営農の効率化および耕地利用率の向上をめざし, 平坦地では大区画水田が求められている. 本研究は標準的構造をもとにしながらも種々の工夫を加えて大区画水田に改良したの水田構造の特徴に注目し主に用排水性, 作業効率および水管理などの視点からその水田構造がもつ機能と効果を量的に評価した.
当地区では, 圃場整備時ばかりではなく, その後も農区均平, 段差の修正および畦畔を外すことなどによって区画が拡大されており, 1992年現在, 6.8ha, 2.5haなどの大区画が存在している。また用排水路の暗渠化,暗渠排水組織の用排兼用化および自動潅漑などによる用排水性の確保, 大区画化, 集団化および乾田直播の導入などにより営農の効率化を実現させている.

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In 1960s, many developments had been carried out to supply houses for citizens; however, several problems have been arisen such as decline of city centers, the growth of aging population and collapse of local communities. To deal with such problems and make the world sustainable, establishment of management system in the developed area is now essential. The purpose of this study is to consider “Area Management” in a suburban city by examining two types of partnership as its agents in order to clarify the issues or potential of the attempt in Japan. The study first reviews the analysis of the contents of Area Management and the role of each sector, followed by the developing processes of local organizations and the transition of the designated sites of Area Management.

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We investigated the water area reclamation projects, in particular the changes of these projects in Japan after the World War II.
Firstly, we explained the institution of water area reclamation projects.
Secondly, we classified these projects and made the distribution maps of the projects.
From these results, the following was found worthy of being reported:
1) Sea coast reclamation projects are concentrated around Ariake Sea, Yatsushiro Sea, Seto Inland Sea, Ise Bay, Mikawa Bay and Kagoshima Bay where tidal range is remarkable.
2) All projects above mentioned except Kagoshima bay belong to alluvial plains
3) Water area reclamation projects at lakes are almost all distributed around large lakes or brackish water lakes, i. e. Lake Shinji, Nakaumi, Lake Biwa, Lake Hamana, Kasumigaura, Imbanuma, Teganuma, Izunuma, Hachirogata, Lake Jusan.
4) The total number of the sea coast reclamation projects is more than that of the water area reclamation projects. But the total project area and the total reclamation area of the latter are larger than those of the former.
Then, from the view of social conditions, international situations and agricultural administrations, we discussed the historical transition of the projects in detail, and explained the change and decay of the projects.
Lastly, we presented some tables of the project area and the reclamation area produced by each projects and these diverted area.

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降雨入力の変動パターンが地盤中を伝搬する現象, および豪雨の中断が持つ意味を明らかにするために円柱土層による実験と考察を行った.M系列信号(疑似不規則信号の一種)状の降雨入力による実験では, 降雨入力と地盤各部での体積含水率の変動との相互相関関数をとることにより, 地表から-4m付近でも体積含水率の変動が降雨パターンに対応していることが観察された.中断を含む降雨を与えた結果では, 中断後の降雨による二次的浸潤前線が一次的な浸潤前線の降下速度を速めることがわかった.これらの現象は, 開放不飽和毛管浸透モデルによって説明できることを示した.最後に, 降雨浸透現象と土砂災害発生との関係について考察した.

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