Flood Tide Research Articles

Typhoon-induced suspended sediment dynamics in the mouth-bar region of a river/wave-dominated estuary

Understanding suspended sediment processes in the mouth-bar region during typhoons is vital for estuarine geomorphic prediction and engineering design. An observation system was applied to explore suspended sediment dynamics during Typhoon Higos in the mouth-bar region of the river/wave-dominated Modaomen Estuary within the Pearl River Delta. The results showed that suspended sediment concentration (SSC) during typhoons could be around 30 times larger than that under normal conditions, primarily attributable to strong bed sediment resuspension induced by typhoon waves. The SSC captured during typhoon exhibited fluctuations of different amplitudes due to the movement of the high concentrated sediment in the mouth-bar region forced by the dominant flow. When the dominant flows were unified within the mouth-bar region in high velocities, including the wind-driven flow near the typhoon landfall and the ebb surge transport combined with the river flooding after landfall, the high concentrated sediment can move in a large distance along the dominant direction of the flow and induced dramatic decrease of SSC. When the dominant flows were not unified within the mouth-bar region and the velocities were relatively lower, the high concentrated sediment was dominated by the tidal process as under normal conditions and the SSC fluctuated in a smaller amplitude, including tidal modulation, flood dilution and ebb replenishment. Compared with the other estuary types, the processes controlling the storm-induced suspended sediment dynamics, including resuspension, wind-driven transportation and tidal transportation, all happened with high intensities in our surveyed river/wave-dominated estuary; and a conceptual model has been proposed to schematize these processes and their combined impacts.

Interannual Changes in Tidal Conversion Modulate M2 Amplitudes in the Gulf of Maine

AbstractThe Gulf of Maine's lunar semidiurnal (M2) ocean tide exhibits spatially coherent amplitude changes of ∼1–3 cm on interannual time scales, though no causative mechanism has been identified. Here we show, using a specially designed numerical modeling framework, that stratification changes account for 32%–48% (Pearson coefficient 0.58–0.69) of the observed M2 variability at tide gauges from 1994 to 2019. Masking experiments and energy diagnoses reveal that the modeled variability is primarily driven by fluctuations in barotropic‐to‐baroclinic energy conversion on the continental slope south of the gulf's mouth, with a 1‐cm amplitude increase at Boston corresponding to a ∼7% (0.30 GW) drop in the area‐integrated conversion rate. Evidence is given for the same process to have caused the decade‐long M2 amplitude decrease in the Gulf of Maine beginning in 1980/81. The study has implications for nuisance flooding predictions and space geodetic analyses seeking highest accuracies.

Improving tidal turbine array performance through the optimisation of layout and yaw angles

Tidal stream currents change in magnitude and direction during flood and ebb tides. Setting the most appropriate yaw angles for a tidal turbine is not only important to account for the performance of a single turbine, but can also be significant for the interactions between the turbines within an array. In this paper, a partial differentiation equation (PDE) constrained optimisation approach is established based on the Thetis coastal ocean modelling framework. The PDE constraint takes the form here of the two-dimensional, depth-averaged shallow water equations which are used to simulate tidal elevations and currents in the presence of tidal stream turbine arrays. The Sequential Least Squares Programming (SLSQP) algorithm is applied with a gradient obtained via the adjoint method in order to perform array design optimisation. An idealised rectangular channel test case is studied to demonstrate this optimisation framework. Located in the centre of the computational domain, arrays comprised of 12 turbines are tested in aligned and staggered layouts. The setups are initially optimised based on their yaw angles alone. In turn, turbine coordinates and yaw angles are also optimized simultaneously. Results indicate that for an aligned turbine array case under steady state conditions, the energy output can be increased by approximately 80\% when considering yaw angle optimisation alone. For the staggered turbine array, the increase is approximately 30\%. The yaw optimised staggered array is able to outperform the yaw optimised aligned array by approximately 8\%. If both layout and the yaw angles of the turbines are considered within the optimisation then the increase is more significant compared with optimising yaw angle alone.

ANALISIS POTENSI PENGEMBANGAN BUDIDAYA IKAN KERAMBA ADAPTIF DI WILAYAH PESISIR

Fish farming with adaptive cages is an alternative for developing fishery business activities in coastal areas. The purpose of this study was to analyze the potential for developing adaptive fish cages farming as a form of adaptation to the impact of tidal flooding and climate change. This research was conducted in Bandengan Village, Pekalongan City from July to August 2022. The research method used was descriptive qualitative with purposive sampling and then a SWOT analysis was carried out. The results showed that the water quality parameters at the aquaculture location were still feasible and suitable for fish farming activities. Then, for harvest productivity indicators, it was still quite appropriate and profitable for this operational business cycle. Furthermore, from the analysis of internal business factors identification, 6 elements of strength and 4 elements of weakness affected the operation of fish farming. Meanwhile, from the identification of external business factors, there were 5 elements of opportunity and 2 elements of threats that could affect the operational aquaculture cycle. From the results of SWOT matrix analysis, by comparing the elements of business opportunities, weaknesses, strengths, and threats, a comparison point was obtained between 2.04 and 1.38, or it was in first quadrant in SWOT matrix, meaning good strength to be developed further. In conclusion, fish farming activities with the concept of adaptive cages were very feasible and profitable to be developed in coastal areas that are vulnerable to tidal flooding and climate change effects.Key words: Coastal, Climate change, Development, Fish aquaculture, SWOT

Nocturnal tidal barrier management improves glass eel migration in times of drought and salinization risk

AbstractAdjusted tidal barrier management (ATBM, setting tidal doors ajar during tidal rise) is currently applied in Belgium to improve glass eel passage through tidal gates. However, salt intrusion in the receiving waters due to upwelling and accumulation of saline groundwater as a result of intensive drought put severe pressure on the unrestrained use of this cost‐efficient mitigation measure. We evaluated the efficacy of a very restricted ATBM at a tidal barrier on a small canalized waterway, located 3.5 km from the sea: one out of seven gate doors was left 20 cm ajar for ca. 30 min when the water levels on both sides of the tidal barrier were approximately equal. During 20 inflow events differing in tidal flow (i.e., flood or ebb tide) and daytime (i.e., day or night) in March/April 2019, migrating glass eels were caught with a fyke net fixed on the temporally opened gate. In total, 12,853 glass eels were captured, almost all during flood tides at night (96%), with a maximum catch of 3,827 individuals per inflow event. These results show that even small windows of opportunity can help glass eels pass tidal barriers.

A novel statistical approach to predict seasonal high tide flooding

Sea level rise is increasing the frequency of high tide flooding in coastal communities across the United States. Although the occurrence and severity of high-tide flooding will continue to increase, skillful prediction of high tide flooding on monthly-to-annual time horizons is lacking in most regions. Here, we present an approach to predict the daily likelihood of high tide flooding at coastal locations throughout the U.S. using a novel probabilistic modeling approach that relies on relative sea-level rise, tide predictions, and climatological non-tidal residuals as measured by NOAA tide gauges. A retrospective skill assessment using the climatological sea level information indicates that this approach is skillful at 61 out of 92 NOAA tide gauges where at least 10 high tide flood days occurred from 1997–2019. In this case, a flood day occurs when the observed water level exceeds the gauge-specific high tide flood threshold. For these 61 gauges, on average 35% of all floods are accurately predicted using this model, with over half of the floods accurately predicted at 18 gauges. The corresponding False-Alarm-Rate is less than 10% for all 61 gauges. Including mean sea level anomaly persistence at leads of 1 and 3 months further improves model skill in many locations, especially the U.S. Pacific Islands and West Coast. Model skill is shown to increase substantially with increasing sea level at nearly all locations as high tides more frequently exceed the high tide flooding threshold. Assuming an intermediate amount of relative sea level rise, the model will likely be skillful at 93 out of the 94 gauges projected to have regular flooding by 2040. These results demonstrate that this approach is viable to be incorporated into NOAA decision-support products to provide guidance on likely high tide flooding days. Further, the structure of the model will enable future incorporation of mean sea level anomaly predictions from numerical, statistical, andmachine learning forecast systems.

Community adaptation strategies toward tidal flood: A Case study in Langsa, Indonesia.

These findings highlight the importance of 'gotong royong' as social capital in disaster risk reduction and government attention to conduct integrated coastal area management.

Effects of Future Increases in Tidal Flooding on Salinity and Groundwater Dynamics in Coastal Aquifers

AbstractFuture increases in the frequency of tidal flooding due to sea level rise (SLR) are likely to affect pore water salinities in coastal aquifers. In this study, we investigate the impact of increased tidal flooding frequency on salinity and flow dynamics in coastal aquifers using numerical variable‐density variably‐saturated groundwater flow and salt transport models. Short (sub‐daily) and long (decadal) period tides are combined with SLR projections to drive continuous 80‐year models of flow and salt transport. Results show that encroaching intertidal zones lead to both periodic and long‐term vertical salinization of the upper aquifer. Salinization of the upper aquifer due to tidal flooding forces the lower interface seaward, even under SLR. System dynamics are controlled by the interplay between SLR and long period tidal forcing associated with perigean spring tides and the 18.6‐year lunar nodal cycle. Periodic tidal flooding substantially enhances intertidal saltwater‐freshwater mixing, resulting in a 6‐ to 10‐fold expansion of the intertidal saltwater‐freshwater mixing area across SLR scenarios. The onset of the expansion coincides with extreme high water levels resulting from lunar nodal cycling of tidal constituent amplitudes. The findings are the first to demonstrate the combined effects of gradual SLR and short and long period tides on aquifer salinity distributions, and reveal competing influences of SLR on saltwater intrusion. The results are likely to have important implications for coastal ocean chemical fluxes and groundwater resources as tidal flooding intensifies worldwide.

Detection of Sea Level Rise Monitored from Surabaya Tidal Station Data from 2013 to 2021

Sea level rise is a certainty because of changes in human life that use machines so that it produces pollution that increases global warming which can make the polar ice caps melt so that the volume of sea water increases. The impact of sea level rise includes changes in coastline, tidal flooding and other impacts that can reduce the quality of life of the community. Surabaya is the second big city on the island of Java after Jakarta which has a population of 2,878,314 people based on the results of the 2020 BPS population census. Of course, this automatically makes the city nicknamed the city of heroes an important city in Indonesia. Therefore, the Geospatial Information Agency as one of the agencies providing tidal data has placed one of its observation stations in the city of Surabaya, located in Ujung Village, Semamir District, Surabaya City, at coordinates 07° 12’ 0.1” South Latitude 112° 44’ 26.1 ” East longitude. The results of data processing using the smallest smoothing method resulted in the LAT tidal datum values, namely -0.636 m, MSL 1.131 m and HAT 2.850 m. The tidal type at the Surabaya tidal station is a mixed mixed tide type which tends to double daily, with an average tidal harmonic constant value of O1 = 0.265 m, S2 = 0.230 m, K1 = 0.476 m, and M2 = 0.377 m. The most dominant tidal harmonic constant is M2, and the lowest harmonic constant is M4 while sea level rise in the city of Surabaya based on the analysis of tidal observation data for 9 (nine) years is 0.199 mm/month.

PEMETAAN POTENSI BANJIR WILAYAH PERKOTAAN DI KECAMATAN SEMATANG BORANG PALEMBANG

<p>Based on the land use of the city of Palembang in the Sematang Borang sub-district, <br />there are still catchment areas or swamp areas which are areas that must continue <br />to be considered regarding water resources. The Semang Borang area is currently <br />still in the safe category in the catchment area, but based on the structure of the <br />spatial pattern, the area is in the medium housing category.This study aimed to 1) <br />analyze land use and river network in Sematang Borang District, 2) analyze areas <br />that have the potential to be inundated by tidal floods in Sematang Borang District, <br />3) analyze the area of land use affected by flood inundation in Sematang Borang <br />District. This study applied survey method and data recapitulation obtained through <br />secondary data from several agencies related to flooding and the River Basin in the <br />Borang River, Sematang Borang District, Palembang City. Based on the results of <br />the analysis of land use maps and river network systems, there are still swamps or <br />open spaces that can be used as water catchments. The magnitude of the potential <br />flood inundation can be observed through a map based on a field inventory with 14 <br />inundation locations. Based on the calculation of rain with a 2-year period of <br />conditions, the river catchment area is still in a safe condition. However, the period <br />5,10,25,50,100 is in the category of flood hazard. The land area based on the <br />analysis of the area affected by the flood is 845 ha or 8.45 km or 23% of the area of <br />Sematang Borang District of 36.97 km. The factors that affect the height of <br />inundation or flooding in the upstream and downstream areas in terms of land <br />geography, land structure, and drainage system are changes in land use from <br />swamp to medium housing.</p>

Hydrodynamics of Meander Bends in Intertidal Mudflats: A Field Study From the Macrotidal Yangkou Coast, China

AbstractMeandering channels are ubiquitous features in intertidal mudflats and play a key role in the eco‐morphosedimentary evolution of such landscapes. However, the hydrodynamics and morphodynamic evolution of these channels are poorly known, and direct flow measurements are virtually nonexistent to date. Here, we present new hydroacoustic data collected synchronously at different sites along a mudflat meander located in the macrotidal Yangkou tidal flat (Jiangsu, China) over an 8‐day period. The studied bend exhibits an overall dominance of flood flows, with velocity surges of about 0.8 m/s occurring immediately below the bankfull stage during both ebb and flood tides. Unlike salt‐marsh channels, velocities attain nearly constant, sustained values as long as tidal flows remain confined within the channel and reduce significantly during overbank stages. In contrast, curvature‐induced cross‐sectional flows are more pronounced during overbank stages. Thus, a phase lag exists between streamwise and cross‐stream velocity maxima, which limits the transfer of secondary flows and likely hinders the formation of curvature‐induced helical flows along the entire meander length. Our results support earlier suggestions that the morphodynamics of intertidal mudflat meanders does not strongly depend on curvature‐induced helical flows and is most likely driven by high velocities and sustains seepage flows at late‐ebb stages, as well as by other tidally‐mediated processes such as waves and intense rainfall events. By unraveling complex flow structures and intertwined morphodynamic processes, our results provide the first step toward a better understanding of intertidal mudflat meanders, with relevant implications for their planform characteristics and dynamic evolution.

Between science, religion, and politics: multi-layered communication responses to maritime disaster in Indonesia

This article aims to analyze multi-layered communication responses to maritime disasters in Indonesia using two significant cases, namely the tidal flooding in Semarang and the tsunami in Banda Aceh. Reducing the risk of disaster is not only a technical matter but also strongly associated with communication issues. Therefore, there has been much research into disaster communication. However, research on multi-layered communication responses to diverse disasters must still be done. Data were collected through interviews with the people, journalists, and government officials in Semarang and Banda Aceh. These data were complemented by field observations and reviews of local media news and government policies. The results show that communication response in the two regions involved a complex triangle of science, religion, and politics. This means that the community, media, and government of these regions communicated these two types of disasters as involving science, religion, and politics to varying degrees. This article also finds that the local media was unable to optimally play its central role as an intermediary actor in disaster communication in the two regions.

Tracking annual changes in the distribution and composition of saltmarsh vegetation on the Jiangsu coast of China using Landsat time series–based phenological parameters

Saltmarshes provide among the most valuable ecosystem services but have undergone continuous modification under the combined pressures of climate change and anthropogenic disturbance. Dynamic monitoring of the distribution and composition of saltmarsh vegetation is an urgent need for understanding the balance of saltmarshes. Previous studies have examined the possibility of identifying the plant species of saltmarshes using Land Surface Phenology (LSP). However, balancing species identification with the timespan of the monitoring remains challenging, given that the available observations are limited by the frequent occurrence of cloudy weather and periodic tidal fluctuations in coastal areas. To overcome the difficulty, we first filtered out observations contaminated by cloud cover and tidal flooding, then proposed an intra-annual time-series model by incorporating inter-annual observations using the inter-calibrated Landsat observations, finally classified the plant species of saltmarshes using phenological parameters derived from the intra-annual time-series model. The annual changes of the three dominant plant species—Spartina alterniflora (S. alterniflora), Suaeda salsa (S. salsa), and Phragmites australis (P. australis) during 2000–2020 in Jiangsu Province, the most abundant salt marsh area of China, were tracked. The results demonstrate the following: (i) The intrinsic phenological differences among the plant species (∼32 days between S. alterniflora and P. australis) are greater than the latitudinal and temporal phenological variations (9–24 days). Large-scale and long-term classification mapping using LSP was thus feasible. (ii) The annual classification maps achieved a favorable performance with an average overall accuracy of 84.8% with minor fluctuations of 5.5%. Sufficient available observations for the spring and autumn seasons (R2 = 0.78, p < 0.05) and for locations far from the sea (>240 m) were the reasons for this good performance. (iii) The saltmarsh vegetation was resilient to tidal flat reclamation on the Jiangsu coast, as indicated by a slight increase in the area from 300.30 to 336.38 km2. However, this was concentrated within the Nature Reserve (38.3%), with the increasing dominance of two species: S. alterniflora (49.6%) and P. australis (42.7%). Special conservation measures are needed for S. salsa to prevent its continuing decrease and possible future disappearance.

Tidal Sediment Supply Maintains Marsh Accretion on the Yangtze Delta despite Rising Sea Levels and Falling Fluvial Sediment Input

Tidal marshes are among the world’s most valuable ecosystems; however, they are increasingly threatened by rising sea levels and a decline in fluvial sediment supply. The survival of a tidal marsh under these twin threats depends upon the net input of tidal sediments, because this will determine the deposition rate. The rate of relative sea level rise currently affecting the Yangtze Delta is rapid (~4 mm/a), and the sediment discharge from the Yangtze River has decreased by &gt;70% over recent decades. In order to improve our understanding of the response of the marshes in the turbid zone of the Yangtze Estuary to these changing environmental conditions, we measured sediment transport in and out of a tidal basin and calculated the deposition rate over eight tidal cycles covering different tidal ranges during the summer and winter seasons. The suspended sediment concentration (SSC) during the flood phase of the tidal cycle (average = 0.395 kg/m3) was markedly higher than that during the ebb (average = 0.164 kg/m3), although water transport during the flood tide was almost equivalent to that during the ebb. As a result, ~40% of the sediment inflow during the flood phase was retained within the marsh. This reason is mainly attributable to the dense marsh vegetation, which attenuates waves and currents and to which the sediments adhere. The annual deposition rate in the marsh was approximately 6.7 mm/a. These findings indicate that under the combined influence of sea level rise and river sediment supply reduction, the sediment transport through the turbidity maximum zone of the Yangtze River estuary could maintain the relative stability of the marsh area to a certain extent.

Tidal effects on periodical variations in the occurrence of singing humpback whales in coastal waters of Chichijima Island, Ogasawara, Japan

Marine organisms inhabiting coastal waters are known to be driven by periodic cycles such as diel, tidal, and seasonal changes. Humpback whales (Megaptera novaeangliae) breed in shallow and warm coastal waters, with males singing complex songs during the breeding season. To investigate periodic variations in humpback whale singing activities, we conducted fixed passive acoustic monitoring in the Ogasawara (Bonin) Islands, Japan, from winter to spring during 2016–2018. The singing activity and individual number of singers were observed throughout the day and night using a very long baseline passive acoustic array. The occurrence of singers peaked before sunrise and in the evening and was reduced during the daytime. The frequency of song reception depended on the tidal phase. A generalised additive model demonstrated that the occurrence of singers increased during the flood tide and decreased during the ebb tide in the waters west of Chichijima Island. These results suggest that the singing behaviour of humpback whales in breeding areas is affected by the diel and tidal cycles. Male humpback whales may change their behaviour or singing location depending on the strength and direction of the tidal current, considering that the selection of a stable location is beneficial for singing whales.

Amphibi House Sebagai Mitigasi Banjir Rob di Daerah Pesisir Belawan Bagan Deli

Generally, tidal flooding that comes every day to belawan Bagan Deli beach is a serious problem. Many of the causes of this tidal flood include global warming, seawater at high tide, and poor drainage due to the large piles of garbage. The tide level reached 2.7 meters from the current sea level, and people's economic activities stopped for a while. The pile of garbage caused the surrounding houses to become shabby and dirty. This study aims to obtain a home design solution in anticipation of high tide due to tidal flooding that enters residents' homes with the concept of floating houses in the Bagan Deli area. The research method uses the floating foundation engineering design method by using a floating system on the foundation (base) of the house and the connection on the pole so that the house remains in place (fixed position). The results of this study will be conveyed back to the community and local government to improve the quality of life of the people in the Bagan Deli Belawan area.

Sustainable Corporate Social Responsibility Program as an Effort for Community Adaptation to Climate Change, Case Study in Bukit Batu District, Bengkalis Regency

Climate change is currently a very troubling problem in the world. Indonesia is also one of the countries affected by climate change This also happened in the Bukit Batu District, Bengkalis Regency, Riau Province. The impact of climate change can be seen directly in the Bukit Batu area with the emergence of disasters that occurred there, in the coastal area the perceived impact is an increase in tidal water levels every year which causes tidal flooding and abrasion, in addition to the problems in peat areas that often occur. There are land and forest fires during the summer season and flooding in the rainy season. Through the Corporate Social Responsibility (CSR) program of PT Kilang Pertamina Internasional Unit Sungai Pakning,like “Program Kampung Iklim”, “Kampung Gambut Berdikari”, “Permata Hijau Pesisir Gambut”, “ Sekolah Cinta Gambut” programs, the community around the company began to be able to adapt in various ways with the assistance provided by the company and government too. So that with the CSR program, the community will be able to live sustainably. In addition, collaboration between stakeholders is also very helpfull for the success of the program in supporting community adaptation efforts to climate change. This study uses a qualitative descriptive method to describe the condition of the area affected by climate change with a purposive sampling procedure for the CSR program of PT Kilang Pertamina Internasional Unit Sungai Pakning. With this collaboration program, climate change problems have begun to be handle, such as in Pangkalan Jambi and Sungai Pakning Village.

Coupling Relationship of Geomorphic Evolution and Marine Hydrodynamics in the Stage-Specific Development of Urban Bays: A Modelling Case Study in Quanzhou Bay (1954–2017), China

With the development of social economy and human activities, the geomorphology and hydrodynamic conditions of coasts have been dramatically changed, causing serious environmental pollution and resource depletion. Taking Quanzhou Bay as an example, this study combined geomorphologic change with a hydrodynamic model to simulate the change in tidal currents in different periods. The results show a change in the coastline was the main cause of hydrodynamic change during the industrialization reform. During the past 70 years, the tidal prism decreased year by year, and the average velocity of the tidal current in the channel decreased by 33.7% and 30.8% at flood and ebb tide, respectively. In the early stages of industrialization, reclamation land was used in a single way. The tidal prism decreased by 22.2% and 29.8% in the spring and neap tide, respectively. In the middle and later stages, the tidal current velocity increased, and reclamation land was used in a variety of ways. In modern society, the reclamation land-use type was unitary. Based on this research, we show the influence of human activities on the evolution of the bay’s geomorphology and provide suggestions for the management of the bay.

The Effect of Asphalt Baths Wearing Coarse (AC–WC) on the Tide

The phenomenon of high tide that occurs in the coastal areas of Indonesia, especially on the island of Java which often results in floods or often called tidal floods. Tidal flooding is a flood event caused by the overflow of sea tides into coastal land. Often the overflow reaches on some roads located in coastal areas so that roads located in those coastal areas are damaged. Therefore, it is necessary to conduct research to investigate the effects caused by stagnant water on road pavement. The study used two standard methods of immersion in high tide and water in the laboratory. This study aims to determine the durability performance of the soaking mixture continuously (continuously) and periodically (intermittently). Soaking specimens (test objects) in a tide with a time variation of 12 hours; 24 hours; 48 hours; and 72 hours. While periodic soaking is carried out by soaking the specimen (test object) for 12 hours, then removed and allowed to stand for the next 12 hours for 3 days. Soaking the asphalt concrete wearing course (AC-WC) mixture either continuously or periodically in the tide has a greater influence compared to the use of laboratory water. This is indicated by the value of the Stability of the asphalt mixture in a bath with a tide smaller than the asphalt mixture soaked with laboratory standard water.

Assessing Environmental Physics: Tidal Flood Impact with Multidiscipline Approach (Case Study Coastal Cities Semarang Indonesia)

Tidal floods and land subsidence often occur in the coastal areas of Semarang, Central Java. The coastal area of Semarang has an essential role in the economy of the city of Semarang, especially the Port of Tanjung Emas. Research with a multidisciplinary approach is expected to obtain conclusions on technical and non-technical problems to prepare mitigation measures and reduce the risk of tidal flooding. This study aims to determine and analyze the impact of tidal flooding in the city of Semarang using a multidisciplinary approach. The data used for the analysis came from literature studies and field observations. This research method is descriptive analysis. The results showed that the tidal flood caused damage to infrastructure, houses, and other public facilities. This damage makes the infrastructure not function optimally. Other impacts the community feels are disruption of economic activities, lower productivity, and increased maintenance costs, thereby reducing overall community income. Therefore, tidal flood prevention is needed from all stakeholders, both individually and collectively.