A demonstration experiment for tropical seagrass bed creation was carried out at Nakagusuku Port in the mainland of Okinawa. During past efforts, some parts of the created seagrass bed were washed away and their coverage was reduced. The reason for this was considered to be the environmental conditions of the sites. Therefore, this study was conducted with the aim of establishing the methodology for seagrass bed creation that enables the maintenance of the continuous growth of seagrasses. Based on the idea that it is necessary to remove the factors that limit the growth of the seagrass, submerged breakwater was installed and the seagrasses were transplanted together with the sands on which the seagrasses grew. The result of the experiment can be considered as the fact that the created seagrass bed continued to grow and expand even after three years, proving the viability of this methodology.

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  For quantitative assessment of water purifying ability in culture substrata that made use of waste shells to promote habitat of various small animals, we observed biochemical changes in tank water with the substrata placed within Tsuruga Port for 9 months. Sticking animals that prey on phytoplankton such as bivalves, polychaetes and sea squirts had majority in total 88 species on/in complex cubic body. After adding some diatoms to the tank, the amount of chlorophyll a and SS was rapidly reduced. Their decrease process was almost completed for 12 hours, and then water became transparent visually. Organic carbon and nitrogen was also rapidly decreased, while nitrate nitrogen continued to increase gradually. We estimated that those animals decrease 1.25mg hr^-1 in chlorophyll a, 264.8mg hr^-1 in SS and 2.9mg hr^-1 in organic nitrogen. Its purifying velocity was as 1.7-17.2 times as that of tidelands with corbiculae or clams. Therefore, it is concluded to work more sufficiently as purifying facilities if to put cubic body up.

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  The planktonic larval snow crab Chionoecetes opilio come up to near the sea surface induced by underwater light after hatching, and start descending when their weight, which increases with growth, exceeds the upward force produced by their swimming behavior towards the surface. Based on these activities, we developed a model representing the swimming pattern of the planktonic larvae until they acquire settlement. The larvae were put in the experimental tank with the same water conditions, and a monochromatic light of different wavelength, from 430 to 645 nm, was irradiated from above. The planktonic larvae in the zoea stage responded sensitively to blue light, showing positive phototaxis. Furthermore, experiments were made under various conditions with water temperatures from 3 to 24℃ and with salinities from 30.0 to 35.0 to examine the geotaxis of the larvae. A strong swimming inhibition was observed in a condition with a water temperature of 21℃ or more, but no influence by salinity was found. Based on these findings, we calculated the average upward swimming force of the larvae and compared it with their weight that produced a downward force. As a result, it was found that the sedimentation of the larvae, caused by their weight, starts at the megalopa stage.

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  For the artificial seedlings of sea cucumber Stichopus Japonicus, we measured how the number of the tube feet and the surface area of the tube feet suckers changed as they grew. We also made measurements of the adhesive strength of the tube-feet to the nursery bed by conducting tension tests. Furthermore, the current flow resistance of the seedlings grown on the nursery bed was examined. The number of the tube feet and the area of the suckers of those young sea cucumbers increased in proportion to the body length as the seedlings grew. The adhesive strength of the tube-feet suckers, depending on the roughness of the nursery bed, increased with a minimum strength value roughly defined by the sucker diameter as the seedlings grew. The adhesive strength of each tube-foot sucker, depending on the roughness of the nursery bed, converged to a certain value. As the stationary flow became stronger, the body of a sea cucumber assumed more of a spindle shape, indicating that it has the current flow resistance similar to or higher than that found in other echinoderms. Based on the ocean conditions in the sea area where the artificial seedlings of sea cucumber are released, it is possible to determine the sea cucumber's size appropriate for release as well as the water depth of such an area ideal for release.

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  The variation characteristics of tidal current and water quality in Hakodate port are investigated through field observation and numerical modeling. Measurements of nutrients, dissolved oxygen, chemical oxygen demand and turbidity are obtained from the whole area of the port. The results show that, during falling tide, the sediments suspension lead to increasing of chemical oxygen demand concentration. This phenomenon is made oxygen consumption speed to accelerate near the seabed. The phosphorus accumulated into the port is supplied from one of the rivers flowing out to Hakodate bay. The daily variation of water quality in the port is estimated using the multi-level model concerned with the ecological system. The results of prediction are in good qualitative agreement with those of observation.

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  In Tokyo Bay, water quality has been deteriorated due to human activities in river basins flowing into Tokyo Bay. Anoxia or hypoxia is one of the most significant water quality problems in Tokyo Bay, and previous studies revealed that the occurrence of hypoxia is controlled by wind stress, river discharge and strong wind effect. In particular, strong wind has a great role in the sudden increase in dissolved oxygen in the lower layer of the bay head. In recent years, meteorological conditions have changed evidently, such as flood disaster due to the increase in strong rainfall intensity. The change in meteorological conditions may also change wind speed and wind direction in the future. Therefore, to project water quality in Tokyo Bay, it is important to understand the future wind conditions. This study thus aims to investigate the applicability of Global Circulation Model (GCM) into the projection of wind conditions over Tokyo Bay by using 12 different GCM models. As a result, it is found that bias correction using cumulative density function should be used for the projection instead of using bias correction based on normal distribution.

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  We demonstrated applicability of a sensor, which can directly measure hydrogen sulfide (H₂S) concentration on-site, to monitoring for marine environment, and characteristics of vertical distribution of H₂S from the data obtained using the sensor. Observations were carried out in Tokyo bay in 2010. The data measured by the sensor correlated with the analyzed data of sampled water, but the former were less than half the latter. Therefore, we think that we should use the sensor for quality examinations at the present time. Regarding to the vertical distribution of H₂S, the followings were shown. H₂S also existed in the bottom layer at the head of the bay. The layer was 2 m high and the concentration of H₂S was about one-tenth of the concentration in the deeply excavated site. And high concentration of H₂S existed in the bottom layer at Shibaura canal, which was only four meter deep.

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  We analyzed a change of the species composition of phytoplanktons with the variation of the nutriment concentration by using existing survey data in Hakata Bay.
  As a result, the removal of phosphorus by advanced sewage treatment was decreased T-P concentration and contributed to restraint of the primary production in the bay. In addition, the cause of the prolongation of the red tide occurrence days of dinoflagellates in summer was not clear, but we understood that diatoms were hard to multiply by the decrease of phosphorus in winter season. Furthermore, it was became clear that Akashiwo sanguinea, which was a kind of dinoflagellates, was easy to multiply because A. sanguinea was hard to influence action to control an increase by the decrease of diatoms and the number of the red tide occurrence days of dinoflagellates increased.
  Essentially, We want to study the adequacy of the volume of primary production that various creature habitation space can secure, and the nutriment supply in the future.

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  To preserve the fishery resources, some maintenance works have been done in Japan. However, it is not easy to assess the effect of these projects because of increasing research cost on the relation between fisheries and environment. In this paper, a simple method of environmental assessment, has been proposed by using Habitat Evaluation Procedure Method (HEP). A model of HSI(Habitat Suitable Index) with two indexes is used to estimate the quality of biotope in an intertidal zone. These two indexes are water quality and number of attached organism there. From the results, it is found that HSI value is closely related to fish catches based on statistical data. This means that the method is available for assessing the effect of environmental change on the resources of fisheries in the intertidal zone.

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  Semidiurnal tides are important factor to vertical mixing, substance transportin and exchange of sea water in semi-enclosed bay. The present work is intended to declare the variation of M₂ and S₂ tidal amplification the inner part and the outer part of Ariake Bay, Ise Bay and Tokyo Bay by using the harmonic analytical tidal data. As a result of this research, it becomes clear that i)a negative Kendall's rank correlation not only the M₂ tidal amplification and the M₂ tidal amplitude at the outer sea, but also between the S₂ tidal amplification and the M₂ tidal amplitude is found in Ariake Bay and Tokyo Bay., ii)the M₂ tidal amplitude in 2000s was the smallest value over the past 30 years.

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  In this study, to examine the topography change of natural beach in semi-closed water area, field observation on the sediment transport in the vicinity of shoreline by boat waves, image analysis of aerial photographs to grasp medium, long-term topographic change and numerical simulation on tidal current and wave were carried out. Study site is Omaehama Beach which is located in the closed-off section of Osaka bay, Nishinomiya City, Hyogo prefecture, JAPAN. In front of the water area of Omaehama Beach, most boats round trip along the coast line, the deviation of sediment transport to one side or the other wasn't observed and we couldn't find the distinguished shoreline change. On the other hand, in terms of medium, long-term topographic change, Omaehama beach remains unchanged due to near landfills which prevent offshore waves.

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  To evaluate impacts of oyster raft placement on tidal current and seawater exchange in Etajima Bay, northern part of Hiroshima Bay, we have developed a coastal circulation model incorporating the drag force of the oyster raft in Etajima Bay. We found that the number of oyster rafts in summer season is twice as large as that in winter season. In Etajima Bay, the seawater exchange is relatively large in the northwest part, whereas the term of the seawater exchange is about one year in the southern part. Moreover, we computed some scenarios which the oyster rafts are reduced at each zone, and then it could be desirable to reduce 40% of the total number of oyster rafts in order to make a plane for reducing organic matter load from the oyster culture.

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  To develop techniques for environment improvement and ecosystem restoration in closed sea area such as harbor, we covered waste oyster shells on the sea bottom with 1,000m² and 0.5m in depth and followed the progress for about one year. In/On the covered area, there were 64-94 macro benthos species, included useful animals such as sea cucumbers, baby octopuses and young dabs. That maximum biomass were 3,800 inds /m² and 1.14 kg w.w. /m², which were as 1.9 times in inds and 28.5 times in wet weight as the control area's respectively. Those may cause the muddiness decrease above the covered area with bio-deposition and physical re-cloud suppress. Therefore, it is obvious to cover waste shell can clean up the polluted sea bottom within a relative short period of time.

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  The blue tide (so-called Aoshio") is one of the most serious problems in the environment of the semi-enclosed inner bay. The objective of this study is to classify the ocean color under the non-Aoshio and the Aoshio conditions. To grasp the spectral reflectance properties of the Aoshio area and to assess quantitatively the ocean color under the Aoshio condition using CIE (Commission Internationale de l'Eclairage) chromaticity coordinates for remote sensing were tried each to achieve the objective. The spectral reflectance measurement under the non-Aoshio and the Aoshio conditions in the inner side of Tokyo Bay from September, 2010 to October (non-Aoshio: September 1, October 6; Aoshio: September 25) was carried out. As a result, a basic spectral reflectance properties (high reflectance in the wavelength range of 450 - 600 nm, a peak shift of the maximum reflectance from 570 nm to 550 nm or less, and a chromaticity coordinate (x:0.23-0.33, y:0.32-0.38) under the Aoshio condition became clear respectively.

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  Capillary barriers have been known and widely used in geoenvironmental engineering applications as soil cover for typical rainfall infiltration control systems. The capillary barrier is consisting of a fine-grained soil layer placed over a coarse-grained soil layer. The applications of capillary barriers are significantly useful to preventing infiltration into waste materials. Natural gravel or coarse-grained soil material had a exhaustion problems in practices. On the contrary, shells a kind of fishery byproduct, are classified as industrial waste in laws concerning waste disposal. The majority of shells are piled and left near the fishing port without controlling system. Therefore, it is proposed that the crushed shells are available to layer material instead of natural coarse-grained soil. This solution is considered to great contribute developing of recycle for fisher byproduct shells and is related to environment conservation. Water retention for crushed shells, however, never been fully investigate.
  This study focuses on the ability of crushed shells to capillary barrier applications. The soil-water characteristic curve for crushed shells with three different grain size distributions was determined using the modified SWCC testing apparatus. Also, it is observed using a conventional model equipment that the getting of fine sand into crushed shell layer is prevented.

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  We developed "Artificial Reef of Scallop Shell" using waste. The reef creates the biotope for the detritus feeders to the space between the shells and it is useful for the removal of organic pollutant in the port. For an attempt using the experimental small reefs,even if three years have passed since they were installed, the continuation of the effect was confirmed. Then, the process was reproduced by ecosystem model. To achieve a further effect, Large-scale reef shell was installed. However the amount of the swarming species has decreased, it is due to lack of water exchange in the central portion. Then, we developed "Practicable Artificial Reef of Scallop Shell" with pass hole. As a result, the species swarmed in the central portion, the effect was proven.

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  An applicability of steel making slag as material for construction of submerged sea reef was examined in the Seto Inland Sea. Coverage of macroalgae on the artificial sea reef was nearly 100% at 4 months after the construction, which was clearly higher than those of surrounding natural area (<10%). Observations at 11 months later the construction, both in quantity and species number of fish were significantly high at the experimental site compared to the surrounding area. Benthic animals were also rich in species number and quantity at the sea reef, in which some species can be appropriate as feed for fish. It was proven that the artificial sea reef made of steel making slag is promising equipment to provide habitat for fish not only hiding space but also feed for fish.

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  It is required to apply concrete with high volume slag fine aggregate without special quality improvement (HVSA concrete) to appropriate concrete structures from the viewpoint of benefiticial utilization of industrial by-products. This paper reports the mechanical properties and durability of HVSA concrete. As a result, the effect of bleeding on the mechanical properties of HVSA concrete was small when the bleeding content was less than 0.5cm³/cm². It was confirmed that the long-term durability of HVSA concrete was almost the same as normal concrete. The results implied that port concrete structures can be produced with HVSA concrete when the bleeding of HVSA concrete is less than 0.5cm³/cm².

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  Sand mastics are often used as impermeable materials for a waste repository. For the evaluation of the quality, compression and bending tests are carried out under a particular temperature and sheering-speed. However, in a previous study, it has been revealed that the strength characteristic of sand mastics is considerably dependent on the temperature or sheering-speed. In this study, triaxial compression tests for sand mastics were conducted in order to evaluate the strengths under various temperature or shearing-speed. From the test results, the internal friction angle was evaluated as almost zero. In addition, it was indicated that the cohesion became small with the increase of temperature or the decrease of shearing-speed. Namely, it is essential for the design to determine the strength of sand mastics according to the environmental conditions.

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  In order to maintain the depth of waterways and sea basins, huge amounts of soft clayey soil are dredged at many ports every year in Japan. In recent years, it has become more difficult to secure disposal areas for dredged soil due to environmental and economical restrictions. The effective use of the dredged soils is therefore required. Granular treated soil, which is dredged clay mixed with cement and polymer, has been developed as a countermeasure against this background and expected to be practical uses for reclamation. This paper reports an applicability of the granular treated soil to a reclamation material of artificial seashore. In this study, a centrifuge model test technique was applied for investigating the behaviour of the artificial seashore reclaimed by high permeable granular treated soil in waves. A centrifuge model test is used for simulating the ground behavior in a proto-type scale by small-sized ground model. The wave generated in centrifugal acceleration was similar to real wind wave.

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  The vacuum consolidation method, which uses vacuum pressure generated by vacuum pumps, has recently been drawing attention as a remarkable method of consolidation ground improvement. The method has the advantages to enable rapid construction of embankment avoiding shear failure of foundation, and bulk attenuation of clayey soil in disposal sites, etc. In this study, a new method is proposed to utilize vacuum pressure by the siphon effect in a water-filled vertical pipe for the vacuum consolidation method. Especially, gas-liquid two phase downflow is realized within a vertical drainpipe in the condition of intensive negative pressure that dissolved oxygen is evaporated. The effects of proposed method for ground improvement are verified by conducting laboratory and field experiments.

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  The anti-liquefaction ground improved by cement-mixing and permeable-grouting shows the spatial variability in soil properties such as shear modulus and liquefaction strength resulting from the spatial variability of soil profile in original ground, the non-uniformities of mixing and grouting, etc. It is expected that liquefaction resistance and nonlinear seismic response of anti-liquefaction ground are affected by the spatial variability, however, the liquefaction properties of anti-liquefaction ground with a large spatial variability in soil properties have not been fully clarified. In order to investigate effects of percent defective of ground improvement, a risk-based method was proposed to assess the liquefaction-induced damage against the anti-liquefaction ground.

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  Tokyo International Airport D Run-way Project is construction that newly establishes the fourth glide slope Tokyo International Airport(Haneda) offshore. D Run-way Project is constructed on the soft ground. It designed in expectation of a strength increase by consolidation. Therefore, it is necessary to understand the situation of the ground accurately. D Run-way Project, the strength management method by RI-CPT was adopted. In this text, the investigation management technique by RI-CPT is described. It is the one that considers the result of the examination. Tokyo International Airport D Run-way Project was completed by adopting this construction management method in a short term of the remainder of 41 months

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  The standard of impervious structure about disposal facilities was defined by the ministerial ordinance to provide for technical guidelines of disposal facilities in 1998. By this law, since new technologies of impervious sea wall have been required, we developed a new structure and material about impervious sea wall with clayey water interception material.
  On the impervious sea wall with clayey water interception material placed in real disposal facilities, this technical paper describes the performance of impervious sea wall, the characteristics of clayey water interception material and method of quality control.

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  In order to recycle dredged clay as an useful material efficiently, our research group has developed a technique called the cement-mixing and mechanical dehydration method (called "CMD"). In the CMD procedure, soft clay mixed with cement is dehydrated with a high dehydration pressure for the purpose of increasing strength. In this paper, large dredged soil blocks were created by a large dehydration apparatus (φ53.4cm×H100cm) in the CMD procedure, and the water content and unconfined compressive strength were measured in order to investigate the uniformity and strength property of the CMD blocks. The main conclusions obtained from this study are as follows: (1) Uniform and large-size blocks are able to be produced irrespective of cement content and soil type. (2) Since the unconfined compressive strength cured for 28 days, q_u28, exceeded 20MPa for more than cement content 40%, the high-strength blocks are able to be produced by controlling the cement content. (3) It is considered that there is close relationship between unconfined compressive strength and water-cement ratio.

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  The artificial fishing mound (AFM) is constructed in deepwater by dumping a large amount of rubble from hopper barge to expand the fishing ground by uplifting the eutrophied water with the upwelling current generated on the mound. In order to construct a designed geometry of AFM accurately and effectively, the operation management for the discharge position of barge, which is taken the transfer displacement of the falling rubble into consideration, is required. The slope-angle of mound calculated by author's previous simulation model on the deposition configuration of rubble dumped from barge was marginally steeper than field measurements. In this study, the simulation model is improved to estimate the slope-angle of mound in the field, the practical applicability of the management system on positioning of the barge with new simulation model is finally verified by the field experiments.

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  Sand capping is a technique to improve polluted sediment. Widely used methods of sand capping are throwing sand into water directly from work ship or pouring in sand through a Toremie pipe. Although these methods are considered handy to operate, there are three points to be improved: (1) turbidity, (2) irregularity of sand layer thickness, and (3) work efficiency. To improve these points, we have developed a new equipment of sand capping. After sand slurry is injected to the equipment, the velocity of sand particles decreases since the cross-section of the equipment gradually expands. When the sand particles fall, the horizontal and vertical velocities are nearly zero, so that turbidity is restrained. And all the opening mouth of the equipment where sand particles go out is covered with a sparse mesh. The mesh separates the current in the equipment from the outside, but it doesn't disturb the motion of water mass. It is confirmed through the experimental tests that this new equipment achieves nearly regular thin sand layer.

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  There are terrible problems that the organic sediments on the sea bed destroy the ecosystem all around the closed water. Generally, the two improving methods for the bottom sediments which target such the organic sediments are executed. The one is a dredging method which removes them outside, and the other is a capping sand method which covers the sea bed with the sand. This paper describes the sand deposition characteristics of thin sand capping when the sand was dumped by either a backhoe or a grab bucket into shallow water, because the construction demands the sand piled up as thinly and uniformly as possible. They were clarified through the field research at our construction site. Finally, the average layer thicknesses were almost equal to the planned layer thicknesses in any case of the dumping either the dredged sand or the pit sand. The coefficient of variation of the layer thickness became larger as the planned layer thickness decreased. Thus in the thin sand capping, it found that we have to set more surcharge for the quantity of sands, because the error of layer thickness would grow.

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  Ariake Bay and Yatsushiro Bay, a typical closed bay on the west of the Kyushu Island, is a sea area where a vast tidal flat develops. Recently, various environmental degradations are reported occur in Ariake Bay and Yatsushiro Bay, as red tidal and anoxic water. Especially, a rapid decrease in the short-necked clam's fish catch is a problem since the latter half of the 1980's. The natural sand is insufficient, even though the sand overlying is done as a rehabilitation technology.
  In this study, we tried the bioassay for short-necked clam's that used the recycled fine aggregate by pulse power aim at application of the sand overlying material. As the result, the possibility that the recycled fine aggregate by pulse power was able to be applied to the sand overlying material was suggested.

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  Environmental assessment on three types of tidal flats located in Tokyo Inner Bay using Water Environment Soundness Index (WESI) was investigated. Sanbanze (the foreshore flat tide), Banzu Tidal Flat (the river mouse flat tide), and Yatsu Tidal Flat (lagoon flat tide) where show different forms one another, were assessed in this study. As results, Sanbanze and Banzu Tidal Flat indicated almost same pentagon graphic form, but Yatsu Tidal Flat was different from them. This outcome was considered as the difference between natural tidal flat as Sanbanze and Banzu Tidal Flat and artificial tidal flat as Yatsu Tidal Flat. Furthermore, the WESI which was developed as a tool for assessment of river environment, should be rearranged to apply to tidal flat assessment.

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  Long term observation for the suspended sediment transport in the inner part of the Ariake Bay, Japan. Acoustic Doppler Current Profiler were used to estimate the vertical distribution of the suspended particle matter. Also, the suspended sediment flux for the two observation station were calculated. The result of the observation shows that the suspended sediment was come from the offshore and accumulated to the tidal flat of the Ariake Bay. In the season of the laver cultivation, suspended sediment from offshore was accumulated in the field of the cultivation. After the season of the laver cultivation, suspended sediment was moved again to the tidal flat. Bottom mud density and shear strength was matched with the suspended sediment budget in the observed field.

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  Recently, the benthos habitat of the tidal flat has been lost by the reclamation for the land reclamation in the farmland and the factory construction at the high economic growth period, etc. in Ariake Bay. Then, the benthos that becomes the index of the reproduction because the survey data is scarce has not been established in the tidal flat region in Ariake Bay though the local proof examination to aim at the spontaneous regeneration in the beach of recovering the place where biodiversity is high is done. Then, it searched for the native habitat of an important kind and a noteworthy kind of the red data book description kind etc. that were able to become indices by the spontaneous regeneration from geographical features, the bottom sediment in the tidal flat region in Ariake Bay, and the benthos investigation result, and making to the index to judge nourishment and sewage was tried in the present study.

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  The objective of this study is to elucidate distribution characteristics and population dynamics of the gastropods, Cerithidea cingulata in Katsuura tidalflat of river mouth, Tokushima Prefecture of the Shikoku Island. C. cingulata is one of the endangered species, but dominant one in this muddy tidal flat.
  It was quantified sediment characteristic of C. cingulata, focused on physical characteristics of sediments such as particle size and difference in elevation. We conducted population investigation in every month for 6 years. It is found that there are two or three cohorts at least and C. cingulata has grown in summer. It was recognized the most highest population density was 246 individuals/m². P/B ratio have fluctuated 0.37 ~ 1.26 in each year. P/B ratio of C. cingulata is smaller than other gastropods. It was need to consider carefully analysis function of ecosystem in tidal flats using P/B ratio.

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  As nutrients fluxes of the tidal flat in the Tokyo Port Wild Bird Park, it is reported that the Nitrogen is consumed of the tidal flat. In order to know the mechanism of nutrient cycles, we carried out the estimations of denitrification and anammox rates of the flat by using revised Isotope Paring Technique(r-IPT) method in June, August and December, 2010. As results of the study, the denitrification rate is 112 to 935 μmol N/m²/h. And the anammox rate is about one-third to half of the denitrification rate. It is thought that the main cause of Nitrogen consumption of the flat is the denitrificatiopn and the anammox.

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  To solve the various environmental degradations cased by sediment deterioration, it was devised the sediment improved technique by using "Artificial nest hole", and then a field experiment had been performed since 2006 in Ariake Bay. a field experiment has been performed by using the new artificial nest hole which improved problems like a deposition of floating mud in the artificial nest hole since 2009.The experiment shows that the new artificial nest hole has the sediment purification effect by the penetration. In addition, seepage analysis performed to evaluate the extent of the impact of sediment purification effect, and considered practicability of "Artificial nest hole".

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  The organic sediment moves with water flowing in estuary. It is carried to the river with flood tide, and settles on the riverbed at a tidal flat. If the purification ability of the organic sediment is small, the sludging of the tidal flat is accelerated. The organic sediment settled there causes the environment deterioration and loss of waterside scene value.
  The environmental quality improvement technology using waste recycling products is proposed. The large pore drain is embedded in the consolidated sediment. It can cause the water movement in the drain with the ebb and flood tide, and the water movement raises living thing habitation environment by supplying oxygen into consolidated sediment.

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  A prototype model experiment was conducted to verify the effectiveness of covering the seabed with fly ash beans to improve the environment in marine areas contaminated by organic sludge buildup. The site of the experiment was Kaita Bay, located in the innermost region of the Hiroshima Bay in Japan. Three different thicknesses of the covering layer were tried in three separate areas. Over approximately six months, the site was monitored, and the degree of improvement is assessed based on monitoring data. Data was gathered on water quality, sediment, interstitial space of beans, and benthos.
  It was found that fly ash beans contributes positively to the improvement of the marine environment, as it is effective at suppressing suspended mud. This material is a likely contributor to sludge breakdown, and alters the environment in a manner favorable to habitation of benthos by decreasing hydrogen sulfide ntration and otherwise improving water quality.

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  It has been verified that covering method using granulated coal ash plays important roles in reducing and preventing the elution of eutrophic elements such as phosphorous, nitrogen and sulfide compounds from sea bottom sediment into sea water in the head of Hiroshima Bay. In this study, a new model is developed for simulating the improvement effects of sediment in granulated coal ash-layer. Parameters used in the model, for example, the trapped amount of sediment in the pores of granulated coal ash- layer, the reduction of sediment volume, etc., are determined by field observations and laboratory experiments. The simulated results are evaluated on the basis of the observed data, and it was found that the relation between the simulated results and the observed results show the another phenomena occurring in the layer.

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  In order to be turned into actual utilization of the coastal environment technique that a muddy sea bed covered with fly ash beans, we evaluated the buried depth of the fly ash beans that generated at the construction in Kaita bay.
The buried depth of fly ash beans occurred 3cm to 7cm. The covering thickness was not contributed to the buried depth. At the construction, fly beans dropped to sea bed 7cm at first, after that requisite amount of fly ash beans was dropped. It demonstrated that intrusion to the sediment fly ash beans occur first layer, but the intrusion does not occur above on the second layer.
The buried depth of fly ash beans correlated to the surface water content, and water content of the buried depth sediment was 144% to 242%. It indicated water content of surface sediment and vertical profile can use predicted buried depth. Additionally we developed simple equipment for predicted the buried depth. It can predict the buried depth by drop the weight sediment core sample and measure the instruction depth of weight.

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  At 3:34 local time on February 27, 2010, a large earthquake of magnitude Mw 8.8 generated tsunami that caused heavy damage to the coastal area of Chile. This paper aims to clarify the characteristics of this tsunami disaster by analyzing the field survey data as well as the effects of bathymetry on tsunami behavior. Tsunami inundation height was 4-10 m in a wide area of Chilean coast and the maximum run-up height was over 20 m. The reflection at the edge of a continental shelf caused several waves to attack the coast. Due to the large earthquake, residents were able to feel the danger of tsunami. The knowledge about tsunami has spread throughout residents living in coastal area, following the 1960 Chile Tsunami and the 2004 Indian Ocean Tsunami. The caution by earthquake and the widespread knowledge about tsunami reduced victims in Chile.

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  The present study aims to estimate the tsunami source of 2010 Chilean Tsunami by the tsunami waveform inversion. The tsunami profiles observed at GPS Buoys, DART Buoys, and the tidal stations along Chilean coast are inputted into the inversion method. The main results of the tsunami waveform inversion are described as follows: 1) The numerical simulation results based on the tsunami sources estimated by the seismic waveform inversion show that the calculated tsunamis arrive at GPS Buoys, DART Buoys, and the tidal stations at the north of the epicenter earlier than the observed tsunami. On the contrary, the calculated tsunamis arrive at the tidal stations at the south of the epicenter later. 2) The tsunami source estimated by the tsunami waveform inversion is located closer to the South American continent and expanded more southward than that by the seismic waveform inversion. The numerical simulation results based on the tsunami source estimated by the tsunami waveform inversion show good agreements with the observed tsunami profiles.

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  A massive earthquake which occurred in Chile on February 27^th, 2010 caused Shizuoka to issue a major tsunami warning throughout the prefecture expecting waves as high as 3 meters. A questionnaire survey was conducted to find about countermeasures against the major tsunami warning fishermen in Shizuoka took, judgments and attitudes toward the warning. The results of the survey should be taken into account in making future countermeasures against tsunami for fishermen and ports.
  According to the survey, there are some different attitudes among fishermen living in different areas of Shizuoka prefecture, which stretches east and west, including the Izu Peninsula. Older fishermen are more cautious about tsunami and rely more on tsunami warnings. This can be explained by the fact that they have strong memories of past catastrophes. The results suggest the need of passing the memories on to younger generations.

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  The counter measures for preventing tsunami disaster have been targeted to the local inhabitants, therefore the effect of mitigating disaster in the seaside resorts where many tourists visit is not adequate. For early evacuation from tsunami disaster, it is essential that beachgoers have consciousness and knowledge of tsunami. In this study, the questionnaire surveys concerning on the beachgoer's awareness of tsunami disaster were conducted in five seaside resorts where the raid of gigantic tsunami was expected when the Tonankai and Nankai earthquake would be happened near future. As a result, it is found that the disaster prevention education and the counter measures influence in the awareness of tsunami disaster, and that the experience of Hanshin-Awaji Earthquake improves the awareness though it is not tsunami damage.

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  A set of wave equations derived on the basis of a variational principle in consideration of both strong nonlinearity and strong dispersion of surface/internal waves is numerically solved through a finite difference method to simulate generation and propagation of tsunamis in the vertical two-dimension. The velocity potential in each fluid layer is expanded into a power series of vertical position z, such that the accuracy of vertical distribution of velocity depends on the number of expansion terms, N. The tsunami generation in the existing experiment is successfully represented using the numerical model when N = 2 or 3. Shorter oscillation in a tsunami tail cannot be expressed in tsunami generation using the set of nonlinear shallow-water equations, where N = 1, as well as a long wave group, which consists of many waves especially in distant-tsunami propagation, leading to overestimation of both the wave height and wave steepness of the first wave. The wave height becomes larger in a stratified ocean than that in the one-layer case, although the present density distribution hardly affects the tsunami phase even after a travel of a long distance.

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  Local scouring around inland structures was observed in field surveys of the 2004 Indian Ocean tsunami and the 2010 Chilean tsunami. Although the mechanism of such local scouring has been elucidated for seawalls and fixed cylinders, local scouring around a movable structure remains to be investigated. In this study, local scouring around a movable cubic structure due to tsunami run-up and subsequent drawdown is investigated using hydraulic experiments. It is found that a scour hole is formed around a seaward edge of the structure regardless of the presence or absence of the drawdown, and the non-dimensional maximum depth of the scour hole relates with the non-dimensional overflow height of an incident tsunami and the non-dimensional embedded depth of the structure. The result suggests that the non-dimensional maximum scour depth around a seaward edge of a movable cubic structure can be predicted from the non-dimensional overflow height and the non-dimensional embedded depth of the structure.

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  Houses placed near coasts of plains are exposed to tsunamis which run up onto the ground. In order to reduce tsunami damage, it is one of practical ideas to make the first floor's walls broken and remaining pillars of houses withstood tsunami attack, so that main properties can be protected on the second floor.
  The impulses of impact forces by driftage on solitary waves are measured and translated into the added masses of driftage. Although the impulse and added mass varies as the phase of crash changes, the impulse becomes the maximum when crash occurs near the wave crest and, there, added mass coefficient is about 1.0. Then, if crashing velocity of driftage can be estimated somehow, would be given the maximum impales of the impact which must be used as the input force for structural calculations.

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  The drag forces acting on the circular cylinders, the model trees and real small trees were measured by using load cell. Drag coefficients decrease with increase of Reynolds number because projected frontal area of tree canopy in still flow decreases with increase of incident flow velocity. The influence of Keulegan-Carpenter number and Froude number to the drag coefficients were also measured. The flow energy damping capacity of trees as a coastal protection from surge flow were evaluated by using drag coefficients of trees and incident flow velocities. The elevation of water depth in trees are estimated by using drag coefficients of trees and flow velocity in trees.

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  Coastal forests have received much attention for their concurrent benefits for environment and tsunami disaster protection. This study has surveyed coastal forests in Japan from viewpoints of tsunami barrier functions.Using detailed land maps and satellite images,their topographic properties,such as altitude,distance from the shoreline, growth areas,etc.are investigated. Next, for each area of the selected coastal forests, the expected tsunami run-up heights which were published by the central and local governments are surveyed. Based on both aspects of the land altitude properties and tsunami vulnerabilities, assessments on the expected tsunami reduction ability of the coastal forests have been performed.

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  Generating of damage to the house by flood damage and tsunami wave force or the structure, an outflow, human damage, and so on were expected by massive earthquake tsunami. Moreover, when tsunami occurs, it is indicated that the collision damage caused by flotsam, such as a vessels and a cars, and so on. We inquired to predict the flotsam damage for Kesennuma-city, Miyagi by using the analysis in consideration on un-deciding of the action of flotsam.
  Through analyzing the flotsam by this issue, we proposed the probable valuation method about destruction of the structure by flotsam.

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  Tsunamis caused by large-scale earthquake are considered imminent in Japan,and damage to port and harbor by tsunami is possible. Ships at port and harbor may be damaged,and ships may turn into tsunami debris.
  This paper describes the countermeasure against tsunamis at port and harbor about ships. In the past,ships ware damaged by tsunami several times. Countermeasures against tsunamis could be considered by analyzing literatures about ship damage. And the investment of countermeasure requests a large amount of money, the study of scale is needed. This paper describes about this matter.
  This study is useful for making countermeasure against tsunamis about ships, and this study shows the future works of the port authority and many researchers.

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