Using Water Chemistry Data to Quantify Source Contribution to Stream Flow in a Coastal Plain Watershed

2010 S.C. Water Resources Conference - Science and Policy Challenges for a Sustainable Futur

Interactive Effects of Climate Change with Nutrients, Mercury, and Freshwater Acidification on Key Taxa in the North Atlantic Landscape Conservation Cooperative Region

The North Atlantic Landscape Conservation Cooperative LCC (NA LCC) is a public-private partnership that provides information to support conservation decisions that may be affected by global climate change (GCC) and other threats. The NA LCC region extends from southeast Virginia to the Canadian Maritime Provinces. Within this region, the US National Climate Assessment documented increases in air temperature, total precipitation, frequency of heavy precipitation events, and rising sea level, and predicted more drastic changes. Here, we synthesize literature on the effects of GCC interacting with selected contaminant, nutrient, and environmental processes to adversely affect natural resources within this region. Using a case study approach, we focused on 3 stressors with sufficient NA LCC region-specific information for an informed discussion. We describe GCC interactions with a contaminant (Hg) and 2 complex environmental phenomena-freshwater acidification and eutrophication. We also prepared taxa case studies on GCC- and GCC-contaminant/nutrient/process effects on amphibians and freshwater mussels. Several avian species of high conservation concern have blood Hg concentrations that have been associated with reduced nesting success. Freshwater acidification has adversely affected terrestrial and aquatic ecosystems in the Adirondacks and other areas of the region that are slowly recovering due to decreased emissions of N and sulfur oxides. Eutrophication in many estuaries within the region is projected to increase from greater storm runoff and less denitrification in riparian wetlands. Estuarine hypoxia may be exacerbated by increased stratification. Elevated water temperature favors algal species that produce harmful algal blooms (HABs). In several of the region\u27s estuaries, HABs have been associated with bird die-offs. In the NA LCC region, amphibian populations appear to be declining. Some species may be adversely affected by GCC through higher temperatures and more frequent droughts. GCC may affect freshwater mussel populations via altered stream temperatures and increased sediment loading during heavy storms. Freshwater mussels are sensitive to un-ionized ammonia that more toxic at higher temperatures. We recommend studying the interactive effects of GCC on generation and bioavailability of methylmercury and how GCC-driven shifts in bird species distributions will affect avian exposure to methylmercury. Research is needed on how decreases in acid deposition concurrent with GCC will alter the structure and function of sensitive watersheds and surface waters. Studies are needed to determine how GCC will affect HABs and avian disease, and how more severe and extensive hypoxia will affect fish and shellfish populations. Regarding amphibians, we suggest research on 1) thermal tolerance and moisture requirements of species of concern, 2) effects of multiple stressors (temperature, desiccation, contaminants, nutrients), and 3) approaches to mitigate impacts of increased temperature and seasonal drought. We recommend studies to assess which mussel species and populations are vulnerable and which are resilient to rising stream temperatures, hydrological shifts, and ionic pollutants, all of which are influenced by GCC

Interactive Effects of Climate Change with Nutrients, Mercury, and Freshwater Acidification on Key Taxa in the North Atlantic Landscape Conservation Cooperative Region

The North Atlantic Landscape Conservation Cooperative LCC (NA LCC) is a public–private partnership that provides information to support conservation decisions that may be affected by global climate change (GCC) and other threats. The NA LCC region extends from southeast Virginia to the Canadian Maritime Provinces. Within this region, the US National Climate Assessment documented increases in air temperature, total precipitation, frequency of heavy precipitation events, and rising sea level, and predicted more drastic changes. Here, we synthesize literature on the effects of GCC interacting with selected contaminant, nutrient, and environmental processes to adversely affect natural resources within this region. Using a case study approach, we focused on 3 stressors with sufficient NA LCC regionspecific information for an informed discussion. We describe GCC interactions with a contaminant (Hg) and 2 complex environmental phenomena—freshwater acidification and eutrophication. We also prepared taxa case studies on GCCand GCC-contaminant/nutrient/process effects on amphibians and freshwater mussels. Several avian species of high conservation concern have blood Hg concentrations that have been associated with reduced nesting success. Freshwater acidification has adversely affected terrestrial and aquatic ecosystems in the Adirondacks and other areas of the region that are slowly recovering due to decreased emissions of N and sulfur oxides. Eutrophication in many estuaries within the region is projected to increase from greater storm runoff and less denitrification in riparian wetlands. Estuarine hypoxia may be exacerbated by increased stratification. Elevated water temperature favors algal species that produce harmful algal blooms (HABs). In several of the region\u27s estuaries, HABs have been associated with bird die-offs. In the NA LCC region, amphibian populations appear to be declining. Some species may be adversely affected by GCC through higher temperatures and more frequent droughts. GCC may affect freshwater mussel populations via altered stream temperatures and increased sediment loading during heavy storms. Freshwater mussels are sensitive to un-ionized ammonia that more toxic at higher temperatures. We recommend studying the interactive effects of GCC on generation and bioavailability of methylmercury and how GCC-driven shifts in bird species distributions will affect avian exposure to methylmercury. Research is needed on how decreases in acid deposition concurrent with GCC will alter the structure and function of sensitive watersheds and surface waters. Studies are needed to determine how GCC will affect HABs and avian disease, and how more severe and extensive hypoxia will affect fish and shellfish populations. Regarding amphibians, we suggest research on 1) thermal tolerance and moisture requirements of species of concern, 2) effects of multiple stressors (temperature, desiccation, contaminants, nutrients), and 3) approaches to mitigate impacts of increased temperature and seasonal drought. We recommend studies to assess which mussel species and populations are vulnerable and which are resilient to rising stream temperatures, hydrological shifts, and ionic pollutants, all of which are influenced by GCC

High flow events as hot moments of reactive Fe and P export: impacts of land cover and seasonality

High flow events often comprise the majority of annual discharge and riverine geochemical flux of phosphorus (P) and metals such as iron (Fe) and manganese (Mn) due to glacial melt, snowmelt, and storm-driven sustained high flow. Aquatic ecosystem productivity in receiving water bodies such as Lake Champlain and the Gulf of Alaska (GoA) are impacted by the riverine import of nutrients. The magnitude of these high flow events can be a strong predictor of receiving water body conditions, and in some cases can contribute to eutrophication. We explore the intersection of high flow events and land cover in contrasting catchments in Vermont and Alaska, covering a range of land covers including glacial, boreal-forested, mixed hardwood-conifer forested, and agricultural. In Vermont, we explore the hypothesis that riverine dissolved and suspended sediment P loads during spring runoff have a particularly high proportion of reactive species due to unique hydrologic pathways and the association of P with Fe. We compared spring runoff and summer storm concentrations and distribution of dissolved P (DP), dissolved and colloidal metals, and redox sensitive suspended sediment P (RSP). Agricultural catchments in Vermont were characterized by enrichment in RSP and DP during both spring runoff and summer storms, particularly at the onset of snowmelt. In 2014, 82% of the annual DP and 74% of annual RSP loads were delivered to Missisquoi Bay during spring runoff, with the majority of suspended sediment significantly more redox sensitive, and carrying potentially bioavailable P, than typical inputs to limnological models, suggesting that the reactivity of this load is systematically underestimated. In Alaska, we investigate Fe size partitioning and flux throughout the hydrologic year, with additional high-resolution sampling during discrete storm events in adjacent forested and glacierized catchments typical of coastal Alaska. There are clear differences between these catchments during individual storm events, and across seasons, reflecting widely varying source environments for Fe. The geochemical character of river water exported from the forested catchment, dominated by dissolved Fe and DOC, reflects the influence of peatlands and organic-rich soil as the dominant source of Fe and P, while the glacial catchment exports significantly more material derived from glacial weathering of bedrock, reflected in higher sediment and colloidal concentrations. Phosphorus concentrations in both watersheds are very low throughout the year, but significantly higher in the forested catchment, driven by organic matter decomposition. Both Vermont and Alaska are likely to be significantly impacted by climate change, with an increase in the frequency of heavy precipitation events, and continued glacial recession in Alaska driven by rising temperatures. Changes in the timing, provenance, and severity of high flow associated with climate and land cover change will have dramatic impacts on total riverine P and Fe loads, and their potential reactivity and bioavailability in receiving water bodies. Development of conceptual models that incorporate the intersection between high flow events (hot moments) and land cover source environments (hot spots) is critical to understanding how these systems are likely to change in the future

Assessment of Climate Change Impacts on Water Quantity and Quality at Small Scale Watersheds

This book was inspired by the Hydrology–H030 Session of the 2019 AGU (America Geophysical Union) Fall Meeting. In recent years, simulating potential future vulnerability and sustainability of water resources due to climate change are mainly focused on global and regional scale watersheds by using climate change scenarios. These scenarios may have low resolution and may not be accurate for local watersheds. This book addresses the impacts of climate change upon water quantity and quality at small scale watersheds. Emphases are on climate-induced water resource vulnerabilities (e.g., flood, drought, groundwater depletion, evapotranspiration, and water pollution) and methodologies (e.g., computer modeling, field measurement, and management practice) employed to mitigation and adapt climate change impacts on water resources. Application implications to local water resource management are also discussed in this book

THE EFFECTS OF CHANGES IN LAND COVER AND LAND USE ON NUTRIENT LOADINGS TO THE CHESAPEAKE BAY USING FORECASTS OF URBANIZATION

This dissertation examined the effects of land cover and land use (LC/LU) change on nutrient loadings (mass for a specified time) to the Chesapeake Bay, after future projections of urbanization were applied. This was accomplished by quantifying the comprehensive impacts of landscape on nutrients throughout the watershed. In order to quantify forecasted impacts of future development and LC/LU change, the current (2000) effects of landscape composition and configuration on total nitrogen (TN) and total phosphorus (TP) were examined. The effects of cover types were examined not only at catchment scales, but within riparian stream buffer to quantify the effects of spatial arrangement. Using the SPAtially Referenced Regressions On Watershed Attributes (SPARROW) model, several compositional and configurational metrics at both scales were significantly correlated to nutrient genesis and transport and helped estimate loadings to the Chesapeake Bay with slightly better accuracy and precision. Remotely sensed forecasts of future (2030) urbanization were integrated into SPARROW using these metrics to project TN and TP loadings into the future. After estimation of these metrics and other LC/LU-based sources, it was found that overall nutrient transport to the Chesapeake Bay will decrease due to agricultural land losses and fertilizer reductions. Although point and non-point source urban loadings increased in the watershed, these gains were not enough to negate decreased agricultural impacts. In catchments forecasted to undergo urban sprawl conditions by 2030, the response of TN locally generated within catchments varied. The forecasted placement of smaller patches of development within agricultural lands of higher nutrient production was correlated to projected losses. However, shifting forecasted growth onto or adjacent to existing development, not agricultural lands, resulted in projected gains. This indicated the importance of forecasted spatial arrangement to projected TN runoff from the watershed. In conclusion, comprehensive landscape analysis resulted in differences in simulations of current and future nutrient loadings to the Chesapeake Bay, as a result of urbanization and LC/LU change. With eutrophication from excess nutrients being the primary challenge to the estuary, information gained from the estimation of these effects could improve the future management and regulation of the Chesapeake Bay

Assessment and prediction of surface water vulnerability from non-point source pollution in Midwestern watersheds

Non-point source pollution is the leading cause of impairment in surface water in the Midwest. In this research, we seek to predict which watersheds are most vulnerable to point source pollution without field sampling using publically available GIS databases. Watersheds with higher vulnerability ratings can then be targeted for water quality monitoring, and funds used to improve watershed health can be distributed with greater efficacy. To better understand and target watershed vulnerability, we used three different approaches. In the first project, 35 sub-watersheds were sampled in the Lower Grand Watershed, which is a highly agricultural watershed in northern Missouri/southern Iowa. Statistical analyses were performed to determine which of these parameters were most correlated with water quality, and predictive relationships of water quality were developed. In the second project, a new methodology for watershed vulnerability to non-point source pollution was developed. Using the results from our first study to guide the weighting of different parameters, a weighted overlay and analytical hierarchy method was used to predict the vulnerability (poor water quality) of watersheds. This new vulnerability prediction method was tested on ten sub-watersheds within the Eagle Creek Watershed in central Indiana, which has a mixture of agricultural, forested, and urban land use. In the last project, the robustness of the new watershed vulnerability assessment method was tested using hydrological modeling. The Soil and Water Assessment Tool (SWAT) modeling program was used to model non-point source pollution in the Eagle Creek sub-watersheds. The results of these models provided a second method for verifying the robustness of the newly developed watershed vulnerability assessment method --Abstract, page iv

Potential climate-change impacts on the Chesapeake Bay

We review current understanding of the potential impact of climate change on the Chesapeake Bay. Scenarios for CO2 emissions indicate that by the end of the 21st century the Bay region will experience significant changes in climate forcings with respect to historical conditions, including increases in CO2 concentrations, sea level, and water temperature of 50–160%, 0.7–1.6m, and 2–6C, respectively. Also likely are increases in precipitation amount (very likely in the winter and spring), precipitation intensity, intensity of tropical and extratropical cyclones (though their frequency may decrease), and sea-level variability. The greatest uncertainty is associatedwith changes in annual streamflow, though it is likely that winter and spring flows will increase. Climate change alone will cause the Bay to function very differently in the future. Likely changes include: (1) an increase in coastal flooding and submergence of estuarine wetlands; (2) an increase in salinity variability on many time scales; (3) an increase in harmful algae; (4) an increase in hypoxia; (5) a reduction of eelgrass, the dominant submergedaquatic vegetation in the Bay; and (6) altered interactions among trophic levels, with subtropical fish and shellfish species ultimately being favored in the Bay. The magnitude of these changes is sensitive to the CO2 emission trajectory, so that actions taken now to reduce CO2 emissions will reduce climate impacts on the Bay. Research needs include improved precipitation and streamflow projections for the Bay watershed and whole-system monitoring, modeling, and process studies that can capture the likely non-linear responses of the Chesapeake Bay system to climate variability, climate change, and their interaction with other anthropogenic stressor

41st annual hydrology days (2021) - online proceedings

The 41st Annual AGU Hydrology Days event at Colorado State University was hosted online March 30-31, 2021.Includes the schedule and presentation abstracts only. The 41st Annual American Geophysical Union Hydrology Days meeting provides a unique opportunity for students, faculty, staff and practitioners to engage in wide range of water-related interdisciplinary research topics. Unfortunately, the global pandemic has left students with limited opportunities to share their research and satisfy graduation requirements. This year the spotlight focused on students to highlight the interconnections of water and linked systems. The 2021 Student Showcase provides an opportunity for students to exchange ideas, present their research findings and refine their science communication skills