Shore Protection Measures Research Articles

Submerged Geosynthetic Reef as Shore Protection Measure for Islands

Submerged Geosynthetic Reef as Shore Protection Measure for Islands

Numerical modelling approach for the feasibility of shore protection measures along the coast of Kavaratti Island, Lakshadweep archipelago

Numerical modelling approach for the feasibility of shore protection measures along the coast of Kavaratti Island, Lakshadweep archipelago

BOAT-BASED MOBILE LASER SCANNING FOR SHORELINE MONITORING OF LARGE LAKES

Abstract. In many applications, it is necessary to measure the shore areas of water bodies in three dimensions, for example for the planning of shore protection measures or regularly for water body monitoring. The complete recording of long shorelines can be very time-consuming with conventional methods. This paper presents the surveying of two lakes using a mobile laser scanner system. In order to close non-visible areas, the measurement was supplemented with terrestrial laser scanning and with UAV-supported photogrammetric methods. The result is an almost complete point cloud of the shoreline, each more than 8 km long, with a point spacing of a few millimetres.

Shore Protection Measures along Indian Coast – Design to Implementation Based on Two Case Studies

Shore Protection Measures along Indian Coast – Design to Implementation Based on Two Case Studies

Coastal vulnerability assessment using GIS-Based multicriteria analysis of Alexandria-northwestern Nile Delta, Egypt

This study intends to map the relative coastal vulnerability index (CVI) for the administrative governorates of Alexandria and adjacent Behera in the northwestern coastal margin of the Nile delta. In addition to other common environmental stresses, these governorates are under threat due to accelerated sea level rise induced from climate change. Of special interest is that the coastal margin of the study area is characterized by markedly constructing geology, morpho-dynamics and land surface topography that varies from low-lying (−3 m below MSL) to high land (~20 m height). Therefore, nine physical and geological variables influencing the vulnerability of the coast are used in this study, including land elevation, seabed/beach composition, beach type (dissipative to reflective), relative sea level, historical shoreline change, tidal range, significant wave height, shore protection measures, and land cover. Results obtained from performing multi-criteria analysis of GIS indicates that about 16.58%, 15.45, 42.03%, 18.16 and 7.78% of the shoreline is under very high, high, moderate, low and very low vulnerability respectively. Of great concern is that although the low-lying broad depression (−1 to −3 m below MSL) east and southeast of Alexandria is protected now by a combination of natural shore-parallel elevated ridges (up to 10 m) and artificial shore-parallel detached structures, it is likely to be accidently flooded by unexpected extreme storm or tsunami events at the lowest waterfront points.

Technological problems of protection of coastal urban areas

Construction and operation of shore protection constructions are associated with a detailed study of abrasive and erosion-landslide processes in the coastal zone. Unfortunately, there are cases when due to the wrong choice of the type of constructions, violations of the technological process during installation is a complete or partial destruction of shore protection structures. The investigations show a low efficiency of individual shore protection measures, as well as a large number of deformations of structures on coastal fortified areas caused by the violation of technological standards in construction. It is also necessary to note the outdated methods and technologies of coastal protection used in the Volgograd region, which should be replaced by more modern and effective. Modern technology of construction of such structures will prevent the impact of abrasive processes and preserve the natural landscape of the site.

DESIGN AND PERFORMANCE OF A MIXED SEDIMENT NOURISHMENT PROJECT ALONG AN URBAN SEDIMENT-STARVED SHORELINE

The long-term shore protection of Boston’s open ocean shoreline has utilized a variety of coastal engineering strategies to prevent or at least inhibit the impacts of coastal flooding and storm wave action to urban development. The Winthrop Beach region is located to the north of the Boston Harbor entrance and historically incorporated a variety of coastal engineering structures, beginning in the late 1880s, to mitigate the impacts of coastal flooding and storm wave action. To some degree, these “hard” shore protection measures have prevented further degradation of upland infrastructure; however, loss of the littoral sediment supply due to coastal armoring of the adjacent upland and the related lowering of the beach fronting the seawall along the length of Winthrop Beach have increased the storm damage potential of the community protected by these structures. Recent, relatively minor northeast storms have caused significant damage to the seawall originally constructed in 1899, requiring temporary stabilization to prevent failure of the wall and the adjacent roadway. Winthrop Beach faces the open ocean, is approximately 2,100 meters in length, and is situated along the east side of Winthrop between two glacial headlands or relic drumlins. To address the issues of shore protection and “sediment starvation” along the Winthrop Beach shoreline, a beach nourishment project has been designed to return the shoreline to historic conditions.

Contemporary Dynamics of the Sea Shore of Kaliningrad Oblast

Abstract The article presents estimations of coastline retreat and advance in Kaliningrad Oblast at 85 monitoring points for a ten-year period of 2007–2017, based on monitoring data supplemented with satellite image analysis. The mean annual rate of coastline retreat and advance was estimated in general for each of the four major morpholithodynamic segments of the coastline: the Vistula (−0.2 m/year) and Curonian (−0.4 m/year) spits, as well as the western (−0.5 m/year) and northern (−0.2 m/year) shores of the Sambia Peninsula. The analysis of the shore protection measures implemented in Kaliningrad Oblast from 2007 to 2017 showed that the length of protected shore segments increased by 30% to 14.5 km, which is 10% of the total coastline. The obtained scheme of long-term mean annual rates of coastline retreat and advance clearly demonstrates an uneven distribution of eroded segments along the shores of Kaliningrad Oblast, however the sea shore of Kaliningrad Oblast is mainly susceptible to erosion (44%). Accumulative segments of the shore make up only 17% of the total coastline, and the remaining 39% of the shore is relatively stable. The results obtained demonstrate that the long-term mean annual rate of coastline retreat has decreased to −0.3 m/year from −1 m/year in the earlier period of 2000–2010. The general condition of the entire coastline of Kaliningrad Oblast can therefore be described as relatively sustainable]. The changes are related to several factors, such as an increase in the length of protected shore segments, the resumption of sand pulp dumping in the beach area by the Amber Mining Plant, and an increase in the amount of analytical data from an expanded local monitoring network.

Wave atlas for Swiss lakes: modeling design waves in mountainous lakes

The present study aims to provide a comprehensive wave atlas for Swiss lakes. The atlas is an adequate tool that contains wave characteristics of extreme events derived from numerical calculations. Swiss lakes are surrounded by mountains, and the wind field over the lakes is highly influenced by the region’s topography. Therefore, it is important to apply the winds with appropriate direction distribution. The numerical weather prediction model COSMO-2 is used for defining the wind directional distribution, whereas the spectral wave model SWAN is used for wave simulations. The evaluation results are ultimately published on a geographical information internet platform, where a wave rose correlates the wave height to the event frequency for each point on a lake. An accurate knowledge of wave parameters is essential for the design of new shore protection measures, beach erosion control and harbor silting studies.

Proposal of 'Moving Gravel Body' Method as a New Shore Protection Measure

`Moving Gravel Body' method was developed, in which beach nourishment using beach material coarser than the original grain size of the beach is carried out as a measure against downcoast erosion on a coast with a predominant longshore sand transport. Numerical simulations using the contour-line-change model considering grain size changes were carried out. The effectiveness of the method was shown in comparison with the beach nourishment using fine sand and the installation of concrete blocks.

Laboratory tests for simulating abrasion damage of a woven geotextile

As a preliminary study on the durability of geosynthetic tubes used for seashore and streambank protections, a circular flow chamber was established to investigate the abrasion damage of a woven geotextile subjected to various turbid flow conditions, such as test durations, flow velocities and particle concentrations. It was found that the ultimate strength loss of the tested woven geotextile subjected to a specific flow duration can be expressed as a linear function of particle concentration and flow velocity, based on the experimental results obtained from a limited number of the laboratory circular flow chamber tests. It was also shown that the equations obtained using a linear regression technique generated small errors in predicting the ultimate strength losses when compared with those obtained in the laboratory circular flow chamber tests. The equations derived herein facilitate the assessment of abrasion damage of the tested geotextile to be used in shore protection measures. These equations are also potentially useful in linking in-field abrasion damage of the tested geotextile to that obtained in laboratory index tests, such as the sliding block sand paper method.

Erosion problems in Alexandroupolis coastline, North-Eastern Greece

This paper deals with the coastal erosion processes and the related problems around the city of Alexandroupolis, NE Aegean Sea, N. Greece. The area is very fast developing, as the city is an important port and a summer resort center in SE Balkans, and will become soon a transportation and energy center, as well. The coastline under study exhibits an east–west orientation and has a length of more than 50 km. The spatial distribution and the characteristics of the changes in the shoreline were studied by comparing old and new air photographs and topographic maps, as well as through repeated series of field observations and local measurements regarding the erosion process. From these studies it was concluded that the greater stretch of the western part of the coast, under consideration, is of moderate to high relief, with a considerable participation of coastal cliffs. It consists of conglomerates of varying granulometry and consistency and is under moderate to severe erosion process. The erosion phenomena in the western part of the coast may be attributed, primarily, to strong S, SW winds, blowing in the area and to trapping of sediments by Alexandroupolis’ port breakwaters; the port stops or/and diverts the sediments to the open sea; and to the east to west longshore sea current, prevailing in the area. The eastern stretch of the coast is a plain area, formed by sandy–silty sediments; being a part of the river Evros’ Delta, it is under deposition and accretes seawards. The majority of the coasts under consideration are classified as coasts of high wave energy potential. Hard structures, as shore protection measures, have been constructed in some places, but they were proved, in rather short time-period, ineffective and suffered extensive failures. Thus, it is argued that for a long-term cost-effective tackling of the various erosion problems on any stretch, priority must be given to soft engineering measures; although, certain hard measures, carefully selected and locally implemented, can contribute to forming a rational combination of protection/mitigation measures. Besides, the development pressures in the coastal zone have to be confronted, in a sustainable way, through new integrated coast management regulations.

The use of soft shore protection measures in shallow lakes: Research methodology and case study

Shore protection in lakes is an issue of major importance in Switzerland where several big lakes in plains suffer from a pronounced bank erosion. For the moment, in shallow lakes, soft and biotechnical protection measures proved their reliability. Unfortunately, the scientific basis for the design of such techniques does not exist in some cases or not appropriate enough in order to have an optimized effect. Therefore, the aim of an on-going research project is to study, on the basis of physical and numerical modeling, the impact of such measures on the shores regarding bank erosion, and to establish the main basis for their dimensioning. A 2-D numerical model was used to simulate the eroded beach of Préverenges on the North coast of Lake Geneva. Hence, this case study allowed a better understanding of the numerical capacities of the program by modelling wave effect on bedload sediment transport and shore erosion as well as wind role in the generation of littoral currents.

Ocean wave height determined from inland seismometer data: Implications for investigating wave climate changes in the NE Pacific

Knowing the wave climate along the California coast is vital from the perspectives of climatological change and planning shore protection measures. Buoy data indicate that the wave climate is very similar along much of the California coast. We show that elements of the wave climate can be accurately reconstructed using near‐coastal inland broadband seismometer data. Such reconstructions are possible because swell approaching the coast generates pressure fluctuations that are locally transformed into seismic waves at the seafloor that propagate inland and are detectable by land‐based seismometers. Buoy and seismometer data show that most of the microseism energy recorded inland near the coast is generated from wave events at nearby coastal locations. A site‐specific, empirically derived seismic‐to‐wave transfer function is demonstrated to be applicable to seismic data from the same location for any year. These results suggest that ocean wave heights estimated from near‐coastal broadband seismometer data are sufficiently reliable for monitoring the coastal wave height when buoy data are unavailable, provided that adequate simultaneous nearby buoy measurements are available to calibrate the seismometer data. The methodology presented here provides an important tool that allows the investigation of potential wave climate changes from reconstructions using archived seismic data collected since the 1930s.

Observed modes of failure of existing shore protection measures in parts of Akwa-Ibom State of Nigeria : Teme, S C Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6–10 August 1990V4, P2873–2879. Publ Rotterdam: A A Balkema, 1990

Observed modes of failure of existing shore protection measures in parts of Akwa-Ibom State of Nigeria : Teme, S C Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6–10 August 1990V4, P2873–2879. Publ Rotterdam: A A Balkema, 1990

Coping with Great Lakes Flood and Erosion Hazards: Long Point, Lake Erie, vs. Minnesota Point, Lake Superior

Based on a systematic sample survey among the residents of Long Point and Minnesota Point, this study tests a central hypothesis that the majority of the residents of low-lying beaches and sandspits on the Great Lakes perceive long-term high lake levels to be the main cause of coastal flooding and erosion hazards. The study found that, despite significant differences in property setting, hazard experience, and shore protection measures between Long Point and Minnesota Point, an overwhelming three-quarters of the respondents from each site would prefer lake regulation as a measure for preventing property hazards. The study compares the processes of water level fluctuations in Lakes Superior and Erie and points out the technical limitations of regulating levels in the context of the existing IJC control structures on Lake Superior and the potential structures on Lake Erie. The study recommends that greater attention should be given to shoreline management for reducing property hazards, but also attempts to provide an explanation for the popularity of lake level regulation as a hazard prevention measure.

PREDICTING SHORELINE CHANGES AT TIDAL INLETS ON A DEVELOPED COAST

Implementation of shore protection measures at tidal inlets in New Jersey has reduced the rate of shoreline change and altered mechanisms for sediment transfer. Shoreline mobility has been reduced to 19 percent of pre-development rates updrift of inlets where new breaches in the islands are prevented by bulkheads or accretion related to human activities. Rates of change downdrift of inlets have been influenced by protection structures and channel dredging. A conversion from cyclic to unidirectional shoreline change has occurred in some areas. Prediction of future changes must be based on probabilities of human action, calibrated with knowledge of physical processes.

Shore Protection in the Town of Stoney Creek, Southwest Lake Ontario, 1934-1979: Historical Changes and Durability of Structures

A study of shore protection measures used by private property owners was carried out along a 10-km stretch of shoreline in the town of Stoney Creek, western Lake Ontario. The area is characterized by low bluffs develped in silty-clay till, with average rates of recession generally in excess of 1.0 m yr −1. Aerial photographs, questionnaires, and field observations were used to compile information on type, dimensions, material used for construction, and state of repair for each structure present at a number of dates between 1934 and 1979. During this period the proportion of protected shoreline rose from 30% to 64%. Seawalls and groynes are the most common form of shore protection, with 60% of properties now protected by a combination of the two. An examination of the durability of individual structures over the whole period indicates that, on average, 71% are damaged or destroyed within 10 years of construction and 87% within 20 years. These rates are highest during periods of high lake levels and lowest during low levels. The low durability reflects poor design and construction of the structures, lack of cooperation between property owners, and the stresses imposed by the physical environment. While the durability of structures can be improved, this would require much greater expenditure and cooperation.