Please login first

List of accepted submissions

Show results per page
Find papers
  • Open access
  • 67 Reads
Measurements of Wave Reduction Due to Artificial Reef With Varying Width on an Atoll

The Spratly Islands consist of many islands, banks and shoals and especially coral reefs. Since 1980s, manmade structures have been increasingly constructed, thus resulting in unexpected negative effects on these shoals and reefs. Reef balls would be a feasible measure to create a favorable environment for restoring corals and sea creatures and to reduce waves attacking any cay of the atoll platforms. Therefore, the article explores how a field of Reef Balls affect the propagation process of and reduce the height of wave on an atoll. Using a 2D physical wave flume, we conducted 75 test scenarios, which combine three crest freeboards, five widths of the Reef Ball field and five deep-water waves. The experimental results reveal that the width and freeboard mainly govern the wave reduction. The wave reduction efficiency tends to be dependent upon the relative field width. Furthermore, the Reef Balls field performs most effectively with a width ranging from 1/5 to 3/5 of the shallow water wavelength (on the atoll platform).

  • Open access
  • 193 Reads
Mangrove Ecological Land Suitability. A Tool for Integrating Mangroves Conservation in Urban Green Infrastructure in Sub-Saharan African Coastal Cities—A Case Study of Maputo, Mozambique
, , , ,

The mangroves along the Mozambique coastline represent 2.3% of the world’s total mangrove area. Theyare fundamental ecosystem services providers, namely as soft infrastructures for mitigation and adaptation to extreme weather events and urban floods. In the context of Maputo, these ecosystems are currently under threat, through ongoing land-use changes (short-term) and sea-level rise (SLR) (mid-term) events. The study presents a methodology to map mangrove potential areas according to their ecological land suitability (MELS) in Maputo by applying a GIS-based integrated model that uses a set of bio-physical criteria. Mapping the existent and potential MELS areas, currently and facing a SLR scenario shows possibilities for integrating mangroves within an urban green infrastructure whilst contributing to mangrove conservation, using MELS as an assessment tool within the scope of coastal climate change adaptation.

  • Open access
  • 150 Reads
Analysis of the Dynamics of the Valdevaqueros Dune

The Valdevaqueros dune, located on the Atlantic coast of Cádiz (SW of Spain), is considered one of the largest transgressive dune in Europe due to its dimensions: 700 m length, 500 m width and 50 m over the sea level. It is expected that the dune will continue growing because, at the current date, any method has achieved to stabilize the dune. Valdevaqueros is located a few kilometers from the Strait of Gibraltar, where the prevalent winds of Levante cause a migration rate of 17 m/year. This fact has provoqued the burial of the regional road, so maintenance task must be done periodically. In view of this troublesome, the Valdevaqueros dune has been the subject of numerous studies with the purpose to obtain a correct characterization of its behavior and evolution. Throw out this work, the dune will be studied between 2008 and 2015 by means of three analysis kind: the spatial and volumetric variation of the dune field using LiDAR data, the shoreline evolution supported by the ArcGIS DSAS extension; and the study of its internal structure using GPR data. The results reveal that the dune has doubled its size and volume, the sedimentary patterns on the windward face of the dune are associated with foreslope and the coastal environment is mostly erosive. This study represents a significant advance in knowledge of this dune dynamic.

  • Open access
  • 87 Reads
Experimental Measurements of Wave Overtopping at Seawalls

There are some 40 cities and more than 50% of the total population living along the coastline of Viet Nam. In line with the rapid urbanization, the natural coast has been gradually concreted thus resulting in more complex and negative impacts of human interventions on the coastal zone. Beside traditional structures as dike and revetment, seawalls have been constructed with various types of cross-sections to protect many towns and tourism areas. However, intensive wave overtopping would possibly threaten the stability of infrastructures and the safety of traffic and residents behind in rough weather conditions such as tropical low pressure, typhoons or monsoons, especially under impacts of climate change. Therefore, the study aims to ascertain quantitatively overtopping phenomenon at seawalls by conducting experiments in a wave flume. We tested four pairs of seawall models with different shapes (curved, steep, straight and stepped), which were positioned on the top of a steep base (1: 1.5). Each pair consists of one model with and another one without bullnose. Test scenarios consists of a normal water level and a higher one taking into account the sea level rise. The obtained data shows that bullnoses help to undermine wave overtopping discharge, and more considerably in case of lower freeboards. In other words, the seawalls with bullnose perform more properly when sea level rise takes place. Besides, bullnoses also help eliminating reflection in front of the structure, thus resulting in less strict requirement of toe protection. To some extent, the findings are expected to partly set-up the base to reduce the scale of coastal protection structures.

  • Open access
  • 69 Reads
A Natural and Anthropogenic Squeeze of the Monsoon Tidal Inlet

This study investigates the influences of natural and human-induced spatial blocking on the morphological and hydrodynamic features of the Tien Chau tidal inlet. It is observed that the absence of the downdrift barrier island and the appearance of the headlands form a squeeze tidal inlet. Moreover, anthropogenic factors, including urbanization and aquacultures, block a large part of the flood-tidal delta. These natural and human-induced spatial restrictions have significant influences on the hydro and morphodynamic characteristics of the inlet. In order to obtain more insight, a schematized numerical model was constructed in the Delft3D model and validated using measured field data.

  • Open access
  • 78 Reads
Coastal Flood Risk Analysis in Turkey’s Black Sea Region

The risk of coastal flooding is increasing as a result of the combined action of storm surges and sea-level rise in the context of global climate change. The rate of sea-level rise is accelerating year by year, and an increase of more than 60 centimeters is expected by the end of the century. The Black Sea, even if it is a semi-closed sea, is also affected by this phenomenon, and its effects are visible especially during storms. The August 2021 climate events in Turkey have brought attention to studying floods in the Black Sea coast. Thus, the objective of this paper is to assess the flood risk at the Turkish Black Sea coast. This study uses an efficient methodology to delineate flood-hazard areas using Geographic Information Systems. The result of the research is the development of a flood risk map covering various scenarios of sea-level rise which lead to coastal flooding. The map for the entire Turkish coastal area of the Black Sea Region revealed that the most affected area would be the province of Samsun. The results of this study can be used by policy-makers to implement appropriate risk mitigation strategies in those high flood risk areas.

1 2