This paper presents a particle-based 3D-modeling of ice-sheet break-up processes during a collision with a structure by the three-dimensional Moving Particle Simulation (MPS) method. The model considers both the ice-sheet and the pile structure as a continuum and the dynamic motion of ice is represented as a set of calculation particles. The model is verified through the comparisons between numerical results and the experiments of ice sheet break-up and failure mode around a pile structure. Quantitative investigation from the numerical results is also made, showing that the difference in the ice failure mode originates from and affected dominantly by pressure wave propagation across the ice. In addition, the model shows applicability for the prediction of impact force exerted by ice sheet collision.

View full abstract

 Reinforced concrete structures in coastal area are dereriolated by various factors such as Cl^- penetration and carbonic acid gas. In this paper, dereriolation characteristics of reinforced concrete structures located on seaside and land were evaluated by surveying the condition of reinforcing bar corrosion in thermal power stations placed in Seto Inland Sea where the width of tide level is over 3m. As the results, it was realized that the main factor of reinforcing bar corrosion is different between marine strutures and land structures; Marine structures' reinforcing bar could be in the corrosion condition after 15 years of their construction mainly because of Cl^- permeation in marine strutures. On the other hand, that of land structures could corrode after 25 years of their construction by carbonation since their covering depth tend to be thin. These estimations are considerablely conservative, but could be used as standard index of considering maintainance time in Seto Inland Sea.

View full abstract

 This paper aims on developing flame for evaluating reinforced bar corrosion by crack width on cover concrete of RC structure. Relation between reinforced bar corrosion amount and corrosion crack width of RC specimens under various environmental condition was organized. Normalized exposing term and normalized corrosion amount by the term of exposed in sea water can predict corrosion amount under different exposed condition. Furthermore, relation between corrosion amount of reinforced bar and corrosion crack width under each two types moisture environment corresponded to splash zone and tidal zone.

View full abstract

 The function diagnosis for fishing port facilities has a lot of issues such as simplifying use and improving accuracy of results and degradation prediction. In addition, concrete parts of the facilities have been exposing and deteriorating by hydrosulfate in seawater. It is pointed out that an intermittent long term survey is necessary, because its deterioration become worse over time.
 We aimed to contribute improving accuracy of nondestructive inspection technique in this research; checking out changings of the shape and compressive strength in long-term seawater exposure, and comparing with the dynamic elastic modulus, the surface of P wave speed, and the mechanical impedance value measured by the non-destructive inspection.
 The result showed that exposed concretes by seawater were consistent with reported results. Also, deterioration (skinned) on concrete surface was caused by magnesium sulfate.
 As a result, weight of the test-piece was decreased, and adding magnesium sulfate led acceleration of deterioration in the dynamic elastic modulus and compressive strength.

View full abstract

 The thickness of the steel sheet pile which is a main structural component of port facilities is measured to evaluate its soundness. It is helpful to estimate the spatial distribution of the thickness of steel sheet pile from small number of the measured data.
 In this study, the authors applied the spatial statistics (kriging) method to predict the spatial distribution of the thickness of steel sheet pile, then the following two were discussed; 1) the optimum combination of the variogram functions, the least square methods and the nugget effect, and 2) the appropriate measurement interval of thickness in a sheet pile quaywall.
 From the result of 1), evaluation of the nugget effect and choice a suitable combination of the variogram function and the least square method were important to enhance the accuracy of the predicted spatial distribution. From the result of 2), to keep the accuracy of the predicted spatial distribution in the tested structure, the appropriate measurement interval was less than 20 m along the normal direction.

View full abstract

 The maintenance of the cathodric protection for marine steel structure has many problems. For example, all aluminium alloy anode investigation is very difficult, the life of aluminium alloy anode is often longer than assumption, and so on.
 In this paper, we analized the investigation results of the weight and electric potential of anodes of steel piles of the jetty. We found the life of anodes is affected from electro coating, and suggest the evaluation method of the life of anodes in consideration of electro coating. Moreover, we suggest the estimation method of aluminium alloy anode weights from electric potential. In maintenance of cathodric protection, this method can lead to measure only electric potential without anode weights by diving survey.
 In surveys, we found the electric potential of the steel structures is equal in spite of some anodes exhaustion. We suggested to evaluate the change of electric potential in anode exhaustion by the entire system modeling of the cathodic protection.
 Utilizing these methods, it is made possible to adequately design to install new anodes.

View full abstract

 Comparisons of the improvement effect of various sand capping materials on the dissolved oxygen (DO) consumption rate in water were investigated by laboratory experiment. For the study, intact sediment cores were collected using acrylic tubes in Shinshiba Canal in Tokyo Bay, and capped the sediments by various sand materials. We estimated the DO consumption rate for 9 different conditions of sand capping materials. From the study, results were obtained that the DO consumption rate was small for shirasu (volcanic ash) and coal ash granule, and the rate was smaller for fine materials than for coarse materials.

View full abstract

 Nutrients and hydrogen sulfide, which are produced with decomposition of the organic matter in bottom soil, accumulate as dissolved form in the bottom soil. Nutrients and hydrogen sulfide productions are influenced by the bottom environment such as temperature, the organic matter form etc, and their release and diffusion are influenced by the pycnocline. The control factor of the production and release of nutrients and hydrogen sulfide at the bottom soil was evaluated by the forms of organic matter, temperature and the thermocline in Lake Nakaumi, and the effectiveness of its factor as the index to verify the effect of covering sand was inspected. Releasing of nutrients and hydrogen sulfide was affected by the content rate of the unstable easily decomposable organic matter and the accumulated temperature. The concentration of dissolved nutrients was able to explained by the accumulated temperature, and its concentration was effective for the confirmation of the covering sand effect. Released nutrients was concentrated under the thermocline, its concentration was affected by the seasonal changing of the thermocline.

View full abstract

 Formation of poor oxygenation at the bottom layer water and sediment in the semi-closed water zone near urban area is a typical agenda and many findings have been reported. However, most of them target sea area and there are few reports on the urban river mouth. In this study, to clarify the characteristics of a time change of oxygen consumption rate at urban river mouth, laboratory experiments were conducted. Sampling spot was Ikuta River mouth in Kobe City, Japan. In this river mouth, fluvial artificial lagoon is created. In each the laboratory experiment, time change of dissolved oxygen of sediment both of fluvial artificial lagoon and main stream was measured. From the series of laboratory experiments, the oxygen consumption rate at fluvial artificial lagoon is larger than at main stream.

View full abstract

 The invasive alien species Mytilus galloprovincialis aggregates to form dense colonies on the surface of port and harbor structures and accelerates eutrophication in the benthic environment by accumulating substantially the mussel feces on the sea bottom. However, the effect on the benthic environment by the mussel feces has not been quantitatively assessed yet. The present study aims to develop the discriminating method of the mussel feces in sinking materials on the basis of the morphological characteristics.
 As a result of the microscopic observation of 60 fecal pellets shed by various sizes of the mussels from Tokyo Bay, 86.7% of the pellets had all of the four characteristics: a longitudinal shape, an uniform width, a depressed shape and a longitudinal groove. The accurate discrimination of the mussel feces in sinking materials is expected by using the four characteristics.

View full abstract

 Granulated coal ash (GCA) has been scattered over 1.5 km in the Kyobashi River locates in the central part of Hiroshima City, for improving water and sediment environments. Flourish algae has grown on the upper part of GCA layer, suggesting the restoration of ecosystem. The main components of GCA are oxidants such as SiO₂ and CaO. Thus, the dissolution of GCA can supply minerals such as Ca and Si with a high rate. Si can be supplied from the dissolution of SiO₂ in noncrystalline glass existing in GCA. The purpose of this study is to reveal the relationship between growth conditions of flourish algae and the supply of minerals from GCA. For this purpose, we examine temporal variation of Si ion in the GCA layer. In addition, we also analyzed Si and chlorophyll-a in sediments.

View full abstract

 Flared Shape Seawall with a deeply curved front section was proposed, and its hydraulic characters such as wave overtopping prevention function and wave pressure have been examined mainly under normal incident wave conditions. The construction site of the seawall has a different incident wave angle, and above hydraulic characters are needed to be examined under oblique incident wave conditions. This study was conducted to clear the characteristics of wave pressure distribution on Flared Shape Seawall under some oblique incident wave conditions. The magnitude of wave pressure on the seawall decreases with incident wave angle, and its decreasing rate differs from an upright seawall. Furthermore, this study evaluated the influence of incidence wave angle on wave pressure that acts on Flared Shape Seawall which is planned on an actual construction site.

View full abstract

 Field experimental studies of offshore wind power generation has been promoted, in order to realize offshore wind farms around Japanese coastal sea area. Nevertheless, sufficient knowledge is not yet established on the evaluation method of wave pressure acting on the auxiliary structure, such as a cable protection tube. This paper introduces results of hydraulic model experiments on wave pressure acting on cable protection tube of offshore wind turbine foundation. The results clarified the acting wave pressure with respect to the incident wave directions. It was found that impulsive wave braking forces can be generated even when the cable protection tube is located at the back side of the foundation to the incident waves.

View full abstract

 Traffic hindrances were often caused by overtopping waves under storm wave conditions on coastal roads behind gently sloping seawalls. In this study, the damage risk of vehicles due to wave overtopping was revealed by the field observation data. Based on the results of hydraulic model experiments with irregular waves, the characteristics of wave overtopping water thickness, wave overtopping rate and the horizontal wave force on the vehicle were disclosed for three wave period conditions at the sea side road section. The relationship between maximum wave overtopping thickness and offshore wave height was shown for wave period conditions. In order to examine the stability of vehicles for the longest wave period condition, the wave pressure distribution was formulated as a function of the wave overtopping thickness on the road. The validity of the calculation formula was also confirmed by the sliding experiment of vehicles.

View full abstract

 Flap-gate seawall is a coastal structure which lies down on the ground usually, and it rises up by buoyancy and closes an opening of embankments when inundation occurs. A traditional flap-gate seawall has counterweights which assist the gate in moving. Although arrangement of the traditional flap-gate's counterweights is effective, it is difficult to support the gate with over 20 meters wide on sides of the gate. Therefore, a long-span type flap-gate seawall has been developed in this study. It equips counterweights behind the gate, and then the counterweight does not prevent width of the gate from extending. In this study, motions of both gates and counterweights and wave force acting on gates were examined through a series of hydraulic experiments using a model of the long-span type flap-gate. As a result, wave force acting on the gates was within ranges in which the flap-gate can be designed reasonably. The experimental works confirmed that the long-span type flap-gate seawall has good performance for protecting target areas against tsunami.

View full abstract

 The influence of wind-driven currents upon the behavior of the fresh water from Chikugo River flowed into the inner part of Ariake Bay was investigated through the comparison between the results of particle tracking simulation by using surface currents obtained by the HF radar and observed surface salinity. As a result, the followings were clarified. While the north wind was blowing, the fresh water flowed toward the mouth of Isahaya Bay in a short period by wind-driven currents as well as ebb currents and density currents. On the other hand, while the south wind was blowing, the fresh water stayed at the northern coastal areas of the bay and the residence time of the fresh water in the inner part of the bay would be prolonged.

View full abstract

 Object of this study is to predict distribution of ¹³⁷Cs radioactivity in front of Fukushima by means of a 3-dimensional flow model linked with a diffusion model, released by the Rivers. It was confirmed that radionuclides(Cs-137) distributions in coastal areas can be predicted by means of nesting form the whole Pacific Ocean model. Results were compared to the published observation data in order to examine applicability of the used models.
 As a result, the impossibility of the influence humanities was suggested to be with in front of Fukushima.

View full abstract

 Interaction between estuaries of a pair is tremendously important since evolution of an estuary will significantly impact to other and again. Lack of knowledge about the relation of them could probably result in unexpected consequences to one when implementing certain approaches to exploit, operate, maintain or protect other. The aim of this study is to investigate mutual interaction between Dinh An estuary and Tran De estuary of Mekong River in Vietnam under variations of upstream conditions. River discharge, water level, suspended sediment and salinity concentration were collected in the study area in 2009. Estuarine, Coastal and Ocean Modeling System with Sediment (ECOMSED) was used as an application of three-dimensional numerical model. Then sensitive numerical experiments were performed to figure out response of Dinh An and Tran De estuary to change of upstream discharge rate. We confirmed that redistributed portion of the upstream discharge has high responsibility to mutual interaction of hydrodynamics, salinity intrusion and sediment transport characteristics of both Tran De and Dinh An estuary.

View full abstract

 This study carried out an annual flow simulation in Lakes Shinji and Nakaumi. The aim of this study is to verify that effects of horizontal mesh size gives on the calculated salinity intrusion. We used numerical model "STOC-LT", and prepared the two case mesh sizes of 200m and 400m. We computed a flow of connected model of Lakes Shinji and Nakaumi until December 31, 2013 from January 1, 2012. In the calculation result, a reproduction of water level and temperature were consistent. But, calculated salinity in 200m and 400m mesh size was overestimated than observation. The calculation of the salinity change is smaller than observation in Ohashi river. Therefore the numerical model is easy to become state of the weak stratification. The flux of 400m mesh is about 2 times of 200m mesh in Ohashi river. It is thought that if using a small mesh size makes flow volume reduce.

View full abstract

 The stability effect of suction dynamics on equilibrium profile of sandy beach under high wave condition is examined through a series of experiments. The major experiments are designed as the model beach is loaded by the annual mean storm wave. The vane shear strength, sand compaction, saturation of the sediment are measured in those experiments. As a result, Improvement of the vane shear strength and compaction in vicinity of upper layer of beach face are induced by the behavior of suction within bed changing. The experiments under huge violent wave condition are also conducted in order to verify the applicability of suction dynamics on high-erosional condition.

View full abstract

 An artificial tidal flat was created in 2007, to compensate for the loss of a natural tidal flat, at Okinosu, Tokushima City. However, five years after its creation, it was found that the ecological conditions in the artificial habitat of benthic animals differed vastly from those in the natural habitat. In particular, the mud snail Batillaria cumingi, which dominates natural tidal flats, was rarely found in the artificial habitat.
 We tested the hypothesis that the “sinking event” was caused due to bioturbation by the ghost shrimp, Nihonotrypaea japonica. The “sinking event” occurred only at the places where N. japonica was abundant. Therefore, it seemed that bioturbation by N. japonica was the cause of the “sinking event”. Although exclusive treatment with N. japonica led to a low-biodiversity assemblage, N. japonica has both positive and negative effects on the tidal flat ecosystem.

View full abstract

 The leakage of backfilling sand through corrosion holes of a quay wall is investigated using hydraulic experiments and numerical simulations. When the hole is located near the still water surface, experimental results show that the sand is leaked through the hole during the phase of wave trough and numerical results show that the water flows into the upper side and out of the lower side in the hole during the phase of wave trough. This result suggests that the sand leakage results from the seaward outflow in the hole. Furthermore, it is revealed that the sand leakage tends to occur for large seaward outflow velocity, suggesting that reducing the seaward outflow velocity in the hole is essential to prevent the sand leakage.

View full abstract

 The construction of fishing ports/commercial port and river works are all carried out according to the related design manuals. However, when these works are conducted faithfully according to these manuals with insufficient recognition of sand movement between the management areas of the coast, some works at a coast may induce beach erosion to the nearby coast. This point was investigated in terms of the explanation of the laws related to the coastal protection. Sand management in related laws and design manuals were studied in detail, and the issues were discussed. Moreover, issues related to the damage restoration system were discussed, and some methods to improve this condition were proposed.

View full abstract

 In this study, the stability of backfilling stones under flat-type armor blocks with a circular hole against waves has been studied experimentally. The mechanism of displacement of the rubble backing under the flat-type armor blocks caused by wave actions is also examined extensively. According to the latest guidelines in Japan, it is recommended that the required mass of under layered gravels should be greater than 1/10 to 1/20 of the mass of a wave dissipating armor block. The covering flat-type block in this study has a comparatively large hole of circular shape at its center for reducing the uplift force and also saving the construction cost. It would be concerned that such covering blocks may cause displacement of the backfilling stones and finally result in the total failures of revetment works. In this study, supposing that the size of the backfilling stones is generally smaller than that of a circular hole on the covering blocks, the stability of such backing stones against waves has been examined extensively by the use of various median grain sizes of the backing. By referring to such experimental results, the displacement mechanism of the rubbles is also discussed precisely.

View full abstract

 Ocean surface current includes drift current, tidal and residual currents, tsunami current and etc. which have various time scales. We have developed a method for decomposing surface currents in Ise Bay obtained by HF ocean radar into tidal, drift and tsunami current component. The model used in the present method includes the multi-AR model with trend and periodic components developed by Kitagawa and Gersch. The trend component extracted by the model, shows residual and drift currents with a longer time scale. The periodic current component with a period of 12 h appears to be S₂ and K₂ tidal current components. The steady component extracted by a steady AR model, has a time scale of several to several decades of hours and shows tidal current components with a period of longer than 12 h, such as M₂, O₁ and K₁ tide components. It is difficult to extract tsunami current component using surface current data measured at each one hour because tsunami current has a period of several min. to hours. The multi-AR model can detects a tsunami component as a short period noise component, attacking Ise Bay at 18:00 on March 11.

View full abstract

 The Advanced Land Observing Satellite-2 (ALOS-2, “DAICHI-2”) operated by Japan Aerospace Exploration Agency (JAXA). The ALOS-2 carries the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2). The PALSAR-2 can observe the disaster affected area day and night in any weather with its high power and high resolution Synthetic Aperture Radar (SAR). In this paper, we report some preliminary experiments of the disaster monitoring in harbor based on Synthetic Aperture Radar Interferometry (InSAR). In order to evaluate the usefulness of the InSAR, we measured the uplift of a working model made of concrete armor units and confirmed its accuracy can be better than 2 cm in standard deviation. We also analyzed the damages in Nagata and Suma ports Kobe prefecture hit by the 11th Typhoon in 2014, and detected the damaged area with interferometric coherence analysis.

View full abstract

 We investigated a methodology to estimate the parapet height of the coastal structures by utilizing original data and ortho image acquired at the time of airborne LiDAR survey. By making comparison and examination of both terrestrial laser measurement data and airborne LiDAR surveyed data, the upper surface height of the parapet could be estimated precisely by our way and it was revealed that our methodology is highly effective for the confirmation of the change detection and the maintenance of the structures.

View full abstract

 Tidal suction and consolidation settlement in the coastal area often result in the occurrence of cavities beneath the pavement around quay walls. As it is difficult to detect the cavities by eyesight, establishment of the method for the detection of cavities efficiently is strongly required. This study focuses the application of microtremor measurement to the detection of cavities. Spectral characteristics of horizontal component of microtremor were found to be different from the points above cavities to the points without cavities. Considering the measurement and analysis load, the proposed method is thought to be highly applicable to the maintenance practice.

View full abstract

 This study was undertaken to clarify the applicability of underwater 3D measurements by structure-from-motion (SfM) for coral reef waters. Both underwater SfM and usual high-cost measurements for branching and massive corals were conducted. Their results were compared and examined.
 Results clarified that underwater SfM can measure the heights and long and short diameters of the corals and the branch widths of branching coral within the error range of maximum 4.5 cm and minimum 0.1 cm. Therefore, underwater SfM are regarded as useful for monitoring coral conservation.

View full abstract

 This paper develops a satellite-based monitoring system for observations of spatial and temporal variations of turbidity of the sea surface around Hai Phong Bay in the northern part of Vietnam. The monitoring system is based on MODIS and consists of sub-tools required for the monitoring, such as cloud masking and turbidity estimations based on multiple band data. The developed system is validated through comparisons of estimated and measured turbidity patterns around Hai Phong Bay. The system is then applied for monitoring of turbidity patterns around the bay over the past sixteen years and it was found through the monitoring that observed turbidity shows decreasing trend after the construction of dams along the upstream of the rivers around the area.

View full abstract

 We studied trends in the annual variations of the items related to turbidity in the water in Ariake Bay and Isahaya Bay, and analyzed the relationships between these variations and decrease in tidal current velocity caused by the mean sea level rise and other influences.
 Transparency observed at the center and mouth of Ariake Bay increased because of a decrease in turbidity, which was caused by a decrease in tidal currents. The decrease in tidal currents was caused by the increase in mean sea level; this has occurred since the 1980s in the whole Kyushu area, including Ariake Bay. We found that the contribution of the changes in turbidity caused by the mean sea level rise was larger than that of the changes caused by the setting of the net during the Nori cultivation period at the head and center of the Bay. We also noted that the changes in turbidity observed at the center and mouth of Isahaya Bay were similar to the ones measured at the head and center of Ariake Bay and that the mean sea level rise in Ariake Bay was the main contributor to these changing trends. Moreover, it was suggested that in addition to the mean sea level rise, the changes in turbidity observed at the head of Isahaya Bay were influenced by the construction of the Isahaya sea-dyke in 1997.

View full abstract

 The purpose of this study is to develop the system that the topography of sandy beach can be observed using UAV(Unmanned Aerial Vehicle), as the one of the method for considering the countermeasures aginst the coastal erosion probrem in Uradome Beach, Tottori. In this paper, the coastal topographic change in the Uradome beach was analyzed from the three-dimensional model using SfM (Structure from Motion) associated with the aerial image obtained by the UAV, and the accuracy of the analyzed result was discussed. The UAV used in this study was four wings flight vehicle, and the areal photos were taken per two seconds with a height of T.P. 80 meters. The photos of approximately 200 sheets were analyzed by using SfM and GIS software. The observation using UAV along the coastline worked out in 20 minutes about 2 kilometers. The accuracy of the observation with RMSE was verified from a result of the comparison between the RTK-GPS and the UAV survey, the RMSE was about 0.05m.

View full abstract

 Shichiri-Mihama Ida beach is suffering from severe beach erosion. To clarify the mechanism of such beach erosion, short-term beach topographic change including shoreline changes and berm developments obtained by UAV-SfM and network camera was investigated in the relation with wave characteristics. Results showed that UAV-SfM measurement provides the three-dimensional image, sectional view, and calculation of volume amounts of the gravel beach very well and it is useful to understand the beach deformation. Furthermore, it is showed that the beach tends to be erosive under the oblique wave of a significant wave height of 4 m or higher, waves of a significant wave height of the order between 2 m and 4 m from the normal direction of coastline tends to cause deposit, and the beach tends to be stable under waves of a significant wave height of about 1 m or less with regardless of the period and the wave direction, at Shichiri-Mihama Ida beach.

View full abstract

 A 1/60° × 1/75° mesh model (DR_E) was developed in order to detect suitable place for ocean current power generation in the southern region of Honshu, Japan. It was shown from the output of the DR_E that the current velocity of the Kuroshio is large in the southern region of Shikoku and the Kii Peninsula. In addition, when considering the installation conditions of the device, it was found that the most suitable place for ocean current power generation exists in the southeastern region of Cape Ashizuri-misaki.

View full abstract

 In this study, the wave-energy-converter of Oscillating-Water-Column type with Projecting-Wall (PW-OWC) is treated, on which an impulse-turbine is installed as a secondary energy converter from air-flow to electricity. When the primary conversion from wave motion to air-flow is improved by PW, as well as the secondary one from air-flow to electricity is refined by applying an impulse-turbine, then the optimum design is newly required of the total system consisting of the primary and the secondary conversion systems. The air-flow after the primary conversion is introduced in the air chamber to the entrance of turbine, where air-flow (Q) with pressure difference (ΔP), difference between the pressure at entrance and that at exit, makes the secondary conversion with rotating the turbine to generate electricity. Accordingly, Q and ΔP are the common parameters connecting the primary conversion system and the secondary one. A numerical model on hydraulics can provide Q and ΔP for an assigning incident wave. The characteristics of the impulse turbine is obtained under the constant flow condition and found independent from its size for the certain range of Q and ΔP. For the coupled analysis of the total system, a graphical method is tried. On the same Q vs P chart, both the hydraulic characteristic curve and the turbine curve can be drawn. The intersection point gives the possible combination of Q and ΔP, which satisfies the primary and the secondary systems at the same time. After the verification by the prototype field experiment, this method can be found useful as a practical design tool for PW-OWC.

View full abstract

 This paper introduces results obtained from offshore observation tower system off the Kita-Kyusyu city, by comparing results obtained from other Japanese NOWPHAS stations. There exists a great difference of the accessibility between the Pacific side and the Sea of Japan side, in both winter and summer seasons. Co-occurrence of the waves and winds was also investigated based on offshore simultaneous observed data. A simple combination method of both the action was proposed.

View full abstract

 This paper discusses the flow field to simulate the tidal power generation device using the fan model and porous media. The porous media is not take into account of the rotation effect of the blades. However, the fan model can be modeled without defining a blade shape in detail and it is possible to further consider the rotation effect. Due to the effect, it is suitable for the surrounding flow analysis. Nevertheless, the flow rate increases artificially in the case of using fan model, so that porous media is used to attenuate energy after passing fan model flow. As a result, around 98% of inlet velocity recovered in 20D downstream placing longitudinally space. For laterally space, 1.5D distance between models achieved inlet velocity at 20D downstream.

View full abstract

 Vortex Induced Vibration (VIV) of an oscillating single circular cylinder elastically supported by cantilever plate springs enhances an oscillation to utilize flicking piezoelectric hydro generator for not only steady-uniform flow but also unsteady and pulsating flow field in a small open channel and a seawater exchanger. In this article, vibration characteristics of the cylinder in unsteady flow and pulsating flow are mentioned first. Then, a novel type of energy harvester using flicking motion was developed. The flicking generator in which a vibrating cylinder flicks a bimorph piezoelectric sheet was evaluated in various flow fields. As the result, relatively large amplitude was achieved in steady-uniform flow field and unsteady flow field. In pulsating flow field, resonance amplitude with the lock-in frequency was obtained when the inlet velocity reaches or exceeds a threshold value. Flicking motion provides higher output voltage, and the flicking VIV generator allow further extension of a charging output into a battery has a highly possible to drive wireless environmental monitoring system.

View full abstract

 There are a lot of drowning accidents occurring on sea bathing areas every year in Japan. In this study, actual situations of beach accidents of Japan caused by drowning and the first aid were investigated using lifesaver's reports. The drowning accidents including unconscious victims were from 1,000 to 3,000 cases every year starting from 1998 to 2015. Also, the first aid was carried out 10,000 to 25,000 times every year in the same period. In addition, the outbreak factors of drowning and injury/disease names were cleared. In order to reduce drowning and first aid, the beach risk assessment method to understand potential risks and an appropriate beach management was proposed.

View full abstract

 A lot of water accidents have occurred at sea bathing areas in Japan, and the honorable life of 100 people or more has been lost every summer season. To reduce these water accidents , We develop the method of multilateral bathing area risk assessment for bathing area. The purpose of this study is to apply this risk assessment to Wakasawada beach. As a result, Wakasawada beach is satisfying 80% of natural Hazards & Risks and 94% of Beach management & Patrol system of safety evaluation items. By using this method, this beach was evaluated as high safety beach, but we point out some risk items. Against these risks, we propose risk mitigation measures. And we can confirm adaptability of this method.

View full abstract

 Generally, environmental recovery projects define the targeted space's way of being for a long time, while it is the nature of natural environment and people's interests/use to change constantly. Therefore, it is necessary to consider the temporal vector when discussing consensus building for such projects. In this study, field and interview surveys were conducted in the Omori Furusato-no-hamabe beach park, Ota-ku, Tokyo, and clarified the sustainable consensus building which makes actors in this project have continued identifying and sharing their interests, knowledge and consciousness on the “Omori in the past and now” to project individual future visions and superimpose them. Also, an analysis of free response text data about the image of Tokyo Bay was conducted to evaluate the progress of one target which includes psychological factor. The result indicated that there is a correlation between the times of visit to the park and the changes in consciousness toward Tokyo Bay.

View full abstract

 To conserve or create “Satoumi”, coastal education on local and community-based comprehension is important. This paper discussed educational contents and direction for “Satoumi” conservation at Iwai beach in Chiba prefecture. Beachcombing, making herbarium specimen of drifted algae, and coastal vegetation and forests investigations were carried out. Both producing and consuming areas of Ocean-fresh seafood for sale in the roadside station, FURARI TOMIYAMA, were investigated. The Photos taken during all investigations were classified by Photographic KJ method. As the results, the selected and tested education contents were properly validated and the network among fisheries ports, the roadside station, the beach and guesthouses was illustrated.

View full abstract

 Various influences due to climate change such as sea level rise, wave characteristics change and strength of the typhoon have been investigated. In parallel, impact assessment and economic valuation on coastal preservation have been recently carried out under the climate change scenarios. However, evaluation of adaptation of sandy beach preservation due to climate change is relatively difficult. In this study, questionnaire survey is conducted against three different kinds of coastal relatives to investigate the citizens' opinion and economic impact due to the climate change. The results are analyzed in terms of three major key items; 1) relationship to coast; 2) influence of preference in coastal management; and 3) willingness to pay for adaptation..
 It is found that the willingness to pay for adaptation under the climate change is about 700 yen/month among existing tax payment. And the willingness to pay is dependent on the CO2 emission (Representative Concentration Pathways) scenarios.

View full abstract

 Large-amplitude waves and long-period waves, which are concurrently induced by winter storms, cause overtopping at breakwaters in Kuriya-chiku of Echizen Fishing Port in Fukui prefecture, hindering safe and smooth fishery activities. For instance, in 7 December 2012th, wave overtopping caused downfall of several fishing boats at the site.
 In this study, we calculated wave overtopping at the port and investigated effective countermeasures to reduce overtopping in case of design wave to enhance safety inside the port.

View full abstract

 In order to promote the efficient transport by large vessels in ports of Japan, one of the useful methods is to use tidal window in case it takes a long time to dredge channels. Such waterway navigation has certain risks, so safety measures are necessary. However its actual practices are not well examined.
 This paper organizes risks, operational standards etc. regarding the use of tidal window over the world. Furthermore this paper analyzes actual conditions and practices such as tidal use policies or draft management of waterway navigation by AIS.

View full abstract

 In fishing ports, a multitude species of marine products captured by means of a variety of fishing methods are unshipped and carried in, and in addition, its conditions (fresh, frozen, live fish, etc.) are diversified, further, taking account of changes in landing and subsequent working procedures, hygienic control and freshness preservation corresponding to these operation procedures and configurations are obtained.
 This study has first of all been arranged in reference to hygienic control and freshness preservation, subsequently, clarified relations with hygienic control standards in HACCP system and fishing ports.
 Furthermore, deliberations of the basic concept for hygienic control and freshness preservation in adaptation to working procedures/conditions in fishing categories such as longline fishery, roll net fishery, Danish trawler fishery, set net fishery or the like and the concept of the improvement of fishing port facilities (products disposing places) have been carried out.

View full abstract

 While Japan is now working on the export promotion of Japan's marine products and food, the functions of production and logistics for their export have yet to be fully studied. The author has clarified that the ports serve vital functions in production and logistics from the production areas to the export destination countries by analyzing related statistical data and other existing data, and concluded that it is effective to export more live fish, fresh fish, chilled fish or fillet by utilizing the proximity shipping routes.

View full abstract

 Typhoon ROKE in 2011 past the Tokyo Bay. Reproducing calculation for this typhoon is performed. Numerical simulations with global warming condition in 2050 case and 2090 case are also performed. In this study, there are several conditions set as an example of dangerous side in future case studies. The damage of storm surge and the cost of protection measures against storm surge are calculated. By using these results and tsunami flood calculation results, the cost and the benefit are compared. The probabilities of occurrence of the tsunami and storm surge in 50 years are calculated and cost-benefit ratios are obtained. As a result, the estimated tsunami damage in 50 years is 14 trillion yen, and the estimated storm surge damage is 5.8 trillion yen. The cost of protection including raising seawall, water gate and maintenance cost in 50 years is 2.1 trillion yen. The cost of building houses with pilotis is 51 trillion yen. The ratio B/C is 9.35 if coat lines are protected by using seawall and water gate. B/C becomes 0.39 if we choose pilotis plan. For plotis plan, B/C becomes above 1.0 if a local government offers public support to house owners up to 38 percent of the cost of construction of pilotis.

View full abstract

 Shoreline change rate has been used to discuss the distribution of sand input from the Thu Bon River. According to the rate of shoreline change, the asymmetric distribution of sediment input from the river at the Cua Dai River mouth, Vietnam has been revealed. Transporting of sediment to the north by wave-driven longshore currents together with asymmetric distribution of sand supplied from Thu Bon River has been causing severe erosion on the left beach of the Cua Dai River mouth. In the future, more detailed analysis will be carried out by accumulating wave data in order to quantify the mechanism of this asymmetric behavior of sediment and resulting morphology change around the Cua Dai River mouth.

View full abstract

 In recent years, the erosion of shoreline at the Da Rang River mouth that is located in Tuy Hoa City in central Vietnam has become serious. This study presents changes of coastal morphology at this river mouth through the analysis of satellite images. Shoreline position in the area of about 9km in length around the river mouth was eroded severely, while it was stable on other adjacent areas. The erosion was most severe at the river mouth, whereas it was mild on the beaches far away from the river mouth. There are demarcations where the severe erosion did not propagate beyond. The roles of sand terrace as submerged sand source proving sediment to the adjacent shoreline is also discussed. The evolution of morphology at this river mouth is very important; hence accumulation of more field survey data and further study are highly required.

View full abstract