Scholarly Works, Center for Coastal Studies

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The anthropogenic salt cycle
Kaushal, Sujay S.; Likens, Gene E.; Mayer, Paul M.; Shatkay, Ruth R.; Shelton, Sydney A.; Grant, Stanley B.; Utz, Ryan M.; Yaculak, Alexis M.; Maas, Carly M.; Reimer, Jenna E.; Bhide, Shantanu V.; Malin, Joseph T.; Rippy, Megan A. (SpringerNature, 2023-10-31)
Increasing salt production and use is shifting the natural balances of salt ions across Earth systems, causing interrelated effects across biophysical systems collectively known as freshwater salinization syndrome. In this Review, we conceptualize the natural salt cycle and synthesize increasing global trends of salt production and riverine salt concentrations and fluxes. The natural salt cycle is primarily driven by relatively slow geologic and hydrologic processes that bring different salts to the surface of the Earth. Anthropogenic activities have accelerated the processes, timescales and magnitudes of salt fluxes and altered their directionality, creating an anthropogenic salt cycle. Global salt production has increased rapidly over the past century for different salts, with approximately 300 Mt of NaCl produced per year. A salt budget for the USA suggests that salt fluxes in rivers can be within similar orders of magnitude as anthropogenic salt fluxes, and there can be substantial accumulation of salt in watersheds. Excess salt propagates along the anthropogenic salt cycle, causing freshwater salinization syndrome to extend beyond freshwater supplies and affect food and energy production, air quality, human health and infrastructure. There is a need to identify environmental limits and thresholds for salt ions and reduce salinization before planetary boundaries are exceeded, causing serious or irreversible damage across Earth systems.
Freshwater salinization syndrome limits management efforts to improve water quality
Maas, Carly M.; Kaushal, Sujay S.; Rippy, Megan A.; Mayer, Paul M.; Grant, Stanley B.; Shatkay, Ruth R.; Malin, Joseph T.; Bhide, Shantanu V.; Vikesland, Peter J.; Krauss, Lauren; Reimer, Jenna E.; Yaculak, Alexis M. (Frontiers, 2023-09-22)
Freshwater Salinization Syndrome (FSS) refers to groups of biological, physical, and chemical impacts which commonly occur together in response to salinization. FSS can be assessed by the mobilization of chemical mixtures, termed “chemical cocktails”, in watersheds. Currently, we do not know if salinization and mobilization of chemical cocktails along streams can be mitigated or reversed using restoration and conservation strategies. We investigated 1) the formation of chemical cocktails temporally and spatially along streams experiencing different levels of restoration and riparian forest conservation and 2) the potential for attenuation of chemical cocktails and salt ions along flowpaths through conservation and restoration areas. We monitored high-frequency temporal and longitudinal changes in streamwater chemistry in response to different pollution events (i.e., road salt, stormwater runoff, wastewater effluent, and baseflow conditions) and several types of watershed management or conservation efforts in six urban watersheds in the Chesapeake Bay watershed. Principal component analysis (PCA) indicates that chemical cocktails which formed along flowpaths (i.e., permanent reaches of a stream) varied due to pollution events. In response to winter road salt applications, the chemical cocktails were enriched in salts and metals (e.g., Na+, Mn, and Cu). During most baseflow and stormflow conditions, chemical cocktails were less enriched in salt ions and trace metals. Downstream attenuation of salt ions occurred during baseflow and stormflow conditions along flowpaths through regional parks, stream-floodplain restorations, and a national park. Conversely, chemical mixtures of salt ions and metals, which formed in response to multiple road salt applications or prolonged road salt exposure, did not show patterns of rapid attenuation downstream. Multiple linear regression was used to investigate variables that influence changes in chemical cocktails along flowpaths. Attenuation and dilution of salt ions and chemical cocktails along stream flowpaths was significantly related to riparian forest buffer width, types of salt pollution, and distance downstream. Although salt ions and chemical cocktails can be attenuated and diluted in response to conservation and restoration efforts at lower concentration ranges, there can be limitations in attenuation during road salt events, particularly if storm drains bypass riparian buffers.
Longitudinal stream synoptic monitoring tracks chemicals along watershed continuums: a typology of trends
Kaushal, Sujay S.; Maas, Carly M.; Mayer, Paul M.; Newcomer-Johnson, Tammy A.; Grant, Stanley B.; Rippy, Megan A.; Shatkay, Ruth R.; Leathers, Jonathan; Gold, Arthur J.; Smith, Cassandra; McMullen, Evan C.; Haq, Shahan; Smith, Rose; Duan, Shuiwang; Malin, Joseph; Yaculak, Alexis; Reimer, Jenna E.; Newcomb, Katie Delaney; Raley, Ashley Sides; Collison, Daniel C.; Galella, Joseph G.; Grese, Melissa; Sivirichi, Gwendolyn; Doody, Thomas R.; Vikesland, Peter J.; Bhide, Shantanu V.; Krauss, Lauren; Daugherty, Madeline; Stavrou, Christina; Etheredge, MaKayla; Ziegler, Jillian; Kirschnick, Andrew; England, William; Belt, Kenneth T. (Frontiers, 2023-06-09)
There are challenges in monitoring and managing water quality due to spatial and temporal heterogeneity in contaminant sources, transport, and transformations. We demonstrate the importance of longitudinal stream synoptic (LSS) monitoring, which can track combinations of water quality parameters along flowpaths across space and time. Specifically, we analyze longitudinal patterns of chemical mixtures of carbon, nutrients, greenhouse gasses, salts, and metals concentrations along 10 flowpaths draining 1,765 km2 of the Chesapeake Bay region. These 10 longitudinal stream flowpaths are drained by watersheds experiencing either urban degradation, forest and wetland conservation, or stream and floodplain restoration. Along the 10 longitudinal stream flowpaths, we monitored over 300 total sampling sites along a combined stream length of 337 km. Synoptic monitoring along longitudinal flowpaths revealed: (1) increasing, decreasing, piecewise, or no trends and transitions in water quality with increasing distance downstream, which provide insights into water quality processes along flowpaths; (2) longitudinal trends and transitions in water quality along flowpaths can be quantified and compared using simple linear and non-linear statistical relationships with distance downstream and/or land use/land cover attributes, (3) attenuation and transformation of chemical cocktails along flowpaths depend on: spatial scales, pollution sources, and transitions in land use and management, hydrology, and restoration. We compared our LSS patterns with others from the global literature to synthesize a typology of longitudinal water quality trends and transitions in streams and rivers based on hydrological, biological, and geochemical processes. Applications of LSS monitoring along flowpaths from our results and the literature reveal: (1) if there are shifts in pollution sources, trends, and transitions along flowpaths, (2) which pollution sources can spread further downstream to sensitive receiving waters such as drinking water supplies and coastal zones, and (3) if transitions in land use, conservation, management, or restoration can attenuate downstream transport of pollution sources. Our typology of longitudinal water quality responses along flowpaths combines many observations across suites of chemicals that can follow predictable patterns based on watershed characteristics. Our typology of longitudinal water quality responses also provides a foundation for future studies, watershed assessments, evaluating watershed management and stream restoration, and comparing watershed responses to non-point and point pollution sources along streams and rivers. LSS monitoring, which integrates both spatial and temporal dimensions and considers multiple contaminants together (a chemical cocktail approach), can be a comprehensive strategy for tracking sources, fate, and transport of pollutants along stream flowpaths and making comparisons of water quality patterns across different watersheds and regions.
Solute Transport Through Unsteady Hydrologic Systems Along a Plug Flow-To-Uniform Sampling Continuum
Grant, Stanley B.; Harman, Ciaran J. (American Geophysical Union, 2022-08-22)
Unsteady transit time distribution (TTD) theory is a promising new approach for merging hydrologic and water quality models at the catchment scale. A major obstacle to widespread adoption of the theory, however, has been the specification of the StorAge Selection (SAS) function, which describes how the selection of water for outflow is biased by age. In this paper we hypothesize that some unsteady hydrologic systems of practical interest can be described, to first-order, by a “shifted-uniform” SAS that falls along a continuum between plug flow sampling (for which only the oldest water in storage is sampled for outflow) and uniform sampling (for which water in storage is sampled randomly for outflow). For this choice of SAS function, explicit formulae are derived for the evolving: (a) age distribution of water in storage; (b) age distribution of water in outflow; and (c) breakthrough concentration of a conservative solute under either continuous or impulsive addition. Model predictions conform closely to chloride and deuterium breakthrough curves measured previously in a sloping lysimeter subject to periodic wetting, although refinements of the model are needed to account for the reconfiguration of flow paths at high storage levels (the so-called inverse storage effect). The analytical results derived in this paper should lower the barrier to applying TTD theory in practice, ease the computational demands associated with simulating solute transport through complex hydrologic systems, and provide physical insights that might not be apparent from traditional numerical solutions of the governing equations.
Real-Time Prediction of Alongshore Near-Field Tsunami Runup Distribution From Heterogeneous Earthquake Slip Distribution
Lee, Jun-Whan; Irish, Jennifer L.; Weiss, Robert (American Geophysical Union, 2023-01-05)
Real-time tsunami prediction is necessary for tsunami forecasting. Although tsunami forecasting based on a precomputed tsunami simulation database is fast, it is difficult to respond to earthquakes that are not in the database. As the computation speed increases, various alternatives based on physics-based models have been proposed. However, physics-based models still require several minutes to simulate tsunamis and can have numerical stability issues that potentially make them unreliable for use in forecasting—particularly in the case of near-field tsunamis. This paper presents a data-driven model called the tsunami runup response function for finite faults (TRRF-FF) model that can predict alongshore near-field tsunami runup distribution from heterogeneous earthquake slip distribution in less than a second. Once the TRRF-FF model is trained and calibrated based on a discrete set of tsunami simulations, the TRRF-FF model can predict alongshore tsunami runup distribution from any combination of finite fault parameters. The TRRF-FF model treats the leading-order contribution and the residual part of the alongshore tsunami runup distribution separately. The interaction between finite faults is modeled based on the leading-order alongshore tsunami runup distribution. We validated the TRRF-FF modeling approach with more than 200 synthetic tsunami scenarios in eastern Japan. We further explored the performance of the TRRF-FF model by applying it to the 2011 Tohoku (Japan) tsunami event. The results show that the TRRF-FF model is more flexible, occupies much less storage space than a precomputed tsunami simulation database, and is more rapid and reliable than real-time physics-based numerical simulation.
Advances in Morphodynamic Modeling of Coastal Barriers: A Review
Hoagland, Steven W. H.; Jeffries, Catherine R.; Irish, Jennifer L.; Weiss, Robert; Mandli, Kyle; Vitousek, Sean; Johnson, Catherine M.; Cialone, Mary A. (ASCE, 2023-05-30)
As scientific understanding of barrier morphodynamics has improved, so has the ability to reproduce observed phenomena and predict future barrier states using mathematical models. To use existing models effectively and improve them, it is important to understand the current state of morphodynamic modeling and the progress that has been made in the field. This manuscript offers a review of the literature regarding advancements in morphodynamic modeling of coastal barrier systems and summarizes current modeling abilities and limitations. Broadly, this review covers both event-scale and long-term morphodynamics. Each of these sections begins with an overview of commonly modeled phenomena and processes, followed by a review of modeling developments. After summarizing the advancements toward the stated modeling goals, we identify research gaps and suggestions for future research under the broad categories of improving our abilities to acquire and access data, furthering our scientific understanding of relevant processes, and advancing our modeling frameworks and approaches.
Projecting barrier island storm erosion
Hoagland, Steven W. H.; Jeffries, Catherine R.; Irish, Jennifer L.; Weiss, Robert; Mandli, Kyle; Vitousek, Sean; Johnson, Catherine M.; Cialone, Mary A. (Center for Coastal Studies, 2023-10-03)
Projecting long-term barrier island change
Hoagland, Steven W. H.; Jeffries, Catherine R.; Irish, Jennifer L.; Weiss, Robert; Mandli, Kyle; Vitousek, Sean; Johnson, Catherine M.; Cialone, Mary A. (Center for Coastal Studies, 2023-10-03)
Perceived services and disservices of natural treatment systems for urban stormwater: Insight from the next generation of designers
Rippy, Megan A.; Pierce, Gregory; Feldman, David; Winfrey, Brandon; Mehring, Andrew S.; Holden, Patricia A.; Ambrose, Richard; Levin, Lisa A. (Wiley, 2022)
1. Natural treatment systems (NTS) for stormwater have the potential to provide a myriad of ecosystem services to society. Realizing this potential requires active collaboration among engineers, ecologists and landscape planners and begins with a paradigm shift in communication whereby these groups are made aware of each other's perceptions about NTS and the presence of knowledge gaps that their respective disciplines can bridge. 2. Here we participate in the first part of what we hope will be a reciprocal exchange: presenting results from a landscape perceptions survey to urban planners, ecologists and landscape architects that illustrates how the next generation of engineers perceives NTS relative to other landscape features, and the implications of those perceptions for future infrastructure development. 3. Our results suggest that although lawns, gardens and native ecosystems were perceived as multifunctional, providing characteristic bundles of services/disservices, perceptions of NTS were more variable (i.e. there was no social norm for their perception). 4. Environmental worldviews, knowledge, attitudes about ecosystem services and demographics were all significant drivers of perceived services. However, students had difficulty identifying NTS correctly, and factual knowledge about NTS did not help students associate NTS with typical design services like flood reduction more than features not designed for those purposes, such as lawns. This suggests that engineering students lack familiarity with the outward appearance of NTS and have difficulty placing NTS services into a broader landscape context. 5. Expertise from urban planning and ecology could help bridge these knowledge gaps, improving the capacity of tomorrow's engineers to co-design NTS to meet diverse community needs.
Capturing complexity: Environmental change and relocation in the North Slope Borough, Alaska
Garland, Anne; Bukvic, Anamaria; Maton-Mosurska, Anuszka (Elsevier, 2022-12)
This paper explores the knowledge, attitudes, and behaviors about emerging hazards, environmental change, and relocation among community groups in Utqiaġvik (Barrow) of the North Slope Borough (NSB), Alaska. This region has been experiencing accelerating erosion and warmer temperatures, permafrost thawing, more frequent and intense storm surges, and increased maritime traffic and extractive industries with ice loss, with direct or cascading effects on the mixed ethnic and indigenous communities. This paper used engagement activities (Participatory Applied Theater) and qualitative approaches (focus groups) during three consecutive summers 2016-2018 to evaluate the risk perceptions and interpretations towards coastal changes and relocation as an adaptive response in this U.S. strategic yet remote location. Each focus group session started with risk ranking activities about regional hazards to assess knowledge and perceptions of risk, followed by an interactive script reading of an Iñupiat disaster legend to facilitate discussion about risk reduction options and engagement with the survey questions. Focus groups were audio recorded, transcribed, and analyzed using qualitative data analysis software Nvivo and a hybrid coding strategy. Results indicate that relocation is considered by some participants but is not planned for nor implemented by community groups, families, or the local government to reduce the hazard risks. However, widespread recognition of accelerated hazards and environmental changes, and the need for adaptation could lead to consideration of relocation in the future. This study provides a case of disaster risk reduction in a remote place with unique place-specific characteristics (e.g., particular forms of subsistence, corporate monopolies, Traditional Ecological Knowledge, and social organizations), but also shaped by significant external influences, accompanied by a changing landscape of risk from the slow and rapid onset of environmental changes.
Adaptive strategy biases in engineered ecosystems: Implications for plant community dynamics and the provisioning of ecosystem services to people
Krauss, Lauren; Rippy, Megan A. (2022-11-22)
1. Plant communities in green stormwater infrastructure (GSI) such as biofilters play an integral role in ecosystem services provisioning, such that many design manuals now feature plant lists that guide vegetation selection. 2. This study looks at the implications of those lists for biofilter plant communities and their services, focusing on (1) how plants are selected across US climate zones, (2) whether selected plants exhibit adaptive strategy biases (i.e. towards competitive, stress tolerant or ruderal strategies that might impact ecosystem services provisioning) and (3) whether human-induced selection or natural climatic processes underly any biases revealed. 3. Our results suggest that biofilter plant strategies are significantly biased towards stress tolerance or competitiveness (depending on the climate zone) and away from ruderalness relative to the broader pool of native and wetland-adapted native species. 4. Competitive bias was evident in humid-continental climates and stress-tolerant bias in hot coastal/arid climates, with some degree of anti-ruderal bias present across all zones. 5. These biases are correlated with human concerns related to water availability and climate (water conservation; p < 0.05, irrigation; p < 0.1, climate extremes; p < 0.1). They do not appear to reflect strict climatological limits (i.e. limits that are independent of preferences or design constraints imposed by people) because they are not also evident for native plants. 6. The benefits and costs of relaxing these biases are discussed, focusing on the implications for water quality, hydrologic, and cultural services provisioning and the dynamicity of GSI ecosystems, particularly their capacity to self-repair, a prerequisite for the development of self-sustaining GSI.
Boulder dislodgement during coastal storms and tsunamis: Insights from a new ensemble model
Weiss, Robert; Irish, Jennifer L.; Goodman Tchernov, Beverly (American Geophysical Union, 2022-03-01)
Boulders are excellent candidate deposits to study coastal inundation events by storms and tsunamis due to their significant preservation potential. However, it is difficult to infer how and what forcing dislodged the boulder. We present a new model that enables ensemble and Monte-Carlo-type simulations to study the sensitivity of boulder, the fluid flow, and environmental parameters. Our examples show that boulder transport is complex and nonlinear, and to acknowledge the uncertainties of the boulder's preexisting transport conditions, a range of velocities and environmental parameters should be used to quantify the flow that caused boulder dislodgement.
Stratigraphic evidence of two historical tsunamis on the semi-arid coast of north-central Chile
DePaolis, Jessica M.; Dura, Tina; MacInnes, Breanyn; Ely, Lisa L.; Cisternas, Marco; Carvajal, Matias; Tang, Hui; Fritz, Hermann M.; Mizobe, Cyntia; Wesson, Robert L.; Figueroa, Gino; Brennan, Nicole; Horton, Benjamin P.; Pilarczyk, Jessica E.; Corbett, D. Reide; Gill, Benjamin C.; Weiss, Robert (Pergamon-Elsevier, 2021-07-21)
On September 16, 2015, a Mw 8.3 earthquake struck the north-central Chile coast, triggering a tsunami observed along 500 km of coastline, between Huasco (28.5°S) and San Antonio (33.5°S). This tsunami provided a unique opportunity to examine the nature of tsunami deposits in a semi-arid, siliciclastic environment where stratigraphic and sedimentological records of past tsunamis are difficult to distinguish. To improve our ability to identify such evidence, we targeted one of the few low-energy, organic-rich depositional environments in north-central Chile: Pachingo marsh in Tongoy Bay (30.3°S). We found sedimentary evidence of the 2015 and one previous tsunami as tabular sand sheets. Both deposits are composed of poorly to moderately sorted, gray-brown, fine-to medium-grained sand and are distinct from underlying and overlying organic-rich silt. Both sand beds thin (from ∼20 cm to <1 cm) and fine landward, and show normal grading. The older sand bed is thicker and extends over 125 m further inland than the 2015 tsunami deposit. To model the relative size of the tsunamis that deposited each sand bed, we employed tsunami flow inversion. Our results show that the older sand bed was produced by higher flow speeds and depths than those in 2015. Anthropogenic evidence along with 137Cs and 210Pb dating constrains the age of the older tsunami to the last ∼110 years. We suggest that the older sand bed was deposited by the large tsunami in 1922 CE sourced to the north of our study site. This deposit represents the first geologic evidence of a pre-2015 tsunami along the semi-arid north-central Chile coast and highlights the current and continuing tsunami hazard in the region.
Moving from interdisciplinary to convergent research across geoscience and social sciences: challenges and strategies
Finn, Donovan; Mandli, Kyle; Bukvic, Anamaria; Davis, Christopher A.; Haacker, Rebecca; Morss, Rebecca E.; O'Lenick, Cassandra R.; Wilhelmi, Olga; Wong-Parodi, Gabrielle; Merdjanoff, Alexis A.; Mayo, Talea L. (IOP Publishing, 2022-06)
Habitat edges influence the distribution of nest predators for Seaside Sparrows, but not nest placement or success
Newsome, Corina D.; Hunter, Elizabeth A. (Oxford University Press, 2022-08-02)
Nest failure for coastal marsh bird species is primarily caused by predation and nest flooding. As sea level rise makes nest flooding more likely, the threat of nest predation will constrain the potential adaptive responses of marsh nesting species. Thus, understanding the predictors of nest predation is important for the conservation of salt marsh-dwelling bird species, such as the Seaside Sparrow (Ammospiza maritima). Predator activity may be influenced by landscape features (particularly habitat edges), potentially making nest predation predictable. We aimed to understand the predictability of Seaside Sparrow nest predation relative to two major landscape features: roads and tidal rivers, as both of these edges may be entryways or attractants for predators in marshes. In coastal Georgia, USA, we assessed mammalian predator activity relative to the two features of interest, and hypothesized that mammalian predator activity would be greater close to roads and tidal rivers. We also recorded Seaside Sparrow nest locations and nest predation events and hypothesized that nest predation events would increase with increasing predator activity. Consistent with our first hypothesis, mammalian predator activity increased close to roads and tidal rivers, but mammalian predator distribution did not explain the spatial variation in Seaside Sparrow nest predation thus not supporting our second hypothesis. Seaside Sparrows also placed their nests in locations with high mammalian predator activity, indicating that the ability to avoid nesting in high-risk areas may be constrained by habitat or resource limitations. Additionally, mammals may not be the primary nest predators, as we found that one bird species-Marsh Wren (Cistothorus palustris)-contributed substantially to nest predation rates. Understanding the predictability of mammalian predator distribution can allow for focused predator management efforts, such as exclusion, to habitat edges where we found the highest mammalian predator activity, which could relax the constraint of nest predation on Seaside Sparrow's ability to respond to the intensifying threat of sea level rise. Lay Summary center dot Seaside Sparrows (Ammospiza maritima) nest in salt marsh grasses. If a nest fails from flooding, they elevate their next nest. However, nests higher from the ground experience increased predation risk. center dot Understanding the spatial pattern of nest predation across Seaside Sparrow habitat is critical in the face of increased nest flooding from sea level rise. center dot We predicted that mammalian predator activity would increase along habitat edges adjacent to roads and rivers in Glynn County, Georgia, and that Seaside Sparrow nests would experience increased predation in these areas. Mammalian predator activity increased near road and water edges, but Seaside Sparrows placed their nests in locations with high predator activity, and nest predation was not correlated with mammalian predator activity. Marsh Wrens depredated Seaside Sparrow nests and may have had an important impact on nest predation patterns. center dot Our results suggest that future predator management be focused on habitat edges along roads and waterways.
Modeling Coastal Environmental Change and the Tsunami Hazard
Weiss, Robert; Dura, Tina; Irish, Jennifer L. (Frontiers, 2022-05-02)
The hazard from earthquake-generated tsunami waves is not only determined by the earthquake's magnitude and mechanisms, and distance to the earthquake area, but also by the geomorphology of the nearshore and onshore areas, which can change over time. In coastal hazard assessments, a changing coastal environment is commonly taken into account by increasing the sea-level to projected values (static). However, sea-level changes and other climate-change impacts influence the entire coastal system causing morphological changes near- and onshore (dynamic). We compare the run-up of the same suite of earthquake-generated tsunamis to a barrier island-marsh-lagoon-marsh system for statically adjusted and dynamically adjusted sea level and bathymetry. Sea-level projections from 2000 to 2100 are considered. The dynamical adjustment is based on a morphokinetic model that incorporates sea-level along with other climate-change impacts. We employ Representative Concentration Pathways 2.6 and 8.5 without and with treatment of Antarctic Ice-sheet processes (known as K14 and K17) as different sea-level projections. It is important to note that we do not account for the occurrence probability of the earthquakes. Our results indicate that the tsunami run-up hazard for the dynamic case is approximately three times larger than for the static case. Furthermore, we show that nonlinear and complex responses of the barrier island-marsh-lagoon-marsh system to climate change profoundly impacts the tsunami hazard, and we caution that the tsunami run-up is sensitive to climate-change impacts that are less well-studied than sea-level rise.
Five state factors control progressive stages of freshwater salinization syndrome
Kaushal, Sujay S.; Mayer, Paul M.; Likens, Gene E.; Reimer, Jenna E.; Maas, Carly M.; Rippy, Megan A.; Grant, Stanley B.; Hart, Ian; Utz, Ryan M.; Shatkay, Ruth R.; Wessel, Barret M.; Maietta, Christine E.; Pace, Michael L.; Duan, Shuiwang; Boger, Walter L.; Yaculak, Alexis M.; Galella, Joseph G.; Wood, Kelsey L.; Morel, Carol J.; Nguyen, William; Querubin, Shane Elizabeth C.; Sukert, Rebecca A.; Lowien, Anna; Houde, Alyssa Wellman; Roussel, Anais; Houston, Andrew J.; Cacopardo, Ari; Ho, Cristy; Talbot-Wendlandt, Haley; Widmer, Jacob M.; Slagle, Jairus; Bader, James A.; Chong, Jeng Hann; Wollney, Jenna; Kim, Jordan; Shepherd, Lauren; Wilfong, Matthew T.; Houlihan, Megan; Sedghi, Nathan; Butcher, Rebecca; Chaudhary, Sona; Becker, William D. (Wiley, 2022-03-16)
Factors driving freshwater salinization syndrome (FSS) influence the severity of impacts and chances for recovery. We hypothesize that spread of FSS across ecosystems is a function of interactions among five state factors: human activities, geology, flowpaths, climate, and time. (1) Human activities drive pulsed or chronic inputs of salt ions and mobilization of chemical contaminants. (2) Geology drives rates of erosion, weathering, ion exchange, and acidification-alkalinization. (3) Flowpaths drive salinization and contaminant mobilization along hydrologic cycles. (4) Climate drives rising water temperatures, salt stress, and evaporative concentration of ions and saltwater intrusion. (5) Time influences consequences, thresholds, and potentials for ecosystem recovery. We hypothesize that state factors advance FSS in distinct stages, which eventually contribute to failures in systems-level functions (supporting drinking water, crops, biodiversity, infrastructure, etc.). We present future research directions for protecting freshwaters at risk based on five state factors and stages from diagnosis to prognosis to cure.
Can Smart Stormwater Systems Outsmart the Weather? Stormwater Capture with Real-Time Control in Southern California
Parker, Emily A.; Grant, Stanley B.; Sahin, Abdullah; Vrugt, Jasper A.; Brand, Matthew W. (2022-01-14)
Stormwater capture systems have the potential to address many urban stormwater management challenges, particularly in water-scarce regions like Southern California. Here, we investigate the potential best-case limits of water supply and stormwater retention benefits delivered by a 10,000 m3 stormwater capture system equipped with real-time control (RTC) on a university campus in Southern California. Using a copula-based conditional probability analysis, two performance metrics (percent of water demand satisfied and the percent of stormwater runoff captured) are benchmarked relative to (1) precipitation seasonality (historical rainfall and a counterfactual in which the same average annual rainfall is distributed evenly over the year); (2) annual precipitation (dry, median, and wet years); and (3) three RTC algorithms (no knowledge of future rainfall or perfect knowledge of future rainfall 1 or 2 days in advance). RTC improves stormwater retention, particularly for the highly seasonal rainfall patterns in Southern California, but not water supply. Improvements to the latter will likely require implementing stormwater capture RTC in conjunction with other stormwater infrastructure innovations, such as spreading basins for groundwater recharge and widespread adoption of green stormwater infrastructure.
Rapid prediction of peak storm surge from tropical cyclone track time series using machine learning
Lee, Jun-Whan; Irish, Jennifer L.; Bensi, Michelle T.; Marcy, Douglas C. (Elsevier, 2021-12-01)
Rapid and accurate prediction of peak storm surges across an extensive coastal region is necessary to inform assessments used to design the systems that protect coastal communities’ life and property. Significant advances in high-fidelity, physics-based numerical models have been made in recent years, but use of these models for probabilistic forecasting and probabilistic hazard assessment is computationally intensive. Several surrogate modeling approaches based on existing databases of high-fidelity synthetic storm surge simulations have been recently suggested to reduce computational burden without substantial loss of accuracy. In these previous studies, however, the surrogate modeling approaches relied on a tropical cyclone condition at one moment (usually at or near landfall), which is not always most correlated with the peak storm surge. In this study, a new one-dimensional convolutional neural network model combined with principal component analysis and a k-means clustering (C1PKNet) is presented that can rapidly predict peak storm surge across an extensive coastal region from time-series of tropical cyclone conditions, namely the storm track. The C1PKNet model was trained and cross-validated for the Chesapeake Bay area of the United States using existing database of 1031 high-fidelity storm surge simulations, including both landfalling and bypassing storms. Moreover, the performance of the C1PKNet model was evaluated based on observations from three historical hurricanes (Hurricane Isabel in 2003, Hurricane Irene in 2011, and Hurricane Sandy in 2012). The results indicate that the C1PKNet model is computationally efficient and can predict peak storm surges from realistic tropical cyclone track time-series. We believe that this new surrogate model can enhance coastal resilience by providing rapid storm surge predictions.
Prevalence of Microplastics in the Eastern Oyster Crassostrea virginica in the Chesapeake Bay: The Impact of Different Digestion Methods on Microplastic Properties
Aung, Thet; Batish, Inayat; Ovissipour, Reza (MDPI, 2022-01-10)
This study aimed to determine the microplastic prevalence in eastern oysters (C. virginica) in three sites in the Chesapeake Bay in Virginia and optimize the digestion methods. The digestion results illustrate that the lowest recovery rate and digestion recovery were related to enzymatic, enzymatic + hydrogen peroxide (H₂O₂), and HCl 5% treatments, while the highest digestion recovery and recovery rate were observed in H₂O₂ and basic (KOH) treatments. Nitric acid digestion resulted in satisfying digestion recovery (100%), while no blue polyethylene microplastics were observed due to the poor recovery rate. In addition, nitric acid altered the color, changed the Raman spectrum intensity, and melted polypropylene (PP) and polyethylene terephthalate (PET). In order to determine the number of microplastics, 144 oysters with an approximately similar size and weight from three sites, including the James River, York River, and Eastern Shore, were evaluated. Fragments were the most abundant microplastics among the different microplastics, followed by fibers and beads, in the three sites. A significantly higher number of fragments were found in the James River, probably due to the greater amount of human activities. The number of microplastics per gram of oyster tissue was higher in the James River, with 7 MPs/g tissue, than in the York River and Eastern Shore, with 6.7 and 5.6 MPs/g tissue.

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