著者
関口 浩二 遠山 哲次郎 荒田 崇 清水 敏晶
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.13, pp.853-858, 1997 (Released:2011-06-27)
参考文献数
4
被引用文献数
1

Lake Saroma is an inland sea-lake on the Sea of Okhotsk. As the lake's environment is suitable for aquiculture, it is widely used for natural sea farming.Ice floes usually reach Okhotsk Sea coast of Hokkaido from late January through early February. When ice floes arrived before Lake Saroma had sufficiently frozen up, the inflow of ice into the lake damaged aquiculture facilities. As a countermeasure for this, construction of ice booms to control ice floes began in 1994 and 10 spans out of 13 planned have since been completed.In this study, the effectiveness of ice booms in controlling ice floes in an actual sea area is confirmed, factoes concerning the tension of the main wire, an important point in design, are analyzed using research results, and the design and actual values are compared.
著者
大川 豊 矢後 清和 太田 真 山田 義則 高野 宰 関田 欣治
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.20, pp.1217-1222, 2004 (Released:2011-06-27)
参考文献数
10
被引用文献数
1

This paper describes the technical feasibility study and the economical evaluation of the floating wind power system. The box-girder type floating structure installed three wind turbines is proposed as a concept. The 5MW class propeller type turbines are adopted. The box girder with simple structures is favorable in the cost performance. Moreover, the wave induced motion and the righting moment can be optimized easily. The estimations of the static inclination and the wave induced motion were carried out in technical study. The relations between wind loads and motions or inclinations were investigated by the wind tunnel test. On the numerical analysis of motions, the fluid dynamic forces were calculated using the potential theory with zero draft assumption in the estimation of motion. The floating structure model was consisted by beam elements of FEM. The calculation result showed that the motion and the inclination in an operation condition are less than 5 degrees. According to the economic estimation, it was presumed that the proposed concept can be attained to the equally cost of water-power generation and others.
著者
中瀬 浩太 林 英子
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.18, pp.31-36, 2002 (Released:2011-06-27)
参考文献数
4
被引用文献数
1 1

Tokyo Port Wild Bird Park, which was originally a part of the reclaimed industrial area, was constructed in 1989 by the request of the local citizens. Since then, the seaside park that includes an artificial lagoon has provided precious opportunities of natural experience for the people in urbanized Tokyo-Bay Area.For the maintenance and management of the park, volunteer citizens groups have played a crucial role. Since the opening of the park, the highly motivated volunteer groups, in cooperation with members of Wild Bird Society of Japan, have continuously monitored the topographical change of the artificial lagoon and the situation of birds, benthos, and vegetation. In addition, the volunteer groups carriedout some field experiments. For example, they constructed an artificial creek and monitored the growth of thereed around it. They also constructed bamboo fences to check their anti-erosion effect at the shoreline and seabed. These continuous activities help to build better understanding of the environmental management in an artificial lagoon. The authors suggest the need of the involvement of more persons with biological knowledge, in addition to the volunteer group, in order to enhance the quality of the management method.
著者
松浦 邦明 鈴木 史朗 橋本 典明 本橋 昌志
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.22, pp.85-90, 2006

We develop a real-time wave information and analysis system on the basis of a data assimilation technique, the optimum interpolation method, applied for wave observation data and forecasted data. The system can provide nowcast wave information for the sea area where there is no wave observation point. In the system, first, the initial estimate (nowcast) is computed in real-time with the observation data and forecasted information, and then the estimate is corrected after 12 hours with more accurate forecasted wave information. Finally, the corrected data is stored in the wave information database for analysis. We investigate the characteristics of the nowcast wave data and confirmed that the accuracy of the data is high enough for practical applications.
著者
山本 吉道 ウィブール ウッチャン 飯田 邦彦 河合 恭平
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.23, pp.81-86, 2007
被引用文献数
1

We tried to devise a method for estimating the degree and geographic extent of tsunami damage using satellite photographs in two case studies of damage to Thailand's west coast due to the Indian Ocean tsunami. Following results were obtained from those case studies: the extent of a flood area can be generally estimated from discoloration of vegetation zone assuming such vegetation originally existed along the coast; house damage could be estimate by deciphering whether each roof was lost or not, however if the roof remained, the degree of damage to walls and pillars could not be discerned.<BR>Therefore, we develop a method to get marginal thickness of walls and marginal width of pillars which break on arbitrary positions using a distribution of tsunami heights on a coastline and a distribution of ground heights. In addition, the extent of a flood area can be presumed if there are the above-mentioned distribution data and elapsed data of sea water levels at the time of a tsunami invasion.
著者
三上 信雄 安藤 亘 石岡 昇 大隈 篤 山本 秀一 北野 倫生
出版者
公益社団法人 土木学会
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
no.23, pp.925-930, 2007

To promote utilization of Okinotorishima island and its surrounding areas mainly in the fishery field, fishery resources and environmental conditions were surveyed in and around the coral reef of the island. Corals were widely distributed in the lagoon. Some useful fishery species were caught through the wide range from the surface to the deep water around the reef. Their preys such as eggs, juveniles and young of some small sized fish species were also observed there. Therefore, it may be possible to utilize the island as a good fishing ground with an artificially increased primary production. To develop this potential, some ideas and their issues to be solved in the future were discussed in this study.
著者
清野 聡子 宇多 高明 前田 耕作 綿末 しのぶ
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.18, pp.431-436, 2002 (Released:2011-06-27)
参考文献数
7

Field observation of spawning ground of horseshoe crab Tachypleus tridentatus was carried out in August 2000 at a river mouth in Seikai-cho in Nagasaki Prefecture. Many eggs spawned under thegroundof river mouth bars were found. Morphological features of spawning ground including surrounding vegetations were investigated and compared with the results of the former studies. Results were well explained by the features summarized in the former studies. A note on conservation of rare species was discussed.
著者
熊田 貴之 小林 昭男
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.16, pp.315-320, 2000 (Released:2011-06-27)
参考文献数
4

In this paper, the results of the field survey on the coastal erosion at Kemigawa beach as the artificial beach are presented, and causes of the erosion are discussed using the sea conditions and the grain-size distribution of sands of the beach. The results of the investigation are summarized as follows:(1) The erosion at Kemigawa beach is intense compared with neighbor artificial beaches that has a characteristic like the Kemigawa beach.(2) The result of the numerical analysis using the cross section of the construction plan shows that the wave conditions of near shore at Kemigawa beach is calmness in the stormy weather.(3) The results of the grain-size analysis of sands show that the small-size sands that flow away from the center of Kemigawa beach maybe deposit at the base of the breakwater.(4) The result of the comparison between d50 of the sands and the gradient of the foreshore about the construction plan of Kemigawa beach shows that the beach has the tendency of the erosion.
著者
吉田 秀樹 中島 謙二郎 川野 泰広 江口 秀之 中村 義文 日向 博文
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.23, pp.709-714, 2007 (Released:2010-08-25)
参考文献数
6
被引用文献数
1 1

The Kyushu Regional Development Bureau, Ministry of Land, Infrastructure and Transport has placed four High-Frequency Oceanic Radar System (HF radar) at the Ariake Sea with the aim of regenerating environmental condition, and has observed the surface current and ocean wave situations since 2005.The paper presents (1) the result of study for precision of HF radar observation, (2) the real-time informing system by internet named “The Ariake Sea current and ocean waves information system”, and (3) the development of “The sea garbage movement prediction system” utilized the surface current observation information by the system with the aims of the improving the sea garbage collecting service by the Advanced Anti-Pollution Vessel “KAIKI” as well as the progress of the installing the system. As result of the development, the precision is verified appropriately, and the system has been operated since April, 2007.
著者
北 賢二 小林 昭男 宇多 高明 野志 保仁 和田 信幸
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.21, pp.409-414, 2005 (Released:2011-06-27)
参考文献数
3

Damages of wind blown sand were investigated at Makuhari artificial beach in Chiba Prefecture, the Chigasaki coast in Kanagawa Prefecture and Nakatajima Sand Dune in Shizuoka Prefecture. Fine sand was transported by wind and deposited on the promenade behind the beach, causing obstruction against traffics. In order to study these phenomena, field study on wind blown sand consideringg rain size effect was carried out at Kujukuri beach. It was confirmed that selective transport of fines and is important and this results in sorting effect in an extensive area.
著者
長尾 毅 藤森 修吾 築地 健太朗
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.24, pp.201-206, 2008 (Released:2010-08-25)
参考文献数
5

The reliability-based design method was recently introduced to the technical standard for port and harbor facilities. The standard method is partial factors method, however, other methods that evaluate the reliability index directly can also be applied. Taking the design of pile supported wharves as an example, performance function is implicit and the application of the methods that evaluate the reliability index directly is difficult to the practical design. This study aims at clarifying the applicability of response surface method for pile supported wharves. As the performance function can be evaluated explicitly by the method, the calculation of reliability indices is comparatively easy. The applicability of first-order second-moment method is also discussed.
著者
本間 大輔 窪内 篤 山本 泰司 畑山 朗 木村 克俊
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.21, pp.927-932, 2005 (Released:2011-06-27)
参考文献数
1
被引用文献数
1 1

On September 8, 2004, Typhoon No.0418 (Typhoon Songda) moved north along the western coast of Hokkaido, bringing high winds to wide areas in the storm zone. Omori Bridge, a 429-m-long I-girder bridge on National Highway 229, suffered the collapse of a 159-m-long section. The bridge spanned a reef that is surrounded by wave-dissipating blocks on the seaward side and precipices on the landward side. On the day of the collapse, waves were extremely high and winds were strong, and abnormal tide levels were attributed to the effect of the local topography. In this research, hydraulic model tests were performed to study the damage mechanism of the bridge and the wave forces that acted on it, in order to assess the safety of the truss bridge that will be erected for temporary restoration. The splash patterns were also examined to determine the conditions under which vehicles can safely run after the restoration.
著者
大中 晋 遠藤 秀文 西平 守孝 吉井 一郎
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.24, pp.825-830, 2008 (Released:2010-08-25)
参考文献数
4

The large-scale coral transplantation has been implemented on the reef flat area at Kuta Beach in Bali Island of Indonesia. The transplantation area is about 1.3 ha and there is no other example like this big scale coral transplantation. The asexual reproduction was applied as transplantation method by fixing coral fragments using nail with cable-tie and the limestone was adopted as artificial substrate for coral transplantation. The major species of coral to be transplanted is Acropora sp. which was taken from the same coral reef area. More than a half year has already passed after the completion of the first coral transplantation and high degree of survival rate with more than 98% could be maintained until now.
著者
和田 清 水谷 法美 村上 宗隆
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.16, pp.291-296, 2000 (Released:2011-06-27)
参考文献数
5

This paper is intended to estimate beach process and wave deformations at the Shitiri-mihama coast in Mie Prefecture. Field investigation by using an aerial photography technique is conducted along the Shitiri-mihama coast from the Kumano river mouth to the Onigashiro cape. It is clear that almost regions occurred beach erosion, especially Udono harbor region located on the left bank of the Kumano river, as the coastal line faced to sea, the beach protection works were struck by strong storms. Based on bottom sounding survey, maximum shoreline retreat was 100 meters for 5 years immediately after extend construction of breakwater around Udono harbor. It is necessary to predict water deformation for erosion control around coastal protection facilities. It is presented a time-depend mild slope equation for estimating wave deformation. Some simple calculations were conducted for modeling breakwater at the worst beach erosion area where located northern Udono harbor. The numerical model has well explanations for generation of partial standing waves, drop of mean sea level behind breakwaters.
著者
窪内 篤 関口 信一郎
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.21, pp.7-12, 2005 (Released:2011-06-27)
参考文献数
16

The HIROI formula, which estimates the wave forces, has been used in breakwater design for many years. As far as the authors know, significant wave height has been used for the HIROI formula in the past. The time when the formula was presented, however, was long before emergence of the concept of significant wave height. We verified the process of derivation of the formula by tracing back to the paper in which Dr. HIROI first presented the formula, studied the changes in wave height used for the formula and investigated the history of changes in the shape of breakwaters.As a result, we found that the highest wave height must be used for the HIROI formula, and that changes in breakwater structure existed behind the use of significant wave height in the formula.
著者
石田 健一 バクテイアル ガファ
出版者
公益社団法人 土木学会
雑誌
土木学会論文集B3(海洋開発) (ISSN:09127348)
巻号頁・発行日
vol.16, pp.547-552, 2000
被引用文献数
1

This study aims to apply the participatory planning method to contribute solving local problems in the fisherysector. Northern Sulawesi, Indonesia was selected as study area. Fish catch had been declining recent ten years and that incident had a serious negative impact not only to fishing operation but also to society. The authors applied the participatory planning methods to analyze problems and attempted to allocate solutions. In many parts the decline of fish catch was suggested by the tremendous increasing fishing effort of foreign fleet as well as non-existence of adequate program for regional fishery management. A Project Design Matrix (PDM) was formed as a trial to solve those issues. The paper also discusses about the lessons learned during the course of participatory workshop.
著者
間瀬 肇
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.19, pp.59-63, 2003 (Released:2011-06-27)
参考文献数
1

This paper shows the development of wave theories and numerical methods for random wave transformations in nearshore sea. When estimating wave conditions acting on coastal structures, a suitable wave model should be chosen, depending on the situation. This paper also describes criteria for selecting wave models and shows several examples of wave predictions.
著者
犬飼 直之 杉本 高志 Pujirahajo ALWAFI 細山田 得三
出版者
Japan Society of Civil Engineers
雑誌
海洋開発論文集 (ISSN:09127348)
巻号頁・発行日
vol.24, pp.153-157, 2008 (Released:2010-08-25)
参考文献数
2

The Niigataken Chuetsu-oki Earthquake occurred on July 16, 2007. The maximum magnitude of this earthquake was recorded 6.8 and the maximum JMA seismic intensity scale was recorded 6 upper, and Chuetsu area, especially around Kasiwazaki city, was damaged extensively. The Tsunami was occurred due to the earthquake, however arrived to Akita and Ishikawa shoreline. This wave was not big and there were not the extensive damage this time. However, the big tsunami following the extensive damage sometime occurs in the Sea of Japan. For example, the Tsunami due to Niigata Earthquake in 1964 became over 4 m wave height at Niigata City. Therefore, even if it was a small-scale wave and small damaged in this time, it is necessary to analysis how the people on the beach when the earthquake occurred thought, for example, how they imaged the arrival of tsunami and how to evacuate from the tsunami. Then, this study researched the hearing investigation for the people who was near from the shoreline when the earthquake occurred. The results mainly indicate that the more any evacuation route information should be shown, because the most people who come from another place do not know the information.