近年，日本各地で極端な豪雨が発生し，土砂災害や堤防決壊などの災害が頻発している．本研究では，北海道最大の経済拠点である札幌及びその周辺市町，交通の要衝である新千歳空港を抱える石狩川水系千歳川流域を対象に，①流域を貯留関数法，②河道を一次元不定流，③氾濫原を平面二次元不定流，で氾濫解析モデルを構築し，最大規模の降雨を想定した浸水予測について研究を行った．なお研究に用いた解析モデルは，千歳川が石狩川の背水影響を30km以上にわたり受ける低平地河川であり，支川・運河・排水路まで背水影響が及ぶことを勘案し，内水・外水を一体化した氾濫解析モデルを構築した．解析モデルの検証には，石狩川水系における観測史上最大の洪水である昭和56年洪水と，平成以降の大規模出水である平成13年洪水を再現した．
In recent years, extreme rainfalls have occurred and disasters that involve landslides and levee failures have frequently occurred in Japan. A flood analysis model was constructed for the Chitose River basin of the Ishikari River System, a basin that includes Sapporo, the largest economic base of Hokkaido; municipalities surrounding Sapporo; and New Chitose Airport. The model used 1) the storage function method for the basin, 2) one-dimensional unsteady flow for the river channel, and 3) planar two-dimensional unsteady flow for the flood plain. Examination was done for flood forecasting that assumes rainfall of the largest scale. A flood analysis model was constructed that integrated the landside and foreland waters, based on the consideration that the Chitose River flows through a low-lying area and is affected by backflow from the Ishikari River for a distance of more than 30km and based on the consideration that the Chitose receives the influence of the Ishikari's back water in the branches, canals, and drainage canals. For verification of the analysis model, the 1981 flood, which was the largest observed flood in the Ishikari River System, and the 2001 flood, which is the large-scale flood in recent years were reproduced.
低平地河川を対象とした内水・外水を一体化した氾濫解析手法の提案
JSCE_72_5_I271_I276
(2.43MB)
