scholarly journals Coastal sediment balance in the eastern part of the Gulf of Riga (2005–2016)

Baltica ◽  
2018 ◽  
Vol 30 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Jānis Lapinskis
Keyword(s):  
Coastal Sediment ◽  
Eastern Coast ◽  
Storm Event ◽  
Fine Sediments ◽  
Coastal Slope ◽  
Sediment Volume ◽  
Quantitative Estimates ◽  
Sediment Balance ◽  
Gulf Of Riga ◽  
Coastal Retreat

A hurricane known as Ervin or Gudrun travelled over Latvia in 8–9 January, 2005. As a result of severe SW and W winds, as well as lack of sea ice, clearly pronounced changes in the distribution of coastal sediment has been induced. Cross-shore profile leveling at various time instants was used to obtain quantitative estimates of the amount of accumulated sediments. The total volume of sediments eroded from the subaerial part of coastal slope reached 0.8 million m3. This paper represents assessment of consequent changes and coastal slope “rebuilding” success after this storm event. The data indicates lack of significant overall net loss of subaerial sediment volume along the most part of the eastern coast of the Gulf of Riga. Significant primary dune growth and beach accumulation is mostly limited to southernmost part of assessed coastal stretch. Total volume of fine sediments in beach and primary dunes still is 5 % lower than before erosion event of 2005. Erosion vulnerability and total length of coastal sections that are expected to be a subject to future coastal retreat is increasing.

scholarly journals Dust Transport from Inland Australia and Its Impact on Air Quality and Health on the Eastern Coast of Australia during the February 2019 Dust Storm

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 141
Author(s):  
Emilie Aragnou ◽  
Sean Watt ◽  
Hiep Nguyen Duc ◽  
Cassandra Cheeseman ◽  
Matthew Riley ◽  
...  
Keyword(s):  
Air Quality ◽  
Dust Storm ◽  
New South ◽  
New South Wales ◽  
The State ◽  
Dust Storms ◽  
Eastern Coast ◽  
Storm Event ◽  
South Wales ◽  
Dust Storm Event

Dust storms originating from Central Australia and western New South Wales frequently cause high particle concentrations at many sites across New South Wales, both inland and along the coast. This study focussed on a dust storm event in February 2019 which affected air quality across the state as detected at many ambient monitoring stations in the Department of Planning, Industry and Environment (DPIE) air quality monitoring network. The WRF-Chem (Weather Research and Forecast Model—Chemistry) model is used to study the formation, dispersion and transport of dust across the state of New South Wales (NSW, Australia). Wildfires also happened in northern NSW at the same time of the dust storm in February 2019, and their emissions are taken into account in the WRF-Chem model by using Fire Inventory from NCAR (FINN) as emission input. The model performance is evaluated and is shown to predict fairly accurate the PM2.5 and PM10 concentration as compared to observation. The predicted PM2.5 concentration over New South Wales during 5 days from 11 to 15 February 2019 is then used to estimate the impact of the February 2019 dust storm event on three health endpoints, namely mortality, respiratory and cardiac disease hospitalisation rates. The results show that even though as the daily average of PM2.5 over some parts of the state, especially in western and north western NSW near the centre of the dust storm and wild fires, are very high (over 900 µg/m3), the population exposure is low due to the sparse population. Generally, the health impact is similar in order of magnitude to that caused by biomass burning events from wildfires or from hazardous reduction burnings (HRBs) near populous centres such as in Sydney in May 2016. One notable difference is the higher respiratory disease hospitalisation for this dust event (161) compared to the fire event (24).

scholarly journals NUMERICAL SIMULATIONS OF RIDGE ACCRETION AND ONSHORE MIGRATION BASED ON FIELD DATA FROM A STEEP MESO-TIDAL ENGINEERED BEACH

2018 ◽  
pp. 1
Author(s):  
Youn Kyung Song ◽  
Jens Figlus ◽  
Patricia Chardon-Maldonado ◽  
Jack A. Puleo
Keyword(s):  
Field Experiment ◽  
Numerical Simulations ◽  
Field Data ◽  
Storm Event ◽  
Swash Zone ◽  
Field Campaign ◽  
Sediment Volume ◽  
Rapid Formation ◽  
Offshore Wave ◽  
In The Beginning

Previously, the accretion of a slip-faced ridge and runnel (RR) system was observed during a 3-week field experiment on a steep meso-tidal engineered beach at South Bethany Beach, Delaware. Detailed measurements of wading depth beach profiles and nearbed flow velocities were obtained in the inner surf and swash zones along with offshore wave and current records. In the beginning of this 3-week field campaign on February 13, 2014 a Nor’easter eroded significant portions of the inner beach during this 1-day long storm event. Immediately after the storm during the less energetic conditions, the rapid formation of a pronounced RR system was observed which then continuously evolved over the duration of 2-week poststorm recovery periods. In the last day of the field campaign, 85% of the sediment volume eroded during the storm was recovered in the swash zone. However, no more evolution of the RR system toward the runnel infilling or landward migration was observed.

scholarly journals Fine Sediment Modeling During Storm-Based Events in the River Bandon, Ireland

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1523 ◽  
Author(s):  
Juan T. García ◽  
Joseph R. Harrington
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Fine Sediment ◽  
Storm Event ◽  
Storm Events ◽  
Event Scale ◽  
Model Based ◽  
Sediment Volume ◽  
Bed Erosion

The River Bandon located in County Cork (Ireland) has been time-continuously monitored by turbidity probes, as well as automatic and manual suspended sediment sampling. The current work evaluates three different models used to estimate the fine sediment concentration during storm-based events over a period of one year. The modeled suspended sediment concentration is compared with that measured at an event scale. Uncertainty indices are calculated and compared with those presented in the bibliography. An empirically-based model was used as a reference, as this model has been previously applied to evaluate sediment behavior over the same time period in the River Bandon. Three other models have been applied to the gathered data. First is an empirically-based storm events model, based on an exponential function for calculation of the sediment output from the bed. A statistically-based approach first developed for sewers was also evaluated. The third model evaluated was a shear stress erosion-based model based on one parameter. The importance of considering the fine sediment volume stored in the bed and its consolidation to predict the suspended sediment concentration during storm events is clearly evident. Taking into account dry weather periods and the bed erosion in previous events, knowledge on the eroded volume for each storm event is necessary to adjust the parameters for each model.

scholarly journals Sediment balance of a cascade of alpine reservoirs based on multi-decadal data records

2018 ◽  
Vol 40 ◽  
pp. 03012
Author(s):  
Sebastián Guillén Ludeña ◽  
Pedro Manso ◽  
Anton J. Schleiss ◽  
Benno Schwegler ◽  
Jan Stamm ◽  
...  
Keyword(s):  
Sedimentation Rate ◽  
Reservoir Sedimentation ◽  
Sediment Fluxes ◽  
Fine Sediments ◽  
Sediment Balance ◽  
Operational Management ◽  
Human Use ◽  
Bottom Outlets ◽  
Total Sedimentation ◽  
Annual Sediment

Reservoir sedimentation is a major concern in the operational management of dams and appurtenant structures. The increasing volume of sediments deposited in reservoirs leads to a loss of water storage, undermining the purpose itself of the dam for human use or protection. The deposition of sediments (mostly fine) in the vicinity of the dam’s operational structures, such as bottom outlets and power intakes, may result in partial or total blockage of these structures. To cope with these problems, it is essential to determine the sediment balance of the reservoirs, by assessing the origin and quantity of the in- and out-fluxes of sediments. This paper presents a methodology to determine the annual sediment balance of a system of interlinked reservoirs across several decades, as well as its application to the alpine hydropower cascade formed by the Oberaar, Grimsel and Räterichsboden reservoirs located in Switzerland. At that aim, the annual sediment fluxes and the sedimentation rates of each reservoir were characterized. Also, the percentage of fine sediments (dm < 10 μm) included in the total sedimentation rate was estimated. The results reveal that the annual sedimentation rate of the lowermost reservoir of the system (Räterichsboden) is highly altered by the flushing operations of the reservoir upstream (Grimsel). Also, for the uppermost reservoir of the system (Oberaar), the volume of fine sediments deposited annually can reach up to 46% of the total sedimentation rate.

scholarly journals Mathematical Modeling the Dynamics of the Bottom Sediments Granulometric Composition in the Balaklava Bay Affected by the Wind Waves

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
K. I. Gurov ◽  
V. V. Fomin ◽  
◽  
Keyword(s):  
Mathematical Modeling ◽  
Bottom Sediments ◽  
Wind Waves ◽  
Water Area ◽  
Eastern Coast ◽  
Storm Event ◽  
Western Coast ◽  
Marine Hydrophysical Institute ◽  
Storm Waves ◽  
Sand Material

Purpose. Based on the mathematical modeling methods, influence of the wind waves on redistribution of the sand fractions in the semi-closed estuary-type water area is estimated using the Balaklava Bay as an example. Methods and Results. A two-dimensional version of the XBeach model with a constant grid spacing 10 m was used. The characteristics of wind waves were preset using the JONSWAP spectrum implying fixed height, wave period and various combinations of the wave direction. The calculations were carried out for a storm event lasting about 12 hours once a year. The in-situ data on the particle size distribution in the bottom sediments resulted from the monitoring observations performed by the Marine Hydrophysical Institute, Russian Academy of Sciences, in the Balaklava Bay region was used in the numerical experiments. Conclusions. The results of modeling showed that the basic determining factors regulating the sediments movement were the depth and the bottom slope. It is noted that changing of the bottom inclination angle between the isobaths 6–7 and 7–8 m leads to deposition of the large and medium fractions, and in the area between the isobaths 9–10 and 10–12 m – to accumulation of fine sand. It was revealed that in the Balaklava Bay water area, the main redistribution of sand material caused by the storm waves took place within the southern basin, as well as at the bay exit in the coastal zone of the Megalo-Yalo Bay. This is primarily determined by the features of the Balaklava Bay coast orography, namely, the knee-shaped narrowness separating the northern and southern basins. Nevertheless, in the isolated northern part of the Balaklava Bay being affected by the storm waves, insignificant dynamics of sand material was observed. The fractions of bottom sediments are redistributed from the western coast to the central part of the basin and to the eastern coast of the bay.

scholarly journals Mathematical Modeling the Dynamics of the Bottom Sediments Granulometric Composition in the Balaklava Bay Affected by the Wind Waves

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
K. I. Gurov ◽  
V. V. Fomin ◽  
◽  
Keyword(s):  
Mathematical Modeling ◽  
Bottom Sediments ◽  
Wind Waves ◽  
Fine Sand ◽  
Water Area ◽  
Eastern Coast ◽  
Storm Event ◽  
Western Coast ◽  
Storm Waves ◽  
Sand Material

Purpose. Based on the mathematical modeling methods, influence of the wind waves on redistribution of the sand fractions in the semi-closed estuary-type water area is estimated using the Balaklava Bay as an example. Methods and Results. A two-dimensional version of the XBeach model with a constant grid spacing 10 m was used. The characteristics of wind waves were preset using the JONSWAP spectrum. The calculations were carried out for a storm event lasting about 12 hours once a year. The in-situ data on the particle size distribution in the bottom sediments resulted from the monitoring observations in the Balaklava Bay region was used in the numerical experiments. Conclusions. The results of modeling showed that the basic determining factors regulating the sediments movement were the depth and the bottom slope. It is noted that changing of the bottom inclination angle between the isobaths 6–7 and 7–8 m leads to deposition of the large and medium fractions, and in the area between the isobaths 9–10 and 10–12 m – to accumulation of fine sand. It was revealed that in the Balaklava Bay water area, the main redistribution of sand material caused by the storm waves took place within the southern basin, as well as at the bay exit in the coastal zone of the Megalo-Yalo Gulf. This is primarily determined by the features of the Balaklava Bay coast orography, namely, the knee-shaped narrowness separating the northern and southern basins. Nevertheless, in the isolated northern part of the Balaklava Bay being affected by the storm waves, insignificant dynamics of sand material was observed. The fractions of bottom sediments are redistributed from the western coast to the central part of the basin and to the eastern coast of the bay.

scholarly journals Influence of Storm Conditions on Changes in the Granulometric Composition of Bottom Sediments in the Coastal Zone of the Western Crimea

2021 ◽  
Author(s):  
K. I. Gurov ◽  
V. V. Fomin ◽  
◽  
Keyword(s):  
Coastal Zone ◽  
Bottom Sediments ◽  
Wind Waves ◽  
Initial Distribution ◽  
Computational Domain ◽  
Model Calculations ◽  
Coastal Slope ◽  
Sediment Volume ◽  
Median Diameter ◽  
Sandy Material

The aim of this work is to study the dynamics of bottom sediments granulometric fractions in the Kalamitsky Gulf coastal zone near the Lake Sakskoe bay-bar under influence of storm surge based on the XBeach numerical morphodynamic model. A series of numerical experiments has been carried out, in which the parameters of waves at the seaward boundary of the computational domain changed in time, simulating the passage of a cyclonic atmospheric anomaly over the investigated region. The initial distribution of the sediment volume concentrations in different parts of the underwater coastal slope profile was set based on the results of field observations. The duration of model calculations was 24 h. The quantitative characteristics of the spatial distribution of various bottom sediments fractions, sediments median diameter and values of bottom deformations were obtained. It has been established that the main morphodynamic changes occurs in the area 0–120 m from the shoreline and are limited by the 3.5 m isobath. It was noted that the maximum changes in the relief of the coastal zone and the upper section of the underwater coastal slope occur during the development and attenuation phases of a storm. In the same time intervals an intensive redistribution of sandy material is observed. It has been established that, with a change in the parameters of wind waves in time at the seaward boundary, the scales of sand material redistribution and deformations of the coastal zone are higher than in the experiment when the direction of the waves does not change with time at the seaward boundary of the computational domain.

Short-term seasonal changes of the Dzita beach of Ghana using geographic information system and photogrammetry

2021 ◽  
pp. 1-50
Author(s):  
Brempong K. Brempong ◽  
Donatus Bapentire Angnuureng ◽  
Kwasi Appeaning-Addo ◽  
Philip-Neri Jayson-Quashigah
Keyword(s):  
Scientific Information ◽  
Eastern Coast ◽  
Second Phase ◽  
Short Term ◽  
High Resolution Data ◽  
Shoreline Changes ◽  
Sediment Volume ◽  
Gravel Mining ◽  
Soft Engineering ◽  
Term Basis

Coastal erosion has become an issue globally. As the sea level continues to rise due to global warming, projections are that erosion would increase. To address the issue sustainably, relevant scientific information such as sediment transport and shoreline dynamics is required at local scales. Over the years, erosion at the eastern coast of Ghana has been mainly evaluated using low-resolution imagery due to the challenges in retrieving high-resolution data in the nearshore region. An unmanned aerial vehicle (UAV) approach was used to assess beach evolution on a seasonal and short-term basis between May 2018 and December 2019. Using the UAV approach, shoreline changes, sediment volume changes, and profile elevation parameters were extracted for the Dzita beach of Ghana. Shoreline changes indicated the dominance of erosion during the first and third phases (May 2018 to December 2018 and June 2019 to December 2019, respectively) at a rate of −7.23 ± 0.23 and −4.85 ± 0.23 m/yr, whereas the second phase showed accretion of +8.44 ± 0.23 m/yr. Beach profiles from the first, second, and third phases had steep and gentle slopes, respectively. From these observations, it was recommended that soft engineering approaches such as beach nourishment should be implemented to protect the shoreline and strict prevention of nearshore sand mining and gravel mining. It is also possible that the beach could go through a cycle of changes. Further studies using this same approach should be done as well as probing into other parameters such as nearshore bathymetry to have a better understanding of beach dynamics as envisaged.

scholarly journals Coastal Dunes of the Baltic Sea Shores: A Review

2018 ◽  
Vol 37 (1) ◽  
pp. 47-71 ◽  
Author(s):  
Tomasz Arkadiusz Łabuz ◽  
Ralf Grunewald ◽  
Valentina Bobykina ◽  
Boris Chubarenko ◽  
Algimantas Česnulevičius ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Coastal Dunes ◽  
Coastal Dune ◽  
Eastern Coast ◽  
Western Coast ◽  
The South ◽  
The Baltic Sea ◽  
Coastal Retreat ◽  
The Baltic ◽  
Sea Coast

Abstract The article summarises results of studies conducted along the Baltic Sea sandy coasts by scientists involved in coastal dune research, and presents an attempt to describe the types and distribution of dune coasts. The Baltic Sea coasts feature lower and higher foredunes. The lowland behind the coastal dune belt is covered by wandering or stabilised inland dunes – transgressive forms, mainly parabolic or barchans. The source of sediment for dune development includes fluvioglacial sands from eroded coasts, river-discharged sand, and older eroded dunes. Due to the ongoing erosion and coastal retreat, many dunes have been eroded, and some are withdrawing onto the adjacent land. There are visible differences between the south-eastern, western, and northern parts of the Baltic Sea coast with respect to dune development. The entire southern and eastern coast abounds in sand, so the coastal dunes are large, formerly or currently wandering formations. The only shifting dunes are found at the Polish and the Russian–Lithuanian coasts on the Łebsko Lake Sandbar as well as on the Vistula and Curonian Spits. The very diverse shoreline of the south-western coast experiences a scarcity of larger sandy formations. Substantial parts of the Baltic Sea sandy coasts have been eroded or transformed by humans. The northern part of the Baltic Sea coast features mainly narrow and low sandy coasts (e.g. in Estonia). Further north, sandy dunes are virtually absent.

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