Flood Tide Research Articles

Contamination of 16 priority polycyclic aromatic hydrocarbons (PAHs) in urban source water at the tidal reach of the Yangtze River.

To explore the occurrence, source, and risk of 16 priority polycyclic aromatic hydrocarbons (PAHs) in urban source water at the tidal reach of the Yangtze River, eighty-nine surface water samples were collected in 8 field campaigns from July 2018 to November 2019. Fifteen of 16 PAHs except for dibenz(a,h)anthracene (DBA) were found in the water. Detection frequencies were observed between 53 and 72% for PAHs with 4 rings, while most of other PAHs were less detected, e.g., benzo(a)pyrene (BaP) in 31% of samples. The total concentrations of 16 priority PAHs reached up to 2.8µg·L-1 and increased during the tidal transitions from flood to ebb. The average concentrations of PAHs in ebb tides were higher than those in flood tides. PAH concentrations and compositions showed great variation with different sampling campaigns, and higher levels and more components were observed in the rainy months and cold months. Those priority PAHs in the tidal water source are mainly from combustion activities (especially fossil fuel combustion), but the contribution from oil spills/leakage is also important in rainy months. High-molecular-weight PAHs in this tidal water source may pose risks to aquatic life, while they pose no carcinogenic risk to human health via ingestion of drinking water.

PEMBUATAN KERAMBA FLOATING CAGE PADA DAERAH RAWAN BANJIR ROB DI PESISIR PEKALONGAN

<p>Floating net cages are models of aquaculture cages for fish cultivation that are adaptable to the phenomenon of flooding and tidal waves. The purpose of this social service is to create a model of floating cages that can be used as a pond for fish cultivation in areas prone to tidal flooding. The method used in the implementation of this social service program is active participation and mentoring which is carried out gradually and periodically to groups of aquaculturist in Jeruksari Village, Pekalongan Regency. The results of this program show that all service activities starting from counseling sessions, mentoring (shopping materials and making cages), to monitoring when the cultivation period goes very smoothly and the aquaculturist partner groups are also quite enthusiastic about participating. The floating cages made from this program are made from cheap and easily available materials in the surrounding environment, such as bamboo, fishing nets, used floating cans, ropes, and stone weights. Based on the implementation of this program, it can be said that the fish farming community in Jeruksari Village is actually able to create practical examples of floating cage models that can be used as a pond for fish cultivation in areas prone to flooding and tidal flooding.</p><strong>Keywords : </strong>fish cultivation, cage, model, mentoring, counseling.

Assessment of hydraulic changes due to construction of a barrage in the Shatt Al-Basrah canal using one dimension model (Mike 11)

Shatt Al-Basrah is an artificial Canal, started in 1971 and completed in 1983. It was established to reduce flood and drain the excess water during the flood seasons, as a canal alternative to Shatt al-Arab during the Iran-Iraq war. It delivers water to the Zubair area and Al Faw town for agricultural purposes. A deterioration of the water quality of the canal was occurred due to many reasons; most importantly was the close of the canal at the junction of Garmat-Ali which is affected by the semidiurnal rhythm of the Arabian Gulf. There is a regulator located at about 22 km from the head of the canal. The main purpose of the canal is to control water drainage during flood and mitigating the effects on both sides land. In this paper the canal was simulated by the existence of controlled barrage on the water way, closed during the flood tide time and opened at the ebb tide. The simulation results after calibration of the mathematical model with field measurements, matched with high accuracy. The tidal effects on the canal can be determined, and the rehabilitation of the canal and water management in the surrounding areas can be preformed. The results indicate the sensitivity of the mathematical model to predict the measurements of water level, volume of water, flow speed of the current, discharge, downstream and upstream direction of discharge and the effect of tidal range at any point along the canal at the closure and opening of the regulator

EDUKASI EKONOMI HIJAU DALAM MENUMBUHKAN SEMANGAT “GREEN ENTREPRENEURSHIP”

<p>Green economy education is an effort to provide information to other people to know and understand environmentally friendly business activities. Limited natural resources due to environmental damage sometimes lead to creative ideas to start a business or business. Community service activities are carried out through education with outreach methods to the community in the Bandengan sub-district, North Pekalongan sub-district. The result of this service activity is that public knowledge and understanding of the green economy increases and fosters the spirit of starting a business by utilizing limited natural resources due to the tidal flood disaster.</p><strong>Keywords: </strong>Green Economy, Entrepreneur, Bandengan.

Coastal Vulnerability Assessment Along The North Java Coastlines-Indonesia

The north coast of Java is an area with very diverse maritime activities. These high activities threaten the ecosystem and environmental sustainability. Several areas already experience environmental degradation and most of the threats come from ocean pollution, coastal erosion, continuous tidal flood (rob), and coastal land subsidence. Furthermore, the coastal degradation is worsened by climate change which may cause the area more vulnerable to disaster. This study aims at evaluating the coastal vulnerability using weighted coastal vulnerability index (CVIw). The method calculates coastal vulnerability by weighting physical coastal parameters using Analytical Hierarchy Process (AHP). CVIw calculation result shows that the vulnerability is dominant at high (39%) and very high (51%) classes. The high vulnerability occurs in Tangerang, Bekasi, Brebes, Demak, Jepara, Pati, and Rembang Regencies. Meanwhile, very high vulnerability takes place in several regencies: Serang, Karawang, Subang, Indramayu, Cirebon, Tegal, Kendal, Semarang, and Gresik. The parameters of relief, coastal features, tidal range and shoreline give contribution more in coastal vulnerability besides lithology, sea level change, and wave height. Identifying vulnerability in these areas might help local governments to prioritize their action plan in coastal disasters mitigation.

Studying the effect of sea level rise on nuisance flooding due to groundwater in a coastal urban area with aging infrastructure

In this paper, we present a study focused on the effect of sea level rise (SLR) on nuisance flooding due to groundwater (or groundwater flooding). A densely populated coastal urban area along a river estuary was selected for this work. We developed a three-dimensional (3D) shallow unconfined aquifer model of the site. We calibrated it with field measurements and used it to predict areas prone to groundwater flooding under different SLR scenarios. Results show that the water table is controlled by the river level as well as by aging infrastructure such as aging combined sewer and drinking water networks which drain and recharge the unconfined aquifer. Steady-state simulations run considering current river level scenarios show a very shallow aquifer throughout the area and simulations under different SLR scenarios predict that the water table starts to emerge from the ground in the low-lying parts of the site for 0.4 m of SLR.Overall, this work suggests that groundwater in coastal urban areas is regulated by anthropogenic and natural systems and is susceptible to climate change contributing to inundation together with marine flooding and intense precipitation.

Fostering science-to-civics literacy through the development and assessment of a sea-level rise curriculum

Coastal communities are at risk to current and future sea-level rise (SLR) impacts, such as increased erosion and more frequent high tide flooding. In the northern Gulf, these impacts are exacerbated due to a confluence of socioeconomic issues, making it harder to plan for and adapt to changing conditions. To break through barriers to action, education of coastal residents and youth about future impacts must be undertaken. We worked with a team of researchers and educators to develop a four-module curriculum addressing sea-level rise impacts and community solutions. Module content was informed using the most recent advancements in coastal and estuarine research by collaborating with researchers active in those fields. The curriculum was launched to educators through professional development workshops and tested in classrooms to adaptively incorporate feedback into the final product. The process to collaborate with educators and researchers led to the successful development of a useable and useful curriculum. Students engaged in the curriculum indicated doing more sustainable actions and demonstrated knowledge gains. Educators who participated in trainings and/or testing the curriculum indicated they were more confident teaching SLR-related concepts and also demonstrated knowledge gains. The curriculum can be used widely, and the process can be replicated for other curriculum development in different regions.

Eutrophication Amplifies the Diel Variability of Carbonate Chemistry in an Equatorial, Semi-Arid, and Negative Estuary

This study presents high-resolution data on diel variations of carbonate chemistry in a semi-arid estuary (Jaguaribe River) in NE Brazil, which has witnessed decreasing annual rainfall and freshwater inputs due to climate change and river damming. In addition, the estuary has been suffering with increasing discharges from shrimp farm and urban effluents. We monitored surface water and atmospheric CO2 partial pressure (pCO2), temperature, salinity, and wind speed with continuous real-time measurements during two eulerian surveys in October 2017 (33 h) and September 2018 (44 h), during spring tides in the dry season. Additionally, pH, total alkalinity (TA), dissolved inorganic carbon (DIC), carbonate (CO32–), and saturation state of calcite (Ωcal) and aragonite (Ωara) were monitored hourly. Higher salinity (>38) during ebb tides confirmed the hypersalinity and negative estuarine circulation. TA and DIC concentrations in the estuary were higher than in the adjacent coastal ocean due to evaporation, showing positive correlation with salinity and negative correlation with tidal height. Measured TA and DIC concentrations were slightly higher than those calculated by the conservative evaporation model, suggesting their production in the estuary by aerobic and anaerobic processes. CO32–, Ωcal, and Ωara showed a clear semi-diurnal (tidal-driven) and diel (24 h; biological-driven) patterns: lowest values occurred at flood tide during night-time (respectively, 185 μmol kg–1, 4.3 and 2.8), whereas highest occurred during ebb tide and daytime (respectively, 251 μmol kg–1, 5.7 and 3.8). DIC/TA ratios were higher at night-time supporting a diel control (linked to solar irradiance) of the carbonate buffering capacity. pCO2 was oversaturated comparing to the atmosphere (512–860 μatm) and the estuary was a source of CO2, with fluxes ranging from 2.2 to 200.0 mmol C m–2 d–1 (51.9 ± 26.7 mmol C m–2 d–1), which are higher than emissions normally found in low-inflow, marine-dominated estuaries. The diel variability of DIC indicated a net heterotrophic metabolism averaging −5.17 ± 7.39 mmol C m–2 h–1. Eutrophication amplifies the diel variability of the CO2 system generating large differences between daytime and night-time. The results highlight the importance of considering diel variability when estimating CO2 fluxes and carbonate chemistry in eutrophic, semi-arid, and tidally dominated estuaries under rapid environmental changes, and may represent future conditions in estuaries worldwide experiencing warming, increasing aridity and eutrophication.

Venice as a paradigm of coastal flooding under multiple compound drivers

Full comprehension of the dynamics of hazardous sea levels is indispensable for assessing and managing coastal flood risk, especially under a changing climate. The 12 November 2019 devastating flood in the historical city of Venice (Italy) stimulated new investigations of the coastal flooding problem from different perspectives and timescales. Here Venice is used as a paradigm for coastal flood risk, due to the complexity of its flood dynamics facing those of many other locations worldwide. Spectral decomposition was applied to the long-term 1872–2019 sea-level time series in order to investigate the relative importance of different drivers of coastal flooding and their temporal changes. Moreover, a multivariate analysis via copulas provided statistical models indispensable for correctly understanding and reproducing the interactions between the variables at play. While storm surges are the main drivers of the most extreme events, tides and long-term forcings associated with planetary atmospheric waves and seasonal to inter-annual oscillations are predominant in determining recurrent nuisance flooding. The non-stationary analysis revealed a positive trend in the intensity of the non-tidal contribution to extreme sea levels in the last three decades, which, along with relative sea-level rise, contributed to an increase in the frequency of floods in Venice.

Effect of Estuary Urbanization on Tidal Dynamics and High Tide Flooding in a Lagoonal Estuary

Effect of Estuary Urbanization on Tidal Dynamics and High Tide Flooding in a Lagoonal Estuary

Modification of Internal Wave Generation and Energy Conversion in the Nearshore Due To Tide‐Tide and Tide‐Wind Interactions

AbstractInternal wave generation due to semi‐diurnal tides (M2) through the acceleration of barotropic tidal flow over sloped topography has received considerable attention over the past several decades. However, the contribution of other tidal constituents and their interactions with M2 have not been as extensively evaluated. Moreover, on the inner shelf, the cross‐shore wind, which is often neglected in the energy conversion studies, dominates the cross‐shore transport and can also affect the energy conversion process. This study addresses this gap by including a diurnal (K1) tidal component and a shoreward diurnal sea breeze in an idealized model of southern Monterey Bay as it represents a highly stratified system that experiences active surface and internal tides. Our simulations demonstrate the role of the K1 tide and its interaction with M2, which is constructive and insensitive to the initial phase lag. Wind‐induced perturbations grow with the wind speed and enhance M2 conversion. On the other hand, the wind interaction with the K1 and M2K1 tides highly depends on the timing with constructive (destructive) conversion occurring when the shoreward wind intensifies during the ebb (flood) tide. Interactions among tides and winds lead to highly variable conversion rates, changes in timing and location of peak conversion, and a range of internal wave frequencies. Such a dynamic alone can be responsible for the complex internal wave environments often observed in the nearshore.

Vulnerability analysis of coastal communities in Merauke as impact of climate change

The coastal area of Merauke is already experiencing the impact of climate change which causes community vulnerability which can lead to structural poverty. The purpose of the study conducted in the coastal area of Merauke Regency with a sample of 2 observation areas namely Merauke and Naukenjerai Districts using a qualitative research approach with survey methods. Research data were collected using questionnaires and in-depth interviews with expert respondents who have competencies related to the topic being studied. Data were analyzed using vulnerability analysis which measures exposure, sensitivity, and resilience in community groups who work as fishermen, farmers, and become fishermen/farmers, traders, and transportation workers. The results of the study indicate that the groups of people who have vulnerability as a result of climate change are fishermen and farmers. The level of vulnerability is caused by pressure from natural resources, namely tidal water disasters and floods due to high rainfall intensity which has an impact on the loss of income and work of the community. While the highest level of pressure caused by human activities, namely from sand excavation and land conversion into settlements and public facilities, population growth, and activities to dispose of garbage and household waste on the coast have the biggest impact on decreasing the carrying capacity of the region, coastal ecosystems, reducing livelihoods. livelihoods and sources of income.

Study on the Methods to Estimate the Bed Shear Stresses in Yangtze Estuary

High spatial and temporal current resolution velocities were measured by use of an acoustic Doppler velocimeter (ADV) in the tidal bottom layer of North Passage Deep water Navigational Channel (DNC) of Yangtze Estuary in China. And the vertical profiles of mean velocity were measured by using a pulse-coherent acoustic Doppler profiler (PC-ADP). The measured data show the vertical profiles of mean velocity are almost logarithmic. For discussing, the turbulent kinetic energy (TKE) method based on the velocity for ADVs-based is chosen and a new logarithmic profile (LP) method ignoring the influence of complex variation of the parameter Z 0 is suggested to estimate the bed shear stresses respectively. The calculated results show that the bed shear stresses estimated by LP method are larger than the ones estimated by TKE method mostly in Yangtze estuary. At the moment of ebb peak, the maximum error can be about twice occurring and the error of ebb tide is almost greater than the one of flood tide. These phenomena are explained in this study by the deduction of formula for steady and unsteady flow. It is concluded that the vertical logarithmic profile of velocities will be influenced by unsteady flow and there is not the same bed shear stress even if there is the same logarithmic velocity profile in vertical. Generally, this has led to a necessary adjustment of the drag coefficient Cd of steady flow in flow model to avoid overestimating the bed stress for unsteady flow in estuary based on the observed data.

Flood Detection in Urban Areas Using Satellite Imagery and Machine Learning

Urban flooding poses risks to the safety of drivers and pedestrians, and damages infrastructures and lifelines. It is important to accommodate cities and local agencies with enhanced rapid flood detection skills and tools to better understand how much flooding a region may experience at a certain period of time. This results in flood management orders being announced in a timely manner, allowing residents and drivers to preemptively avoid flooded areas. This research combines information received from ground observed data derived from road closure reports from the police department, with remotely sensed satellite imagery to develop and train machine-learning models for flood detection for the City of San Diego, CA, USA. For this purpose, flooding information are extracted from Sentinel 1 satellite imagery and fed into various supervised and unsupervised machine learning models, including Random Forest (RF), Support Vector Machine (SVM), and Maximum Likelihood Classifier (MLC), to detect flooded pixels in images and evaluate the performance of these ML models. Moreover, a new unsupervised machine learning framework is developed which works based on the change detection (CD) approach and combines the Otsu algorithm, fuzzy rules, and iso-clustering methods for urban flood detection. Results from the performance evaluation of RF, SVM, MLC and CD models show 0.53, 0.85, 0.75 and 0.81 precision measures, 0.9, 0.85, 0.85 and 0.9 for recall values, 0.67, 0.85, 0.79 and 0.85 for the F1-score, and 0.69, 0.87, 0.83 and 0.87 for the accuracy measure, respectively, for each model. In conclusion, the new unsupervised flood image classification and detection method offers better performance with the least required data and computational time for enhanced rapid flood mapping. This systematic approach will be potentially useful for other cities at risk of urban flooding, and hopefully for detecting nuisance floods, by using satellite images and reducing the flood risk of transportation design and urban infrastructure planning.

Assessing the Meteorological Impacts of Time‐Varying Land Cover in the Intertidal Zone

AbstractThe meteorological impacts of intertidal land cover variation during summer and winter were simulated using the weather research and forecasting (WRF) meteorological model through two experiments: a TIDE experiment with time‐varying land cover by tidal effects in the intertidal zone using a new modeling method used hourly surface boundary conditions obtained using ocean model and satellite data, and a CNTL experiment with fixed land cover in the intertidal zone using a typical WRF modeling method used to fix the surface boundary conditions. The results of the TIDE experiment were more consistent with the recorded observations, especially during high tides. During summer daytime, the sensible heat flux (SHF) became negative (downward exchanging process) in the intertidal zone due to a low sea surface temperature, which decreased the temperature and increased the water vapor mixing ratio in the intertidal zone and inland areas. The wind speeds in intertidal zones and inland areas increased due to strong sea winds at altitudes from 80 m to 1.5 km, thereby increasing the sea breeze intensity and resulting in meteorological changes in inland areas. During winter, land cover changes in the intertidal zone impacted fog formation. During nighttime high tides, the SHF became positive in the intertidal zone and the latent heat flux increased prior to fog formation. During flood tide, the relative humidity increased and wind speed decreased in the intertidal zone and coastal areas coincident with fog occurrence. Overall, meteorological changes due to tidal effects were more pronounced in the summer.

Flood Risk in Urban Areas: Modelling, Management and Adaptation to Climate Change. A Review

The modelling and management of flood risk in urban areas are increasingly recognized as global challenges. The complexity of these issues is a consequence of the existence of several distinct sources of risk, including not only fluvial, tidal and coastal flooding, but also exposure to urban runoff and local drainage failure, and the various management strategies that can be proposed. The high degree of vulnerability that characterizes such areas is expected to increase in the future due to the effects of climate change, the growth of the population living in cities, and urban densification. An increasing awareness of the socio-economic losses and environmental impact of urban flooding is clearly reflected in the recent expansion of the number of studies related to the modelling and management of urban flooding, sometimes within the framework of adaptation to climate change. The goal of the current paper is to provide a general review of the recent advances in flood-risk modelling and management, while also exploring future perspectives in these fields of research.

Social vulnerability of coastal fish farming community to tidal (Rob) flooding: a case study from Indramayu, Indonesia

Climate-related disasters increasingly threaten over one-third of the global population, specifical communities within 100 km of coastal zones. Indonesia, the world’s largest archipelago with the second-longest coastline, faces tidal (Rob) flooding from high tides, land subsidence, and sea-level rise. This study assess fish farmers’ vulnerability to Rob flooding in Java’s Indramayu District. Our Social Vulnerability Index (SoVI)’s development involved 150 questionnaires, focus group discussion, and key-informant interviews between 16 and 20 October 2019. It found a high vulnerability, a SoVI score of + 1.76 comprising nine principal components (PCs): external support and government mitigation, local knowledge, income, expenditure, family size, seasonal-expenditure, education, experience, and ethnicity. Contributing to ‘vulnerability’ and ‘resilience’ concepts, it highlights community memory of repeated disasters and its impact on local adaptive capacity. Findings inform policymakers to address the PCs influencing vulnerability, including critically-needed livelihood support and early-warning systems relevant to the country’s 12,000 + coastal-villages and developing countries where over 90% of fishermen live.

Dimension of community capability and its effect on the social vulnerability at Semarang coastal area

PurposeTanjung Mas, an urban village located in the northern part of Semarang city, has been facing a major impact of coastal inundation occurring along North Java Coastline. This by-product of global climate change is also affecting a 37-hectares slum, one of the largest slums in Semarang city. As the coastal flood tends to escalate every year, the affected areas must have a coping ability to reduce its impact, while also having adequate resources to recover. Considering Tanjung Mas’ dense demographic condition and its function as the city’s seaport, social vulnerability and capability play a significant role in mitigating and recovering flood impacts, in supplement to local government’s effort of strengthening the Northern Java Seawall. Therefore, this study aims to scored and correlated Tanjung Mas’ social vulnerability index (SoVI) and community capability index to assess how well its population can recover from the tidal flood in the future.Design/methodology/approachThis study used the SoVI framework analysis to synthesize relevant social vulnerability indicators and community capability indicators in Tanjung Mas. The two sets of indicators were correlated with Pearson R-squared correlation method to seek a possible non-causal relation. Bivariate indices mapping method exhibit the SoVI and community capability index spatially to show every area’s vulnerability and capability level.FindingsThe vulnerability and capability level in Tanjung Mas vary within its smaller area, as six combinations of social vulnerability and community capability level were found. The worst combination was found on areas closer to the coastline, with high social vulnerability and low community capability level. These areas need to be strengthened in both its capability and coping ability toward coastal flood to realize a resilient community.Originality/valueThis study will be useful for local governments as a supplement to the strategic spatial plan, predominantly in prioritizing vulnerable area treatment prior to the completion of Northern Java Seawall in 2025. This study provides information and a simplified quantitative scoring result of vulnerability and capability level in slum area that has been customized according to Indonesia’s demographic characteristic. These results and framework might be relevant to SoVI and capability scoring in developing countries.

An evaluation of the efficacy of shell hash for the mitigation of intertidal sediment acidification

AbstractOur objectives were twofold: (1) to determine whether the addition of shell hash to intertidal sediments would mitigate porewater acidification and (2) whether its effectiveness was dependent on the type of sediment as described by organic matter (OM) and particle grain size (PGS). Field experiments were conducted at two sites within Burrard Inlet, British Columbia; Maplewood Mudflats (MM), high in OM and silt and Whey‐ah‐Wichen/Cates Park (WAW), low in OM and an equal PGS among very coarse, coarse, fine sand, and silt. Shell hash was added to triplicate treatment plots matched with triplicate controls at each site and porewater pH measured at flood and ebb tide over eight tidal cycles. Sampling occurred during June and July when tidal cycles were at their maximum inundation and exposure. Porewater pH was significantly greater for ebb versus flood tide and also between sites with MM significantly lower (7.59) as compared to WAW (8.03). Although pH was not mitigated by the shell hash, for WAW, variation in pH was reduced as compared to MM, as indicated by coefficients of variation over the 6‐week sampling period. We suggest that the application of shell hash to reduce the impact of ocean acidification (OA) on intertidal sediments will be site dependent. The combined processes of eutrophication in sediments with high OM and respiration of infauna, especially at high densities, could act in concert with OA to create an intertidal region unsuitable for bivalve larvae settlement and development.

Sources, Mechanisms, and Timescales of Sediment Delivery to a New England Salt Marsh

AbstractThe availability and delivery of an external clastic sediment source is a key factor in determining salt marsh resilience to future sea level rise. However, information on sources, mechanisms, and timescales of sediment delivery are lacking, particularly for wave‐protected mesotidal estuaries. Here we show that marine sediment mobilized and delivered during coastal storms is a primary source to the North and South Rivers, a mesotidal bar‐built estuary in a small river system impacted by frequent, moderate‐intensity storms that is typical to New England (United States). On the marsh platform, deposition rates, clastic content, and dilution of fluvially‐sourced contaminated sediment by marine material all increase down‐estuary toward the inlet, consistent with a predominantly marine‐derived sediment source. Marsh clastic deposition rates are also highest in the storm season. We observe that periods of elevated turbidity in channels and over the marsh are concurrent with storm surge and high wave activity offshore, rather than with high river discharge. Flood tide turbidity also exceeds ebb tide turbidity during storm events. Timescales of storm‐driven marine sediment delivery range from 2.5 days to 2 weeks, depending on location within the estuary; therefore the phasing of storm surge and waves with the spring‐neap cycle determines how effectively post‐event suspended sediment is delivered to the marsh platform. This study reveals that sediment supply and the associated resilience of New England mesotidal salt marshes involves the interplay of coastal and estuarine processes, underscoring the importance of looking both up‐ and downstream to identify key drivers of environmental change.