{"title":"EFFECT OF VEGETATION BIOSHIELD BY TROPICAL TREES ON TSUNAMI MITIGATION CONSIDERING THE BREAKING THRESHOLD OF THE TREE TRUNK","authors":"N. Tanaka, N. B. Thủy, K. Tanimoto","doi":"10.2208/JSCEJB.66.434","DOIUrl":"https://doi.org/10.2208/JSCEJB.66.434","url":null,"abstract":"津波による樹林帯破壊が，熱帯地域で防潮林として期待されているアダン樹林帯背後における津波力低減効果に与える感度を，破壊の有無と樹林帯幅に注目して定量的に評価した．算定した破壊限界値は，2m以上の樹木に対し樹高の8割を津波浸水深がこえた場合に破壊されるという既往知見を概ね満足していた．また，樹林帯幅が厚くなると樹林帯全体としての反射の影響で破壊限界値は大きくなった．樹高が 2，4mの場合は，樹林帯の前面部が破壊されると，樹林帯全部の破壊につながりやすい．樹高が 6m，8mの場合は途中で破壊が止まり，高い津波減衰効果を維持可能である．気根上部が破壊されても，気根のみによる津波力低減効果は大きいが，潜在的津波力減衰率の評価値に対し樹高2，4mの場合で2割程度，樹高6，8mで1割程度の影響を与える．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"18 1","pages":"434-443"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75740705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"CHARACTERISTIC OF NITROGEN AND PHOSPHORUS BUDGETS AT A TIDAL FLAT IN TOKYO PORT WILD BIRD PARK","authors":"Takumi Hatano, K. Murakami, Hirotsugu Ishii, Asato Kadowaki, T. Kuwae, K. Nakase","doi":"10.2208/JSCEJB.66.419","DOIUrl":"https://doi.org/10.2208/JSCEJB.66.419","url":null,"abstract":"本研究では，大都市沿岸域に造成された潟湖型の干潟である「東京港野鳥公園・潮入りの池」において，夏期2潮汐間の水質調査を3年間行い，干潟域における窒素・リン・クロロフィルαの収支，動態について検討した．また，飛来した水鳥の個体数と，底生動物の現存量の調査を行い，干潟域の生物相を把握した．調査の結果，当該干潟は夏期に，リンの供給源，窒素・クロロフィルαの消費源として機能しており，堆積物と直上水間の無機態窒素，リンの交換フラックスは干潟全体の収支の主要因であることが明らかになった．干潟域には年間を通してカワウの飛来数が数多く観測された．水鳥が干潟系外へ持ち去るTN量は最大でも，夏期に水中から除去されるTN量の12%程度，TP量は最大でも隣接海域へ流出するTP量の10%程度と，その値は小さかった．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"26 1","pages":"419-433"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91029724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"TURBULENT STRUCTURE AND CONCENTRATION TRANSPORT PROPERTIES IN COMPOUND OPEN-CHANNEL FLOWS WITH ONE-LINE EMERGENT TREES","authors":"M. Sanjou, K. Itai, I. Nezu","doi":"10.2208/JSCEJB.66.384","DOIUrl":"https://doi.org/10.2208/JSCEJB.66.384","url":null,"abstract":"実河川の高水敷には多様な樹木群が形成される．特に低水路と高水敷の境界部では一般に群生密度が大きい．高水時には境界部の樹木群によって大きな抵抗が発生し，主流速分布は低水路と高水敷のそれぞれに変曲点をもち，従来の単一変曲点をもつ混合層的な流れとはその様相は大きく異なる．そこで本研究では境界部に単列樹木を有する複断面開水路流れにおける乱流構造を明らかにするために，超音波流速計(ADV)を用いた流速3成分計測を行い，植生の配置間隔が2次流や乱流統計量の分布に与える影響やと2次流，レイノルズ応力およびせん断抵抗の関係を定量的に評価・考察する．さらにLESによって低水路／高水敷間の濃度交換特性を計算するとともに，効率的な交換を促進する樹木間隔の存在を明らかにした．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"52 1","pages":"384-394"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88823968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"IMPROVING THE FLOOD CONTROL OF DAMS DURING THE SNOWMELT SEASON BASED ON FORECASTED CUMULATIVE RAINFALL","authors":"T. Usutani, M. Nakatsugawa","doi":"10.2208/JSCEJB.66.268","DOIUrl":"https://doi.org/10.2208/JSCEJB.66.268","url":null,"abstract":"気候変動に対する適応策の一環として多目的ダムの治水・利水機能が注目されている．その背景の一つに，積雪寒冷地の多目的ダムでは，利水容量の確保を優先した融雪期における大雨への対応が懸念されていることがある．そこで本論文では，ダムの洪水調節機能の向上を目指し，予測雨量を利用したダムの事前放流の可能性を検討した．最初に，積算予測雨量と時系列予測雨量の精度を比較し，積算予測雨量の優位性を明らかにした．次に，積算予測雨量に基づいた事前放流方法を提案し過去の大雨を伴う融雪洪水に適用した．以上の結果，積算予測雨量の利用は融雪期のダムの洪水調節機能の向上に有効であることがわかった．さらに，融雪期の多目的ダムの管理においては，事前放流によって治水機能の向上が可能であることを示唆することができた．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"1 1","pages":"268-279"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87796181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"FIELD OBSERVATION FOR CONVECTIVE CIRCULATION DUE TO SURFACE COOLING IN THE SIDEARM OF A RESERVOIR","authors":"Yuichi Kouchi, T. Yamatogi, Yu Yamamoto, K. Okubo","doi":"10.2208/JSCEJB.65.46","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.46","url":null,"abstract":"2005年秋，岡山県のダム貯水池の側湾底層に水質・流速計を係留した．機器の設置（10月31日）と回収（11月9日）の際，側湾奥から本川下流ダム壁近傍まで水質プロファイルを測定した．設置時には貯水池下流端深部に溶存酸素量が0mg/Lに近い低温の貧酸素層が存在したが，回収時には10mg/Lに回復するとともに水温が上昇していた．その間，連続計測した側湾底層の流速記録から冷却性対流循環により側湾から本川へ向かう下層密度流の発生が確認された．下層密度流の貯水池内の縦断流れ構造を斜面で発生する下層プルームの相似解と比較して評価した結果より10月31日の貧酸素・低温の貯水池底水が側湾から下層密度流として潜入した水に置換えられたと考えられる．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"18 1","pages":"46-55"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73787322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"STUDY ON BURST SPEED OF SEVERAL FISHES LIVING IN RIVERS","authors":"K. Onitsuka, J. Akiyama, Akiyoshi Yamamoto, Takuya Watanabe, T. Waki","doi":"10.2208/JSCEJB.65.296","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.296","url":null,"abstract":"魚が魚道内を遡上できる条件として，魚道内の流速が魚の突進速度以下であることが挙げられる．突進速度とは1秒∼数秒間しか維持できない魚の最大遊泳速度である．突進速度に関する既往のデータは極めて少なく，しかも，同一魚種で同一体長であっても研究者によって提示している値が異なっているのが現状である．よって，魚道設計に採用すべき突進速度が不明確という問題点がある．本研究では多くの河川に生息するアユ，オイカワ，カワムツおよびギンブナを対象として，流速および体長別の突進速度を実験的に求めた．その結果，上記の魚種については，流速および体長に基づき突進速度を求めることが可能となった．また，突進速度に達するまでの時間および遊泳距離を解明した．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"65 1","pages":"296-307"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90172943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For predicting discharge hydrograph and progress of inundation flow caused by the levee breach, it is important to evaluate inundation discharge precisely. In this study, utilizing that the change in hydraulic and geometrical conditions during the flood appear in the temporal changes in water surface profiles, we developed a calculation model to estimate inundation discharge hydrograph using unsteady two-dimensional flow equations and the temporal change in water surface profiles including effects of the levee breach. To validate the model, we carried out field experiments of levee breach of a channel constructed in the Joganji River. Compared with the experimental results, the simulated inundation discharges showed acceptable accuracy. Finally, several issues were raised during appllying this method to actual rivers.
{"title":"CALCULATION METHOD OF INUNDATION DISCHARGE HYDROGRAPH FROM THE TEMPORAL CHANGES IN WATER SURFACE PROFILES DUE TO RIVER LEVEE BREACH","authors":"Tomonori Abe, S. Fukuoka, Y. Tsukamoto","doi":"10.2208/JSCEJB.65.166","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.166","url":null,"abstract":"For predicting discharge hydrograph and progress of inundation flow caused by the levee breach, it is important to evaluate inundation discharge precisely. In this study, utilizing that the change in hydraulic and geometrical conditions during the flood appear in the temporal changes in water surface profiles, we developed a calculation model to estimate inundation discharge hydrograph using unsteady two-dimensional flow equations and the temporal change in water surface profiles including effects of the levee breach. To validate the model, we carried out field experiments of levee breach of a channel constructed in the Joganji River. Compared with the experimental results, the simulated inundation discharges showed acceptable accuracy. Finally, several issues were raised during appllying this method to actual rivers.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"7 1","pages":"166-178"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90003986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"OXYGEN CONSUMPTION PROCESS DURING THE RESUSPENSION OF MUDDY SEDIMENT FROM ARIAKE BAY","authors":"T. Tokunaga, Masanori Isono, N. Matsunaga","doi":"10.2208/JSCEJB.65.269","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.269","url":null,"abstract":"","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"77 6 1","pages":"269-276"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77414509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"EXPERIMENTAL STUDY ON COHERENT STRUCTURE AND MONAMI PHENOMENA IN CANOPY OPEN-CHANNEL FLOWS WITH FLEXIBLE VEGETATIONS","authors":"T. Okamoto, I. Nezu, M. Sanjou","doi":"10.2208/JSCEJB.65.190","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.190","url":null,"abstract":"","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"80 1","pages":"190-202"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75951210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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