JP4253838B2

JP4253838B2 - Water supply and drainage system for paddy fields

Info

Publication number: JP4253838B2
Application number: JP2003202108A
Authority: JP
Inventors: 國夫宮嶋; 正明宮嶋; 博宮嶋
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-07-25
Filing date: 2003-07-25
Publication date: 2009-04-15
Anticipated expiration: 2023-07-25
Also published as: JP2005040038A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば水田の暗渠排水あるいは土中灌水施設に用いられる水田用給水及び排水システムに関する。
【０００２】
【従来の技術】
従来、この種の水田用給水及び排水システムとして特許文献１に示す暗渠排水用バルブが知られている。この暗渠排水用バルブは、前記排水管が両端側にそれぞれ接続される継手部を有し、この継手部の中間部から立ち管８が立ち上がっている。この立ち管は、畦畔において地上に露出している。前記継手部７には、ここに形成される水路を開閉する弁体が昇降自在に設けられており、この弁体から立ち上がる操作杆が立ち管内を通ってその上方まで突出している。また、地上に露出した立ち管の上端部には、キャップが立ち管の外周側に嵌合して取り付けられている。このキャップの中央部には、前記操作杆が貫通した筒部が形成されており、この筒部には、固定リングが螺着されている。さらに、キャップから上方へ突出した操作杆の上端部には操作取手が固定されている。
【０００３】
そして、湿田、乾田化の管理のために、地上で操作取手を上下することにより弁体を開閉操作する。本暗渠排水用バルブを開いた状態では、水田下の地中水が吸水管内に吸水され、排水管および継手部を通って排水路に排水され、乾田化が図られる。一方、本暗渠排水用バルブを閉じた状態では、吸水管からの排水が遮断されるので、地中水が水田下に止まり、湿田化が図られる。
【０００４】
【特許文献１】
特開２００１−１０７３４７号公報
【０００５】
【発明が解決しようとする課題】
前記従来の暗渠排水用バルブでは、単に地中水を水田に埋設した吸水管で吸水することによってのみ成されており、吸水効率が悪い。特に、吸水管は、その外周に形成する小孔から、吸水管の内部に地中水を導水しており、吸水管の上面には籾殻などを被せて吸水管の周囲に疎水部を構成するなど方法も採用されている。しかし、こうした籾殻は腐ってしまい長期に渡って安定的に吸水効率を維持することができない面がある。
【０００６】
本発明は、このような問題点を解決しようとするもので、地中水を効率的に吸水可能な水田用給水及び排水システムを提供することを第１の目的とする。また、本発明は、吸水管周辺の疎水性を長期に渡って安定的に維持することが可能な水田用給水及び排水システムを提供することを第２の目的とする。
【０００７】
【課題を解決するための手段】
請求項１記載の水田用給水及び排水システムは、排水路に連通する複数の通水孔を備えた暗渠吸水管と、この暗渠吸水管の一端から地表に立ち上がる立ち上がり管と、前記暗渠吸水管の反対側端部に接続して前記排水路と、前記暗渠吸水管に接続して該暗渠吸水管を開閉する水閘と、前記暗渠吸水管上に立設した吸水性に優れた誘導疎水体とを備え、水閘を解放して水田の余剰の地中水を排水路に排出するとともに、前記水閘を遮断した状態で前記立ち上がり管から暗渠吸水管に給水した用水を土壌の中に供給して湿田化するように構成し、前記誘導疎水体が、前記暗渠吸水管に対してほぼ垂立したネット又は複数の多孔質状の中空袋で構成した通水部材と、この通水部材内に充填した疎水材と、前記通水部材に挿通した導水パイプとで構成したものである。
【０００８】
上記のように構成される水田用給水及び排水システムは、水田下の地中水が誘導疎水体および吸水管内に吸水され、湿田、乾田化の管理のために水閘を開いた状態では、吸水管から排水路へと排水され、乾田化が図られる。一方、水閘を閉じた状態では、暗渠吸水管からの排水が遮断されるので、立ち上がり管から給水された用水が暗渠吸水管から誘導疎水体を通過して水田に給水され、湿田化が図られる。また、水田の地中水は、通水部材を通って疎水材間に浸透し、その地中水が吸水管へと吸水されるとともに、疎水材に浸透した地中水の一部が導水パイプを伝って吸水管へと効率的に吸水される。
【０００９】
請求項２記載の水田用給水及び排水システムは、前記疎水材として複数の粒状部材を充填もしくは複数の短パイプ部材等あるいは複数の細長部材を束ねて前記通水部材に装填して成るものである。
【００１０】
上記構成により、水田下の地中水は、粒状部材、短パイプ部材等又は束ねた細長部材間に隙間に浸透し、その地中水が吸水管へと吸水される。
【００１１】
請求項３記載の水田用給水及び排水システムは、前記導水パイプの表面及び内面に複数の導水用突起又は導水用溝部を該導水パイプの軸方向に沿って設けたものである。
【００１２】
上記構成により、導水パイプの表面積が拡大し、導水パイプの集水機能が高まる。
【００１３】
請求項４記載の水田用給水及び排水システムは、排水路に連通する複数の通水孔を備えた暗渠吸水管と、この暗渠吸水管の一端から地表に立ち上がる立ち上がり管と、前記暗渠吸水管の反対側端部に接続して前記排水路と、前記暗渠吸水管に接続して該暗渠吸水管を開閉する水閘と、前記暗渠吸水管上に立設した吸水性に優れた誘導疎水体とを備え、水閘を解放して水田の余剰の地中水を排水路に排出するとともに、前記水閘を遮断した状態で前記立ち上がり管から暗渠吸水管に給水した用水を土壌の中に供給して湿田化するように構成し、前記誘導疎水体に小木杭または突刺部を連結し、前記暗渠吸水管上に前記誘導疎水体を立設する際、前記小木杭または突刺部材を水田の掘削部周辺に突き刺して前記誘導疎水体を起立状態で保持するように構成したものである。
【００１４】
上記構成により、水田下の地中水が誘導疎水体および吸水管内に吸水され、湿田、乾田化の管理のために水閘を開いた状態では、吸水管から排水路へと排水され、乾田化が図られる。一方、水閘を閉じた状態では、暗渠吸水管からの排水が遮断されるので、立ち上がり管から給水された用水が暗渠吸水管から誘導疎水体を通過して水田に給水され、湿田化が図られる。また、水田に敷設した暗渠吸水管上に誘導疎水体を設置する際、水田を掘削して暗渠吸水管を敷設し、暗渠吸水管の底部を除いた周囲に被覆疎水材を設置した後、誘導疎水体を立設する。この時、小木杭または突刺部を水田の掘削部に突き刺すことによって、誘導疎水体を起立状態で保持することが可能であり、誘導疎水体の施工性が向上する。
【００１５】
請求項５記載の水田用給水及び排水システムは、前記暗渠吸水管の底部を除いて該暗渠吸水管を覆う耐食性に優れた被覆疎水体を設けたものである。
【００１６】
上記構成により、水田下の地中水は、被覆疎水体を透過して吸水管へと吸水されるとともに、被覆疎水体が耐食性に優れることから、吸水管の疎水性を長期に渡って安定的に維持できる。
【００１７】
請求項６記載の水田用給水及び排水システムは、前記被覆疎水体が疎水材として複数の粒状部材又は複数の短パイプ部材等あるいは複数の細長部材を前記通水部材に装填したネット又は多孔質状の中空袋とで構成したものである。
【００１８】
上記構成により、水田の地中水は、被覆疎水体を透過して粒状部材又は複数の短パイプ部材等あるいは束ねた細長部材間に隙間に浸透し、その地中水が吸水管へと吸水される。
【００１９】
【発明の実施形態】
以下、本発明の暗渠排水用バルブの一実施例について、図１から図５を参照しながら説明する。図１において、２１は水田、２２は畦畔、２３は畦畔または農道路肩、２４は水田２１下の地中、２５は排水フリュームである。そして、水田２１下の地中２４の６０ｃｍ〜１ｍ程度の深さの位置に暗渠吸水管２６が埋設されている。この吸水管２６は、複数本を継ぎ合わせてある。この吸水管２６の周壁部には複数の通水孔２８が開口形成されている。また、２９は９０°曲がった立ち上がり管で、この立ち上がり管２９は、一端部が吸水管２６に接続されているとともに、他端が畦畔または農道路肩２３の地面に露出させてある。この立ち上がり管２９の他端の開口は、小さい孔により吸気孔を備えたねじキャップ３０により取り外し可能に設けられている。
【００２０】
そして、前記吸水管２６中に水閘たる暗渠排水用バルブ４０が地中２４に埋設させて設けられている。この暗渠排水用バルブ４０は、ほぼＴ字型の合成樹脂からなる継手部４２を有し、この継手部４２に吸水管２６をそれぞれ嵌合されて接続し、吸水管２６から排水フリューム２５へ連通する水路が形成されている。また、前記継手部４２には立ち管４３の下端部が嵌合されて接着剤により固定されている。この立ち管４３は、硬質塩化ビニールなどの切断が比較的容易な合成樹脂からなり、鉛直な円筒形状になっており、その立ち管４３の上端部に管接続部４１を介して硬質塩化ポリエチレンなどの合成樹脂からなる保護ボックス４４が接続されている。そして、前記継手部４２内には水路を開閉する弁体４５が設けられ、この弁体４５に前記立ち管４３内に位置する操作杆４６が接続されるとともに、この操作杆４６を操作する操作取手４７が保護ボックス４４の内部に設けられている。なお、図中４８は保護ボックス４４を塞ぐ蓋体である。
【００２１】
５０は前記吸水管２６及び後述する被覆疎水材の上面に接続した誘導疎水体であり、吸水管２６上に間隔を置いて、複数並設されている。これら誘導疎水体５０は、下端部を前記吸水管２６及び後述する被覆疎水材５５の上面に接触させた状態で、その上端部を田面から２０〜３０ｃｍ程度離して地中２４に埋設させて設けられている。この誘導疎水体５０は、例えばネットあるいは多孔質状の中空袋からなる通水部材５１と、この通水部材５１内に貫挿した合成樹脂ならなる導水パイプ５２と、この通水部材５１と導水パイプ５２との間に充填した疎水材５３とで構成されている。なお、本実施例では、疎水材５３として細かな砂利などの粒状部材５３ａを誘導疎水体５０に充填または装填する他、図４に示すように、藁などの有機質あるいは無機質細管状の細長部材５３ｂもしくは短パイプ部材等（図示しない）を束ねて構成してもよい。また、導水パイプ５２の形状としてパイプ状、多角形状、円柱状など種々の形状に形成すればよい。なお、導水パイプ５２は、その表面積を拡大して粒状部材５３ａの間に浸透した地中水を吸水管２６の周囲の被覆疎水体５５へと案内するために、図３に示すように、導水パイプ５２の外周面に複数の導水用突起５４を軸方向に沿って一体成形したり、あるいは図４に示すように、導水パイプ５２の内面に複数の導水用溝部５４ａを軸方向に沿って一体成形している。このように、導水パイプ５２の外周面に導水用突起５４又は導水用溝起５４ａを形成することにより、粒状部材５３ａあるいは細長部材５３ｂの間に浸透した地中水を被覆疎水体５５へと効率よく案内することが可能となる。
【００２２】
５５は、前記吸水管２６の上面を覆う透水性の被覆疎水体であり、図７に示すように、細長状の袋状のネット５６を複数の幅方向並びに長さ方向に連結し、これらネット５６内に疎水材５７として砂利などの細かな砂利などの粒状部材５３ａを充填して構成している。これを吸水管２６の上面に被せることによって、吸水管２６の底部を除いて吸水管２６の上部及び側部を覆うようにしている。また、粒状部材５３ａを充填するものはネット５６に限らず図９に示すように、樹脂などの角筒状に形成され、かつ、周縁に多数の開口孔５８ａを備えた多孔質状の中空袋５８を幅方向に連結し、これに粒状部材５３ａを充填するように構成してもよい。
【００２３】
６０は誘導疎水体５０に連結した突刺部であり、通水部材５１の上端部に連結した紐体６１によって誘導疎水体５０と連結されている。この突刺部６０を水田の掘削部に突き刺すことによって、吸水管２６上に誘導疎水体５０を立設する際、前記誘導疎水体５０を起立状態で保持している。
【００２４】
つぎに、前記の構成について、その作用を説明する。まず、水田２１に敷設した吸水管２６上に誘導疎水体５０を設置するには、水田２１を掘削し、吸水管２６を敷設し、吸水管２６を覆う被覆疎水体５５を敷設する。その後、被覆疎水体５５上に誘導疎水体５０を間隔をおいて立設する。この時、吸水管２６上の誘導疎水体５０には自立性が無いが、掘削した水田２１の掘削部の壁面に突刺部６０を突き刺すことによって、吸水管２６上において誘導疎水体５０を起立状態で保持することができる。この後、掘削部を埋め戻すことによって、誘導疎水体５０と被覆疎水体５５を水田２１下の地中２４に埋設する。
【００２５】
そして、常時は蓋体４８を閉じておくが、湿田、乾田化の管理のために本暗渠排水用バルブ４０を開閉するには、蓋体４８を開け、固定キャップ（図示しない）を緩めた上で、操作取手４７を上下して弁体４５を開閉操作する。なお、固定キャップを締め付ければ、操作杆４６とともに弁体４５が固定される。暗渠排水用バルブ４０を開いた状態では、図１に矢印ａで示すように、水田２１下の地中水が通水孔２８から吸水管２６内に直接的に吸水される。これとともに、水田２１下の地中水が被覆疎水体５５に立設した誘導疎水体５０の通水部材５１及び吸水管２６の上部及び側部を覆う被覆疎水体５５のネット５６あるいは中空袋５８の開口孔５８ａを通して内部に充填した疎水材５３となる砂利などの粒状部材５３ａあるいは藁などの有機質あるいは無機質の細管状の細長部材５３ｂ間の隙間に浸透し、こうして誘導疎水体５０で吸水した地中水が通水孔２８から吸水管２６内に間接的に排水される。また、誘導疎水体５０に内設した導水パイプ５２は、砂利などの粒状部材５３ａを充填した通水部材５１を起立状態で保持する芯材として機能するとともに、その外周面に複数の導水用突起５４または導水用溝部５４ａを軸方向に一体成形することで、導水パイプ５２の表面積が増大し、疎水材５３に浸透した地中水が導水パイプ５２に伝って吸水管２６に効果的に導水することができる。こうして吸水管２６内の地中水が吸水管２６から排水フリューム２５へと排水され、水田２１の乾田化が図られる。一方、暗渠排水用バルブ４０を閉じた状態では、吸水管２６からの排水が継手部４２において弁体４５により遮断されるので、地中水が水田２１下に止まり、湿田化が図られる。さらに、用水をパイプライン３１および立ち上がり管２９を介して給水することにより、図１に矢印ｂで示すように、吸水管２６及び誘導疎水体５０から積極的に土中灌水を行うこともできる。
【００２６】
以上のように、本実施例においては、地中２４に埋設した吸水管２６上に複数の誘導疎水体５０を立ち上げることによって、水田２１下の地中水が誘導疎水体５０の通水部材５１を通して誘導疎水体５０内に充填した疎水材５３となる細かな砂利などの粒状部材５３ａあるいは藁などの有機質あるいは無機質の細管状の細長部材５３ｂ間の隙間に浸透し、この地中水を吸水管２６へと効率的に導水することができる。このように、通水孔２８から吸水管２６に直接、地中水を排水するばかりでなく、誘導疎水体５０に浸透した地中水を吸水管２６へと排水することができる。これにより、水田２１下の地中水を効率的に排水して水田２１の乾田化を図ることができるとともに、暗渠排水用バルブ４０を閉じた状態では、地下水溝からパイプライン３１および立ち上がり管２９を介して給水され、吸水管２６及び誘導疎水体５０から積極的に土中灌水を行うこともできる。
【００２７】
また、誘導疎水体５０に内設した導水パイプ５２の軸方向に沿って複数の導水用突起５４あるいは導水用溝部５４ａを成形することで導水パイプ５２の表面積を増大させ、その導水パイプ５２に沿って地中水を吸水管２６に効果的に導水することができる。
【００２８】
さらに、吸水管２６を耐食性に優れた被覆疎水体５５で覆うことにより、腐食による疎水性の低下を招くことなく、吸水管２６周辺の疎水性を長期に渡って安定的に維持することができる。また、被覆疎水体５５上に誘導疎水体５０を立設する際、掘削した水田２１の掘削部の壁面に突刺部６０を突き刺すことによって、吸水管２６上において誘導疎水体５０を起立状態で保持することができ、人手により誘導疎水体５０を支えるといった手間も掛からない。また、吸水管２６上の上面を被覆疎水体５５は、ネット５６あるいは周縁に多数の開口孔５８ａを備えた樹脂製の中空袋５８を幅方向に連結して構成しているから、吸水管２６に被せて吸水管２６に簡単に装着できるから、施工性にも優れる。
【００２９】
なお、本発明は、前記実施例に限定されるものではなく、種々の変形実施が可能である。例えば、誘導疎水体５０や被覆疎水体５５は耐食性に優れ、吸水管２６側への通水性を損なわない構成であればよく、例えば通水性のコンクリート品や通水性を有する発泡した合成樹脂品で一体で構成するなど、要は疎水性を優れた構成であればよい。また、導水パイプ５２に導水用突起５４又は導水用突起５４ａを形成した例を示したが、導水パイプ５２を円筒状、円柱状に形成するようにしてもよく、また、材質は合成樹脂や木材でもよい。また、突刺部を小木杭で構成してもよく、要は掘削部に突き刺す構成であればよい。
【００３０】
【発明の効果】
請求項１記載の水田用給水及び排水システムによれば、排水路に連通する複数の通水孔を備えた暗渠吸水管と、この暗渠吸水管の一端から地表に立ち上がる立ち上がり管と、前記暗渠吸水管の反対側端部に接続して前記排水路と、前記暗渠吸水管に接続して該暗渠吸水管を開閉する水閘と、前記暗渠吸水管上に立設した吸水性に優れた誘導疎水体とを備え、水閘を解放して水田の余剰の地中水を排水路に排出するとともに、前記水閘を遮断した状態で前記立ち上がり管から暗渠吸水管に給水した用水を土壌の中に供給して湿田化するように構成し、前記誘導疎水体が、前記暗渠吸水管に対してほぼ垂立したネット又は複数の多孔質状の中空袋で構成した通水部材と、この通水部材内に充填した疎水材と、前記通水部材に挿通した導水パイプとで構成したものであるから、水田下の地中水が直接的に吸水管へと吸水されるのみならず、誘導疎水体に浸透した地下水が吸水管内に吸水され、乾田化の管理のために水閘を開いた状態では、吸水管から排水路へと排水され、乾田化が図られる。一方、水閘を閉じた状態では、暗渠吸水管からの排水が遮断されるので、立ち上がり管から給水された用水が暗渠吸水管から水田に給水することで積極的な湿田化や土中灌水が図られる。また、水田の地中水は、通水部材を通って疎水材間に浸透し、その地中水が吸水管へと吸水されるとともに、疎水材に浸透した地中水の一部が導水パイプを伝って吸水管へと効率的に吸水される。
【００３１】
請求項２記載の水田用給水及び排水システムによれば、前記疎水材として複数の粒状部材を充填もしくは複数の短パイプ部材等あるいは複数の細長部材を束ねて前記通水部材に装填したものであるから、水田下の地中水は、粒状部材又は短パイプ部材等あるいは束ねた細長部材間に隙間に浸透し、その地中水が吸水管へと吸水される。
【００３２】
請求項３記載の水田用給水及び排水システムによれば、前記導水パイプの表面に複数の導水用突起又は導水用溝部を該導水パイプの軸方向に沿って設けたものであから、導水パイプの表面積が拡大し、導水パイプの集水機能が高まる。
【００３３】
請求項４記載の水田用給水及び排水システムによれば、排水路に連通する複数の通水孔を備えた暗渠吸水管と、この暗渠吸水管の一端から地表に立ち上がる立ち上がり管と、前記暗渠吸水管の反対側端部に接続して前記排水路と、前記暗渠吸水管に接続して該暗渠吸水管を開閉する水閘と、前記暗渠吸水管上に立設した吸水性に優れた誘導疎水体とを備え、水閘を解放して水田の余剰の地中水を排水路に排出するとともに、前記水閘を遮断した状態で前記立ち上がり管から暗渠吸水管に給水した用水を土壌の中に供給して湿田化するように構成し、前記誘導疎水体に小木杭または突刺部を連結し、前記暗渠吸水管上に前記誘導疎水体を立設する際、前記小木杭または突刺部材を水田の掘削部周辺に突き刺して前記誘導疎水体を起立状態で保持するように構成したものであるから、水田下の地中水が誘導疎水体および吸水管内に吸水され、湿田、乾田化の管理のために水閘を開いた状態では、吸水管から排水路へと排水され、乾田化が図られる。一方、水閘を閉じた状態では、暗渠吸水管からの排水が遮断されるので、立ち上がり管から給水された用水が暗渠吸水管から誘導疎水体を通過して水田に給水され、湿田化が図られる。また、誘導疎水体を起立状態で保持することが可能であり、誘導疎水体の施工性が向上する。
【００３４】
請求項５記載の水田用給水及び排水システムによれば、前記暗渠吸水管の底部を除いて該暗渠吸水管を覆う耐食性に優れた被覆疎水体を設けたものであるから、水田下の地中水は、被覆疎水体を透過して吸水管へと吸水されるとともに、被覆疎水体が耐食性に優れることから、吸水管の疎水性を長期に渡って安定的に維持できる。
【００３５】
請求項６記載の水田用給水及び排水システムによれば、前記被覆疎水体が疎水材として複数の粒状部材又は複数の短パイプ部材等あるいは複数の細長部材を前記通水部材に装填したネット又は多孔質状の中空袋とで構成したものであるから、水田下の地中水は、被覆疎水体を透過して粒状部材等又は束ねた細長部材間に隙間に浸透し、その地中水が吸水管へと吸水される。
【図面の簡単な説明】
【図１】本発明の一実施例を示す暗渠排水施設全体の断面図である。
【図２】同上図１のＡ−Ａ線断面図である。
【図３】同上導水パイプの斜視図である。
【図４】同上疎水材の変形例を示す斜視図である。
【図５】同上導水パイプの変形例を示す斜視図である。
【図６】同上誘導疎水体を示す斜視図である。
【図７】同上被覆疎水体と吸水管の分解斜視図である。
【図８】同上図１のＢ−Ｂ線断面図である。
【図９】同上被覆疎水体の変形例を示す斜視図である。
【符号の説明】
２１水田
２５排水フリューム（排水路）
２６吸水管
２９立ち上がり管
４１暗渠排水用バルブ（水閘）
５０誘導疎水体
５１通水部材
５２導水パイプ
５３疎水材
５４導水用突起
５４ａ導水用溝部
５５，６０被覆疎水体
５６ネット
５７疎水材
５８中空袋
６０突刺部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water supply and drainage system for paddy fields used in, for example, underdrainage or paddy irrigation facilities in paddy fields.
[0002]
[Prior art]
Conventionally, a culvert drainage valve shown in Patent Document 1 is known as this type of paddy field water supply and drainage system. This culvert drainage valve has joint portions to which the drainage pipes are respectively connected at both end sides, and a standing pipe 8 rises from an intermediate portion of the joint portion. This standing pipe is exposed to the ground on the shore. The joint portion 7 is provided with a valve body that opens and closes a water channel formed therein, and an operating rod that rises from the valve body projects through the standing pipe to the upper side. A cap is fitted and attached to the outer peripheral side of the standing pipe at the upper end of the standing pipe exposed to the ground. A cylindrical portion through which the operation rod passes is formed at the center of the cap, and a fixing ring is screwed into the cylindrical portion. Further, an operation handle is fixed to an upper end portion of the operation rod protruding upward from the cap.
[0003]
And in order to manage wet fields and dry fields, the valve body is opened and closed by raising and lowering the operation handle on the ground. In the state where the valve for drainage of the underdrain is opened, the underground water under the paddy field is absorbed into the water absorption pipe, drained through the drain pipe and the joint portion to the drainage channel, and the paddy field is made. On the other hand, when the underdrain valve is closed, the drainage from the water absorption pipe is blocked, so that the underground water stops under the paddy field and the paddy field is converted into a wetland.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-107347
[Problems to be solved by the invention]
The conventional underground drainage valve is formed only by absorbing underground water through a water absorption pipe embedded in a paddy field, and has poor water absorption efficiency. In particular, the water absorption pipe introduces underground water into the inside of the water absorption pipe from a small hole formed in the outer periphery thereof, and a hydrophobic portion is formed around the water absorption pipe by covering the upper surface of the water absorption pipe with a rice husk or the like. The method is also adopted. However, such rice husks rot and cannot absorb water stably for a long time.
[0006]
The present invention is intended to solve such problems, and a first object thereof is to provide a water supply and drainage system for paddy fields that can efficiently absorb underground water. Moreover, this invention makes it the 2nd objective to provide the water supply and drainage system for paddy fields which can maintain the hydrophobicity around a water absorption pipe stably over a long period of time.
[0007]
[Means for Solving the Problems]
The water supply and drainage system for paddy fields according to claim 1 is a culvert water intake pipe provided with a plurality of water passage holes communicating with the drainage channel, a rising pipe rising from one end of the culvert water intake pipe to the ground surface, and The drainage channel connected to the opposite end, the water tank connected to the culvert water absorption pipe to open and close the culvert water absorption pipe, and the induced hydrophobic body excellent in water absorption standing on the culvert water absorption pipe The paddy field is released to discharge excess groundwater from the paddy field to the drainage channel, and the water supplied from the riser pipe to the underdrain water absorption pipe is supplied into the soil while the paddy field is shut off to make the paddy field wet. A water-permeable member constituted by a net or a plurality of porous hollow bags substantially perpendicular to the underdrain water-absorbing pipe, and a hydrophobic material filled in the water-permeable member. Material and a water pipe inserted through the water passage member Those were.
[0008]
The water supply and drainage system for paddy fields configured as described above is that the underground water under the paddy field is absorbed into the induction hydrophobic body and the water absorption pipe, and the water tank is opened for the management of wet fields and dry paddy fields. The water is drained into the drainage channel and converted to dry fields. On the other hand, when the water tank is closed, the drainage from the underdrain pipe is cut off, so that the water supplied from the riser pipe passes through the induction hydrophobic body from the underdrain pipe and is supplied to the paddy field, so that the paddy field is formed. . In addition, groundwater in paddy fields penetrates between hydrophobic materials through water-permeable members, the groundwater is absorbed into the water absorption pipe, and part of the groundwater that has penetrated into the hydrophobic material is also introduced into the pipe. The water is efficiently absorbed into the water absorption pipe.
[0009]
The water supply and drainage system for paddy fields according to claim 2 is configured such that a plurality of granular members are filled as the hydrophobic material or a plurality of short pipe members or the like or a plurality of elongated members are bundled and loaded into the water flow member. .
[0010]
With the above configuration, the underground water under the paddy field penetrates into the gap between the granular member, the short pipe member, or the bundled elongated members, and the underground water is absorbed into the water absorption pipe.
[0011]
The paddy field water supply and drainage system according to claim 3 is provided with a plurality of water guide protrusions or water guide grooves on the surface and the inner surface of the water guide pipe along the axial direction of the water guide pipe.
[0012]
With the above configuration, the surface area of the water guide pipe is increased, and the water collecting function of the water guide pipe is enhanced.
[0013]
The water supply and drainage system for paddy fields according to claim 4 includes a culvert water absorption pipe having a plurality of water passages communicating with the drainage channel, a rising pipe that rises from one end of the culvert water absorption pipe to the ground surface, and the culvert water absorption pipe The drainage channel connected to the opposite end, the water tank connected to the culvert water absorption pipe to open and close the culvert water absorption pipe, and the induced hydrophobic body excellent in water absorption standing on the culvert water absorption pipe The paddy field is released to discharge excess groundwater from the paddy field to the drainage channel, and the water supplied from the riser pipe to the underdrain water absorption pipe is supplied into the soil while the paddy field is shut off to make the paddy field wet. When the guide hydrophobic body is connected to the guide hydrophobic body and the guide hydrophobic body is erected on the culvert water absorption pipe, the small tree pile or the piercing member is inserted into the periphery of the paddy field excavation section. To hold the induced hydrophobic body in an upright state. It is those that you have configured.
[0014]
With the above configuration, underground water under the paddy field is absorbed into the induction hydrophobic body and the water absorption pipe, and when the paddle is opened for the management of wet fields and dry paddies, the water is drained from the water absorption pipe to the drainage channel. Figured. On the other hand, when the water tank is closed, the drainage from the underdrain pipe is cut off, so that the water supplied from the riser pipe passes through the induction hydrophobic body from the underdrain pipe and is supplied to the paddy field, so that the paddy field is formed. . In addition, when installing the induction hydrophobic body on the underdrain water pipe laid in the paddy field, excavating the paddy field and laying the underwater absorption pipe, installing the coated hydrophobic material around the bottom of the underdrain water absorption pipe, Establish a hydrophobic body. At this time, it is possible to hold the induced hydrophobic body in an upright state by piercing the excavation portion of the paddy field with the small wooden pile or the pierced portion, and the workability of the induced hydrophobic body is improved.
[0015]
The water supply and drainage system for paddy fields according to claim 5 is provided with a coated hydrophobic body excellent in corrosion resistance that covers the underdrain water absorption pipe except for the bottom of the underdrain water absorption pipe.
[0016]
With the above configuration, underground water under the paddy field penetrates the coated hydrophobic body and is absorbed into the water absorption pipe, and the coated hydrophobic body is excellent in corrosion resistance, so that the hydrophobicity of the water absorption pipe is stable over a long period of time. Can be maintained.
[0017]
The water supply and drainage system for paddy fields according to claim 6, wherein the coated hydrophobic body is a net or a porous shape in which a plurality of granular members, a plurality of short pipe members, or the like or a plurality of elongated members are loaded on the water passage member as a hydrophobic material. It is comprised with the hollow bag of this.
[0018]
With the above configuration, the underground water in the paddy field penetrates the coated hydrophobic body and penetrates into the gaps between the granular member, the plurality of short pipe members, or the bundled elongated members, and the underground water is absorbed into the water absorption pipe. The
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a valve for drainage of a culvert according to the present invention will be described with reference to FIGS. In FIG. 1, 21 is a paddy field, 22 is a shore, 23 is a shore or a shoulder on a farm road, 24 is an underground under the paddy field 21, and 25 is a drainage flume. And the underdrain water absorption pipe 26 is embed | buried in the position of the depth of about 60 cm-1m of the underground 24 under the paddy field 21. A plurality of the water absorption pipes 26 are joined together. A plurality of water passage holes 28 are formed in the peripheral wall portion of the water absorption pipe 26. Reference numeral 29 denotes a rising pipe bent by 90 °. One end of the rising pipe 29 is connected to the water absorption pipe 26, and the other end is exposed to the ground of the bank or the road 23 of the farm road. The opening at the other end of the rising pipe 29 is detachably provided by a screw cap 30 having a suction hole with a small hole.
[0020]
A culvert drainage valve 40 is buried in the underground 24 in the water absorption pipe 26. The underdrain drainage valve 40 has a joint portion 42 made of a substantially T-shaped synthetic resin, and a water absorption pipe 26 is fitted and connected to the joint portion 42 to communicate with the drainage flume 25 from the water absorption pipe 26. A water channel is formed. Moreover, the lower end part of the standing pipe 43 is fitted to the joint part 42 and fixed by an adhesive. The standing pipe 43 is made of a synthetic resin that is relatively easy to cut, such as hard vinyl chloride, and has a vertical cylindrical shape. The standing pipe 43 is connected to the upper end portion of the standing pipe 43 through a pipe connecting portion 41 and the like. A protective box 44 made of the above synthetic resin is connected. A valve body 45 for opening and closing the water channel is provided in the joint portion 42, and an operation rod 46 located in the standing pipe 43 is connected to the valve body 45, and an operation for operating the operation rod 46 is performed. A handle 47 is provided inside the protective box 44. In the figure, reference numeral 48 denotes a lid that closes the protective box 44.
[0021]
Reference numeral 50 denotes an induction hydrophobic body connected to the upper surface of the water absorption pipe 26 and a coated hydrophobic material to be described later, and a plurality of them are arranged on the water absorption pipe 26 at intervals. These inductive hydrophobic bodies 50 are provided in such a manner that their lower end portions are in contact with the upper surfaces of the water-absorbing pipe 26 and the covering hydrophobic material 55 described later, and their upper end portions are embedded in the underground 24 with a distance of about 20 to 30 cm from the rice field. It has been. The inductive hydrophobic body 50 includes, for example, a water passage member 51 made of, for example, a net or a porous hollow bag, a water guide pipe 52 made of a synthetic resin inserted into the water passage member 51, and the water guide member 51 and the water guide member. It is comprised with the hydrophobic material 53 with which it filled between the pipes 52. FIG. In this embodiment, a granular member 53a such as fine gravel is filled or loaded as the hydrophobic material 53 into the inductive hydrophobic body 50, and as shown in FIG. 4, an organic or inorganic thin tubular elongated member 53b such as cocoon is used. Alternatively, short pipe members or the like (not shown) may be bundled. Moreover, what is necessary is just to form in various shapes, such as pipe shape, polygonal shape, and column shape, as the shape of the water conveyance pipe 52. FIG. As shown in FIG. 3, the water guide pipe 52 expands its surface area and guides underground water permeated between the granular members 53 a to the coated hydrophobic body 55 around the water absorption pipe 26, as shown in FIG. 3. A plurality of water guide protrusions 54 are integrally formed along the axial direction on the outer peripheral surface of the pipe 52, or a plurality of water guide grooves 54a are integrally formed along the axial direction on the inner surface of the water guide pipe 52 as shown in FIG. Molding. In this way, by forming the water guide protrusion 54 or the water guide groove rise 54a on the outer peripheral surface of the water guide pipe 52, the ground water that has penetrated between the granular member 53a or the elongated member 53b is efficiently transferred to the coated hydrophobic body 55. It is possible to guide well.
[0022]
Reference numeral 55 denotes a water-permeable coated hydrophobic body that covers the upper surface of the water absorption pipe 26. As shown in FIG. 7, the elongated bag-like net 56 is connected in a plurality of width directions and length directions, and these nets are connected. 56 is filled with a granular material 53a such as fine gravel such as gravel as a hydrophobic material 57. By covering this on the upper surface of the water absorption pipe 26, the upper and side portions of the water absorption pipe 26 are covered except for the bottom of the water absorption pipe 26. What fills the granular member 53a is not limited to the net 56, and as shown in FIG. 9, a porous hollow bag is formed in a rectangular tube shape such as resin and has a large number of opening holes 58a on the periphery. 58 may be connected in the width direction and filled with the granular member 53a.
[0023]
Reference numeral 60 denotes a piercing portion connected to the induction hydrophobic body 50, and is connected to the induction hydrophobic body 50 by a string body 61 connected to the upper end portion of the water passage member 51. By piercing this piercing part 60 into the excavation part of a paddy field, when the guiding hydrophobic body 50 is erected on the water absorption pipe 26, the guiding hydrophobic body 50 is held upright.
[0024]
Next, the operation of the above configuration will be described. First, in order to install the induction hydrophobic body 50 on the water absorption pipe 26 laid in the paddy field 21, the paddy field 21 is excavated, the water absorption pipe 26 is laid, and the covering hydrophobic body 55 covering the water absorption pipe 26 is laid. Thereafter, the induced hydrophobic body 50 is erected on the coated hydrophobic body 55 with an interval. At this time, the induced hydrophobic body 50 on the water absorption pipe 26 is not self-supporting, but the induced hydrophobic body 50 is raised on the water absorption pipe 26 by piercing the piercing portion 60 into the wall surface of the excavated portion of the excavated paddy field 21. Can be held in. Thereafter, the induced hydrophobic body 50 and the coated hydrophobic body 55 are buried in the underground 24 under the paddy field 21 by backfilling the excavated portion.
[0025]
The lid 48 is always closed, but in order to open and close the underdrain drainage valve 40 for the management of wetlands and dry rice fields, the lid 48 is opened and the fixing cap (not shown) is loosened. Then, the operation handle 47 is moved up and down to open and close the valve body 45. If the fixing cap is tightened, the valve body 45 is fixed together with the operation rod 46. In the state in which the underdrain drainage valve 40 is opened, the underground water under the paddy field 21 is directly absorbed into the water absorption pipe 26 from the water passage hole 28 as shown by an arrow a in FIG. At the same time, the net 56 or the hollow bag 58 of the coated hydrophobic body 55 that covers the upper and side portions of the water-permeable member 51 of the induction hydrophobic body 50 and the water absorption pipe 26 in which the underground water under the paddy field 21 stands on the coated hydrophobic body 55. The ground material 53a, which is a granular material 53a, such as gravel, or an organic or inorganic thin tubular member 53b, such as a cocoon, which becomes the hydrophobic material 53 filled therein, penetrates into the gap between the opening holes 58a and thus is absorbed by the induction hydrophobic body 50. Middle water is indirectly drained from the water passage hole 28 into the water absorption pipe 26. In addition, the water guide pipe 52 provided in the induction hydrophobic body 50 functions as a core member that holds the water passage member 51 filled with the granular member 53a such as gravel in an upright state, and a plurality of water guide protrusions on the outer peripheral surface thereof. 54 or the water guiding groove 54a is integrally formed in the axial direction, the surface area of the water guiding pipe 52 is increased, and the underground water that has penetrated the hydrophobic material 53 is transferred to the water guiding pipe 52 and effectively conducts water to the water absorption pipe 26. be able to. In this way, underground water in the water absorption pipe 26 is drained from the water absorption pipe 26 to the drainage flume 25, and the paddy field 21 is made dry. On the other hand, in the state where the underdrain drainage valve 40 is closed, the drainage from the water suction pipe 26 is blocked by the valve body 45 at the joint portion 42, so that the underground water stops under the paddy field 21, so that it becomes wetted. Further, by supplying water through the pipeline 31 and the rising pipe 29, the soil can be actively irrigated from the water absorption pipe 26 and the induced hydrophobic body 50 as shown by an arrow b in FIG.
[0026]
As described above, in this embodiment, a plurality of induced hydrophobic bodies 50 are raised on the water absorption pipe 26 embedded in the underground 24, so that the underground water under the paddy field 21 is a water-permeable member of the induced hydrophobic body 50. 51 penetrates into the gap between the granular member 53a such as fine gravel or the like or the organic or inorganic narrow tubular elongated member 53b such as cocoon, which becomes the hydrophobic material 53 filled in the induction hydrophobic body 50, and absorbs this underground water. Water can be efficiently guided to the pipe 26. Thus, not only the underground water is drained directly from the water passage hole 28 to the water absorption pipe 26, but also the underground water that has permeated the induction hydrophobic body 50 can be drained to the water absorption pipe 26. As a result, the underground water under the paddy field 21 can be efficiently drained to make the paddy field 21 dry, and the pipeline 31 and the riser pipe 29 from the underground water trench in a state in which the underdrain drainage valve 40 is closed. It is also possible to actively irrigate the soil from the water absorption pipe 26 and the induction hydrophobic body 50.
[0027]
Further, the surface area of the water guide pipe 52 is increased by forming a plurality of water guide protrusions 54 or water guide grooves 54 a along the axial direction of the water guide pipe 52 provided in the guiding hydrophobic body 50, and along the water guide pipe 52. Thus, the underground water can be effectively guided to the water absorption pipe 26.
[0028]
Furthermore, by covering the water absorption pipe 26 with the coated hydrophobic body 55 having excellent corrosion resistance, the hydrophobicity around the water absorption pipe 26 can be stably maintained over a long period of time without causing a decrease in hydrophobicity due to corrosion. . Further, when the induced hydrophobic body 50 is erected on the coated hydrophobic body 55, the induced hydrophobic body 50 is held in an upright state on the water absorption pipe 26 by piercing the piercing portion 60 into the wall surface of the excavated portion of the drilled paddy field 21. It is not necessary to support the induced hydrophobic body 50 manually. In addition, the hydrophobic body 55 covering the upper surface of the water absorption pipe 26 is configured by connecting the net 56 or a resin-made hollow bag 58 having a large number of opening holes 58a on the periphery in the width direction. Since it can be easily attached to the water absorption pipe 26, it is excellent in workability.
[0029]
In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, the induction hydrophobic body 50 and the coated hydrophobic body 55 may be configured to have excellent corrosion resistance and do not impair the water permeability to the water absorption pipe 26 side. For example, the guided hydrophobic body 50 and the coated hydrophobic body 55 may be a water-permeable concrete product or a foamed synthetic resin product having water permeability. What is necessary is just a structure with excellent hydrophobicity, such as a single structure. Moreover, although the example which formed the protrusion 54 for water conveyance or the protrusion 54a for water conveyance on the water conveyance pipe 52 was shown, you may make it form the water conveyance pipe 52 in cylindrical shape and a column shape, and the material is synthetic resin or wood. But you can. Further, the piercing portion may be constituted by a small timber pile, and the point is only required to pierce the excavation portion.
[0030]
【The invention's effect】
According to the water supply and drainage system for paddy fields according to claim 1, the underdrain water pipe provided with a plurality of water passages communicating with the drainage channel, the rising pipe rising on the ground surface from one end of the underdrain water pipe, and the underdrain water absorption The drainage channel connected to the opposite end of the pipe, the water tank connected to the culvert water absorption pipe to open and close the culvert water absorption pipe, and the induction hydrophobic body excellent in water absorption standing on the culvert water absorption pipe The paddy field is released to discharge surplus underground water from the paddy field to the drainage channel, and the water supplied from the rising pipe to the culvert suction pipe is supplied into the soil while the paddy field is shut off. A water-permeable member configured so as to be wetted, and the inductive hydrophobic body is configured by a net or a plurality of porous hollow bags substantially vertically suspended with respect to the underdrain water-absorbing pipe, and filled in the water-permeable member A hydrophobic material, and a water pipe inserted through the water passage member, Since those configured not only ground water under paddy are water and directly to the water suction pipe, ground water penetrated into the induction hydrophobic substance is absorbed by the water absorbing tube, for the management of dry paddy field of In the state where the water tank is opened, the water is drained from the water absorption pipe to the drainage channel, and the paddy field is made. On the other hand, when the water tank is closed, the drainage from the underdrain pipe is cut off, so that the water supplied from the riser pipe is supplied to the paddy field through the underdrain pipe, so that the wet paddy field and soil irrigation are promoted. It is done. In addition, groundwater in paddy fields penetrates between hydrophobic materials through water-permeable members, the groundwater is absorbed into the water absorption pipe, and part of the groundwater that has penetrated into the hydrophobic material is also introduced into the pipe. The water is efficiently absorbed into the water absorption pipe.
[0031]
According to the water supply and drainage system for paddy fields according to claim 2 , a plurality of granular members are filled as the hydrophobic material, or a plurality of short pipe members or the like or a plurality of elongated members are bundled and loaded into the water flow member. Therefore, the underground water under the paddy field penetrates into the gap between the granular member, the short pipe member or the like or the bundled elongated members, and the underground water is absorbed into the water absorption pipe.
[0032]
According to the water supply and drainage system for paddy fields according to claim 3 , since a plurality of water guide protrusions or water guide grooves are provided on the surface of the water guide pipe along the axial direction of the water guide pipe, The surface area is expanded and the water collecting function of the water guide pipe is enhanced.
[0033]
According to the water supply and drainage system for paddy fields according to claim 4, the underdrain water pipe provided with a plurality of water passages communicating with the drainage channel, the rising pipe rising from one end of the underdrain water pipe to the ground surface, and the underdrain water absorption The drainage channel connected to the opposite end of the pipe, the water tank connected to the culvert water absorption pipe to open and close the culvert water absorption pipe, and the induction hydrophobic body excellent in water absorption standing on the culvert water absorption pipe The paddy field is released to discharge surplus underground water from the paddy field to the drainage channel, and the water supplied from the rising pipe to the culvert suction pipe is supplied into the soil while the paddy field is shut off. It is configured so as to become a wet field, and when the guided hydrophobic body is connected to the guided hydrophobic body and the guided hydrophobic body is erected on the culvert water absorption pipe, the small wooden pile or the pierced member is placed around the excavated portion of the paddy field. The induced hydrophobic body is held upright by piercing Since those configured to so that is absorbed by the ground water derived hydrophobic substance and water pipe under paddy Shitsuden, in an open state Mizu閘for the management of dry paddy field of, from the water suction pipe to the drainage Drained and dried. On the other hand, when the water tank is closed, the drainage from the underdrain pipe is cut off, so that the water supplied from the riser pipe passes through the induction hydrophobic body from the underdrain pipe and is supplied to the paddy field, so that the paddy field is formed. . In addition, it is possible to hold the induced hydrophobic body in an upright state, and the workability of the induced hydrophobic body is improved.
[0034]
According to the water supply and drainage system for paddy fields according to claim 5, since the coated hydrophobic body excellent in corrosion resistance covering the underdrain water absorption pipe except for the bottom of the underdrain water absorption pipe is provided, Water permeates the coated hydrophobic body and is absorbed into the water absorption pipe, and the coated hydrophobic body is excellent in corrosion resistance. Therefore, the hydrophobicity of the water absorption pipe can be stably maintained over a long period of time.
[0035]
According to the water supply and drainage system for paddy fields according to claim 6, a net or a porous body in which the covering hydrophobic body is loaded with a plurality of granular members, a plurality of short pipe members, or the like or a plurality of elongated members as a hydrophobic material. The ground water under the paddy field penetrates the coated hydrophobic body and penetrates into the gaps between the granular members or the elongated members that are bundled, and the ground water absorbs water. Water is absorbed into the tube.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an entire underdrain drainage facility according to an embodiment of the present invention.
2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a perspective view of the same water guiding pipe.
FIG. 4 is a perspective view showing a modification of the hydrophobic material.
FIG. 5 is a perspective view showing a modified example of the water guide pipe.
FIG. 6 is a perspective view showing the same derived hydrophobic body.
FIG. 7 is an exploded perspective view of the above-mentioned coated hydrophobic body and a water absorption pipe.
8 is a cross-sectional view taken along the line BB in FIG.
FIG. 9 is a perspective view showing a modification of the coated hydrophobic body.
[Explanation of symbols]
21 Paddy field 25 Drainage flume (drainage)
26 Water absorption pipe 29 Rising pipe 41 Underdrain valve (water tank)
50 Hydrophobic member 51 Water-permeable member 52 Water-conducting pipe 53 Hydrophobic material 54 Water-conducting protrusion 54 a Water-conducting groove 55, 60 Covered hydrophobic material 56 Net 57 Hydrophobic material 58 Hollow bag 60 Puncture

Claims

Underdrain pipe having a plurality of water passages communicating with the drainage channel, a rising pipe rising from the end of the underdrain water pipe to the ground surface, and the drainage channel connected to the opposite end of the underdrain water pipe, A water tank that opens and closes the underdrain water pipe connected to the underdrain water absorption pipe, and an inductive hydrophobic body that is excellent in water absorption standing on the underdrain water absorption pipe. It is configured to discharge water into a drainage channel and supply water supplied from the rising pipe to the underdrain water absorption pipe into the soil in a state where the water tank is cut off, and to make a wet field, A water-permeable member composed of a net or a plurality of porous hollow bags substantially suspended with respect to the culvert water-absorbing pipe, a hydrophobic material filled in the water-permeable member, and a water guide pipe inserted into the water-permeable member; in water supply and drainage system for paddy fields, characterized by being configured .

Feedwater and drainage systems for paddy fields according to claim 1, characterized by comprising loading the water passage member by bundling a filling or a plurality of short pipe member or the like or a plurality of elongate members a plurality of granular members as the hydrophobic material .

Feedwater and drainage systems for paddy fields according to claim 1, wherein a plurality of water guide projections or the water guide groove on the surface of the water guide pipe is provided along the axial direction of the conductor water pipe.

Underdrain pipe having a plurality of water passages communicating with the drainage channel, a rising pipe rising from the end of the underdrain water pipe to the ground surface, and the drainage channel connected to the opposite end of the underdrain water pipe, A water tank that opens and closes the underdrain water pipe connected to the underdrain water absorption pipe, and an inductive hydrophobic body that is excellent in water absorption standing on the underdrain water absorption pipe. Water is discharged to the drainage channel, and the water supplied from the riser pipe to the underdrain water absorption pipe is supplied into the soil in a state where the water tank is cut off, and is made into a wet paddy. Alternatively, when connecting the piercing portion and standing the induced hydrophobic body on the underdrain water absorption pipe, the pierced stake or the piercing member is pierced around the excavated portion of the paddy field so as to hold the guided hydrophobic body in an upright state. water and waste for paddy fields, characterized in that configuration the System.

The underdrain water pipe water supply and drainage system for paddy field according to claim 1, wherein the bottom except characterized in that a coating hydrophobic body having excellent corrosion resistance covering the underdrain water tubes.

The coated hydrophobic body is composed of a plurality of granular members, a plurality of short pipe members, or the like as a hydrophobic material, or a net or a porous hollow bag in which a plurality of elongated members are loaded in the water passage member. Item 5. Water supply and drainage system for paddy fields.