The aim of this study is to discuss experimentally how the breaking limit, breaker type and broken wave characteristics are changed by the scale ratio of wave and submerged structure. It is shown that the breaking limit and breaker type are independent of B/L_i for B/L_i>0.5 and that the breaker type is classified into spilling, spilling-plunging and double breakers with increasing of H_i/R. Energy dissipation due to wave breaking becomes much larger with an increment of B/L_i and D/h. It is also found that the steady flow generates a circulation at the onshoreside of the structure.

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Coastal regions represent the “third sector of the earth” which is neither land nor sea, but a peculiar mix of the two. There is no accurate technical description for this sector.
Studies of salt damage, as an environmental problem of coastal regions, have been conducted for a considerable time. As previously reported, a field measurement of seawater and meteorological information, coastal forms, and the distribution of aerial sea-salt particles near the coast of the Kitakyushu area (within 100m of the coastline) was conducted to obtain fundamental data for comprehensive, wide-area planning of the development of the coastal region from an environmental point of view. A field measurement was also conducted of the area within a distance of 2, 000 m from the coastline.
This paper presents an outline of the field measurement methods employed in surveying distribution of aerial sea-salt particles, and explains the results of measurement and analysis.

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We assessed and investigated actual states of intermediate breedings, fish preservation and aquaculture using water areas in third and fourth class fishing ports in Hokkaido. We also investigated future usage plans for these water areas. We then examined critical wave conditions for different kinds of fish/shellfish breeding works, based on interviews with fishermen. We summarized ploblems in using water areas in fishing ports and presented a case study of Kudoh Fishing Port to provide specific examples of ploblems and possible countermeasures. Finally, we reported on a case study of water exchange breakwaters which enable fish/shellfish breeding in water areas in fishing ports.

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When constructing and improving fishing ports and villages, fundamental concepts bases on ecological aspects are required to recognize the value of the ecosysytem and to coexist with nature. As a first step to assess the construction and improvement of fishing ports and villages from ecological viewpoints, we conducted the following surveys and studies.
We conducted a questionnaire survey on the natural environments and the living conditions of wildlife in fishing ports, as well as on the habitat conditions of the wildlife listed in the category subject to assessments, in our country.
Furthermore, the ecosystem-friendly fishing port construction and improvement method was examined to conserve and restore the ecosystem around fishing ports.

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The incidental facilities of waterfront hotels, such as tennis courts and marinas, are constructed for urban waterfront utilization. In designing and planning a waterfront it is necessary to determine the significance of the waterfront to urban residents and to reflect such considerations in environmental planning, as well as to clarify variations in visitors' behavior and perception of the waterfront.
To this aim. a questionnaire survey, as previously reported, was conducted of the Kitakyushu and Fukuoka Cities' private and public marinas, regarding “Utilization Status and Visitors' Perception”. A similar questionnaire survey was conducted on the marina and tennis court of the Hotel UMINONAKAMICHI, which serves as accommodation for visitors to the Uminonakamichi Seaside Park.
This paper will begin by introducing a summary of the marina and tennis court of the Hotel UMINONAKAMICHI, followed by details and analysis of the questionnaire survey, and characteristics of urban residents' ideas and perceptions toward each of the facilities.

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Pricing marina slip rental fees is a crucial financial consideration in marina planning. Unfortunately it is often very difficult because fees vary widely with the location, access and profile of boating age residents in the primary market. A new computer system that calculates standardized price units (such as Yen/foot of rentable slip of proposed marina) has been developed to overcome these problems. In this paper the standardized price units for each administractive district of the whole of Japan have been analysed using this new computer system with various indicators of social and economic conditions. The paper therefore facilitates regional strategic planning exercises.

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Ice sheets in harbors, rivers, lakes and ponds in cold regions are used for a variety of purpose. For example, tracks on the ice, roads for automobils, runways for airplanes, footholds for the construction of structures. Using ice sheets, it is important to estimate the bearing capacity of an infinite ice sheet in order to ensure their safety. In this study, the authors show method to estimate the bearing capacity of an infinite ice sheets by graphs and charts. And compare with the bearing capacity under the condition of three types of loads.

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The Okhotsk Sea coast of Hokkaido is covered with ice floes during winter. Aota et al. showed that the temperature in this region has been rising every winter, and in the last ten years the amount of sea ice has been decreasing. Therefore the period of coexistence of waves and ice floes has become more longer and it is very important problem to make clear the impact ice load acting on offshore, harbor and coastal structures which are constructed on Okhotsk Sea coast of Hokkaido. Saeki et al. and Takahashi et al. reported that the velocity of ice floes due to wind wave, overtopping over breakwater and tsunami was about 4-8m/s. In this paper, the authors clarified the impact ice load acting on flat-rigid plate through the systematic experiments.

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The Okhotsk Sea coast of Hokkaido is covered with ice floes during winter. Aota et al. showed that the temperature in this region has been rising every winter, and in the last ten years the amount of sea ice has been decreasing. Therefore the period of coexistence of waves and ice floes has become more longer and it is very important problem to make clear the impact ice load acting on offshore, harbor and coastal structures which are constructed on Okhotsk Sea coast of Hokkaido. Saeki et al. and Takahashi et al. reported that the velocity of ice floes due to wind wave, overtopping over breakwater and tsunami was about 4-8m/s. In this paper, the authors clarified the impact ice load when ice sheets collide vertically with a circular cross-sectional structure.

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In cold regions, natural ice sheets adfreeze to piles, bridge piers, intake towers, etc. constructed in sea. When the ice sheets adfreeze to these upright structures, vertical ice loads act on the structures due to changes in the sea water level. These vertical ice loads need to be studied to design upright structures affected by natural ice sheets.
Vertical ice loads acting on upright structures with a circular cross-section have been explained analytically. However, ice loads acting on upright structures except those with a circular cross-section, such as upright structures with a rectangular or an elliptical cross-section, have never been researched. In this report, we show a technique to calculate the vertical ice loads acting on upright structures with an elliptical cross-section.

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Ice sheets in rivers, lakes, lagoons in cold regions are used for a variety of purposes. They are used astracks on the ice, as roads for automobiles, as runways for airplanes, and as footholds for the constructionof structures. Knowledge of physical and dynamic characteristics of natural ice sheets and techniques toestimate the bearing capacity of natural ice sheets against vertical loads are required to safety use icesheets. In this study, the authors indicate the theoretical values of the bearing capacity and the deflectionof ice sheets under the condition of partial flooding, and compare with the experiments values.

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Uniaxial compressive Strength is one of the main parameters, which determines the valueof load on marine structures in ice-infested sea area. Sea ice has defferent properties bymaritime and weather condition, and strength of natural sea ice has much dispersion, becauseit depends on a number of factors (ice temperature, salinity, structure, etc.). therefore, it isnessesary for the exploitation in Okhotsk Sea to estimate the appricabitity of formula andfactor influencing on uniaxial compressive strength of sea ice in Okhotsk Sea.

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The coastal area facing the sea of Okhotsk in Hokkaido is annually covered with drifting ice. When theseice floes with a deep draft move toward the shore, they gouge sandy sea bottoms.Due to this ice gouging, marine resources along the shallow sandy coast are damaged. For example, sea shells, buriedstructures, pipelines.In this study, the Authors understand the mechanism of ice gouging and obtain basicknowledge necessary to take preventive measures in future against damage by ice floes.

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This paper presents the ice influences on the floating structures in cold regions .Recentlythe marine recreation such as yachts and motorboats becomes popular in Japan.In Hokkaido, four public marinas are constructed in the coast of the Pacific Ocean and the Sea of Japan.This leads the marine activities more popular.But no marinas have beenconstructed in the coast of the Sea of Okhotsk where sea ice cause many problems to themarina structures.On the other hand, a lot of marinas are constructed in the coast of Northern Europe under the same climatic conditions as the Sea of Okhotsk, and marinasare used actively except the period when harbors are covered by sea ice.In this paper, theauthors propose the design methods for marina facilities considering the ice influences onthe floating structures.

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The consiruction of structure in ice in fested arca requires the proper evaluation ofdesign ice load on structure.For that, it is required to clarify that the scale effect, that indentation ice pressure decreases as an area of structure with ice sheetincreascs, is caused by the nonsimulaneo us failure of ice sheet. Medium scale fieldindenlation test (MSFIT) in JOIA project includes ice in dentation tests, tests onphysical pmperties of ice sheet and image sensing on ice deformaion. In thispaper, the whole plan of MSFIT and the resuhs of ice indemation tests conducted in 1996 winter are reported.

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Satellite imagery of LANDSAT, SPOT, JERS-1 is used to estimate a water depth. Analgorithm for water depth mapping is used of Lyzenga algorithm. As bathymetry method for satellite imagery, we used a linear-regression method to obtain correlation R² between water depth and estimated depth. The main purpose is to obtain the maximum R² for each sensor and to obtain a contribution band for correlation. In this study, we analyze the relation between absolute water depth and remotely sensed data by linearregression, specially, STEPWISE method of SAS cluster. JERS-1/OPS is new sensors by NASDA, and which is used for the first analysis for bathymetry.

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A method predicting predominant wave direction to a pocket beach from the asymmetry in the configuration of the pocket beach is shown. The method is applied to the coastline in Kyoto Prefecture facing the Sea of Japan. In total the shape of ten pocket beaches is compared and it is shown that predicted wave directions agree well. In addition beach changes in a pocket beach due to seasonal changes in wave direction is also studied through the comparison of aerial photos and sounding maps.

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Beach changes of Torigasaki Area in Lake Shinji Located in Shimane Prefecture wereinvestigated. On this beach a cuspate foreland was formed behind an offshore breakwater built for protecting cultivation facilities of shells against wave action. Aerial photogaraphs were compared to investigate tong-term shoreline changes of this cuspate foreland. Seasonal, cyclic beach changes due to the change in wave direction corresponding to the wind direction were found at the head of the foreland. Grain size distribution around the foreland was measured.

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A design method of optimum arrangement of headlands is shown using calculationmethod of stable shoreline given by Hsu·EEvans (1989) through a case study on Numazu-Ushibuse coast.On this coast a headland was constructed to create stable shoreline as well as the beach nourishment.Further nourishment is planned to widen foreshore by installing additional small scale headlands.This procedure is shown in view of least sand loss and least influence to the surrounding coast.

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Formative process of scarp due to waves was investigated by field observation at the Oarai coast in Ibaraki Prefecture. On this coast construction of headlands are under way. Due to the field observation scarp was found on the south side of each headland, whereas on the northern side of each headland berm was formed, inferring that formation of scarp strongly relates to longshore sand movement in a area separated by structures obstructing longshore sand movement. Formation process of scarp is summarized and the difference with the beach changes due to on-offshore sandmovement is clarified.

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The characteristics of coastal process in IRAGO-NISINOHAMA beach are discussed this paper. Since this coast has been eroded, several protection works against beach erosion have been one. The northerly sediment transport can be found to be caused by the winter wind from the western-side directions. Moreover, the wind waves from the Pacific Ocean caused by the typhoons encourage the northerly sediment transport. The detached breakwaters and groins work effectively for IRAGO-NISINOHAMA beach

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This paper deals with long-term sea-level change along the coast of Sea of Japan (East Sea) and an expectation of shoreline retreat by sea-level rise. Tidal level data have been analyzed by 12 months moving average and this result shows a tendency to rise. Wave tank experiment shows not only static retreat by water-level rise but also additional retreat by waves plays an important role in total retreat by water-level rise. Shoreline retreat has been predicted with some assumptions using analyzed sea-level data.

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It is required in coastal projects that the balance of natural environment, disaster prevention and coastal zone utilization are considered.In this paper, characteristics of coastal zone in the Ise bay are described, and simple method for composite estimation of the index is proposed using questionnaire data for the authorities concerned. The main results are summarized as follows: The coastal zone are divided into several groups that depend on influence of industrial port and fishery harbor, inner bay and open sea. Municipalities advancing multipurpose utility have high score of composite estimation, and the method support the applicability for management and control of the coastal zone.

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Relation between river mouth improvement and coastal reservation is studied by taking the Ayaragi coast in Yamaguchi Prefecture as an example.In this pocket beach of around 2 km long shoreline three rivers flow into the sea and at their mouths river mouth closure has been caused by storm waves in winter.As the measures against this, dredging of thr river mouth bed was extensively conducted before extending paralell jetties of enough length at the river mouth to induce beach erosion on the adjacent coastline.This situation was analyzed by the comparison ofaerial photographs and bottom sounding data.Extension of the jetty is considered to be best solution against beach erosion.

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An artificial reef is applied to the river mouth improvement.Numerical simulation of wave, nearshore currents and flood currents were conducted under the condition, in which an artificial reef is installed in front of the mouth in order to reduce wave height in the river and to induce outward currents to enhance scouring in the reef gap so as to be safely used for navigation channel of small fishing boats. As a result of the numerical simulation optimum design of artificial reef as a river mouth improvement was determined.

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The changes in river mouth bar topography triggered by the construction of detached breakawaters and habor breakwaters in the ajacent area of the river mouth were analyzed through the case study. Three rivers, the Torikai, Toshi and Iwato rivers, on Awaji Island in Hyogo Prefecture were selected as the study area. It is concluded that retreat of river mouth bar may be caused by the disrupion of continuous longshore sand transport due to structures and creation of wave calm zone in the area next to a river mouth by construction of breakwaters, which facilitates longshore sand movement. Key words: river mouth bar, beach changes, detached breakwater, aerial photo

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The purpose of this paper is to descrive the process how we planned and preserved the environment of Tokiwa-Dejima water front area in Nagasaki Harbor. According to the remote sensing survey, the green zone in Nagasaki urban area is reducing, especially along the water front. The amount of green area allocated in urban space planning may be limited but connecting this green area with the existing vegetation, the total bio-activity area (“biotope”) will be enlarged. When we design waterfront area, we have to create a wholesame evironment for the bio-activity in beach, tidal and sub marine area. And also we should not use up all the spaces for human beings but we should save the space for bufferings and relieving the human pressure against the bio-activity.

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The beach is an indispensable component of the Water Front in the port. Tokyo Port is in the innermost environs of Tokyo Bay which is an enclosed area. Odaiba Seaside Park is in a central location of Tokyo Port. This park which consists mainly of the water is enclosed with Daiba, its breakwater and reclamation land. In this area, the artificial beach and its sea life are innabitants at present. This paper aims to investigate the relativity of the change of sea bottom and its organisms. We will compare the recreation area with the conserv ation area in this park, and will find out tae merit of the artificial beach on the enclosed water.

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The wave condition to develop the habitat for Panadalus Kesseri is determined by this experimental study. In this study its thrust force and fluid force in oscillatory flow are measured, and the habitable condition is estimated from the balance of them. Consequently, the maximum wave height Hmax is approximately 3.47×10^-2 BL^0.8d^0.5 on small amplitude wave theory.Where BL is body length of P.kesseri, d is water depth. Therefore, the wave height need to be restrained below Hmax, to develop an habitat of P. kesseri by using an algae zone.

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Surf clam (Pseudocardium sybillae) which live in sandy beaches along the open sea in northern Japan are important fishery resources.Bivalves are forced out of the sandinto the water due to waves. This movement is dangerous for the bivalves, and is thought to be the first phase in the mortality process. To understand the first phase of the mortality process, (1) the critical condition for which bivalves forced out of the sand into the water by oscillatory flow, (2) the critical flow velocity at which bivalves can burrow intothe sand, (3) the burrowing rate of bivalves, (4) bed erosion velocity under where sand ripples are formed, (5) the release probability of the bivalves, are experimentally studied by useof a U-shaped oscillatory flow tube.

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To improve methods for developing and maintaining short-necked clam fishing grounds in cold regions, the relationship between short-necked clams and ground environment was investigated. Density of young short-necked clams decreases as the ground becomes harder. Daily dry-up time in short-necked clam habitats in Hokkaido are longer than in either Kyushu or the Inland Sea, and temperatures are rarely over 30°C . Therefore, ground temperatures don't inhibit shortnecked clam growth. When seas and lakes freeze, because ice tends to attract sand in areas with smaller grain size sediment, mud can't accumulate in fishing grounds and young short-necked clam density decreases.

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The purpose of this study is to clarify the best habitable conditions for marine organisms in a tide pool. Field observation on marine organisms and the sea water auality are conducted in the eleven tide cools located at natural lagoon. It is found that the diversity index on marine organism is changed with the size variation and total volume of boulders scattered in the tide pool. The number of species of marine organisms in the tide pool located at natural lagoon is larger than that at man-made one.

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Areas along Sea of Japan coast in Hokkaido suffer serious “isoyake” (shore burning, or seaweed withering phenomenon at a beach) problems. A decrease in algae has resulted in, among other things, a shortage of food for algae-eating animala, including sea urchins and abalone, and a decrease of spawning and breeding are as for fish. It is vital that secondary fishery coordination and symbiotic environmental functions be introduced in construction and improvement projects at fishing ports and harbors to maintain coordination with the surrounding fishing environment, and to preserve the natural environment. In this paper deals with an algsl propagation method, which is a basic condition for encouraging fish and shellfish to gather. Anew prous material (“BI0UNIT”) was produced using recycled desulfurizing agents (trade name: “Ecosand”) discharged from dry-type desulfurizers of the Tomatoatsuma Power Plant of the Hokkaido Electric Power Co., Inc. Since 1992, Biounit has been examined at 19 places in coastal places around Hokkaido to develop a substrate with superior adhesive properties for algae.

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To avoid the environmental deterioration due to installation/construction of coastal structures, the assessment procedure for marine environment should be investigated. To attract fishes and the other marine organisms on artificial fish reef or the other type of coastal structures, the biological investigation of sesentary organisms and benthos is generally required. It is effective to investigate the attached organisms on silt curtains, for overview the habitat of attached marine organisms on coastal structures. Because silt curtains develop in various marine environments, that is in various water depth under wave and current actions. This paper discussed the relationship between the marine environment and the attached organisms on silt curtains.

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This paper discusses submerged breakwaters with cylindrical fish reefs. Various model tests were carried out to investigate regular and irregular wave transmissions. The tests revealed several fundamental principles about the wave transmission of the reef-type breakwaters. When the reef crest width is large, the wave dissipation can be expected to have a wide range of relative crest depths because of the function of the waves breaking on the crest. The transmission coefficient of the environmental submerged breakwater becomes slightly smaller than for the normal submerged breakwater.

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To investigate the influence of changes in physical environments, including waves and currents, on the ecosystem of rosky shores, ecological research was conducted at three points on rocky shores, each of which had diifferent wave conditions. It was found that differences in sea urchin popurlation and seaweed volume corresponded to differences in wave conditions at each point. The diversity of phytal fauna at each point corresponded to differences in the volume of seaweed.

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Man-made perturbation on the environment has resulted in many problems such as eutrophication and sedimentation in water bodies. In recent years, domestic sewage and industrial waste water are having a bad infuluence on water quality, especially, estury and closed bay area. Therefore, water quality controlling and monitoring activities are inevitable.
We tried to apply satellite remote sensing techniques to investigate the sea water exchange of the Omura Bay and the Sasebo Bay. Maximum likelihood method was used to classify and confirm the exchange condition of sea water bodies. And also, the result are compared with an outcome of numerical simulation methode by workstation computer.

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