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Due to sea‐level rise, small river‐dominated deltas (<100 km2) are expected to become more exposed to tidal influences in the future. However, there remains a knowledge gap in the impending hydrodynamics of such deltas, particularly with the interactions between river and tidal flows. In addition to sea‐level rise, river‐tide interactions in these deltas depend on their morphology, which is influenced by the sand proportion in the particulate matter delivered by rivers. This study investigates river‐tide interactions predicted for small deltas formed by different sand‐to‐mud ratios under various sea‐level rise scenarios. Delta morphologies were generated using reduced‐order complexity model (DeltaRCM), and hydrodynamic simulations were performed using advanced circulation (ADCIRC) modeling. The findings indicate that sea‐level rise promotes deeper tidal penetration into deltas. Deltas formed by finer sediments exhibit deeper channels flanked by large natural levees, whereas those formed by coarser sands are characterized by shallow channels with smaller levees. Consequently, tides primarily propagate along the channels of deltas formed by finer material, while deltas formed by coarser material experience greater tidal inundation. The findings are meaningful toward the adaptive management of deltas.

Freshwater diversions manage water shortages, salinity, and control floodwater by redirecting river flows; however, their full ecological and hydrological impact remains unknown. This study examines the Lake Pontchartrain Estuary in Louisiana using a hydrodynamic model and Lagrangian particle tracking to assess how diversion operations (open, closed) and tributary discharge levels (low, median, high) influence water exposure time—the cumulative duration water remains in a domain, including re‐entry. Exposure time was analyzed based on the time required for 50%, 75%, and 90% of released particles (E50 ${E}_{50}$, E75 ${E}_{75}$, and E90 ${E}_{90}$) to leave a defined region of interest (ROI). Results show that when the diversion is open, high tributary discharge reduces exposure times by 51% compared to low discharge. In contrast, when closed, tributary discharge has minimal effect. To identify zones vulnerable to poor water quality due to stagnant water, the spatial heterogeneity of exposure time was evaluated using two metrics: system‐wide (time water remains in a system) and localized (time water remains within a ROI) exposure times. The spatial distribution and magnitude of increased exposure times varied between metrics and tributary discharge, highlighting the complexity of transport dynamics. For example, low tributary discharge led to larger isolated zones with longer system‐wide and localized exposure times. High tributary discharge created direct flow paths of diversion‐sourced water through tidal inlets, short‐circuiting the system and creating flow separation. These findings establish a framework for identifying transport mechanisms that influence exposure time and highlighting areas that may be vulnerable to poor water quality.

This study analyzes the climatology, spatial and temporal trends of wind speeds and significant wave height (H s ) of combined wind-seas and swells and H s of separated swells and wind-seas on annual and seasonal scales in the Gulf of Mexico (GoM) using 50 years of atmospheric reanalysis data. The H s data showed strong agreement with in-situ measurements, with minimal bias (+/-< 0.08 m) and high correlation (r > 0.9) across both deep and shallow regions, although a slight underestimation is noted for wind speed data. Wind speeds showed seasonal variability in the GoM, though they did not exhibit significant long-term increases, except for a notable decrease (~ -1.0 cm/s/yr) along the southern Florida region. Conversely, the significant wave height of combined wind-seas and swells (H s,c ) exhibits a significant increase, particularly in the western and central GoM (> 0.2 cm/yr). Seasonally, H s,c peaks in winter and is lowest in summer, with notable increases across most parts of the GoM. The increase in H s of swell waves closely mirrors that of H s,c. . In contrast, H s of wind-seas is primarily driven by local winds, does not significantly increase over time, instead showing a strong seasonal coupling with wind speed and its trends across all seasons, suggesting that swell waves are likely responsible for the increase in H s,c . The study highlights that the significant increase in H s,c and H s of swell waves along the GoM are primarily driven by remote swell waves from the Caribbean Sea and westward-propagating waves generated within the GoM, underscoring the growing importance of swell waves in shaping the wave climate and coastal dynamics.

The effects of passing atmospheric cold fronts with different orientations and moving directions on the hydrodynamics of the Wax Lake Delta (WLD) were analyzed by considering the influence of river discharge, cold front moving direction, wind magnitude, and Coriolis effect. The study employs numerical simulations using the Delft-3D model and an analytical model to explore water volume transport, water level variations, water circulation, and particle trajectories during nine cold front events. Results indicate that cold fronts cause a decrease in the average contribution of the water transport through western channels and an increase of that in central and eastern channels. A westerly cold front with an average wind speed of ~12 m/s can increase water transport through eastern channels by about 35%. During the passage of a cold front, the intertidal islands between the main channels and East Bay experience the largest fluctuations in subtidal water levels, which can be attributed to the influence of local wind stress. For example, a westerly cold front can result in a water level variation of approximately 0.45 m over some of the intertidal Islands and 0.65 m in the East Bay. Results also show that the subtidal water circulation in the WLD is correlated with the Wax Lake Outlet (WLO) discharge and wind magnitude. The findings illustrate that when WLO discharge is low, the impact of cold fronts is more pronounced, and cold fronts from the west have a greater impact compared to those from the northwest and north. This study identifies the significance of WLO discharge and Coriolis force by the trajectories of particles in the water column. The results of the simulations indicate that under low WLO discharge (less than 2000 m 3 /s), the majority of particles are found to exit through Campground Pass instead of Gadwall because of the dominance of Coriolis force. To summarize, this study assesses the impact of cold fronts on the hydrodynamics of the Wax Lake Delta, underscoring the contributions of multiple factors, including the cold front moving direction, river discharge, wind strength, and Coriolis force.

Atmospheric frontal passage is a common meteorological event that can significantly affect hydrodynamics in coastal environments, including the hydrological connectivity between channels and floodplains that regulates material transport in river deltas. This study is focused on the influence of atmospheric cold fronts on the hydrological connectivity between channels and floodplains within the Wax Lake Delta using the Delft3D FM model. The results demonstrate a substantial effect of passing cold fronts on the exchange of water and transport fraction between the primary channels and floodplains. This impact is intricately connected to the morphodynamical characteristics of the floodplains, the intensity of cold fronts, river discharge, Coriolis force, and tidal currents. The passing cold fronts can enhance or reverse the direction of water exchange between channels and floodplains. For floodplains, the passage of cold fronts can lead to an increase in the rate of water exchange by as much as five times. In the WLD, a substantial fraction of water, 39-58%, is flowing through the floodplains to the bay at the delta front influenced by the prevailing discharge, although there is a significant spatial heterogeneity. Passing cold fronts can alter the transport distribution, depending on the phase of the front. An increase in river discharge tends to bolster floodplain connectivity and lessen the effects of cold fronts. Conversely, decreased river discharge results in reduced connectivity and exacerbates the fluctuations induced by cold fronts. Moreover, the findings indicate that from the apex to downstream, the contribution of channels decreases as they become shallower, while the role of the floodplains increases, leading to a less distinct demarcation between channels and floodplains. It has also been noted that an increase in river discharge correlates with an increased contribution from floodplains to transfer water to the bay.

Harmful cyanobacteria blooms (cyanoHABs) are a global phenomenon, especially in calm, warm, and nutrient-rich freshwater and estuarine systems. These blooms can produce various potent toxins responsible for animal poisoning and human health problems. Nutrient-rich freshwater pulsed into estuaries affects turbidity, water temperature, salinity, and nutrient concentrations and ratios at irregular intervals, creating a highly dynamic habitat. However, the underlying processes that lead to the selective development of cyanoHABs for certain species and the fate of their toxins are still uncertain. This paper draws upon the rich body of research available for one such system, the Lake Pontchartrain Estuary, Louisiana, to generate insights about future research directions in pulsed-nutrient-delivery estuaries. Toxin-producing cyanobacteria blooms in river-dominated Louisiana coastal ecosystems have already been documented at high concentrations, presenting a potential risk to human health as $2.4 billion worth of Louisiana’s fish and shellfish are consumed by millions of people throughout the US every year. Recent studies have shown that the Lake Pontchartrain Estuary, just north of New Orleans, Louisiana has been experiencing cyanoHABs, likely connected to combinations of (a) high interannual variability in nutrient loading associated with seasonal and episodic rainfall, (b) the timing, duration, and magnitude of the flood-stage Mississippi River water diverted into the Lake Pontchartrain Estuary, and (c) saltwater inputs from tropical storms. It is expected that cyanoHABs will become more frequent in Louisiana with a warming climate and changes to the timing and magnitude of river water diverted into the Lake Pontchartrain Estuary, which will play a dominant role in the development of blooms in this region. More studies are needed to focus on the environmental conditions that control the succession or/and co-existence of different cyanobacteria species and their toxins, optimally culminating in a near-term forecasting tool since this information is critical for health agencies to mitigate or to provide early warnings. Toxin forecasts for pulsed-nutrient estuaries, including Lake Pontchartrain, could directly inform state and municipal health agencies on human exposure risks to upcoming cyanobacteria toxicity events by predicting cyanobacteria species shifts, potency, and toxin modality along the freshwater-to-marine continuum while also informing a longer-term projection on how the changing climate will impact the frequency and potency of such blooms.

Estuaries in the Gulf, especially Lake Pontchartrain Estuary in southeastern Louisiana, USA, are experiencing significant changes due to climate change and coastal restoration efforts. Lake Pontchartrain Estuary receives nutrient-rich Mississippi River water through a controlled diversion called Bonnet Carré Spillway (BCS), which has been associated with toxic cyanobacterial blooms (cyanoHABs). This study examines the seasonal factors influencing cyanoHABs in the Lake Pontchartrain Estuary when the BCS is closed, addressing gaps in the understanding of HABs related to other physical drivers. Field samples collected in 2021, during the closure of the spillway, revealed significant evidence of seasonal variations in cyanoHAB formation. Results indicate that water leakage from the spillway and tributary discharge are critical for supporting cyanoHABs during the summer months. Moreover, nitrogen-fixing cyanobacteria, such as nitrogen-fixing Dolichospermum and Cylindrospermum , were more abundant following strong winds from significant weather events, including cold fronts and hurricanes, which can resuspend phosphorus that is bound to sediment. This research improves our understanding of the physical factors that drive the formation of cyanoHABs, the prevalence of different species, and the production of toxins in the Lake Pontchartrain Estuary. The insights gained from this study are essential for environmental managers to develop effective, long-term monitoring strategies for harmful algal blooms.

Traditional flood prediction approaches either rely on numerical models, which are accurate but computationally intensive, or machine learning models, which are faster but limited by data availability. To address these limitations, we developed a Prediction-to-Map (P2M) framework that combines the strengths of both methods. Trained on observed data and numerical model outputs, P2M delivers rapid, accurate spatial flood predictions. Applied to predict the flood event during Hurricane Nicholas (2021) near Galveston Bay, Texas, P2M produced flood depth maps that closely matched numerical simulations. Comparisons with observed data suggested P2M’s superior performance, as evidenced by higher R-squared and lower RMSE than the numerical model. Moreover, P2M demonstrated remarkable computational efficiency, producing a flood depth map with a 115,200-fold increase in speed. By achieving both faster speed and higher accuracy, this framework overcomes the trade-off in common surrogate models, providing a useful tool for rapid spatial flood prediction.

This study tested the extent to which professors could be trained to help enhance students’ experiences of spirituality in their classes. Three areas of focus that may be important to incorporating spirituality into the classroom were identified in the integration of faith and learning literature: 1) Professor Self-Disclosure, 2) Intellectual Connections, and 3) Interpersonal Connections. In a quasi-experimental design, two professors were trained to incorporate these focus areas into four experimental conditions. A sample of 203 student participants attended different teaching conditions and rated their perception of the teaching quality. Statistical tests revealed that professor ratings on General Teaching Skills and Spirituality greatly improved after training; however, ratings also depended on the professor. Results indicated that applying such a pedagogical training can be a useful tool in educating faculty to successfully incorporate spirituality in the classroom and improve student perceptions of their general teaching skills.

Atmospheric cold fronts can periodically generate storm surges and affect sediment transport in the Northern Gulf of Mexico (NGOM). In this paper, we evaluate water circulation spatiotemporal patterns induced by six atmospheric cold front events in the Wax Lake Delta (WLD) in coastal Louisiana using the 3-D hydrodynamic model ECOM-si. Model simulations show that channelized and inter-distributary water flow is significantly impacted by cold fronts. Water volume transport throughout the deltaic channel network is not just constrained to the main channels but also occurs laterally across channels accounting for about a quarter of the total flow. Results show that a significant landward flow occurs across the delta prior to the frontal passage, resulting in a positive storm surge on the coast. The along-channel current velocity dominates while cross-channel water transport occurs at the southwest lobe during the post-frontal stage. Depending on local weather conditions, the cold-front-induced flushing event lasts for 1.7 to 7 days and can flush 32–76% of the total water mass out of the system, a greater range of variability than previous reports. The magnitude of water flushed out of the system is not necessarily dependent on the duration of the frontal events. An energy partitioning analysis shows that the relative importance of subtidal energy (10–45% of the total) and tidal energy (20–70%) varies substantially from station to station and is linked to the weather impact. It is important to note that within the WLD region, the weather-induced subtidal energy (46–66% of the total) is much greater than the diurnal tidal energy (13–25% of the total). The wind associated with cold fronts in winter is the main factor controlling water circulation in the WLD and is a major driver in the spatial configuration of the channel network and delta progradation rates.