Elevated Water Levels Research Articles

A numerical estimate of water level elevation due to a cyclone associated with a different landfall angle

<p>Bangladesh is a disaster-prone riverine country in South Asia, most of them are cyclone-related. That's why research on cyclones in this region is very important. This study investigates the surge height associated with the changes of landfall angle due to climate change. The deflected angle of landfall was investigated from the data analysis of Bangladesh Meteorological Department (BMD), Joint typhoon warning center (JTWC), and Meteorological Research Institute- Atmospheric global circulation model (MRI-AGCM). A cyclone of future climate has been investigated from the Database for Policy Decision-Making for Future Climate Change (d4PDF) data under present and future climate conditions. To find the surge height, a vertically shallow water Cartesian coordinate model has been used to simulate the surge height. The shallow water model equations were discretized through finite difference technique with the Arakawa C grid system and solved by a conditionally stable semi-implicit manner. The fluctuated striking angle due to climate change was then applied to the known cyclone BOB 01 and the associated surge height was then investigated. We found that our simulated result and the observed result make a good agreement. We have also seen that different types of cyclones have a significant effect on the water level elevation due to their landfall angle</p>

Inundation of Stormwater Infrastructure Is Common and Increases Risk of Flooding in Coastal Urban Areas Along the US Atlantic Coast

AbstractStormwater infrastructure can manage precipitation‐driven flooding when there are no obstructions to draining. Coastal areas increasingly experience recurrent flooding due to elevated water levels from storms or tides, but the inundation of coastal stormwater infrastructure by elevated water levels has not been broadly assessed. We conservatively estimated stormwater infrastructure inundation in municipalities along the Atlantic United States coast by using areas of high‐tide flooding (HTF) on roads as a proxy. We also modeled stormwater infrastructure inundation in four North Carolina municipalities and measured infrastructure inundation in one of the modeled municipalities. Combining methodologies at different scales provides context and allows the scope of stormwater infrastructure inundation to be broadly estimated. We found 137 census‐designated urban areas along the Atlantic coast with road area impacted by HTF, with a median percent of total road area subject to HTF of 0.16% (IQR: 0.02%–0.53%). Based on 2010 census block data, the median number of people per urban area that live in census blocks with HTF on roads was 1,622 (IQR: 366–5,779). In total, we estimate that over 2 million people live in census blocks where HTF occurs on roadways along the US Atlantic coast. Modeling results and water level measurements indicated that extensive inundation of underground stormwater infrastructure likely occurs at water levels within the mean tidal range. These results suggest that stormwater infrastructure inundation along the US Atlantic coast is likely widespread, affects a large number of people, occurs frequently, and increases the occurrence of urban flooding.

Factors Controlling Storm-Induced Morphology Changes at an Erosional Hot Spot on a Nourished Beach, Sand Key Barrier Island, West-Central Florida

Cheng, J. and Wang, P., 2022. Factors controlling storm-induced morphology changes at an erosional hot spot on a nourished beach, Sand Key barrier island, west-central Florida. Journal of Coastal Research, 38(4), 750–765. Coconut Creek (Florida), ISSN 0749-0208. Beach nourishment has become the dominant sandy shore protection method over the past 40 years. The performance of nourished beaches and therefore the design of renourishment projects are significantly controlled by the presence of erosional hot spots and storm impacts. Based on 5.5-year bimonthly beach profile surveys, along a nourished beach spanning an erosional hot spot, this study examines the hydrodynamic conditions of extratropical (winter) and tropical (summer) storms that cause significant morphology changes. The sand volume loss above the short-term closure depth averaged along the 1.8-km stretch erosional hot spot was 178 m3/m over the 5.5 years after the nourishment. A large portion of this volume loss was caused by several extratropical storms and Hurricane Irma in 2017, when the high, northerly approaching waves were associated with a depressed water level. The northerly approaching waves induced a large longshore sediment transport gradient along the generally north-south trending coast due to wave refraction over a nearby ebb tidal delta. The energetic Hurricane Irma induced a large negative surge and also transported sediment seaward beyond the short-term closure depth. On the other hand, during the passages of typical tropical storms, the southerly approaching waves superimposed on elevated water levels caused substantial beach volume loss above the mean sea level. The eroded sediment deposited on the nearshore sandbar, resulting in conserved sand volume above the short-term closure depth. Understanding the different beach response to extratropical and tropical storms would benefit beach management, especially under the circumstance of increasing storm activities due to climate change.

An automatic lake-model application using near-real-time data forcing: development of an operational forecast workflow (COASTLINES) for Lake Erie

Abstract. For enhanced public safety and water resource management, a three-dimensional operational lake hydrodynamic forecasting system, COASTLINES (Canadian cOASTal and Lake forecastINg modEl System), was developed. The modeling system is built upon the three-dimensional Aquatic Ecosystem Model (AEM3D) model, with predictive simulation capabilities developed and tested for a large lake (i.e., Lake Erie). The open-access workflow derives model forcing, code execution, post-processing, and web-based visualization of the model outputs, including water level elevations and temperatures, in near-real time. COASTLINES also generates 240 h predictions using atmospheric forcing from 15 and 25 km horizontal-resolution operational meteorological products from the Environment Canada Global Deterministic Forecast System (GDPS). Simulated water levels were validated against observations from six gauge stations, with model error increasing with forecast horizon. Satellite images and lake buoys were used to validate forecast lake surface temperature and the water column thermal stratification. The forecast lake surface temperature is as accurate as hindcasts, with a root-mean-square deviation <2 ∘C. COASTLINES predicted storm surges and up-/downwelling events that are important for coastal flooding and drinking water/fishery management, respectively. Model forecasts are available in real time at https://coastlines.engineering.queensu.ca/ (last access: January 2022​​​​​​​). This study provides an example of the successful development of an operational forecasting workflow, entirely driven by open-access data, that may be easily adapted to simulate aquatic systems or to drive other computational models, as required for management and public safety.

Robust Image-Based Water-Level Estimation Using Single-Camera Monitoring

This study proposes an automatic image water-level measurement system using a single camera. The inverse perspective mapping (IPM) technology is used to rectify an image to improve deviations because the optical axis of the camera and staff gauge are not orthogonal, causing a perspective distortion in the real environment. The initial position of the current watermark is first determined from the staff gauge’s image by applying basic digital image-processing technology. The system uses the image histogram of staff gauge’s region of interest to provide a reference region for determining accurate water levels from the preliminary watermark position. Furthermore, the proposed system can correctly and automatically determine the current water-level elevation by establishing the control points to convert the pixel distance to the real-world distance as well as through the setting of the reference water-level elevation. The images are shifted because of camera vibration, which will also shift the waterline coordinates. To prevent the image shift due to camera vibration from interfering with the accuracy of water-level measurement, we used the normalized cross correlation (NCC) technology with the proposed camera-vibration calibration scheme for removing the impact. The proposed distance calibration (DISCAL) module further optimizes the results of the images rectified using the IPM technology. The suggested automatic water-level measurement system can improve the traditional linear interpolation approach by >90%, and the deviation value of the real water level is < 0.5 cm, which is ideal for water-level measurement in confined spaces according to experimental results.

Investigation on atmospheric dispersion of limestone particulates at the sea port

In this study, low-level dispersion of particulates discharged during handling of limestone at the harbour is modelled using AERMOD software. The influences of key meteorological and operational variables on distribution of particulates are also studied. The key variables such as wind velocity, limestone water level, relative humidity, ambient temperature, and limestone drop elevation are considered for this study. In low-level emissions (0 m to 8 m from sea level) atmospheric temperature and relative humidity have a weak negative correlation with particulate concentration. Wind velocity, limestone moisture content and limestone drop elevation have a considerable effect on the distribution of particulates. At wind velocities (<3m/s) the limestone particles continue hovering in the atmosphere for a longer period and reach longer distance from the source of the particulate pollution. The concentration of particulates decreases with rise in limestone moister level. For low-level emissions, limestone moisture level and limestone drop elevation are important operational variables in dispersion of emissions. The model results are validated with measured values of the particulate concentrations and it is observed that predicted levels of PM10 and PM2.5 are in concurrence to that of measured levels of PM10 and PM2.5 with mean error of 21 % and 19.37 % respectively.

First-trimester prediction of gestational hypertension through the bioelectrical impedance analysis of the body composition.

Obesity is a risk factor for the development of gestational hypertension, with important consequences for both the mother and fetus. This prospective observational study aims to propose an early prediction model of hypertensive disorders in pregnancy among obese women, through the bioelectrical impedance analysis (BIA) at the first trimester, thus allowing early recognition of obese women that are at risk to develop gestational hypertension, in order to target preventive interventions. Singleton obese women (BMI ≥ 30 kg/m2) between the 9th and 12th week of pregnancy were included in the study. The exclusion criteria were chronic diseases, like type 2 diabetes mellitus, hypertension, and other medical pre-existing conditions. Eligible women were followed up at 20, 28, and 36 weeks of gestation by measuring blood pressure, weight, and body composition with the use of the BIA. The diagnosis of gestational hypertension was made after the 20th week of gestation. Pregnancy and perinatal outcomes were then recorded. Of the 479 women included in the study, 85 (17.7%) developed gestational hypertension; the remaining 394 (82.3%) resulted to be normotensive. A higher rate of nulliparous women was found in the hypertensive group (50.6% vs. 37.6%, p = 0.02), together with a higher rate of induction of labor (55.3% vs. 40.9%, p = 0.02) and of small for gestational age (SGA) newborns (12.9% vs. 6.9%, p = 0.03). Significant differences emerged in the body composition between the two groups already from the first trimester, indeed women developing gestational hypertension showed elevated values of Total body Mass, FM, FFM, TBW (p < 0.02), and of leg's FM, FFM (p < 0.006). At the multivariate logistics regression, the risk of developing gestational hypertension resulted higher in women with elevated total body water levels in the first trimester (OR 1.10 95% CI 1.04 -1.92). The BIA is a rapid, easy, non-invasive, and inexpensive tool to evaluate the body composition of obese pregnant women. It represents a promising predictor of hypertensive disorders in pregnancy, which allows an early identification of the patients at risk of developing gestational hypertension, thus opening a window of opportunity for strictly monitoring and target preventive intervention.

Potential of tidal power plants with least square method on Toaya Beach

The use of energy, especially electrical power, is needed by the wider community— lots of alternative energy from nature, especially in Indonesia that can be utilized to produce electricity. One of the newest alternative examples is the energy produced by tides. Tidal energy is a type of renewable energy that is relatively more predictable in number. One method that can process the waves is the Least Square Method. Where the results of data processing using this method can be known based on tidal observations for 15 days on Toaya Beach located in Donggala Regency, Central Sulawesi, the types of tidal types that occur based on the results of Formzahl’s count is 0.357 that the tidal types that occur are varied types leaning to double daily, with a Root Mean Square Error (RMSE) of 0.028, which means that the difference between predictive results and observational data is accurate. Then also obtained the value of the design water level elevation that is the highest high water level (HHWL) is 2.7 meters, and the lowest low water level (LLWL) is -0.3 meters with a height difference is 3.0 meters. So with the high height difference, the total energy generated by two times a day with a sea area of 9 km2 which is capable of producing energy movement from seawater can be calculated the potential energy generated from the waves of Toaya Beach, which is 5,53 MW.

Predictive modeling of groundwater nitrate pollution and evaluating its main impact factors using random forest

Groundwater quality in plains and basins of arid and semi-arid regions with increased agriculture and urbanization development faces severe nitrate pollution, which is affected by both climate and anthropogenic activities. Here, shallow groundwater nitrate concentrations in the Yinchuan Region in central Yinchuan Plain were modeled during 2000, 2005, 2010, and 2015 using random forest. Multiple spatial environment factors were taken as predictor variables. The relative importance of these factors was also calculated using the constructed model. Remote sensing and GIS methods were used to compile various environmental factors to generate training and test sets for training and validation of the random forest model. Mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2) between the observed and predicted groundwater nitrate concentrations were used to measure the model performance. As indicated by these metrics, the random forest model for groundwater nitrate prediction was performed well. The relative importance of the predictor variables computed by the model indicated groundwater nitrate was mainly affected by the distance to the Yellow River, meteorological elements (precipitation, evaporation, and mean air temperature), and water level elevation. Additionally, urban and arable land were the two land use/land cover types that mainly influenced groundwater nitrate concentration in the Yinchuan Region, of which urban land was more influential than arable land as a result of intense expansion of urban land from 2000 to 2015. Overall, the current study provides an approach to integrate multiple environmental factors for groundwater quality study and is also significant for sustainable groundwater management in the Yinchuan Region.

Multi-method Approach in Fulfilling Clean Water Resources for Inhabitants in A Rural Area: Preliminary Results

Clean water scarcity is among the crucial issues for inhabitants at Cikakaban Village, Tasikmalaya City. The complexity of the geological and hydrogeological conditions around Cikakaban Village makes groundwater exploration quite difficult. Regionally, Cikakaban Village has low aquifer productivity and is located at the contact of two formations which are passed by a fault. Therefore, a multi-method approach should be used in water sources exploration to obtain comprehensive results. In this paper, we presented the preliminary results which consist of the detailed geological and hydrogeological conditions of Cikakaban Village and its surroundings based on direct field observations. These observations aim to know the lithology that composes the research area and its characteristics, the potential of aquifers and water resources around the research area, as well as an overview of the distribution of groundwater depth and its flow direction. Geological survey includes observation of outcrops, both lithological description and geological structure evidence. Meanwhile, hydrogeological survey includes observation wells (location plotting, measuring ground water level elevation and depth, and checking water quality), as well as observation of the other potential water resources around Cikakaban Village. It can be inferred that rocks underlying the study area have fine grain sizes, dominated by claystone and tuff. However, the presence of geological structure causes these rocks to potentially become productive aquifers. Other potential water sources around the research area are springs and intermittent rivers.

Atmospheric Stilling Promotes Summer Algal Growth in Eutrophic Shallow Lakes.

Algal blooms are environmental challenges confronting lakes worldwide and are significantly influenced by chlorophyll a yields per unit phosphorus (Chla/TP), or nitrogen (Chla/TN). Here, the influence of inter-annual hydrometeorological variations on Chla/TP and Chla/TN were evaluated in eutrophic shallow Lake Taihu, China. Our results demonstrated significant increases (p < 0.001) in both Chla/TN and Chla/TP from 2005 to 2017, and increased Chla yields during the winter months were mainly correlated with higher water temperature and longer sunshine hours, which may cause severer blooms in winter and spring. In remaining months from 2005 to 2017, typical associations between atmospheric stilling (or water level elevation) and higher Chla yields were observed. The results also indicate that atmospheric stilling and water level elevation significantly (p < 0.001) decreased background turbidity and promoted buoyant cyanobacterial biomass, alleviating phytoplankton light limitation. Given the subtropical location, eutrophic status, and high background turbidity of Lake Taihu, light may be the critical limiting factor for summer phytoplankton growth; thus, improved light availability would promote Chla yields until self-shading caused further light limitations. If the mechanism is general, promoting the effect of atmospheric stilling on annual peak Chla in shallow lakes may be greatly underestimated, and our finding will affect future bloom mitigation efforts in such systems.

The AD 1755 Lisbon Earthquake-Tsunami: Seismic source modelling from the analysis of ESI-07 environmental data

This work presents a macroseismic analysis of the AD 1755 Lisbon Earthquake-Tsunami event by means of the combination of intensity data derived from the EMS-98 scale and the ESI-07 scale (Environmental damage). About 600 records of secondary earthquake environmental effects (EEEs) for the whole Spain have been used to define intensities, focused on the SW portion of the Iberian Peninsula. The Spanish data have been complemented with 308 EEEs records from Portugal. The analyses indicate maximum intensities of X EMS-ESI along the Atlantic margin of the Iberian Peninsula with 76 records of Tsunami environmental effects (TEEs). An important amplification (VIII – VII) occurred all along the Guadalquivir basin and the adjacent Betic front at epicentral distances of 300–700 km. In these zones 55 records of ground effects (ground cracks, Liquefactions and slope movements) are catalogued. In the rest of the territory of the Peninsula the most widespread effects were hydrogeological changes with 505 records in Spain and 196 in Portugal (total 701 records) covering all the intensity levels. Increase of flow discharges in springs and elevation of water level in wells was the common groundwater response to seismic shacking, especially in SW Iberia. In this zone water elevation in wells was between 5 and 3 m and persistent increases of discharges long-lasting (several days to two months). Persistent discharges on springs were linked in 143 cases to important SW-NE crustal faults (e.g., Alentejo-Plasencia Fault). From the Intensity distribution the historic seismic scenarios are explored by means of the development of empirical ShakeMaps. These consider the three classical seismic sources proposed for this earthquake: Gorringe Bank (G); Marques de Pombal Fault (M) and Atlantic delamination beneath the Gulf of Cadiz (C). However, individually these seismic sources are too small and unable to generate the resulting seismic scenario depicted by the intensity map developed in this work, with onshore seismic accelerations (PGA) up to 0.82 g. These acceleration values and the great amplification experienced throughout the Guadalquivir basin (0.34–0.52 g) are only possible considering a combination of the three seismic sources (GMC Source) probably related to shallow subduction or lithospheric delamination beneath SW Iberia and the Gulf of Cadiz. This will suggest an NNE-SSW offshore rupture length of 350–360 km with an overall rupture area of c. 84,500 km2 resulting in an event magnitude 8.6 Mw calculated from empirical relationships. The results demonstrate the efficacy of these kind of approaches for better identifying and modelling seismic sources for historical events.

Can sea level rise help us restore coastal wetlands? The hydrologic restoration of the Slop Bowl, Brazoria National Wildlife Refuge, Texas

The Slop Bowl marsh in the Brazoria National Wildlife Refuge provides extraordinarily high quality, heavily used bird habitat. Much of this habitat has experienced hypersaline conditions due to both hydrologic alteration by humans and a rapidly and changing physical environment over the past several decades. Oil and natural gas extraction activities have resulted in excavation and channelization along pipelines and hydrologic obstruction by an access road. In addition, subsidence along growth faults has altered hydrologic pathways and lowered surface elevations in the center of the marsh. Our objective was to understand the underlying processes that contribute to hypersaline conditions and to evaluate possible restoration alternatives to reduce the severity of those conditions. Accordingly, we conducted extensive field and hydrologic modeling efforts, and identified the past, present, and future of this marsh habitat under a baseline scenario. We then compared various restoration action scenarios against this baseline. We found that, beginning in about 15 years, relative sea level rise will improve the hydrologic conditions by enhancing tidal flushing. However, if fill material is continually added to elevate the obstructing road as the sea rises, this hydrologic relief may never be realized. Moreover, we found that if a drought occurs during this critical period, a difference of only a few centimeters in the relative water level and road elevation, or changes in marsh surface elevations driven by fault motion and subsidence, may have catastrophic consequences. The modeling also suggests that several potential interventions can bridge this gap over the next 15 years and beyond. Actions that improve tidal circulation, reduce salinity, and enhance marsh accretion are being developed by the project team to enhance and restore habitat in the near term. The most optimal approaches evaluated thus far include the installation of culverts at critical locations, the excavation of a small channel, the modification of flow pathways, and the beneficial use of sediments and vegetative plantings. We conclude that, under specific circumstances or at unique locations such as the Slop Bowl marsh, sea level rise can be leveraged to improve coastal wetland health.

Beaching and Natural Removal Dynamics of Pelagic Sargassum in a Fringing‐Reef Lagoon

AbstractMassive quantities of the pelagic brown macroalgae Sargassum spp. (sargassum) have been invading the Caribbean and West African shores since 2011, causing devastating effects on the coastal ecosystem and local economy. Little is known about sargassum beaching dynamics and the capacity of the coastal system to naturally remove beached sargassum. Here, we characterize the temporal variation in arriving and beached sargassum in a reef lagoon using a 5.2‐year data set of hourly optical imagery, and identify the governing hydrometeorological conditions. Image classification reveals interannual variability in the start, duration, and intensity of the sargassum arrival season. Arrivals are associated with relatively low energy onshore directed winds and waves, and offshore abundance of sargassum. Furthermore, nearshore sargassum mat size is found to decrease with decreasing wave/wind energy. Once sargassum beaches, a berm of wrack is formed. Natural wrack removal was observed under elevated water levels and increased wave action. Three types of wrack removal were distinguished, depending on the water level with respect to the berm crest height and berm crest toe : gradual berm destruction with gaps developing in the seaward berm edge that grow larger with time (Type I; ) and abrupt berm destruction with part of the wrack depositing on the upper beach (Type II; ) or in the dunes (Type III; ). Higher energy waves activate the reef circulation, which is suspected to flush part of the wrack out of the reef lagoon. We propose a conceptual model of nearshore sargassum dynamics in a reef lagoon system.

Centrifugal model test of deformation law under different reservoir water fluctuation rates: Muyubao landslide case study

Many ancient landslides have become active due to the impoundment of the Three Gorges Reservoir. Considering the Muyubao landslide in the Three Gorges Reservoir area as the research object, we analyzed the long-term deformation law since the impoundment of the reservoir and conducted centrifugal model tests of the landslide deformation process under different reservoir water fluctuation rates. The monitoring data analysis reveals that the deformation of the Muyubao landslide is mainly affected by the elevation of the reservoir water level and its rising and falling rate. A deformation greater than 30 mm mainly occurs at the water level of 165–175 m. A higher reservoir water rising rate promotes landslide deformation, with a monthly cumulative displacement of above 30 mm in the reservoir water rising stage. Further, a lower reservoir water decline rate can promote several landslide deformation events with monthly cumulative displacement greater than 30 mm. A Centrifugal model test demonstrates the Muyubao landslide deformation to the hydrodynamic buoyancy pressure of reservoir water. The head difference inside and outside the slope is minimal when the reservoir water rising and the falling rate is small, and the reservoir water buoyancy controls the deformation of landslides. However, the head difference inside and outside the slope increases with the reservoir water rise and fall rate, leading to increased hydrodynamic pressure, which weakens the landslide deformation in the reservoir water rising stage, and strengthens the deformation in the reservoir water-falling stage. The results provide a significant reference for landslide control and reservoir operation optimization in the Three Gorges Reservoir area.

Formation of a barrier island breach and its contributions to lagoonal circulation

Barrier islands are a primary coastal defense and often experience erosion during storms. When they fail due to storm-induced breaching, there can be significant changes to the small- and large-scale hydrodynamics and morphodynamics of the region. In this study, we explore the formation of a breach on Hatteras Island, North Carolina, during Isabel (2003) and the subsequent flooding into Pamlico Sound. Two-way coupling of high-fidelity, high-resolution numerical models for coastal erosion and flooding enables a better understanding of the formation of the breach, as well as scenarios of the breach’s effects on the circulation in the region. The breach connecting the ocean to the sound formed during the day of landfall. It is shown that, during the storm, overwash and inundation from the ocean led to deterioration of the beach and dunes, and then after the storm, the creation of channels through the island was sensitive to elevated water levels in the lagoon. Then flooding scenarios are considered in which the ground surface of the hydrodynamic model was (a) static, updated with the (b) pre- and post-storm observations, and updated dynamically with (c) erosion model predictions and (d) erosion model predictions with elevated lagoon-side water levels. The model results show that the breach has region-scale effects on flooding that extend 10to13km into the lagoon, increasing the local water levels by as much as 1.5m. These results have implications for similar island-lagoon systems threatened by storms.

Corrigendum: Evaluation of the implications of ice‐jam flood mitigation measures

Journal of Flood Risk ManagementVolume 14, Issue 4 e12759 LETTER TO THE EDITOROpen Access Corrigendum: Evaluation of the implications of ice-jam flood mitigation measures First published: 20 September 2021 https://doi.org/10.1111/jfr3.12759AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Corrigendum for the article: Das, A. and Lindenschmidt, K.-E. (2021) Evaluation of the implications of ice-jam flood mitigation measures. Journal of Flood Risk Management 2021: e12697. https://doi.org/10.1111/jfr3.12697 Since its publication, we have replaced our exceedance probabilities P in Equation (3) with a formulation provided by Gerard and Karpuk (1979). While distributions and associated parameters to developed exceedance probabilities are well developed in open-water hydrology, there is no solid or well-developed approach for ice-affected river stages. Therefore, scientists and engineers rely on graphical or nonparametric statistical techniques, such as Weibull, Hazen, median or the formula proposed by Gerard and Karpuk (1979) to calculate exceedance probabilities. Hence, for this study, we decided to use the latter formula (Gerard & Karpuk, 1979): where m is the rank of each ice-jam water level elevation, N is the total number of simulations and X is a value exceeding x (White & Beltaos, 2008). We found that the overall conclusions do not change but that only the total annual expected damages are scaled up by a factor of approximately 3, to $11.3 million for the town of Fort McMurray, a value which is in line with a result of $10.4 million by IBI and Golder Associates Ltd. (2014). Updated Figures 7 and 8 are provided below. FIGURE 7Open in figure viewerPowerPoint Flood risk maps for different mitigation scenarios along the Athabasca River at Fort McMurray FIGURE 8Open in figure viewerPowerPoint The expected annual damages from the ensemble of flood risk maps for different mitigation scenarios at Fort McMurray The paragraph immediately before Section 4 should read: The EAD of different mitigation scenarios are demonstrated in Figure 8. The results show that artificial breakup and 250 m a.s.l dike crest elevation can reduce the most ice-jam flood risk among all the mitigation scenarios. While the base scenario has the maximum EAD, about $11.2 million, artificial breakup has an EAD of about $1.7 million. The 250 m a.s.l dike crest elevation also has a great potential to reduce the flood risk, which could reduce the EAD to $0.95 million. Although the sediment dredging scenarios could reduce the EAD to a certain level, they may be less effective compared to the other two mitigation measures, 250 m a.s.l. crest-elevation dike and artificial breakup. Moreover, the optimum result was found to be for 3 m dredging in which the EAD was reduced to about $5.8 million. Further studies, by changing the dredging location, can be applied to identify the potential of sediment dredging to reduce flood risk. The tenth line in Section 4 “Discussion and concluding remarks” should read: “… the results show that artificial breakup has the second highest potential to reduce the EAD, as the number of buildings exposed to flood risk significantly reduce in this scenario.” Open Research DATA AVAILABILITY STATEMENT Data sharing is not applicable to this article as no new data were created or analyzed in this study. REFERENCES Gerard, R., & Karpuk, E. W. (1979). Probability analysis of historical flood data. Journal of the Hydraulics Division, 105(9), 1153– 1165. CrossrefGoogle Scholar IBI and Golder Associates Ltd. (2014). Report feasibility study—Athabasca River Basins. Prepared for Government of Alberta—Flood recovery Task Force. Retrieved from https://open.alberta.ca/publications/35751. Google Scholar White, K., & Beltaos, S. (2008). Chapter 9: Development of ice-affected stage frequency curves. In River ice break-up. Water Resources Publications, Highlands Ranch, Co. Google Scholar Volume14, Issue4December 2021e12759 FiguresReferencesRelatedInformation

A storm hazard matrix combining coastal flooding and beach erosion

Coastal storms cause widespread damage to property, infrastructure, economic activity, and the environment. Along open sandy coastlines, two of the primary coastal storm hazards are coastal flooding by elevated ocean water levels and beach erosion as the result of storm wave action. At continental margins characterized by a shallow, wide continental shelf, coastal storms are more commonly associated with amplified storm surge and the damaging impacts caused by flooding of low-lying land. In contrast, along margins where the continental shelf is narrow and deep, coastal storm impacts are more often characterized by beach erosion, due to the typically lower magnitude of storm surge but a higher proportion of deepwater wave energy reaching the shoreline. A new Storm Hazard Matrix is presented that integrates these two distinct but inherently linked open coast hazards. The approach is based on the combination of two hazard scales. The first is a ‘coastal flooding hazard scale’ that follows an established framework in which hazards are predominately driven by the vertical increase in ocean water levels during storms and any significant morphological changes caused by the storm are inferred. The second is a storm wave ‘beach erosion hazard scale’ where hazards are predominately determined by the horizontal recession of the sandy beach and dune without necessarily large increases in water levels. The resulting framework comprises a total of sixteen unique combinations of flooding/erosion storm hazard regimes, each potentially requiring different disaster risk reduction approaches. Real-world application of the Storm Hazard Matrix is explored at contrasting coastlines for two major storm events, encompassing an extratropical cyclone that impacted the coastline of southeast Australia in June 2016, and a large hurricane (Hurricane Ivan) that impacted the Gulf Coast of the United States in 2004. The new approach identifies and distinguishes between the severity of localized coastal flooding and/or coastal erosion, and also provides enhanced insight to the nature, magnitude and alongshore variation of coastal storm hazards along the impacted coastline. Within the context of disaster risk reduction, preparedness and operational early warning, implementation of the Storm Hazard Matrix has the potential to deliver robust evaluations of storm hazards spanning a wider variety of both wave-dominated and surge-dominated coasts.

Modeling an arrested salt-wedge estuary subjected to variable river flow

In this study we present an approach to calibrate a three-dimensional hydrodynamic model of a salt-wedge estuary, the Araranguá Estuary, southern Brazil, based on the Delft3D-FLOW model. The calibration was carried out in four steps to predict the vertical salinity structure along the estuary in an efficient and effective way. Skill assessment was used to evaluate the calibration quality. The model is forced by water-level elevation along the offshore open boundary and river-discharge inflows from the two major tributaries. The hydrodynamic model was calibrated using field observation of water level, currents and longitudinal salinity structure. Calibration was performed adjusting vertical grid resolution, bottom-friction coefficient and background eddy viscosity. The model achieves high skill values at water level and currents variations during a 113-day period (in 2008) covering a wide range of river discharge and tidal forcing. Water surface fluctuations obtained from the model are in good agreement with the field data. Modeled depth-averaged currents reproduce the temporal pattern of observed data. Longitudinal salinity structure is also well reproduced, although the vertical structure is more diffusive than the observations. Results also demonstrate that the model predicts the overall measured phenomena and the effects of the flash-flood event, with the discharge affecting water level, currents and salinity.

The relative role of constructive and destructive processes in dune evolution on Cape Lookout National Seashore, North Carolina, USA

AbstractCoastal dunes are dynamic features that are continuously evolving due to constructive (e.g., wind‐ and wave‐driven sediment transport) and destructive (e.g., elevated total water levels during storm events) processes. However, the relative importance of these processes in determining dune evolution is often poorly understood. In this study, ten lidar datasets from 1997 to 2016 are used to determine the relative role of erosion and accretion processes driving foredune change on the coast of Cape Lookout National Seashore, North Carolina, USA. Beach and dune morphometrics reveal that dune toe locations have generally retreated since 1997, while dune crest heights accreted by 0.01–0.02 m/year. We develop three univariate metrics that represent (1) the potential for erosion, i.e., total water level impact hours per year, (2) accretion, i.e., dune building hours per year, and (3) the relative net effect of foredune accretion and erosion processes, i.e., constructive–destructive dune forcing (CDDF) ratio, and test the correlative power of these metrics in explaining changes in foredune morphology. The total water level impact hours per year metric explained as much as 66% and 67% of the variance in dune crest and toe elevations, respectively, across the nearly two decades of dune evolution. The greatest number of dune building hours per year and largest dunes within the study site co‐occurred at locations exposed to the dominant cross‐shore wind direction as a result of varying shoreline orientation. The CDDF ratio was positively correlated to changes in the dune toe elevation in approximately 70% of dunes within the study site, outperforming the impact and dune building hours per year metrics. Our results show that these three metrics can provide first‐order estimates of dune morphometric change across multiple spatial and temporal scales, which may be particularly useful at sites where lidar acquisition is intermittent.