FLOOD CONTROL FUNCTION OF FARMLAND AS GREEN INFRASTRUCTURE USING INUNDATION ANALYSIS MODEL
| Jazyk: | japonština |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | 土木学会論文集B1(水工学). 76(2):I_463-I_468 |
| ISSN: | 2185-467X |
| Popis: | 本研究では,徳島県にある海部川支川善蔵川流域を対象とし,農地や湿地をグリーンインフラとし,洪水調節機能を定量的に評価する内水氾濫解析モデルを構築し,人口減少が進む当該流域における将来の土地利用の在り方を考察した.平成26年台風12号を元に,Hazen法によって確率雨量を評価し,降雨外力の違いと土地利用の違いによる洪水調節機能に与える影響を評価した.前者では,床上浸水の被害が20年確率降雨以上で顕著に増加したことから,水害リスクの高い場所と農地による洪水調節機能の発揮限界について検討した.後者では,宅地転換が進む前の過去の土地利用では,湛水量の増減の応答が早く,とりわけ集中的に浸水する領域を特定した.以上から,浸水リスクがある場所での開発を控え,社会状況に連動した優先的な退避の施策の成立が今後重要視される. In this paper, flood control function of agricultural land and wetlands were considered using an inundation analysis model, expecting to work as green infrastructure against flood. The study area is located in Zenzo River basin, a tributary of the Kaifu River, Tokushima Prefecture, where population decline is severe in recent years. Based on the rainfall by Typhoon 1412 several probable rainfalls were evaluated, and the flood control function was examined with the different rainfalls, as well as the difference of land use. The results show that, since the flood damage due to inundation above floor level remarkably increase at and over 20-year period probable rainfall, the flood control function has a limit at some stage against extreme rainfall events. On the other hand, in the past land use where more farmlands existed, temporal variation of inundation volume reduces more rapidly compared with the current land use. The results indicate it will be necessary to suppress development in high risk areas, and the past land use will be a good reference for a wise land use. |
| Databáze: | OpenAIRE |
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