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The purpose of the study is to evaluate the flood disaster risk considering the rain water infiltration and storage function of land use. I calculated two indexes. One is the surface water caused by the torrential rain of typhoon in 2016. Another is the future elderly household distribution in 2040. Flood disaster risk was evaluated by the number of elderly household on the area with the surface water over 100 mm/h, considering 4 scenarios about land use change. Based on the results of these evaluation, I showed the future land use policy in Tokushima Urban Area.

The evacuation decision-making support system is proposed to prepare for a flood, sediment disaster in this research. Based on the reproduced result for 2009 event at the Sayou River basin, the risk map of the above-mentioned disasters is drawn by the time sequence. By using this map, we can give the river management administrators and the concerned residents an appropriate direction for evacuation. We are going to raise the completeness of this system to reduce the victims of these disasters.

We demonstrate the performance of the integrated runoff system to prepare for a flood disaster. To be concrete, we try a reproduction calculation featuring flood and inundation events at the Sayou River basin. To reduce the victims of flood disasters, let us at first show directions on evacuation decision for the river management administrators and the concerned residents using evacuation-warning system to be proposed in this research. We start with the simulation on floods to consider the above-mentioned system.

台風MORAKOT(8号)は2009年8月7日に台湾東部に上陸し，7日から9日にかけて，3日間雨量が世界記録にほぼ匹敵するような豪雨をもたらし，中南部を中心として甚大な土砂災害や洪水災害を引き起こした。死者は700人にものぼる大惨事であった。積算雨量が極めて大きいこの台風により，高雄県甲仙郷小林村では，表層崩壊，深層崩壊，土石流，天然ダムの形成と決壊が連続して発生し，一夜にして村が壊滅した。気候変動により降雨の極端現象が増加すれば，我が国でもこのような複合土砂災害は増加すると思われ，早急に対策を考えておく必要がある。本報告は，土木学会と砂防学会の調査団による台湾における台風MORAKOT災害の調査結果を取りまとめたものである。, Typhoon MORAKOT (No.8) landed the Taiwan eastern part on August 7, 2009 and brought a heavyrainfall approximately equal to a world record for three days. It caused serious sediment disasters and flooddisasters around middle and southern areas. The catastrophic disaster resulted in 700 dead people. By thistyphoon with extremely large cumulative precipitation, a multimodal sediment disaster due to some shallowPhoto 19 Accumulation of driftwoods (Left: high quality, Right: low quality)― 82 ―landslides, a deep landslide, some debris flows, the formation and the collapse of the landslide dams tookplace occurred in Siaolin Village, Kaohsiung Country and the village was completely destroyed overnight. Ifextreme phenomena of the rainfall increase, it seems that such disasters occur frequently in our country, andit is necessary to think about measures for such a disaster immediately. This report gathered findings by theinvestigating group of Japan Society of Civil Engineering and Japan Society of Erosion Control Engineering.

気候変動に起因する氷河湖決壊洪水(GLOF)による洪水災害と土砂災害は南アジアのヒマラヤ地域やその他の氷河地帯においてたびたび発生し、下流において深刻な洪水災害をもたらす脅威となっている。氷河湖の決壊の主な原因は、氷塊の移動が急激な水位上昇や浸透流、氷河サージを引き起こし、それによってモレーンダムが破壊されることである。本報は、モレーンダムの破壊に起因する氷河湖決壊を研究したものである。浸透流と水位上昇による越流がもたらすモレーンダム破壊を一連の実験によって検証し、浸透とモレーンダムの破壊について行った数値解析結果と比較した。また、氷河湖に与える全球気候変化の影響も解析し、観測記録にもとづいて氷河湖決壊洪水流量を予測する経験的関係を導いた。, Due to impact of climate change flood and sediment disasters caused by Glacial Lake Outburst Flood (GLOF) are frequently occurred in the Himalaya of South Asia or glacier regions of the world. GLOF poses a serious threat of flood disasters at downstream valley. Outburst of glacial lakes typically occurs due to moraine dam failure caused by glacier mass movement leading to a rapid rise of water level, seepage flow and a surge. The outburst of glacial lake due to moraine dam failure has been investigated. The moraine dam failure by seepage flow and overtopping due to water level rising has been investigated though a series of flume experiments. Numerical analysis of seepage and moraine dam failure has been also performed. The simulated results are compared with the experimental results. The impact of global climate change on glacial lakes is also analyzed. The empirical relationship to predict GLOF discharge has been also developed based on the recorded GLOFs discharge.

本論文は、巨大スケールの洪水災害に対する脆弱性特徴づける手法を述べたものである。まず脆弱性を解析するための概念的枠組みを構築する。次に生物物理学的な脆弱性解析と社会的な脆弱性評価を考慮して、洪水災害に対する包括的な脆弱性を定量化する手法を述べ、2003年に発生した洪水事象のシナリオ解析に焦点を当てている。ここで確立された脆弱性評価のアプローチの有用性が中国・淮河流域において例証されている。最後に、包括的な脆弱性評価について議論している。本研究は、洪水災害に対する脆弱性を減少させるべき地域が明らかにし、またこのような増大する洪水の危険地域に居住する住民の回復能力を高める事に貢献するものである。, The paper attempts to present a methodology for characterizing vulnerability to large-scale flood hazards. Firstly the conceptual framework for analyzing vulnerability to flood hazards is put forth. Then according to biophysical vulnerability analysis and social vulnerability assessment, it presents a methodology for quantifying holistic vulnerability to flood hazards, which is focusing on scenario analysis of a flood event occurred in 2003. The utility of this approach in an assessment of vulnerability is illustrated in the Huaihe River Basin, China. Finally, the evaluation of holistic vulnerability is discussed. This study helps illustrate the zones necessary to decrease vulnerability to flood hazards and strengthen their resilience while living with increasing floods.

韓国は，1960年以降の急激な経済発展以降，北西部太平洋域における主要経済国の一つとして発展を遂げてきた。この経済発展は同時に，社会システムの劇的な変化を引き起こし，自然災害に対して社会は極めて脆弱なものとなった。洪水災害は韓国においてもっとも一般的な自然災害であり，洪水災害による被害は年々増加している。本研究では，近年，韓国で発生した極めて甚大な自然災害に焦点を当て，それに対する社会的対応，科学的対応，そして対策について調査した結果をまとめる。朝鮮半島を襲った最近の台風とそれによる洪水災害を調査し，それと日本の洪水災害を対比することで，洪水災害を軽減するための方策を考えたい。, Since the explosive economic development after the 1960s, Korea has emerged as one of the major economic powers in Northwestern Pacific region. However, the same growth in economy accompanied by a drastic change of social system made the country more vulnerable to exterior effects, namely natural disasters. Floods are the most common form of these natural disasters and the property damage by these disasters has continuously increased. This study examines social and scientific responses and countermeasures on historic natural disasters in Korea. By reviewing the recent typhoon and related flood damage of Korea, this study intends to search the way to mitigate flood disaster of both countries.

足羽川流域においては，2004 年7 月に梅雨前線の集中豪雨によって河川の流下能力を大幅に超える洪水が発生し，流域の各所で激甚な被害を被った。本研究においては，足羽川中流部の水害の実態を詳細に調べ，山地河川の水害の発生構造を検討した。その結果，谷底平野の形態，河道湾曲部における土地利用，橋梁や取水堰などの河道内の構造物，土石の堆積による河床上昇，各地区内にある道路や鉄道線路の状態が水害の発生に大きな影響を与えることがわかった。また，得られた知見に基づいて考えられる治水対策について述べた。, Severe flood disasters due to heavy rainfall occurred in the Asuwa River basin on July 18, 2004. In this paper, the flood disasters in mountainous area of the basin are discussed by investigating the aerial photographs taken after the flood and the results of precise field surveys. The main conclusions are that the aspects of flood disaster are characterized by the following points; (1) the characteristics of flood plains in valley, (2) land usage around river channels, (3) obstructing effect by bridges and barrages, (4) sedimentation in river channels and (5) the role of roads for inundation.

1998年の余笹川の洪水は，調査対象区間の洪水流量が河道の平均的な流下能力の4倍前後と極めて大きかったため，激甚な被害をもたらした。水害に重要な関わりを持つ新流路の形成の問題を水害の実態に基づいて検討した。さらに，水害と土地利用との関係についてそれらの地域性に着目して検討し，土地利用の背景にあるそれぞれの河川区間の自然条件および社会条件について考察を加えた。その結果，水害と土地利用とは密接な関係があり，土地利用は流域の自然条件に支配されていることがわかった。, Severe flood disasters were occurred in the Yosasagawa River basin due to heavy rainfall on August 27, 1998. The discharge of flood flow was about fore times as large as the average capacity discharge of riverchannel in the investigated section. In this paper, the cause of some new channels formed by inundation wasdiscussed by investigating the field and aerial photographs taken before and after the flood around theYosasagawa River. It was cleared that the new channels were formed in the place where curved river channelswere narrow extremely and the disaster like this is related with land usage around curved river channels.

1998年の余笹川の洪水は，洪水流量が河道の流下能力の2～5 倍と極めて大きかったため，激甚な被害をもたらした。水害に重要な関わりを持つ側方侵食と新流路の形成の原因を明らかにするため，水害の実態を丁寧に調べた。その結果，河道の側方侵食や新流路の形成が旧河道の存在と深く関係していること，湾曲部河道の河道幅の違いによって新流路の形成状況が変わることなどがわかった。最後に水害実態の検討結果に基づいて考えられる治水対策について述べた。, Severe flood disasters were occurred in the Yosasagawa River basin due to heavy rainfall on August 27, 1998. The discharge of flood flow was about fore times as large as the average capacity discharge of riverchannel in the investigated section. In this paper, the cause of some new channels formed by inundation wasdiscussed by investigating the field, old maps and aerial photographs taken before and after the flood around theYosasagawa River. It was cleared that the new channels were formed on the old river channels and in the placewhere curved river channels were narrow extremely. The flood control measures of the Yosasagawa River wereconsidered, based on the results of investigations.

既往洪水から同定された貯留関数パラメータは洪水ごとに異なる値を示す。したがって現に起こりつつある洪水に適合するモデルパラメータは, 一般には過去に同定したモデルパラメータとは一致しない。適合しないモデルパラメータを用いた場合は当然, 良い予測結果は得られない。そこで, 貯留関数パラメータが洪水ごとに変化することを考慮するために, 複数の予測更新システムを同時に実行してそれらの重みを逐次更新する手法を導入した実時間流出予測手法を提案し, 実流域に適用してその効果を検証する。, The storage function method developed by Kimura is often used for short‐term runoff simulation, and some on‐line prediction methods which use the storage function method incorporating forecast updating using Kalman filterimig have beemi developed by several investigators including the authors. In this paper, the framework of our flood runoff pmediction muethod is introduced and treatment of uncertainty of model parameters of the storage function method is newly devised.In the new method, a number of filters with different parameters are rumi simultaneously, and the probability distribution assigned to these filters is updated by using Kalman filtering with real‐time observation data. The results of application of this treatment show that the new treatment enhances the prediction accuracy.

application/pdf, 【学位授与の要件】中央大学学位規則第4条第2項 【論文審査委員主査】山田 正（中央大学理工学部教授） 【論文審査委員副査】齋藤 邦夫（中央大学理工学部教授）、谷下 雅義（中央大学理工学部教授）、鎌倉 稔成（中央大学理工学部教授）、田中 規夫（埼玉大学大学院理工学研究科教授）、福岡 捷二（中央大学研究開発機構専任研究員（機構教授））