The authors propose a new configuration of columns, which is called irregular configuration. The presented configuration is considered to reduce the amount of subsoil that passes through the in-between gap of columns, compared with the square configuration. This paper discusses the optimal configuration of cement-treated soil columns for the purpose of reducing the amount of lateral flow by using three-dimensional fluid analyses and centrifugal model tests. As a result of the three-dimensional analyses and the centrifugal model tests, it was found that cement-treated soil columns reduce the amount of lateral flow. It was also verified that irregular configuration is effective to reduce it better than square configuration.

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 The vacuum consolidation method is one of volume reduction methods for dredged clay ground in disposal ponds. In this paper, the design of vacuum consolidation and monitoring results of reclaimed ground with dredged clay are reported. The determination method for ground model based on the reclamation analysis is proposed. The stopping time of vacuum loading is also evaluated by the comparison with the results of Barron's Equation.

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 The present study investigated the processes of liquefaction of sandy ground under combined earthquake motions involving main shock, calm period and after shock. The experimental results demonstrate three distinct liquefaction mechanisms associated with the upward and downward progress of liquefied zones and the decrease of lateral stresses. A numerical framework considering the propagation and dissipation of excess pore pressures has been constructed and verified aginst the experimental results. The stability of the improved ground to the combined earthquake motions and under elapsed time has also been examined. The results obtained may effectively contribute to the evaluation, prediction and countermeasures of the liquefaction risk under combined earthquake motions.

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 The present study investigated and elucidated the liquefaction characteristics of sand-clay layered ground under combined earthquake motions by performing a series of shaking table tests. The design concept for sand compaction pile as liquefaction countermeasures was also re-evaluated, and it is shown that the influences of both increase in relative densities and lateral stresses due to the compaction can be assessed uniquely by the relationship between the N-value and the liquefaction resistance. On the basis of these results, the application of the SCP to the sand-clay layered ground is found to work effectively in light of the three distinct mechanisms involving densification, stress enhancement, and partial drainage through the sand pile penetrating the clay layer. These findings are important for the rational liquefaction assessment and its countermeasures of sand-clay layered ground.

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 The present study investigated the dynamic characteristics of rock debris by performing a comprehensive set of large simple shear tests with various rock debris. The results demonstrate that the volume contraction characteristics of rock debris subjected to cyclic shearing depends on its density, confining stress, and cyclic shear stress ratio applied. The wet density and void state of the rock debris ground were also confirmed when deposited in water by direct pouring. On the basis of the test results and their analysis, we presented a chart which can be used for assessment and prediction of the residual volumetric strain and settlement of rock debris ground under future earthquakes.

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 Shake table tests of a large model in 1g gravitational field were conducted to confirm performance of subsidence countermeasures for breakwaters based on the replaced sand layer during a trench type earthquake motion. As countermeasures for existing breakwaters, sheet pile method and solidification method which do not improve the relaced sand layer just under the caisson were adoped. Forthermore placing rubble on the back of the caisson as the scouring protection for tsunami was adapted. It is difficult for all countermeasures to prevent subsicence completely as a result of the shake table tests because all countermeasures do not improve the replaced sand layer under the foundation. However, even if placing rubble on the back of the caisson, delay of the time when excess pore water pressure rises and shortening of the period by the increase of liquefaction resistance by the increase of effective overburden pressure showed that the amount of subsidence could be reduced compared with the case without countermeasure.

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 Enormous damage occurred to infrastructures such as tide embankments in Tarou, Miyako City, due to the 2011 off the Pacific coast of Tohoku Earthquake (M_W9.0). To evaluate the performance of structures before the attack of tsunami, it is necessary to estimate strong motions in Tarou Area with sufficient accuracy, taking into account site effects. In this study, seismic waveforms along the tide embankments were estimated based on a SPGA model considering empirical site amplification and phase effects. The estimated seismic waveform will be useful in the detailed study of seismic performance of the tide embankments before the attack of tsunami.

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 Waves, currents, and winds are important factors for safe and economic ship navigation, especially in coastal areas where ship density is relatively higher and the topography is more complicated. In this research, the eastern Seto Inland Sea, also known as the Harima Nada area, was selected for conducting numerical ship navigation. Ship traffic information was given from AIS, and WRF, SWAN, and POM models were used to produce numerical simulations of wind, waves, and currents, respectively.
 The high-resolution weather and ocean information was then used to conduct numerical ship navigation. To verify their accuracy, results simulating the weather and ocean were compared with actual observation data. The findings showed that the estimation of a ship's position using the proposed numerical navigation simulation method was effective in helping a ship navigate safely and economically.

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 Because of the high speed development of the world economy in recent years, the rapid increase of transportations led to maritime accidents frequently. For safety and efficient maritime transport, it is necessary to grasp the actual condition of ships. we are here concerned with the ship's waiting activities in offshore, which activities have a bearing on ship entering and departing port. However the observation of waiting ships is too difficult to be obtained the data in long time, the actual situation of ship's wating activity has been never studied so far.
 Based on this background, this study grasps the actual situation of ship by using Automatic Identification System (AIS) data and analyzes the congestion n area on Osaka Bay.

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 In the major bays vessels might harborage in congested waters under stomy weather. Moreover in the current technical standard for port planning, an equation to estimate the necessary size of water for harborage is missing. In this styudy, the actual behavior of harborage in the major bays is captured and analyzed by AIS and the relevance of the said equation is examined, and utilization of the equation for the estimation of water area is discussed further in order to secure safer use of such bay waters.

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 About planning of fairway, in the case that the design ship and navigation environment is designated, class 2 verification method can be used. But, for the public fairway, the design ship can not be designated to the specific ship.
 Against this background, this study evaluated the fluctuating range of required fairway width based on the difference of maneuverability in the same type and class ships, with the aim of progress of applicability of class 2 verification method to public fairway. As a result, under 75% cumulative probability, safety margin to fluctuating by ship maneuverabilities was evaluated as 3% for one-way and 6% for two-way fairway.

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 In this research, the portable remote monitoring system for navigational support of ship was constructed for the purpose of preservation of the safety of marine traffic. This system can provide useful information also to the ship operator of a different operating situation. Furthermore, although this system consists of low-cost equipments, it is very functional. Moreover, installation and use of apparatus are very easy. In order to verify the usefulness of this built system, the ship operator with an insufficient navigation experience conducted the experiment which uses a proposal system, and the ship operator with abundant navigation experience conducted the experiment which uses this system in the first ocean space to cruise. The validity of the proposal system was confirmed by each from those experimental results.

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 When the tsunami attacks in harbors, the vessels moored at the wharf may be unable to be evacuated. In such a case, damages such as, breaking the mooring tethers, grounding on a wharf, drift to land areas and the collision with buildings are assumed. And, after suffering a disaster, the base for supporting medical treatment and a life is necessary to disaster victims.
 In this research, the floating tsunami protection wharf (FTPW) is proposed. This present paper describes the tsunami simulation and the motion analysis of vessel moored at the FTPW using the MPS Method. In this research, the 3D-MPS method is applied. The applicability of the FTPW was examined. Moreover, the feasibility of the disaster victim support base on the FTPW deck was examined.

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 Tsunami disasters of floating vessels moored on the quay are complex, such as breaking of the mooring line and then drifting and collision of floating vessel. There was an example in which a mooring tether does not break in the ship moored to the floating pier in the damage of tsunami. It was confirmed in the Miyagi Shiogama port in case of the East Japan great earthquake which occurred on March 11, 2011. In this paper, the objectives are to clarify the effect of reducing mooring tether force in case of that ship is moored to floating pier by using 3D-MPS method and also the advantages of floating pier for fixed mooring quay.
 In addition, in this paper the authors discussed the following items: 1) Response characteristics due to the difference in the Wave elevation in Tsunami. 2) Response characteristics in various incidence angles.

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 This research aims to elucidate the navigational situation of ships during the massive tsunami that occurred in the Tohoku district of Japan on 11 March, 2011. In particular, it focuses on the time the massive tsunami encountered ships. AIS, which is required to be fitted aboard large ships for identifying and locating vessels, was used for the analysis of the navigational status of ships. It was confirmed that a group of ships sailing off the coast suddenly changed course. It was also verified that the ships had been struck by the tsunami, and the time of the strike was identified. The novelty and importance of this research are as follows. First, the behaviour of many ships that encountered the massive tsunami was clarified. There are no earlier instances of simultaneous and detailed recording of the behaviour of many ships encountering a massive tsunami. Second, the movement of the ships that encountered the tsunami was analysed, and the time of the maximum wave of the tsunami was verified. The research presents, for the first time in ship history, the status of a ship at the time of a tsunami using objective navigational data.

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 The port function became a completely paralyzed situation temporarily at the Great East Japan Earthquake, since in addition to the damage caused by the earthquake, the cargo, rubble, etc. flowed in large quantities in port and blockaded the traffic route and basin.
 It may happen that the function of the metropolitan will be paralyzed if the massive tsunami of the Great East Japan Earthquake class attacks to Tokyo Bay, early sweeping of traffic route obstacles for performing emergency aid cargo shipment is indispensable.In this paper, we considered to the practicality of 4D sonar system which can survey the form, the size, the coordinates, etc. of a submarine obstacle at an early stage, and report having evaluated the validity of 4D sonar system as the technology of sweeping for traffic route obstacles.

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 In Osaka bay area, several railroads have been built along coastline. The facilities of railroad companies such as elevated structure and railroad embankments are useful against tsunami disaster. In this study, to grasp the present conditions of railroad facilities in Osaka bay area, the availability of those facility against tsunami disaster by earthquake in the Nankai Trough was examined. Moreover, the countermeasures against tsunami disaster by railroad companies was clarified.

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 Beach sand were collected in selected 27 beaches in the Biwa Lake shore and in 14 rivers which flow into the Lake, to examine supply sources of the beach sand. Sand colors were analyzed using the simple color analyzing method proposed in our preceding papers. Rrelationships between the sand colors and geological stratums around the lake were investigated and it is comfirmed that sand colors of the beaches were obviously depend on the geological stratums. Color relationships between the beach sand and the river sand were examined using a simple optimization analysis.

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 An approach to facilitate environmental and technical communication in local community for environmental problem solutions was discussed. A comprehensible methodology for understanding bottom mud improvement was introduced by applying an index sheet on the structural and physical elements of biotopes based on the works of Sugiyama(1995). After setting up three type instruments by combining different elements, field surveys were executed at Kikuta river and Edo river floodway in Chiba prefecture. Stability of replaced bottom material and upper water supply into bottom material were investigated. As a result, the introduced methodology helped benefitical and better understanding of various phenomena by bottom mud improvement.

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 In this study, the thoughts of fishermen about the physical environment of the Ariake Sea were summarized using the results of a hearing survey in 2006, and these were compared with the latest scientific findings to determine the amount of correlation between the fishermen's reports and the latest scientific findings. Due to the fact that the period after the Isahaya reclamation works were completed occurred during the peak of the ascending node motion of the moon, and that a rise in the sea level at the scale of the Pacific Ocean occurred in the same period, these changes were easily mistaken to be the effect of completion of the Isahaya reclamation works. Therefore, many things can be explained scientifically by rephrasing "the effect of closing" in the verbal survey with "the period of closing."

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 Matsukawaura inlet in Fukushima Prefecture, Japan is located north side of Sendai Bay. Freshwater discharge including underwater flow into Matsukawaura inlet is estimated by a water budget method. The river flow is estimated as much as 1.1×10⁸ m³ /yr. On the other hand, the groundwater flow is estimated as much as 8.2×10⁶ m³ /yr. The river discharge and groundwater discharge into Matsukawaura inlet are estimated as 93.1 % and 6.9 %, respectively. The subaerial topography around an entrance is characterized by a flood tidal shoal and a connected channel, but not an ebb tidal shoal. Three dimensional water velocity distributions at an ebb tide are measured. Horizontal velocity distributions in surface layer and bottom layer were similar and the highest velocity was approximately 1.0 m/s during the field study. In addition, Chlorophyll-a concentration was ranged from 0.1to 9.9 μg/ℓ, and mean value was 3.6 μg/ℓ.

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 Coastal vegetation establishment on new beach formed by dike set back from the shorelines was investigated by field observations on the Isewan-Seinan Coast for 4.5 years. It was observed that during the first 3 months, non-coastal plants appeared and rapidly spread out to cover almost the entire beach surface. Subsequently, coastal plants invaded the area and gradually increased their expanse. This shift in the nature of vegetation was observed to be more rapid in areas that experienced active wave run-up than in areas that were relatively shielded from waves. Estimates of the wave run-up experienced during the study period revealed that the wave wash disturbances were effectively promoting the establishment of coastal vegetation.

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 To elucidate the influence of optical attenuation on the primary production, field observation of light photon and water quality were conducted in the Mukawa coast, the Pacific Ocean of northern Japan. During the flood event, the primary production was limited by scattering of light by suspended sediment. Attenuation of light by suspended sediment was large in the coastal, but the chlorophyll-a was large offshore. The extinction coefficient is decided with the suspended sediment in the coast, and decided with the chlorophyll-a offshore. Therefore, we propose a model of extinction coefficient to apply between the coast and offshore. The results of this study, it is considered to become a knowledge effective for prediction and analysis in the low-order ecosystem model and primary production of coastal areas. In addition, it will contribute to understand the habitat of Japanese surf clam (Pseudocardium sachalinensis) of Mukawa coast.

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 The regional peculiarity and environmental condition of eelgrass growth in the Yatsushiro Ocean were examined. During the observation, it was a decline period from the golden age of eelgrass. The result of geographical feature investigation showed that the average slope of a turtle grass place was 1/100 or less. Growing the altitude TP in -3〜-2m was checked. Moreover, as compared with the past result of research, growth at 28°C or more was checked for the mud content of 40% or more in the average water August.

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 As one of the barren ground measures, seaweed bed recovery by the sea urchin eliminating is executed in various places.
 However, in the sea area where the feeding environment is bad, the gonad index of the sea urchin is low and there is no commercial value.
 In parallel with the measures of sea urchin's feeding damage against seaweed plumule, the feeding supply of the sea urchin becomes a problem.
 In this study, the examination of seaweed promoting method and feeding system to seaweed-eating animals are introduced. The seaweed cultivation ropes by biodegradable material was established. It keeps strength for seaweed plumule period, and seaweed grows up. It is deteriorated, it falls with seaweed, and food is supplied to the sea urchin. And the degradation characteristic of this rope is clarified.

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 In recent years, when ports, fishing harbours and coastal structures are constructed, it is desirable to consider the natural environment. There is a hope that seaweed will attach onto wave dissipating blocks or armor blocks, but conventional blocks do not have a shape condensive. In response to this, we have developed new wave dissipation blocks and armor blocks. These have shapes which accommodate ecofriendliness. Stability and hydraulic functions are equal to or greater than conventional blocks. Field observations were carried out to verify the eco-friendly functions of these blocks. In all the observations, large seaweed growths such as Ecklonia cava or Eisenia bicyclis were observed. Furthermore, the abalone or the tutban shells congregations were observed. Eco-friendliness of these newly designed blocks was verified.

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 The Japanese government launched the construction of artificial nursery reefs to increase resources of snow crab and flathead flounder in Japan's Exclusive Economic Zone of the western part(off the coast of Hyogo Prefecture - Shimane Prefecture) of Japan Sea in FY2007, and completed 9 sites out of 21 planned sites at the end of FY2012.
 We conducted field survey and analysis of the existing data regarding catches of target speices to clarify the project effect of artificial nursery reefs. As a result of this study, we mainly found the following.
 - Inbabiting situation in a protected area protected by artificial nursery reefs can be clarified by small trawl net and basket trap.
 - Habitat density of protected areas is higher than that of control areas.
 - Sea areas surrounding protected areas are good fishing grounds judging by high CPUE.

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 To clarify water quality improvement function and its change factor in pro-environmental seawall, we investigated artificial tidal flat that made on pro-environmental seawall in Tokyo Bay. The artificial tidal flat was composed from three-different ground level bench at the front of seawall. Population dynamics of R. philippinarum suggested adult population disappearance occurred in the late summer to early autumn, because of the hypoxia was developed in Tokyo Bay. Therefore, amount of particulate nitrogen filtration and nitrogen fixation by the R. philippinarum was reduced, and R. philippinarum become a source of nutrients in these seasons. Hypoxia gave a serious damage for the water quality improvement function of pro-environmental seawall, therefore hypoxia provision was important for maintenance of function on pro-environmental seawall.

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 The Enhalus acrides, distribute around the iriomote islands . Distribution and the growth situation of E.a. were investigated over the coastline of 45Km on northwest part of the iriomote island. The distribution of E.a. was compared with wave and tidal resodial carrents by simulation , and past distribution from past aerophotograph in 1974 . E.a. was found to 0-0.5m in depth, where the wave from the open sea was interrupted. Dence colonies were found only 14% of area, where E.a. was found . The distribution of E.a. has decreased to 62% in 39years. E.a. was found in 47% of the coast, and high density area of E.a. was only 14% within the range.

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 This study aims at evaluation of a seed dispersal of Enhalus acoroides in Amitori Bay, Iriomote Island, Japan from the perspective of numerical analysis. An ecological investigation of Enhalus acoroides was conducted to provide input data for a numerical model. Reproduction of coastal currents in Amitori Bay was done using an ocean current model CCM. Characteristics of the seed dispersal of Enhalus acoroides were examined using particle tracking analysis. Results showed that the average value of migration distance of seeds was 266 m per 3 hours. It means that the seed dispersal of Enhalus acoroides is very weak.

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 We studied the comparison between the floating larval behavior of Manila clam with the difference of the season in Hakata Bay by using numerical simulation. As a result, we appreciated the following. (1) The characteristics of the distribution and the characteristic of the floating larvae transferred in the bay were different by the flow around the spawning field and the surface seawater flow with the flood. In addition, many floating larvae were flown to outside of the bay at the time of flood compared with normal stage of water, and the larval numbers supplied to each habitation field were decreased. (2) The Manila clam quantity of natural resources was changed by the growth and survival of larvae, which were born in spring and fall with a few floods, after the settlement on the sea bottom. (3) The natural resources and the number of larvae which supplied to the western area of the Bay could be increased by keeping the habitation field located in the central area in good condition and increasing quantity.

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 Cylindrical mesh substrata filled with waste shells have been demonstrated to promote suitable habitat of diverse small marine animals in recent studies. In this work, we divided these animals into two groups, prey and purifier (suspended feeder), throughout 31 water area data across this country, and estimated shell substrata value with different techniques, respectively. Those are, the former, to calculate amount of circulated carbon through food chain, and the latter, to quantify TOC remove from marine water with filter-feeding. As a result, organic carbon was estimated to remove 10 to 30 kg·m-3·yr-1, and if to convert in COD, equivalent to 65 to 79 m2 tideland, and sewage treatment for 1.2 to 1.7 human unit. For expected economical worth 56, 000 to 76, 000 yen, could develop the technology to help coastal material cycle.

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 The authors found that an employment of crushed scallop shells in the lower layer instead of gravel greatly helps to reduce the transport of the finer particles in the upper layer into the lower layer, and to provide an effective function of capillary barriers. In this study, the diversion lengths are measured in the field experiments using crushed shells instead of gravel in the lower layer, and compared it with the diversion lengths of the inclined capillary barrier having cover soil. As the result, the authors make clearly the diversion length of the inclined capillary barrier having cover soil.

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 Excessive nutrients were recovered from the waters of Amagasaki Port, Osaka Bay, and utilized as a compost material in order to improve the sea environment and resolve regional issues. In this project, the land-sea nutrient cycle in an area along the Amagasaki coast was evaluated, and the necessary amount of sessile organisms to be obtained from the area's vertical sea wall to get curative clarifying properties was determined. It was found that the experiences with nature that the project afforded heightened the environmental consciousness of the project participants. The participant's' awareness of Amagasaki Port changed: though they had previously believed that Amagasaki Port was dirty, dangerous and an area that was off-limits, by the end of the project, the participants felt that although it was dirty, it was enjoyable and was a part of the coast near their own homes. People with divergent interests in topics such as environment conservation, greening, renewable energy, natural experiences, and school education, participated in this project because of its wide-ranging contents and ability to accommodate the participants diverse interests.

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 For the purpose of sludge purification of Kyobashi River Bank, the tidal flat environmental remediational examination has conducted by using granulated coal ash(GCA). For spraying work of the GCA by heavy equipment in tidal flats which sludge deposited, temporary work floor from land area has required.
 Therefore, we developed a temporary structure construction techniques using GCA.This construction technique has the unnecessary withdrawal after construction. And, as well as contribute to sediment improvement, it is possible to make the promenade, etc. By using the construction technique, we built the temporary structure for spraying the GCA.And we constructed infilation channel and permeable layer by GCA on thickness of 0.5m. After that, it was assumed that the environment of the tidal flats changes. In addition, we evaluated the construction techinique by monitoring investigation.

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 Deposition rate of sludge on the riverbank of the Kyobashi river (a branch river of the Ota river) is about 1 cm per year, leading to the large amounts of sludge on the riverbank which exacerbate both substratum and water environments of the river. To date, we have proposed some methods using granulated coal ash (GCA), which is alkaline granulated material (AGM) for recovering the environments. Here, we aim at evaluating organic properties of the sludge remediated by AGM. For this purpose, measurements of organic elements, ignition behavior, pH, ORP, oxygen consumption, and n-hexane extract of the sludge were conducted, and relationships between these parameters were used. It was confirmed that GCA mollified the reduction level of the sludge, and improved the mobility of pore water. The results also ensured that the substratum and water environments were improved after applying GCA.

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 The creation for intertidal flat carries the role that is important as not only the role as the disposal of the dredged soil but also the fishing ground for clams and nature restoration project. It is necessary to longterm study, manage and evaluate not only the geomorphic change but also the development and succession of fauna, thereby carrying out appropriate evaluation and management.
 Hence, in this study, we investigated succession of benthic community on Oshima intertidal flat which was created in 2008 for the period of five years. In particular, we studied the primary succession, geoenvironment and the characteristic of fauna. As a result, ecosystems on Oshima intertidal flat were found to be composed of rich fauna, depending on the geoenvironment, with appearance of many species only five years after the artificial flat was created.

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 The most northern part of Kagoshima Bay was designated as "Kirishima-Kinko Bay National Park" on March 16, 2012. The Shigetomi-higata tidal flat in the national park was also designated as a seashore park. This tidal flat is important to biologically purify water inside Kagoshima Bay. Shigetomi-higata was productive tidal flat with abundant clams, but production of clams and other shellfish has been decreased recently. Thus collection of clams has been banned. Local benthic ecosystem would be affected by the change in sediment composition and topography. Therefore, understanding of the physical environment such as terrain and sediment characteristics should be examined. Terrain and sediment characteristic had been surveyed for four years from 2009 to 2012 in this paper. In addition, river discharge and representative wave characteristics which affect sediment transport and topography change are estimated.

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 Law for the Promotion of Nature Restoration was based on restore work of spoiled natural environments by local residents with scientific knowledge. The most important thing was to be based on local resident's initiative in the law. But for large-scaled project, it was needed local enterprises join in restore work and the work is passed down to public work.
 In this paper, through the restoration work in Lake Nakaumi, it became one of model in the importance of strong and comprehensive approach by restore work of residents and that of local enterprises. And it was mentioned that collaboration with local enterprises and residents was necessary, and proceeded process of verification project with resident's will. This project will be one of representative model of the nature restoration projects in Japan.

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 The present paper shows the effect of the Isahaya Sea Dyke on the baroclinic structure due to freshwater inflow from rivers in the Ariake Sea. Numerical simulation of tidal current and salinity stratification was conducted in case of rainy season in 2006 with and without the dyke.
 As a result, the followings were cralified:
 1) The dyke can decrease the velocity of tidal current and strengthen salinewater and freshwater stratification in Isahaya Bay and in coastal area off Shimabara Penninsula; 2) Stratification can be seen to be strengthened in a term from neap tide to spring one; and 3)The influence of the dyke on baroclinic structure due to freshwater inflow depends on conbination of tide and flow rate of rivers.

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 Turbidity which occurs in a marine construction should be daily controlled. For the management of turbidity control, a numerical simulation of the turbidity dispersion based on the current prediction is useful. However, the commonly-used numerical simulation needs a long computational time for the predictions of nearshore current and wind drift current. In this study, the simplified numerical calculation method was developed with a reef current. In this method, the total current field is predicted by superposing the tidal current and the nearshore current, which are respectively predicted.The proposed method was validated by comparing with the commonly-used full simulation of the turbidity dispersion for the supposed construction sea area. As a result, the proposed method accurately reproduced the full simulation results by taking the tide level variation into account for the tidal current field prediction.

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 In Around Nagashima, Shishijima located in the southern part of the Yatsushiro Sea, the culture of yellowtails is carried out flourishingly and circulates in not only the country but also the world. However, in this culture sea area, Chattonella antiqua red tide is often generated and the culture amount of damage after 1988 exceeds 10, 400 million yen and this kind red tide measures become the important issue. The writers develop the red tide occurrence prediction technique that applied HSI model based on red tide survey data of the northern area of the sea. In this study, inspected the HSI model in the southern part area of the sea where cultured damage was enhanced by a red tide. After having clarified quality of the water environment properties of the occurrence area of the sea from the comparison of red tide occurrence year and non- occurrence year, as a result of having reproduced a chronological order change of the cell density in a red tide generated at southern area of the sea in 2009, a high coefficient of correlation was provided.

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 For the proper planning of coastal environmental improvement works utilizing steel-making slag, evaluation for influence on pH of surrounding seawater is indispensable. However, alkalinity elution from steel-making slag piled in seawater is complicated process with mass transport in porous medium which depend on the many factors such as slag diameter, porosity and pile thickness . In this study, an analytical model for alkalinity elution from steel-making slag piled in seawater was proposed and verified by previous flume experiment. Dependence of alkalinity elution on piling condition was revealed.

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 Cause of eutrophication in Hasunuma Seaside Park Pond is nutrients that accumulated in the sediment bottom. This study was aimed to analysis the influence on bottom sediment environment by sprinkling shell as regional unused resources. In addition, adsorption isotherm was calculated by culture experiments of bottom sediment material improvement. And adsorption effect of the nutrient in each processing was assessed. By result of pore water, T-N in pore water showed the low concentration by sprinkled shells as regional unused resources. T-P in pore water showed the low concentration by sprinkled shells, and moreover it was remarkable in burning-treated system more than in non-treated system. By assessment by adsorption isotherm, NH₄-N and T-N showed the negative adsorption isotherm. As reason for this, NH₄-N eluted in water by sprinkled bottom sediment improvement materials, and nitrogen in the pore water decreased. For T-P and PO₄-P, all bottom sediment improvement materials showed positive adsorption effects. CRM treatment using CaO showed the highest effect.

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 This paper is described results of examination in connection with the time-series data of seawater temperature, salinity and tide lebel of the Ariake and Yatstushiro Seas and the meteorological and oceanographic data arround of the Ariake and Yatstushiro Seas. Result of the examination, It was found that the seawater temperature of the Ariake and Yatsushiro Seas are influenced by the sea surface temperature of the nothern East China Sea and temperature arround the Ariake and Yatsushiro Seas, and the seawater temperature variation to be one of the variable factors of tide level was suggested. Increase of river flow in the rainy season greatly reduce the salinity of the bay mouth and it affects the marine ecosystem.

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 This study investigates the generation mechanism of storm surge and the variability of water mass structure in Mikawa Bay under the influence of Typhoon 0918 on the basis of meteorological and oceanographic observation data. As a result, it could be said that the storm surge observed in Mikawa Bay was attributed to the inflow of water mass from Ise Bay as a free long wave due to the sudden change in wind direction. Moreover, the observation data showed that the water mass structure was significantly changed during the typhoon period with strong wind and large floods after typhoon passing.

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 In Lake Komuke, which is one of the most significant lakes for immigration birds, we carried out field experiments of flow field and water quality. Lake Komuke consists of a main lake and the other two small lakes. The main lake is found to have higher salinity compared to the other two small lakes. During the snow melt period, the small lakes are found to have less salinity compared to summer, which is confirmed by the numerical computations using three-dimensional numerical model. As a result, tidal flats in the small lakes have larger residual time of sea water which is significant for immigration birds.

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 In Lake Komuke, an important flyway in Japan, salinity, water level, and seepage flow were observed in tidal flats and seasonal variation of dissolved organic matters were identified by fluorescence spectroscopy in order to clarify the relationship between water qualities and groundwater flow during spring and summer. At the offshore of the sandbar, the seasonality of fluorescence intensity of fulvic acid-like substances derived from soil in large lake means the seasonal variation of influence of river water and groundwater on water quality in the tidal flat. Groundwater in the tidal flat flew upward by an order of magnitude larger in spring than in summer. From the results of surface water in the tidal flat and the profiles of groundwater, upward flow likely reduces the increase of salinity in the groundwater.

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 Field investigations were performed to examine environmental factors (wind speed, water temperature, salinity, total alkalinity (TA), dissolved inorganic carbon (DIC), and community metabolism (e.g. ecosystem production and respiration)) affecting air-sea CO₂ flux at the lake Komuke, Japan. We statistically analyzed the observed data using the structured equation modeling (SEM). Specifically, we implemented the path analysis to examine the direct and indirect effects of the environmental factors on the air-sea CO₂ flux. Our results showed that autotrophic sites at central lake can be sinks for atmospheric CO₂. The key factors directly affecting the air-sea CO₂ flux were indicated to be wind speed and salinity; in turn, the community metabolism were indicated to be an indirect but significant factor.

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 Since IPCC published 5th Assessment Report of WG1, we estimated future damage risk all over Japanese land caused by storm surge under global warming. For the estimation, heights of sea level rise were set on conditions that representative concentration pathways were RCP2.6, RCP4.5 and RCP8.5, and that climate models were MRI-CGCM3, MIROC5 and HadMED2-ESX. The estimation years were 2050 and 2100. We estimated storm surge damage risks of 893 areas divided into from whole of Japanese low land, and gathered those risks. We understood spatial distribution and changes of 100 years on storm surge risk. The results indicated that 3 major bays, Set Inland Sea and Ariake / Yatsushiro Sea have relatively high storm surge risks, and that storm surge risks increase almost linearly during 100 years.

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