A SUSTAINABLE HOMESTEAD PROTOTYPE IN SUNDARBANS Disaster adaptability through alternative building materials

Sundarbans as the primary coastal defense of Bangladesh against various natural disaster encounters recurrent homelessness due to these calamities, resulting in cutting down forests for housing materials from the only nearby resource. The traditional vernacular practice and socio-cultural studies show a symbiotic relationship between the forest and inhabitants, but the ecological imbalance created by climate change made life difficult for them, whose livelihood solely depends on the forest as well. The inability to reuse the building materials any disaster causes an ever-increasing cycle of carbon footprint. Regarding these, the non-experimental research aims to build such a homestead prototype that creates an adaptable solution. The existing building practices consist of non-reusable materials, poor structural integrity, and lack of sustainable approaches, thus unfit to withstand the increasing disasters and calamities. The approach discussed here utilizes plastic waste, drums, bamboo for disaster adaptability, structural flexibility, rainwater harvesting, solar, and biogas energy for a sustainable lifestyle. So, the goal is to provide a sustainable solution for the economically challenged population. This prototype creates an adaptive strategy for mitigating the disastrous events in Sundarbans to promote resilience and sustainability.

Mangroves As Coastal Bio-Shield: A Review of Mangroves Performance in Wave Attenuation

Mangroves have been recognized as soft structures that provide coastline protection. The capability of dampening waves helps minimize destruction from catastrophic events including erosive wave attacks, torrential storms, and tsunamis. Mangroves act as the first line of coastal defense in natural tragedies such as during the Super Typhoon Haiyan 2013 and Indian Ocean Tsunami 2004, whereby the leeward mangrove area encountered less damage than the unprotected area. This has further brought the attention of researchers to study the attenuation performance of these coastal vegetations. Based on an extensive literature review, this paper discusses the attenuation mechanism of mangroves, the factors influencing the dissipation performance, studies on mangrove dissipation via different approaches, the dissipation efficiency, mangrove conservation and rehabilitation efforts in Malaysia and implementation of mangrove as coastal bio-shield in other countries. The study highlights that mangrove parameters (such as species, width, density etc.) and wave parameters (such as wave period and incident wave height) are among the contributing factors in mangroves-induced wave attenuation, with different efficiency rates performed by different mangroves and waves parameters. Towards that end, several improvements are proposed for future research such as to incorporate all influencing dissipation factors with specific analysis for each species of mangroves, to perform validation on the studied mangroves attenuation capacity in different settings and circumstances, as well as to address the extent of protection by the rehabilitated mangroves. A systematic and effective management strategy incorporating ecological, forestry, and coastal engineering knowledge should be considered to ensure a sustainable mangroves ecosystem and promising coastline protection by mangroves. Doi: 10.28991/cej-2021-03091772 Full Text: PDF

Adaptation strategy to coastal erosion by rural communities: Lessons learned from Ujunggebang village, Indramayu, West Java, Indonesia

Coastal hazard due to wave activity, in the form of coastal erosion, has long been a problem in the coastal area of Ujunggebang. Loss of coastal land in the coastal area has removed a lot of rice fields, settlements, and public facilities. Efforts to maintain the coastline along 3,300 m of the coastal area, by building coastal defense structures (CDS), have been carried out by the central government since 2006 but, until 2015, the CDS that has been built is still only around 1782 m long, in some places the structure is damaged due to wave activity, and in general the structure is not enough to prevent overtopping. Meanwhile, unprotected coastal segments with CDS have experienced significant erosion. The idea of land use change as an effort to adapt coastal hazards, which was conveyed through an idea socialization approach and through showing examples of coastal area management practices to villagers, gave birth to the idea of developing a coastal tourism area in the village as a complementary measure for the existing coastal defense structure. Although the main problem faced- coastal erosion- has not been resolved, the development of the tourism area has been recognized by the local government as successfully changing the life of the village community.

Key Performance Indicators for the Upgrade of Existing Coastal Defense Structures

Due to the effects of climate change on the sea levels and on the frequency and intensity of extreme weather events, many coastal defense structures are expected to be exposed to increased loads with respect to their design conditions in the near future and need to be upgraded. Often, several design alternatives are available, and the identification of the ideal solution is not straightforward. Solutions that are effective in reducing overtopping and ensuring hydraulic safety may reduce or compromise the structural performance. Solutions that are both hydraulically and structurally effective may be extremely expensive and/or environmentally harmful. Using consolidated techniques of Multi-criteria analysis, this contribution proposes a simple methodology to consistently compare and rank the performance of several alternative approaches to upgrade existing structures, and to individuate the best solution. The proposed methodology consists of Key Performance Indicators (KPIs) of alternative solutions of upgrades, considering the reduction in the wave overtopping discharge (q) and the wave forces (F) by limiting costs and environmental impact. The definition of the KPIs was developed on the basis of new experimental data of q and F at dikes with crown walls and parapets, but it can be applied to various structure types, sea levels, and wave conditions. The application of the KPIs to the new experiments prompts a few conclusions of practical utility concerning the effectiveness of berms, crown walls, and parapets as elements to upgrade existing dikes.

Beach Monitoring and Morphological Response in the Presence of Coastal Defense Strategies at Riccione (Italy)

The coastal area at Riccione, in the southern Emilia-Romagna littoral region, is exposed to erosive processes, which are expected to be enhanced by climate change. The beach, mostly composed of fine sand, is maintained through various defense strategies, including frequent nourishment interventions for balancing the sediment deficit and other experimental solutions for reducing coastal erosion. Artificial reshaping of the beach and “common practices” in the sediment management redefine the beach morphology and the sediment redistribution almost continuously. These activities overlap each other and with the coastal dynamics, and this makes it very difficult to evaluate their effectiveness, as well as the role of natural processes on the beach morphological evolution. Topo-bathymetric and sedimentological monitoring of the beach has been carried out on a regular basis since 2000 by the Regional Agency for Prevention, Environment and Energy of Emilia-Romagna (Arpae). Further monitoring of the emerged and submerged beach has been carried out in 2019–2021 in the framework of the research project STIMARE, focusing on innovative strategies for coastal monitoring in relation with erosion risk. The aim of this study is to assess the coastal behavior at the interannual/seasonal scale in the southern coastal stretch of Riccione, where the adopted coastal defense strategies and management actions mostly control the morphological variations in the emerged and submerged beach besides the wave and current regime. The topo-bathymetric variations and erosion/accretion patterns provided by multitemporal monitoring have been related to natural processes and to anthropogenic activities. The morphological variations have been also assessed in volumetric terms in the different subzones of the beach, with the aim of better understanding the onshore/offshore sediment exchange in relation with nourishments and in the presence of protection structures. The effectiveness of the adopted interventions to combat erosion, and to cope with future climate change-related impacts, appears not fully successful in the presence of an overall sediment deficit at the coast. This demonstrates the need for repeated monitoring of the emerged and submerged beach in such a critical setting.

3D Physical Modeling of an Artificial Beach Nourishment: Laboratory Procedures and Nourishment Performance

Beach nourishment represents a type of coastal defense intervention, keeping the beach as a natural coastal defense system. Altering the cross-shore profile geometry, due to the introduction of new sediments, induces a non-equilibrium situation regarding the local wave dynamics. This work aims to increase our knowledge concerning 3D movable bed physical modeling and beach nourishment impacts on the hydrodynamics, sediment transport, and morphodynamics. A set of experiments with an artificial beach nourishment movable bed model was prepared. Hydrodynamic, sediment transport, and morphological variations and impacts due to the presence of the nourishment were monitored with specific equipment. Special attention was given to the number and positioning of the monitoring equipment and the inherent constraints of 3D movable beds laboratory tests. The nourishment induced changes in the beach dynamics, leading to an increase in the flow velocities range and suspended sediment concentration, and effectively increasing the emerged beach width. Predicting and anticipating the morphological evolution of the modeled beach has a major impact on data accuracy, since it might influence the monitoring equipment’s correct position. Laboratory results and constraints were characterized to help better define future laboratory procedures and strategies for increasing movable bed models’ accuracy and performance.

Implementation of a Modified Faster R-CNN for Target Detection Technology of Coastal Defense Radar

The traditional method of constant false-alarm rate detection is based on the assumption of an echo statistical model. The target recognition accuracy rate and the high false-alarm rate under the background of sea clutter and other interferences are very low. Therefore, computer vision technology is widely discussed to improve the detection performance. However, the majority of studies have focused on the synthetic aperture radar because of its high resolution. For the defense radar, the detection performance is not satisfactory because of its low resolution. To this end, we herein propose a novel target detection method for the coastal defense radar based on faster region-based convolutional neural network (Faster R-CNN). The main processing steps are as follows: (1) the Faster R-CNN is selected as the sea-surface target detector because of its high target detection accuracy; (2) a modified Faster R-CNN based on the characteristics of sparsity and small target size in the data set is employed; and (3) soft non-maximum suppression is exploited to eliminate the possible overlapped detection boxes. Furthermore, detailed comparative experiments based on a real data set of coastal defense radar are performed. The mean average precision of the proposed method is improved by 10.86% compared with that of the original Faster R-CNN.

COMPONENT ANALYSIS AT FORT KEDUNG COWEK BUILDINGS IN SURABAYA, EAST JAVA: OBSERVATION ON PANOPTICON CONCEPT

The fortress in the 20th century has certain characteristics to match the war strategy that is applied at this time. In 1900 the Kustbatterij Kedoeng-Tjowek project or Kedung Cowek fortress was built as a coastal defense for the city of Surabaya by the Dutch colonial. This study aims to identify the function of each building contained in the Kedung Cowek fort military area using a component review by their availability and categorization. Based on the analysis results it is known that each building has a specific function related to the concept of panopticon to apply the value of surveillance in its defense system.