lung cancer and associated premature mortality and quantified the economic value of these benefits to indicate the potential utility of using geologic map data in radon communication strategies. METHODS: We estimated the change in radon testing among all 120 counties in Kentucky following a new communication strategy reliant on geologic maps. We approximated the resultant potential change in radon mitigation rates and subsequent expected lung cancer cases and mortality avoided among smokers and non-smokers exposed to 4 pCi/L of radon in the home. We then applied the value of a statistical life to derive the economic value of the expected avoided mortality. RESULTS: The new communication strategy is estimated to help 75 Kentucky residents in 1 year avoid exposure to harmful radon levels via increased testing and mitigation rates. This equated to the potential avoidance of approximately one premature death due to lung cancer, with a net present value of $3.4 to $8.5 million (2016 USD). CONCLUSIONS: Our analysis illustrates the potential economic value of health benefits associated with geologic map data used as part of a communication strategy conveying radon risk to the public. Geologic map data are freely available in varying resolutions throughout the United States, suggesting Kentucky's radon communication strategy using geologic maps can be employed in other states to educate the public about radon. As this is only a single application, in a single state, the economic and health benefits of geologic map data in educating the public about radon are likely to exceed our estimates.

Trends in biodiversity and habitat quantification tools used for market-based conservation in the United States.

Market-based conservation mechanisms are designed to facilitate the mitigation of harm to and conservation of habitats and biodiversity. Their potential is partly hindered, however, by the quantification tools used to assess habitat quality and functionality. Of specific concern are the lack of transparency and standardization in tool development and gaps in tool availability. To address these issues, we collected information via internet and literature searchers and through conversations with tool developers and users on tools used in U.S. conservation mechanisms, such as payments for ecosystem services (PES) and ecolabel programs, conservation banking, and habitat exchanges. We summarized information about tools and explored trends among and within mechanisms based on criteria detailing geographic, ecological, and technical features of tools. We identified 69 tools that assessed at least 34 species and 39 habitat types. Where tools reported pricing, 98% were freely available. More tools were applied to states along the U.S. West Coast than elsewhere, and the level of tool transferability varied markedly among mechanisms. Tools most often incorporated conditions at numerous spatial scales, frequently addressed multiple risks to site viability, and required 1-83 data inputs. Most tools required a moderate or greater level of user skill. Average tool-complexity estimates were similar among all mechanisms except PES programs. Our results illustrate the diversity among tools in their ecological features, data needs, and geographic application, supporting concerns about a lack of standardization. However, consistency among tools in user skill requirements, incorporation of multiple spatial scales, and complexity highlight important commonalities that could serve as a starting point for establishing more standardized tool development and feature-incorporation processes. Greater standardization in tool design may expand market participation and facilitate a needed assessment of the effectiveness of market-based conservation.

Tendencias en la Biodiversidad y en las Herramientas de Cuantificación de Hábitat Usadas para la Conservación Basada en el Mercado en los Estados Unidos Resumen Los mecanismos de conservación basada en el mercado están diseñados para facilitar la mitigación del daño y la conservación de los hábitats y la biodiversidad. Sin embargo, el potencial de estos mecanismos está parcialmente reducido por las herramientas de cuantificación usadas para evaluar la calidad y funcionalidad del hábitat. Son de preocupación específica la falta de transparencia y la estandarización del desarrollo de herramientas y los vacíos en la disponibilidad de las herramientas. Para tratar estos temas recolectamos información por medio del internet y los buscadores de literatura y a través de conversaciones con los desarrolladores y usuarios de las herramientas utilizadas en los mecanismos de conservación en los Estados Unidos, como la eco-etiqueta y los programas de pago por servicios ambientales (PES, en inglés), el banco de conservación y el intercambio de hábitats. Resumimos la información sobre las herramientas y exploramos tendencias entre y dentro de los mecanismos basados en criterios que detallan las características geográficas, ecológicas y técnicas de las herramientas. Identificamos 69 herramientas que evaluaron al menos a 34 especies y 39 tipos de hábitat. En donde las herramientas reportaron tarificación, el 98% estaban disponibles gratuitamente. Más herramientas estaban aplicadas a estados ubicados a lo largo de la costa oeste de los Estados Unidos que en cualquier otro sitio y el nivel de transferibilidad de las herramientas varió notablemente entre los mecanismos. Las herramientas comúnmente incorporaron las condiciones a numerosas escalas espaciales, trataron con frecuencia los múltiples riesgos para la viabilidad de sitio y requirieron 1 - 83 entradas de datos. La mayoría de las herramientas requirió un nivel moderado o mayor de habilidad para el usuario. Los estimados medios de la complejidad de las herramientas fueron similares entre todos los mecanismos, a excepción de los programas PES. Nuestros resultados ilustran la diversidad de características ecológicas, necesidades de datos y aplicación geográfica que existe entre las herramientas, lo que respalda las preocupaciones sobre la falta de estandarización. Sin embargo, la consistencia entre las herramientas en cuanto a los requerimientos de habilidades para el usuario, la incorporación de múltiples escalas espaciales y la complejidad resaltan las similitudes importantes que podrían servir como punto inicial para el establecimiento de un desarrollo más estandarizado de herramientas y procesos que incorporen las características del sitio. Una mayor estandarización del diseño de herramientas podría expandir la participación del mercado y facilitar una urgente evaluación de la efectividad de la conservación basada en el mercado.

Valuation of the flood attenuation ecosystem service in Difficult Run, VA, USA.

Floodplains and riparian wetlands provide several ecosystem services that directly benefit people. We present a methodology for valuing the flood attenuation ecosystem service in Difficult Run, a suburban watershed with extensive natural floodplains in northern Virginia. High-resolution lidar-derived data were combined with GIS modeling techniques to produce estimates of flood inundation. We combined the modeled estimates with parcel-level property and primary economic data using a baseline and a counterfactual scenario to estimate the magnitude of flood attenuation and the associated value of the ecosystem service. Our framework brings new models and data to look at floodplains and an alternative land surface scenario in a way that has not previously been done. Annualized avoided property losses totaled $42,184 in the baseline scenario and $115,596 in the counterfactual scenario for the combined 200-, 100-, 50-, 20-, 10-, and 5-year flood events. We estimate the total annualized value of the flood attenuation ecosystem service in Difficult Run is $73,412, which is $77 per hectare of floodplain area and is consistent with similar valuation studies of floodplains. The framework presented here is not specific to the study area and could be deployed at larger spatial areas in other locations. Our methods may better inform land use decision making on the impacts of development in and surrounding floodplain areas.

A method to quantify and value floodplain sediment and nutrient retention ecosystem services.

Floodplains provide critical ecosystem services to local and downstream communities by retaining floodwaters, sediments, and nutrients. The dynamic nature of floodplains is such that these areas can both accumulate sediment and nutrients through deposition, and export material downstream through erosion. Therefore, estimating floodplain sediment and nutrient retention should consider the net flux of both depositional and erosive processes. An ecosystem services framework was used to quantify and value the sediment and nutrient ecosystem service provided by floodplains in the Difficult Run watershed, a small (151 km2) suburban watershed located in the Piedmont of Virginia (USA). A sediment balance was developed for Difficult Run and two nested watersheds. The balance included upland sediment delivery to streams, stream bank flux, floodplain flux, and stream load. Upland sediment delivery was estimated using geospatial datasets and a modified Revised Universal Soil Loss Equation. Predictive models were developed to extrapolate field measurements of the flux of sediment, sediment-bound nitrogen (N), and sediment-bound phosphorus (P) from stream banks and floodplains to 3232 delineated stream segments in the study area. A replacement cost approach was used to estimate the economic value of the sediment and nutrient retention ecosystem service based on estimated net stream bank and floodplain flux of sediment-bound N for all streams in the study area. Results indicated the net fluvial fluxes of sediment, sediment-bound N, and sediment-bound P were -10,439 Mg yr-1 (net export), 57,300 kg-N yr-1 (net trapping), and 98 kg-P yr-1(net trapping), respectively. For sediment, floodplain retention was offset by substantial losses from stream bank erosion, particularly in headwater catchments, resulting in a net export of sediment. Nutrient retention in the floodplain exceeded that lost through stream bank erosion resulting in net retention of nutrients (TN and TP). Using a conservative cost estimate of $12.69 (USD) per kilogram of nitrogen, derived from wastewater treatment costs, the estimated annual value for sediment and nutrient retention on Difficult Run floodplains was $727,226 ±â€¯194,220 USD/yr. Values and differences in floodplain nitrogen retention among stream reaches can be used to target areas for floodplain conservation and stream restoration. The methods presented are scalable and transferable to other areas if appropriate datasets are available for validation.