著：（比利時）布魯諾·德·梅爾德 （比利時）凱莉·香農(nóng) 譯：賈綠媛 校：王晞月

1 自然水文過程干預(yù)工程

洞里薩湖（Tonle Sap Lake）是東南亞最大的永久性淡水湖和濕地生態(tài)系統(tǒng)（圖1）。它位于1 000年前“柬埔寨平臺”（Cambodia platform）沉降所形成的西北—東南地質(zhì)斷層帶上，發(fā)源于湄公河的支流洞里薩河并匯聚眾多區(qū)域徑流，平均海拔15～20 m[1]31,[2]46。洞里薩湖95%的匯水區(qū)位于柬埔寨，5%位于泰國[3]1723。水動力學(xué)模型表明，該湖的大部分水源（53.5%）來自湄公河干流，34%來源于支流，還有12.5%來源于降水[3]1729。洞里薩湖是湄公河三角洲的重要組成部分，作為天然的蓄水池，洞里薩湖在濕潤西南季風(fēng)為主導(dǎo)的時期（5—10月）發(fā)揮著區(qū)域防洪功能，在旱季（11月—次年4月）又為下游廣大地區(qū)提供水源（圖2），因此享有“跳動的心臟”的美譽。此外，洞里薩湖還因為一個特別的現(xiàn)象而聲名遠揚：在季風(fēng)季節(jié)（即雨季）湄公河水量大漲注入洞里薩河后，湖面會從2 300 km2擴大至5 000 km2，湖水深度由1.44 m增至10.30 m[4]1415（圖3）。洞里薩湖旱季（最低水線）和雨季（最高水線）的水線相差10 km，這里的“水線”（waterline）是一個相對性的術(shù)語，指湖水水平邊緣線，因為湖水水平邊緣有一種微妙的濕度梯度，它可能延伸到很多公里外，也可能在某一范圍內(nèi)徘徊[5]8（圖4）。

洞里薩湖洪泛區(qū)包含5種生境群：1）開放水域（1年中12個月都處于水下）；2）廊道森林（每年被洪水淹沒9個月）；3）以灌木叢和草地為主的季節(jié)性淹沒區(qū)（每年被洪水淹沒5～8個月）；4）過渡區(qū)，以廢棄耕地、稻田和低地草原為主（每年被洪水淹沒1～5個月）；5）雨水灌溉區(qū)，主要包括雨季稻田和村莊（每年被洪水淹沒時間少于1個月）[1-3]。豐沛的水量和廣泛的沖積區(qū)為多樣的物種創(chuàng)造了有利的生長環(huán)境，這使得洞里薩湖成為世界上最高產(chǎn)的淡水生態(tài)系統(tǒng)之一。季節(jié)性的水文動力將陸地營養(yǎng)物質(zhì)帶入水中，滯洪區(qū)的廊道森林和灌木叢為自湄公河洄游而來的魚類提供了豐富的產(chǎn)卵、孵化、棲息和攝取營養(yǎng)的場所[4]1415。洞里薩湖的魚類等水產(chǎn)品約供給了目前柬埔寨蛋白質(zhì)總攝取量的80%[6]5427。

高棉人（Khmer）有超過1 200年歷史傳統(tǒng)水管理方式，他們建立的水利設(shè)施之全面、精妙和復(fù)雜，令人難以置信。吉蔑族（Mon-Khmer）的早期聚居點位于湄公河中下游流域帶有防御性堤壩和護城河的圓形土丘上，并散布在被農(nóng)田包圍和森林分割的土地上。他們構(gòu)筑了房屋，通過社區(qū)（人）建立和管理的人工運河（高棉語：prek，位于天然河流河岸后面的運河水渠）和池塘（高棉語：beng），在旱季將雨季蓄積的洪水排入農(nóng)田，灌溉后匯入河流[1]3-4,[7]45。人們環(huán)湖居住于被稱作Kampong（馬來語，意為“登陸點”）的聚居區(qū)內(nèi)，這些聚居區(qū)布局井然有序，與地勢較高的村莊（種植水稻）相互依存。如今洞里薩湖區(qū)共生活著170多萬人[6]5423，有不少城市和較大的村莊緊臨5號和6號國道，國道與堤壩共同發(fā)揮著控制洞里薩湖泛洪區(qū)擴張的作用（圖5）。

在吳哥帝國時期（802—1432年），歷代國王在建造了一系列無與倫比的寺廟的同時，還修建了復(fù)雜的灌溉系統(tǒng)，將東北部的庫倫山（Kulen Hills）與湖泊相連（圖6）。吳哥帝國位于洞里薩湖一個較小的一個洪泛區(qū)內(nèi)，城市規(guī)劃“整合山、城市和水，形成了有序且富有象征意義的系統(tǒng)”[1]14。這個龐大且高度工程化的農(nóng)業(yè)–城市景觀在前工業(yè)化時期堪稱舉世無雙[8]。到了13世紀(jì)，吳哥的城市核心區(qū)面積達35 km2，城區(qū)總面積達1 000 km2[8]。龐大而精巧的水系統(tǒng)是其構(gòu)建農(nóng)業(yè)–城市景觀的基礎(chǔ)，其中，植被也發(fā)揮了重要作用，因為除宗教建筑外，包括皇宮在內(nèi)的所有建筑都由木頭或茅草建造而成。吳哥的城市景觀由城市建設(shè)與景觀工程結(jié)合而成，使地區(qū)在人口不斷擴張的情況下仍然能夠保持穩(wěn)定的農(nóng)業(yè)用地和食物產(chǎn)量[8]。高棉人精心修建了由運河、水壩、人工建造的蓄水池（高棉語：baray，由堤壩圍合，與自然河流相通，可提供灌溉用水）和挖掘的池塘（高棉語：trapeang，用于收集雨水，供家庭生活用水和小規(guī)模農(nóng)業(yè)澆灌用水）構(gòu)成的水調(diào)蓄網(wǎng)絡(luò)（圖7）。人工蓄水池在雨季儲蓄雨水，旱季用于灌溉?，F(xiàn)在已經(jīng)干涸的東池（East Baray，于890年建成）就是一個大型的人工湖（1.8 km×7.5 km），由暹粒河（Siem Reap River）提供水源，東池東部有4～5 m高的擋土墻（圖8）。幾個世紀(jì)后，出現(xiàn)了西池（West Baray，2.1 km×7.8 km）。此外，在這個水系統(tǒng)中，還有一系列規(guī)模較小的人工蓄水池。為了紀(jì)念神靈和祖先，高棉人修建了一系列的圣殿山（有些圣殿山位于人工蓄水池中）作為各個國王的陵墓，旨在展示高棉帝國的至高無上（圖9）。吳哥城的面積遠遠超過了由護城河所環(huán)繞的寺廟區(qū)以及網(wǎng)格狀街區(qū)所劃分的城內(nèi)和城外區(qū)域的面積[8]。在吳哥帝國的全盛時期，吳哥城人口近75萬人。

圖9 西巴萊湖規(guī)模宏大的護城河The majestically-scaled moat of the West Baray

幾個世紀(jì)以來，高棉人的農(nóng)業(yè)–城市景觀逐步完善，但始終是一個有著強烈?guī)缀沃刃虻母叨裙こ袒南到y(tǒng)，并且形成了一個復(fù)雜的、以水為基礎(chǔ)的農(nóng)業(yè)–城市網(wǎng)絡(luò)。紅色高棉統(tǒng)治時期（1970—1979年）完成了工程的重要一步，建成了一個百年的全國性農(nóng)業(yè)骨干工程，包括350多個大型水庫（水壩）和眾多水渠、運河水網(wǎng)（其中主運河長達7 000 km、寬度超過10 m，每隔100 m就為一系列小的運河和溝渠提供水源）。這些小規(guī)模的水利基礎(chǔ)設(shè)施占據(jù)了數(shù)萬平方公里的土地，并通過水系將這里劃分成1 km×1 km的網(wǎng)格[9]。運河水網(wǎng)支撐了作為國家經(jīng)濟發(fā)展基礎(chǔ)產(chǎn)業(yè)——水稻種植業(yè)的規(guī)模擴張，并推進了森林和農(nóng)業(yè)平衡發(fā)展的新人居環(huán)境模式的形成。種植區(qū)主要集中在洞里薩湖周邊的平原，尤其是西北部（Sisophon市附近）。

上述大規(guī)模水利設(shè)施的運營是建立在“對水資源全面、細致的計算方法上的”[10]104。區(qū)域內(nèi)地貌特征和水文條件的差異使得不同區(qū)域的灌溉方式不同，這既反映出人們在建造過程中對場地的深入了解，又體現(xiàn)了當(dāng)時對中國工程技術(shù)的學(xué)習(xí)。區(qū)域內(nèi)有6種類型、規(guī)模不一的水資源管理方式：內(nèi)部水管理、外部水管理、連通性水管理、水存儲、地形控制系統(tǒng)及運河水管理[10]1114。這些水利基礎(chǔ)設(shè)施提供的空間載荷力，能夠錨固更多的人居環(huán)境體系。

2 基于水的生計活動與公共資源的管理

湄公河下游流域系統(tǒng)的生態(tài)，包括洞里薩湖在內(nèi)，都與柬埔寨人民的經(jīng)濟、文化和自我認(rèn)知密不可分[11-12]。洞里薩湖獨特的水位變化維系著當(dāng)?shù)馗鞣N以水為基礎(chǔ)的生計活動。反過來，這些生計活動通常又可支撐相關(guān)副業(yè)的生產(chǎn)活動，進而引發(fā)大規(guī)模人口和村莊的季節(jié)性遷徙[13]。社會的職業(yè)活動反映了洞里薩湖的物態(tài)多樣性，湖泊是大量高棉人及暹粒–高棉人（Sino-Khmer）、占族（Cham，高棉伊斯蘭教）和越南人（被認(rèn)定為合法的外來人）等民族的家園。每個群體都占據(jù)著一個“文化生態(tài)位”[14]。信奉佛教的高棉人主要從事自給自足的水稻種植，并在洪水淹沒期在稻田里開展小規(guī)模的漁業(yè)活動。雖然講高棉語的暹粒–高棉人在該地區(qū)的農(nóng)業(yè)活動最少，但他們憑借傳統(tǒng)貿(mào)易商的身份以及資本獲取渠道，成為當(dāng)?shù)靥卦S的商業(yè)漁民。自1471年以來，湄公河三角洲的占族穆斯林開始從事農(nóng)業(yè)和漁業(yè)。而后，在洞里薩湖附近又聚居了大量的越南人。

如今，洞里薩湖的年捕魚量位居世界商業(yè)捕魚量的第4位，年產(chǎn)量超70萬噸[15]2。湖中設(shè)置有各種各樣的竹籬和捕魚器，包括傳統(tǒng)的箭形籬笆捕魚系統(tǒng)，以及近些年出現(xiàn)的捕魚效果顯著但會破壞生態(tài)環(huán)境的電捕魚系統(tǒng)、尼龍網(wǎng)和刺網(wǎng)等。洞里薩湖以其物種多樣性而聞名，湖中已被識別的物種超過200種，其中有100種是捕撈中經(jīng)常出現(xiàn)的物種[2]85。生物學(xué)家將湖中的魚分為“白魚”（white fish）和“黑魚”（black fish）。白魚大部分時間生活在水流較快的“白水”（white water）中，每年都有漫長的洄游和產(chǎn)卵期（將卵和幼蟲帶到洪泛區(qū)），生理周期與洪水周期同步，雨季時其在營養(yǎng)豐富的洪泛區(qū)覓食。黑魚的游動距離較短，全年集中在洪泛區(qū)活動，在湖邊的廊道森林（淡水紅樹林）和灌木叢中產(chǎn)卵[2]。在法國殖民之前，洞里薩湖以及柬埔寨的所有自然資源（包括森林和土地）都屬于國王，但管理松散，按照慣例，人們可以通過開墾土地的方式獲得土地權(quán)并定居，森林和水域是開放可進入的。法國殖民后一定程度上變更、破壞并取締了這一制度。在諾羅敦（Norodom）國王統(tǒng)治時期（1864—1904年）①，制定的新法規(guī)對漁具、捕魚器的大小和類型做出規(guī)定并對漁場進行分類。國王還通過向中國大亨出售許可證的方式謀取利潤[16]。

按照發(fā)展生產(chǎn)增加稅收的理念，法國殖民者制定了一系列促進私有化的法律使非正式的活動合法化，涉及1884年的土地改革、1889年的林業(yè)局建立和1908年頒布的漁業(yè)法。吸引投資的商業(yè)性捕魚區(qū)取代了傳統(tǒng)的魚類養(yǎng)殖和捕撈區(qū)，許多當(dāng)?shù)貪O民被迫放棄捕撈。各種競爭下形成了復(fù)雜的管理系統(tǒng)，如在1911年成立了第一個旨在控制和管理商業(yè)性捕魚區(qū)的漁業(yè)協(xié)會。到了20世紀(jì)20年代，人們意識到洪泛區(qū)的廊道森林作為魚類的產(chǎn)卵地具有重要的生態(tài)價值，因而，在洞里薩湖洪泛范圍內(nèi)出現(xiàn)了保護區(qū)?！氨Ｗo”在當(dāng)時被理解為：必須限制對自然的開發(fā)，堅決恢復(fù)和保護生態(tài)。在紅色高棉統(tǒng)治時期，商業(yè)性捕魚基本廢棄，捕魚業(yè)整體停滯，只有少量捕魚區(qū)可用于向領(lǐng)導(dǎo)層供魚和向中國出口[15]270。由于紅色高棉時期的重點是發(fā)展農(nóng)業(yè)，當(dāng)?shù)佤~類資源因人類干擾的減少而蓬勃發(fā)展。

20世紀(jì)80年代，漁業(yè)的恢復(fù)被重新提上日程，1987年頒布的《漁業(yè)法》將漁業(yè)劃分成3個層次：家庭漁業(yè)（基本生計）、中等規(guī)模漁業(yè)（個體經(jīng)營）和大規(guī)模漁業(yè)（工業(yè)、商業(yè)）。全年準(zhǔn)許家庭漁業(yè)的捕撈，而其他2類捕撈只在11月至次年6月開放。捕魚區(qū)每半年進行一次拍賣，賣給價高者[2,15]。隨著腐敗、侵占和偷獵活動的出現(xiàn)，人們的爭議和不滿逐漸加大。2012年，政府廢除了給私人租賃捕魚區(qū)的規(guī)定，將捕魚區(qū)分給社區(qū)用于漁業(yè)生產(chǎn)，并劃定了17個保護區(qū)（面積相當(dāng)于之前租賃區(qū)面積的35%），使禁捕區(qū)達到25個[17]453（圖10）。雖 然 與Wilson[18]提 出 的“平分地球原則”（half-earth principle，保護地球50%的領(lǐng)土不被人類占用）崇高目標(biāo)相去甚遠，但確實限制了人類的過度開發(fā)。

人們早就認(rèn)識到了洞里薩湖與河流、山林生態(tài)之間的相互依存關(guān)系。即使在紅色高棉時期，人們也意識到了城市化發(fā)展與森林、水生態(tài)之間密不可分的關(guān)系。Pol Pot說：“……森林是可以伐除的，但我們必須設(shè)定一個限度。如果我們砍盡了洞里薩湖周圍所有的森林，10年后的洞里薩湖就會干涸；我們將沒有水源，也沒有魚。并且當(dāng)湄公河河水不再流入洞里薩湖時，洞里薩湖就會面臨干涸，而湄公河下游的金邊及周邊地區(qū)將全部被湄公河淹沒?！盵9]132今天共同水資源管理的成功得益于政府管控和洞里薩河周邊社區(qū)及其上游居民的集體行動。

柬埔寨環(huán)境部（1994年根據(jù)皇家法令成立）負責(zé)“保護”水和森林，而農(nóng)林漁業(yè)部則負責(zé)管理這些資源的開發(fā)利用。盡管有書面形式的法規(guī)條文，但現(xiàn)實卻與法規(guī)要求格格不入。當(dāng)?shù)厣种胁粌H有非法開發(fā)的道路，還存在大量的非法砍伐和獵殺野生動物的行為。此外，還有大面積森林被伐除后用于土地倒賣。森林砍伐造成了當(dāng)?shù)貧鉁厣仙樗?、土壤侵蝕和淤積量增加。1997年，聯(lián)合國教科文組織宣布將洞里薩湖劃為生物圈保護區(qū)。此外，柬埔寨有5個被公約認(rèn)定的拉姆薩爾濕地（Ramsar site），具有國際保護意義，其中有3個濕地位于洞里薩湖，即：1）西北上游地區(qū)的普列托爾鳥類保護區(qū)（Prek Toal，21 342 hm2，2015年列入）；2）中東部地區(qū)的Boeng Chhmar野生動物保護區(qū)以及周邊河流水系和洪泛區(qū)（28 000 hm2，1999年列入）；3）洞里薩湖、斯登森河（Stung Sen）和湄公河三水交匯處附近的斯登森區(qū)域（9 293 hm2，2018年列入）[19]。根據(jù)柬埔寨法律規(guī)定，這3個核心區(qū)屬于“嚴(yán)格保護區(qū)”，禁止任何自然資源開發(fā)活動[19]750。

最后，了解柬埔寨的歷法和節(jié)氣非常必要，因為其與生計休戚相關(guān)。受洪水和魚類洄游影響，洞里薩湖的魚類在11月—次年4月的旱季最為豐富；到了雨季，魚類大幅度減少，水稻種植成為首要的經(jīng)濟活動，以捕魚為生的村民可進行漁具制作，并通過晾曬、熏制、發(fā)酵等對魚類進行加工。高棉人的新年在每年的4月中旬（以當(dāng)?shù)毓珰v計）。在作物收割后，人們焚燒放牧地塊并期盼5月季風(fēng)和降雨的到來。在陸地的水稻種植區(qū)，只要土壤中有足夠的水分將土壤軟化，就可以建立苗床，再在7—8月將幼苗移栽到田間。深水水稻（水稻在生長季內(nèi)至少1個月淹沒深度超過50 cm）[2]可在2月開始整地，5月—6月中旬（取決于降水情況）進行耕作和播種。浮水水稻種植在水深大于100 cm的地區(qū)，不進行移栽，也不使用化肥（很少使用殺蟲劑），長達5～6 m的空心莖使得水稻在豐水期可浮在水面上，在1—2月由人工用鐮刀收割，但浮水水稻的產(chǎn)量較低。傳統(tǒng)的高莖水稻憑借其高度和長莖可在淺水區(qū)茁壯生長。深水水稻的2個變種在柬埔寨都有悠久的種植歷史，早在13世紀(jì)就有記載。在20世紀(jì)30年代，水稻種植面積達540 000 hm2，而到了1960年，種植面積減少到70 000 hm2[2]54。如今，水稻種植區(qū)主要集中在磅同?。↘ampong Thom）附近，這里散布著1 600 km2的季節(jié)性草原。由于該地區(qū)每年有6個月不適合居住，人們每年1月開始遷徙。

3 適應(yīng)性特征

盡管這里有大量村莊遷徙，但仍有不少村民常年居住在洞里薩湖上或周邊地區(qū)，他們的住宅具有與水的動態(tài)變化高度適應(yīng)的結(jié)構(gòu)。房子都是木結(jié)構(gòu)（木材是柬埔寨傳統(tǒng)建房材料，石料只用于寺廟），因為在當(dāng)?shù)厝说恼J(rèn)知里，生命起源于木制的搖籃，而后到木制的房屋，最后是木制的棺材或是用于火葬的木盒。建筑與木材關(guān)系密切，木材不僅是材料，還是領(lǐng)域標(biāo)識。樹木和森林是高棉文化的核心內(nèi)容?！凹砥艺朔浅Ｐ叛鰜碜宰嫦褥`魂（Neak ta）的無形力量”[20]41，他們相信這些力量棲息在高大的樹木上。這一信仰，對人們選擇木材、村莊布局與空間組織等方面都有影響。此外，村莊和房屋的選址與關(guān)于“荒野”環(huán)境的描述有關(guān)，人們通常會選址在能躲避“荒野”的安全區(qū)域，以確保免受棲息在野外的無形力量的傷害?！吧质腔囊暗摹⑽粗?，而村莊是人和神靈和諧相處的地方”[20]48。對于生活在湖面或湖畔的村民來說，雨季持續(xù)不斷的季風(fēng)會讓洞里薩湖變得“可怕、充滿野性和恐怖”，季節(jié)性變化的湖水強化了森林的“荒野”特征[20]48。

人類的定居不可避免地會導(dǎo)致砍伐上述的“荒野”森林。在5號和6號國道內(nèi)側(cè)的水上漁村和湖畔高腳屋呈環(huán)狀圍繞于堤壩（位于歷史上經(jīng)常性淹沒的洪泛區(qū)邊緣，圖11）。大約有8萬人居住在水上漁村[20]44，這些村莊隨水的動態(tài)變化而不斷調(diào)整形態(tài)：在旱季多排布成分散而離心的線型，在雨季則傾向于集中式、向心的組合方式。實際上，水上漁村的移動更多地展現(xiàn)了人們對自然環(huán)境變化的響應(yīng)。在旱季，“寬闊而平靜的洞里薩湖面”[20]48聚集了大量水上漁村，而在雨季，這些漁村都退至較安寧的河口以躲避變化的湖水。村莊的選址和布局是與湖泊的兩個極端水量環(huán)境動態(tài)適應(yīng)的結(jié)果，景觀和聚落相輔相成。水上漁村的房屋居住面積較小，通常建在浮桶支撐的木平臺上，由竹子和水生植物建成，方便移動（圖12、13）。

住宅以及公共設(shè)施（商業(yè)建筑、學(xué)校、寺廟、清真寺等）的類型與湖水水位變化相適應(yīng)。水上漁村和高腳屋均采用梁柱結(jié)構(gòu)，針對雨季水位的快速上升，高腳屋還設(shè)有結(jié)構(gòu)支撐系統(tǒng)。高腳屋的形成較早，已有數(shù)代的居住歷史，多分布于廊道森林附近，并通過水渠或溪流與湖水相連。20世紀(jì)40年代以來，傳統(tǒng)生態(tài)知識（traditional ecological knowledge,TEK）使住在高腳屋的諸多長者養(yǎng)成了森林保護的思想，并積極抵制農(nóng)業(yè)的擴張。在湖區(qū)的6個省中，班迭棉吉?。˙antay Meanchey）、暹粒?。⊿iem Reap）和磅清揚?。↘ampong Chhnang）3個省內(nèi)尤其流行使用高腳屋[21]3。高腳屋的支柱（多由細長的木條制成）有6～7 m高。在旱季，高腳屋的村莊以土路為中心，房屋在路兩側(cè)排列；在雨季，所有的房屋只能通過水路進出。房屋通常由木頭和茅草制成，但隨著居民財力的增加，會使用瓦片和瓦楞金屬板作屋頂。這些房屋寬3～8 m，長6～20 m，具體規(guī)模取決于居民的富裕程度[22]8。在最干旱的月份里，許多村民養(yǎng)殖豬、鴨、雞和鱷魚（養(yǎng)在魚籠上方的浮籠中，用風(fēng)信子和從湖中收獲的魚養(yǎng)殖，牲畜的排泄物又為水中的魚類提供營養(yǎng)和食物），并進行家庭園藝。此外，有些家庭會遷移到開闊的湖面上，在那里建立臨時住房，以便于養(yǎng)殖和捕魚（圖14、15）。高棉人房屋的內(nèi)部一般是單開間，“與其他文化群體（越南人、占族穆斯林和中國人）房屋空間單元截然不同”[20]49。

圖13 水上漁村的村落形態(tài)隨湖水的變化而變化，在雨季，單從水面形態(tài)上看高腳屋也變成了水上漁村The morphology of the floating village changes with the flood pulse of the lake as the elevated dwellings become only water-based during the monsoon season

圖14 甘邦魯浮村的高腳屋村落沿Rolous河的一條路（14-1），該路在雨季需乘船進入（14-2）The stand-stilt village of Kampong Phluk along the Rolous River and an earthen road(14-1) becomes only accessible by boat in the monsoon season (14-2)

4 大型水利工程與TEK之間的迭代

洞里薩湖在區(qū)域、流域、國家和地方層面都有著重要的生態(tài)、社會和政治意義。歷史上的洞里薩湖一直是可調(diào)節(jié)下游水量的大型水庫和擁有極豐富水生生物資源、承載大量社會活動的大型內(nèi)陸漁業(yè)區(qū)。然而，由于自然資源受到不同程度的開發(fā)，導(dǎo)致與社會之間沖突不斷，湖泊許多方面的豐富性受到威脅。能源和全球變暖是洞里薩湖功能轉(zhuǎn)變的主要因素。湄公河流域已有的和待建的水電大壩對洞里薩湖的水文環(huán)境有很大影響。根據(jù)2032—2042年預(yù)測模型顯示，水電站大壩的運行將導(dǎo)致旱季水位升高（估計比目前的水位提高0.5～0.9 m，湖水的蓄水面積將增加18～31%）、洪峰值降低，這將導(dǎo)致湖水的水位波動曲線變緩，洪泛區(qū)面積縮小（至少減少75%）。然而，關(guān)于氣候變化是否會影響洞里薩河的汛期水位，結(jié)果不得而知（原因是大氣環(huán)流模型和流域排放水平之間有差異）[6]5422。此外，“最近的地質(zhì)活動”顯示，整個盆地正在下沉，西北地區(qū)的下沉程度低于南部地區(qū)，導(dǎo)致盆地向南傾斜（并形成了大面積的可淹沒的廊道森林）[1]48。新的洪水模式將對洪泛區(qū)的生境產(chǎn)生不利影響（破壞魚類產(chǎn)卵、鳥類和其他物種覓食和繁殖所需的廊道森林、灌木叢和草地）；當(dāng)?shù)氐乃a(chǎn)能力也會下降，進而造成重大的社會和經(jīng)濟危機。淹沒區(qū)廊道森林的消亡以及上游大規(guī)模的森林砍伐，將對河水流量以及侵蝕、沉淀和淤積等過程產(chǎn)生顯著影響。雖然上游洪泛區(qū)的農(nóng)業(yè)面積很可能會增加，但魚類資源的減少將不可避免地導(dǎo)致區(qū)域自給自足能力下降，這一變化，會加大該地區(qū)對于糧食進口的依賴。

此外，生態(tài)旅游及與之相關(guān)的不同類型、規(guī)模的基礎(chǔ)設(shè)施建設(shè)（包括暹粒國際機場）也會受到影響，因為大部分的生態(tài)核心區(qū)會被永久淹沒[1]5427。眾多新建的基礎(chǔ)設(shè)施（帶來大規(guī)模生態(tài)破壞的同時加重了國家財政負擔(dān)）將面臨閑置和廢棄的境地。與此同時，在過去20年里，爆炸式的旅游開發(fā)嚴(yán)重破壞了該地區(qū)的生態(tài)健康，成群結(jié)隊的游客踩踏在吳哥遺址上，造成了明顯破壞。顯然，眾多考古遺跡（如歷史上的伊卡利亞水利工程）被植物大幅度吞噬，大自然正在以毫不過分的方式，對人類古代遺跡進行報復(fù)。紅色高棉時期的水利工程、殖民時期的基礎(chǔ)設(shè)施也在遭受同樣的命運。有意思的是，人類的侵占活動仍在這些巨大廢墟的陰影中繼續(xù)著。雖然人類的行為情有可原（以至于法國殖民者曾聲稱自己發(fā)現(xiàn)了遺址），但我們事后認(rèn)識到，人類的行為并未改寫或改造自然，人類只不過是在尊重自然建構(gòu)的邏輯的基礎(chǔ)上重復(fù)進行自我刻畫而已。

圖15 高腳屋高高的立柱保護村莊結(jié)構(gòu)在雨季不受洪水侵襲，并創(chuàng)造了一個依賴于水的生活環(huán)境The tall stilts protect the village’s structures during the monsoon season and create a water-only based living environment

近些年，TEK在生物多樣性保護方面發(fā)揮著重要作用?？傮w而言，當(dāng)?shù)鼐用裢ㄟ^努力擴大領(lǐng)土，企圖占有更多類型的場地，增加可用資源，減少單一資源波動所帶來的風(fēng)險。傳統(tǒng)的管理方式不斷演變，“傳統(tǒng)知識的‘傳統(tǒng)’不在于它的古老性，而是在于它獲取和使用的方式”（注：原文強調(diào)的重點）[23]22。數(shù)千年來，最初的管理者是部族長者和知名人士，并組織當(dāng)?shù)鼐用耖_展水資源管理的集體活動[1]10。平原上的灌溉系統(tǒng)，包括吳哥城的人工蓄水池，已經(jīng)年久失修，也許最終可以像Molyvann提議的那樣被重新利用。這種再利用顯然不是單純地對高棉帝國的伊卡利亞水利工程進行恢復(fù)性重建，而是在人與自然的反復(fù)調(diào)和下，形成一種新的設(shè)施，使之更好地適應(yīng)當(dāng)下需求并具有可持續(xù)性。對藝術(shù)品進行保護是生態(tài)恢復(fù)的手段[24]，也可支持農(nóng)業(yè)和聚落的復(fù)興，在這一點上，可能沒有比吳哥城更有說服力的例子了。與此同時，應(yīng)注重森林、水岸植被與水系統(tǒng)之間的依存關(guān)系。以社區(qū)為單位的林業(yè)和漁業(yè)管理成為當(dāng)?shù)刭Y源管理的具體手段，表明人們意識到了自殖民主義以來砍伐式資源獵取方式的弊端，并在過去幾十年間的新自由主義時期，向著保護性開發(fā)的方向發(fā)展。

不過，TEK是否能夠解決人口激增、氣候變化和極度貧困所帶來的危機，還有待探索。對這些傳統(tǒng)知識的重新運用意味著，自19世紀(jì)后，隨著新自由主義政策的實施和持續(xù)的私有化方案和運動的開展，土地使用權(quán)極端不平等的情況有所緩解。幾個世紀(jì)以來，各種尊重自然的活動在這片土地上正在持續(xù)發(fā)生，從高棉帝國大規(guī)模水利工程的修建到紅色高棉時期的反城市化戰(zhàn)略，再到法國殖民時期的掠奪活動和公共土地私有化，以及新自由主義所帶來的土地開墾活動，再到軍事行動和游擊隊內(nèi)戰(zhàn)，最后到不同程度上強制要求的保護理念。由此可見，TEK引導(dǎo)各族民眾以傳統(tǒng)信念支撐社會實踐，由此建立起與自然環(huán)境相適應(yīng)的人居空間，構(gòu)建了人、自然和聚居地和諧共生的環(huán)境，居民將自己錨固而不是凌駕于這些建筑物之上，因此，他們更像是在模仿自然，在不承擔(dān)過多傳承職責(zé)的基礎(chǔ)上營建新的傳統(tǒng)。在Henneghan的理解中，恢復(fù)是建立在過去的狀態(tài)之上的，而不是對過去狀態(tài)的重建[24]。

世界范圍內(nèi)，TEK被廣泛應(yīng)用于現(xiàn)實生活、歷史復(fù)興等方面，為人們尋找以尊重自然資源為前提、建立符合地域文化和特殊語境的人居環(huán)境方法提供了替代性的解決方案。因而，TEK在德語中具有雙重含義：即指導(dǎo)性（在政策或治理模式中）和使命性（在行動、計劃、愿景等方面）。TEK理念的興起，意味著對自然和文化、現(xiàn)代和傳統(tǒng)、工程建設(shè)和生態(tài)等提出了挑戰(zhàn)。這些知識揭示了古代工程及管理模式蘊含的智慧，是長期發(fā)展過程中，人類不斷適應(yīng)自然、人口變化及整治環(huán)境所形成的。面對全球氣候危機，TEK更是為人類建設(shè)用地和非建設(shè)用地的生態(tài)修復(fù)提供了現(xiàn)實而有效的解決方案。鄉(xiāng)土營建技術(shù)和TEK揭示了土地利用的復(fù)雜關(guān)系，其中大部分內(nèi)容是反對新自由主義的發(fā)展模式，并傾向于公眾。TEK向西方科學(xué)生態(tài)知識（scientific ecological knowledge, SEK）發(fā)出挑戰(zhàn)，前者所包含的世界觀和道德觀更受人們的推崇。筆者對洞里薩湖的研究揭示了什么是TEK，揭示了歷史上大型工程建設(shè)和生態(tài)環(huán)境反復(fù)迭代中人們是如何在一個特定的環(huán)境（自然環(huán)境或其附近）中定居的，并且，這一體系還能支持自殖民主義以來自相矛盾的資源開發(fā)和自給自足的多種發(fā)展模式。

注釋：

① 法國殖民統(tǒng)治時期（1863—1953年）任命的第一位君王。

圖片來源：

圖1、9、11?凱 莉·香 農(nóng)；圖2、3、5、7、8、10、12～15由本文作者基于實地調(diào)查、湄公河三角洲區(qū)域計劃和柬埔寨開放發(fā)展信息的RUA 2021繪制；圖4、6來源于艾克斯省國家海洋檔案館（編號為：OF-TOL-17010983，OF-TOL-17010974）

（編輯/李清清）

Cambodia’s Tonle Sap Lake: Iterating Between Disruptive Water Engineering and TEK

Authors: (BEL) Bruno De Meulder, (BEL) Kelly Shannon

Translator: JIA Lyuyuan Proofreader: WANG Xiyue

1 Natural Hydrology Engineered

The Tonle Sap Lake is the largest permanent freshwater lake and wetland ecosystem in Southeast Asia. The environs of the lake host numerous productive landscapes and settlements (Fig. 1). It lies on a northwest-southeast geological fault line and was created by subsidence of the “Cambodian platform”millennia ago; it occupies an area with an average altitude of 15-20 meters above sea level[1]31,[2]46.It is fed by the Tonle Sap River, a tributary of the Mekong and runoff of numerous catchments;95% percent of the Tonle Sap Lake catchment is in Cambodia, while 5% is in Thailand[3]1723. A hydrodynamic model found that majority (53.5%)of the lake’s water originates from the Mekong mainstream, while the lake’s tributaries contribute 34% of the annual flow and 12.5% is derived from precipitation[3]1729. The lake is an important component of the Mekong River Delta, often referred to as its “beating heart” since as a natural floodwater reservoir it performs as flood protection in the wet southwest monsoon season (May-October) and assures dry season flows (November-April) to vast areas downstream (Fig. 2). It is renowned for a remarkable phenomenon where during the monsoon season the massively increased flows from the Mekong reverses the direction of the Tonle Sap River and the lake’s coverage expands from 2,300-15,000 square kilometers and from 1.44-10.30 meters depth[4]1415(Fig. 3). The distance of the maximum and minimum waterlines is approximately 10 kilometers, although “waterline”is a relative term since the edge of the lake is a subtle gradation of wetness that stretches for many more kilometers that is continuously moving back and forth[5]8. For millennia, there has been an interplay of natural and engineered systems for the area’s complex water management (Fig. 4).

The Tonle Sap floodplain is divided into five distinct habitat groups: 1) open water (under water 12 months a year); 2) gallery forest (annual flood duration of 9 months); 3) seasonally flooded habitats dominated by shrublands and grasslands(flooded 5-8 months); 4) transitional habitats,nowadays dominated by abandoned agricultural fields, receding rice/floating rice, and lowland grasslands (flooded 1-5 months); 5) rainfed habitats,consisting mainly of wet season rice fields and village crops (flood duration less than 1 month)[1-3].The rich alluvial fans and immense inundation host an extremely high level of biodiversity. The Tonle Sap is among the most productive freshwater ecosystems in the world. The dynamic hydrology of the seasonal inflow flood pulse transfers terrestrial nutrients into the aquatic system and the flood plain’s gallery forest and scrublands offer rich grounds for the water-flow migration of eggs, fry and fish from the Mekong River[4]1415. The lake’s fisheries and aquaculture account for approximately 80% of the current protein consumption of Cambodia[6]5427.

Traditional water management regimes of the Khmer are more than 1,200 years old and always have been astonishingly comprehensive, drastic and sophisticated. Early settlements of the Mon-Khmer were located along the middle and lower valley of the Mekong and were dominated by a circular geometry of mounds with defensive embankments and moats. They were dispersed across the territory,surrounded by agriculture fields and separated from one another by forests. They had raised houses and an ingenious system of communally built and managed man-made prek (canals located behind the natural embankments of riverbanks) and beng(ponds), a system that choreographed flood water into the fields and back towards the river at the dry season[1]3-4,[7]45. Around the lake, people lived in villages called kampong (“l(fā)anding place” in Malay);they operated as a constellation and were interdependent on the slightly higher-land rice-growing villages. Altogether, the Tonle Sap has more than 1.7 million people[6]5423. Today there are a number of cities and larger villages directly adjacent to national roads 5 and 6 which function as a continuous dike,constraining the flood plain around the lake (Fig. 5).

During the Khmer Empire of Angkor(802-1432), successive kings built not only a collection of unrivalled temple precincts, but also a complex irrigation system — connecting the Kulen Hills in the northeast to the lake (Fig. 6). Angkor is located on one of the narrowest and steepest parts of the Tonle Sap floodplain. Its urban planning“integrates the mountain, the city, and water into an ordered and productive symbolic system”[1]14.The enormous, highly engineered and essentially an agro-urban landscape was without parallel in the preindustrial world[8]. Already by the 13thcentury,merely the urban core of Angkor encompassed 35 km2while the extensive urban complex stretched over 1,000 km2[8]. The ingenious water system formed the backbone of the agro-urban landscape,in which also forestry no doubt played a role since,except for the religious buildings, all construction was, even the royal palaces, in wood or thatch. The urban landscapes in Greater Angkor combined urban intensification and landscape engineering in which a very large population “was highly dependent on the delivery of consistent agricultural yields from an extended agro-urban landscape”[8].The Khmers development of a carefully engineered network of canals, dams, barays (artificial reservoirs connected to the natural river regime made by embankments or dykes that were a means of both irrigation and transport) and trapeang (excavated ponds for collecting rainwater used by households for drinking, bathing, watering animals, small-scale hydro-agriculture, etc., Fig. 7). The barays stored water during the torrential monsoons to be used for irrigation in the dry season (Fig. 8). The now dry East Baray (completed in 890) was a monumental artificial lake, fed by the Siem Reap River,measuring 1.8 km by 7.5 km; its eastern retaining walls are 4～5m high. The enormous West Baray(2.1 km by 7.8 km) came centuries later (Fig. 9).A collection of smaller barays complemented the water supply system. A series of Temple Mountains were built (sometimes as islands within the barays) to honour gods and ancestors, serve as mausoleums for the various kings and display the Khmer Empire’s omnipotence. Urban space continued far beyond the moated precincts of the temples and rectilinear grids encompassed intramural as well as extramural areas[8]. In its heyday, the urban landscape of Angkor may have supported a population approaching 750,000.

The Khmer agro-urban landscape was gradually defined over centuries, but always as a highly engineered system with a strong geometrical order and converging into the complex, water based,agro-urban net. A last significant step in radical engineering came during the reign of the Khmer Rouge (1970–1979) that created a major rural engineering project for almost the whole country,with the construction of more than 350 large water reservoirs (dams), numerous dykes and an extensive net of canals (at least 7,000 km main canals of at least 10 meters wide that fed series of perpendicular smaller canals or ditches, evenly spaced, every 100 meters). These smaller scale features account for up to tens of thousands of kilometers that then often fit into one-by-one kilometer grids of larger canals[9]. This supported a massive expansion of rice culture that was envisioned as base for the national economy as well as for a new form of settlement in which forests and agriculture where to remain in balance. The plains around the Tonle Sap were the main areas of intervention with a concentration in the Northwest Zone (around Sisophon).

The massive operation was the result of a “deliberate, comprehensive and calculated approach to water-management”[10]104. Distinct geomorphological and hydrological conditions across the territory led to significant geographic and functional variations among the applied irrigation schemes, that resonate both nuanced local knowledge and the widely employed Chinese engineering and technical assistance of the time. Six different types of water-management were adopted with varying sizes (external, internal, linked and segregated storage besides topographically controlled systems and largescale canal systems)[10]1114. This water infrastructure delivered a spatial register on which the new settlement system would be anchored.

2 Water-Based Livelihoods and Common Resource Management

The ecology of the lower Mekong River system,including the Tonle Sap Lake, is inextricably tied to the economy, culture and identity of the Cambodian people[11-12]. The exceptional pulse system of the lake supports a wide variety of water-based livelihoods based on locational assets. In turn, livelihoods are commonly supported by a diversity of secondary occupations and there is extensive seasonal migration of both people and actual villages[13]. The physical diversity of the lake is reflected in social aspects of occupation. The lake is home to a large Khmer population as well as other ethnic groups, including Sino-Khmer, Cham (Khmer Islam) and Vietnamese(who are considered legal aliens). Each of the groups occupy a “eco-cultural niche”[14]. The Buddhist Khmer are predominately involved as subsistence rice farmers and practice small-scale fishing in the paddy fields during periods of inundation. The Khmer-speaking Sino-Khmer are the least visible in the region, but due to their heritage as traders and with access to capital, are important actors as commercial fishing concessionaires. The Muslim Cham, in the Mekong Delta since 1471, are active in both farming and fishing. Finally, there are relatively large populations of Vietnamese in the vicinity of the Tonle Sap.

Today, the Tonle Sap’s annual catch is the fourth most productive captive fishery in the world,with more than 700,000 metric tons per year[15]2.The lake hosts a wide array of bamboo fences and assorted fish traps, including traditional systems of extensive sequences of fence-arrow traps as well as a more recent proliferation of more efficient,yet ecologically destructive, electro-fishing, nylon monofilament and gill-nets. The lake is renowned for its species diversity, with more than 200 identified species, 100 of which regularly occur in catches[2]85. Biologists classify the lake’s fish into“white fish” and “black fish”. The white fish spend the large proportion of their lives in fast-flowing“white water” with annual, lengthy migrations and spawning (bring eggs and larvae flowing into the floodplain) synchronized with the flood cycle. In the wet season, the white fish fatten themselves in the nutrient-rich inundated floodplain. Black fish only migrate short distances and remain in the floodplain throughout the year. They spawn in the lake’s gallery forest and scrublands[2]. Prior to French colonialism,the lake — and for that matter all of Cambodia’s natural resources, including forests and land —belonged to the king and were loosely managed. As in many customary systems, people can claim rights and settle land by clearing it, while forest and water are open access. Colonialism partially distorts and disrupts, as well as partially replaces these systems.During King Norodom’s reign (1864–1904)①new regulations were introduced. The size and types of fishing gear and traps were regulated and fishing lots were classified. The king also profited from the Tonle Sap by selling licenses to Chinese tycoons[16].

In keeping with the notion extractive practices and generation of revenue from taxes, the French formalized informal practices through various privatization laws, including land reform in 1884,creation of a forest service in 1889 and a fisheries law in 1908. Traditional fishing and fish-farming were replaced by a system of commercial fishing lots(that were intended to attract investors) and many local fishermen were expelled. Various contestations led to a complex management system which includes fishery associations (the first established in 1911) to control and manage lots. By the 1920s, conservation areas began to appear in the Tonle Sap, since the importance of flooded forests was recognized for their vital role in preserving fish stocks as spawning sites. Conservation results from the understanding that exploitation of nature must be restrained, with explicit ecologies restored or safeguarded. During the Khmer Rouge era the fishing lots system was largely abandoned, since fishing largely forbidden;a small number of fishing units were maintained solely to provide fish to the leadership and for export to China[15]270. Due to the Khmer Rouge focus on agriculture, the fishery resources had a period of non-human intervention and thrived. In the 1980s, fishing recovered its importance and a 1987 Fishery Law defined three levels of fisheries:family (subsistence), medium-scale (artisanal) and large-scale (industrial/ commercial). Subsistence fishing is allowed year-round, while the other two are only permitted in the open season (November-June). Fishing lots were auctioned bi-annually to highest bidders[2,15]. Contestations continued to rise with grievances over corruption, encroachment and poaching. In 2012, the government abolished the private leasehold fishing lots and instead allocated lots as community fishing grounds while simultaneously reserving areas for 17 new conservation areas (equivalent to 35% of the former leasehold areas), bringing the total to 25 areas where fishing was prohibited[17]453(Fig. 10).It is far from the noble “half-earth principle” of preserving fifty percent the earth’s territory from humankind’s occupation proposed by Wilson[18]but has resulted from the absolute necessity to reverse overexploitation.

The recognition of the interdependency of the Tonle Sap’s water and the lake and mountain forest ecologies has long been established. Even during the Khmer Rouge period, the intimate relation of forest and water ecologies and urbanism was recognized. According to Pol Pot, “… forest(s)must be cleared, but we must set a limit. Because if we clear all the forests around the Tonle Sap, in ten years’ time the Tonle Sap will have dried up; we will have no water source and no fish. Moreover, when the water coming down the Mekong stops flowing into the Tonle Sap, the Tonle Sap will dry up. Water from the Mekong enters the belly of the Tonle Sap.If the Mekong water does not enter the Tonle Sap,the area around Phnom Penh and the riverbanks downstream will be all submerged by the flooding Mekong”[9]132. Today, the successful management of the common pool resources is dependent on collective action of various lake-side communities and upstream inhabitants, as well as governmental regulations for use.

Cambodia’s Ministry of the Environment(established by royal decree in 1994) “protects”a number of water and forest entities while the Ministry of Agriculture, Forest and Fisheries is responsible for their managed use. However, despite intentions and decrees on paper, reality on the ground is quite different. In the forests, there is extensive logging and wildlife hunting in addition to the development of illegal access roads. There is also massive forest clearing for land speculation.Deforestation is, of course, linked to increased floods, temperatures, soil erosion and siltation. The lake was declared a UNESCO biosphere reserve in 1997 and Cambodia has five UNESCO Ramsar site designations, indicating wetlands of international importance; three are in the Tonle Sap: Prek Toal in the northwest upstream area (21,342 hectares,inscribed in 2015), Boeng Chhmar and associated river system and floodplain in the central eastern area (28,000 hectares, inscribed in 1999), Stung Sen in the south near the confluence of the lake, Stung Sen and Mekong rivers (9,293 hectares, inscribed in 2018)[19]. According to Cambodian law, the three core zones are as well “strictly protected areas” where any exploitation of natural resources is prohibited[19]750.

Finally, it is important to understand that the Cambodian calendar is tied to seasons and livelihoods. Due to the dynamics of flooding and fish migration, fish in the Tonle Sap are abundant in the 4-month dry season and decreases sharply during the rainy season, when rice cultivation becomes the chief economic activity. Inhabitants of the lake use the period to repair fishing gear and processing their catch, through developed methods of drying and smoking as well as a fermented fish paste. The Khmer New Year is in mid-April(following the solar calendar as in other parts of the region), at the end of the harvesting season when grazing land is burned and all eagerly await the May monsoon rains. For land-based rice farming, soil is plowed once there is enough water that has softened it and seedbeds are established. In July and August,seedlings are transferred to fields. For deep-water rice — defined as growing in areas flooded deeper than 50 centimeters for at least one month during the growing season[2]— land preparation begins in February with ploughing and seeding between May to mid-June (depending on rainfall). Floating rice grows in areas where the water depth is greater than 100 centimeters, it is never transplanted and never uses fertilizers (and rarely pesticides); its hollow stem grows up to 5-6 meters as the water rises and floats on the water’s surface. Its relatively lowyield harvesting occurs in January and February and done with hand sickles. Traditional rice grows in shallower areas where it thrives due to its height and long stalks. Both variants of deepwater rice have long traditions in Cambodia are mentioned in records of Angkor already in the 13thcentury. In the 1930s, the area of deep-water rice was estimated at 540,000 hectares, while by the 1960 it had been reduced to a mere 70,000 hectares[2]54. Today it primarily exists near Kampong Thom where it is interspersed among 1,600 square kilometers of flooded grasslands. Since the area is largely uninhabitable for six months of the year,people begin annual migration in January.

3 Adaptive Typologies

Although some villagers migrate, others remain year-round near or on the Tonle Sap. The highly adaptive settlement structure of housing around the lake is noteworthy. The houses are all wood(traditionally in Cambodia stone was only used for temples) — and it is commonly said that life starts with a wooden cradle, then a wooden house and as its close a wooden coffin and cubic meter of firewood for the cremation. The relationship between housing and villages and wood as both a material and as a domain is important. In Khmer culture, trees have a central role, as do forests. “Cambodian people have a great respect for the invisible powers called Neak ta (ancestral spirits)”[20]41that are believed to inhabit large trees. This has impacts on all scale levels, from the choice of trees for timber to spatial organization and location of villages, a choice always made with care. The choosing of village and house siting goes hand in hand with delineating the “wild” as unsafe from the domesticated. Villagers have to be protected from the invisible forces that inhabit the wild. “While the forest is wild and unknown, the village is where people and spirits live in harmony”[20]48. Interestingly for communities living along or on the lake, the lake’s waters seasonally complement the forest as the “wild” during the wet season when incessant monsoons render the Tonle Sap “formidable, wild and claustrophobic”[20]48.

Settling inevitably implies a clearing of the forest that remains to be seen as the “wild” for villages outside of the floodplain, or for those who migrate during the wet season towards the more tranquil edges of the lake or — as a last option —staying somehow at the edge of the lake as floating or stand-stilt villages within the floodplain. There is an array of floating and stand-stilt villages that are within national roads 5 and 6 which encircle the lake as dykes (and that actually are situated on the (historic) edge of the (average inundation)floodplain (Fig. 11). There are approximately 80,000 people living[20]44in floating villages,which adapt their morphology in relation to the intensity of water dynamics: organized as linear rows and dispersed and centrifugal during the dry season versus a more concentrated and centripetal configuration organization in the monsoon season.Village movements literally respond to the shifting landscape conditions and in the dry season conquer the vast water surface that is “conducive of expansive, calm vistas on Tonle Sap”[20]48and shelter from the turbulent and agitated water body by retreating into more tranquil river mouths during the wet season. The seasonal shifts in village location and configurations are adaptations to the radical two faces of the lake as landscape.Relationships between landscape and settlement are reciprocal and mutually assertive. Floating fishing villages have quite small houses built on platforms (of barrels) and are constructed of bamboo and aquatic plants, which allows for easy mobility (Fig. 12-13).

Housing, as well as collective facilities(commerce, school, temples, mosques, etc.),typologies work with the remarkable variation of the lake’s water level. Both the stand-stilt and floating houses are built with a post-beam system.The stand-stilt houses also have a structural bracing system so that they can withstand the rapid water level rise in the monsoon period. The stand-stilt villages have existed already for several generations and are located on or near patches of inundated gallery forest (with freshwater mangroves) and linked to the lake via a channel or stream. Since in 1940s, traditional ecological knowledge (TEK) led many elders of the stand-stilt villages to protect the forests and actively resist the expansion of agriculture. The stand-stilt villages are prevalent in three of the lake’s six provinces: Bantay Meanchey,Siem Reap and Kampong Chhnang[21]3. Houses have high, 6-7-meter stilts (primarily made of long small trees), and in the dry season are centered on an earthen road with rows of houses facing one another; in the wet season all is only accessible via water. The houses are typically made of wood and thatch, although as wealth increases tiled or corrugated metal roofs proliferate. The houses range from 3-8 meters wide by 6-20 meters long depending on the inhabitants’ affluence[22]8. During the driest months, a number of villagers practice pig,duck, chicken and crocodile-raising (in floating cages over fish cages, fed hyacinths and fish harvested from the lake, with their waste providing fish food)and home gardening. As well, there is a migration of some families onto the open lake where they establish temporary housing where it is easier to care for cages of fish or crocodiles as well as daily fishing(Fig. 14-15). Khmer house plans are generally characterized by a single interior partition “and clearly established the fundamental unit plan for all the structures of the remaining cultural groups(Vietnamese, Cham Muslims, and Chinese)”[20]49.

4 Iterating Between Disruptive Water Engineering and TEK

The Tonle Sap Lake is ecologically, socially and politically important at the regional, basinwide, national and local scales. Historically, the lake has been a great reservoir which tempers flooding pulses downstream. It also has an exceptionally rich aquatic biodiversity, operates as a tremendous inland fishing resource and accommodates significant societal diversity. However, the richness of the lake is threatened on numerous fronts as conflicts between natural resource exploitation arise across scales and communities. Energy and global warming are the primary transboundary drivers that have impacts on the Tonle Sap. Existing and planned hydropower dam development in the Greater Mekong River Basin will significantly impact the Tonle Sap’s hydrology. According to models which analyzed projected changes from 2032—2042, the operation of planned hydropower dams will flatten the hydrograph (flood pulse) by causing higher dry season water levels (estimated at 0.5-0.9 meters above current levels, increasing the permanent surface of the late by 18-31%) and lower flood peaks(which would minimally reduce the floodplain area by a drastic 75%). At the same time, modelling was inconclusive (due to differences in the GCMs —general circulation models — and levels of emissions in the basin) with regards to whether climate change will increase or decrease the flood season water level in the Tonle Sap[6]5422. As well, “relatively recent geological activities” has revealed that the entire basin is sinking, with the northwestern part sinking less than the southern area — resulting in the basin’s slanting towards the south (and the creation of large pockets of flooded forests)[1]48. The new flood regime will adversely affect floodplain habitats (the destruction of gallery forests, scrub and grasslands where fish spawn and birds and other species feed and breed); aquatic productivity will be reduced which will, in turn, lead to significant social and economic impacts. The demise of flooded forests,in addition to large-scale upstream deforestation would have a notable impact on flow amplitudes,erosion, sedimentation and siltation processes.There will most likely be increases in agricultural areas in the upper floodplain, but the expected reduction of fish stocks will inevitably lead to decreased self-sufficiency and increased dependency on food imports.

Additionally, ecotourism — the rise of which is causing the development of infrastructures of all kinds and all scales (the international airport of Siem Reap included) — would suffer since large parts of current core conservation areas would be permanently submerged[1]5427. Large parts of the relatively new infrastructure (that already triggers substantial ecological disturbances and increases financial burdens of the country) will become useless or redundant. In parallel, the overwhelming mass-tourism development of the last two decades is eroding the territory’s ecological healthiness. The literal overwhelming of Angkor’s archaeological sites by hordes of tourists is only an obvious sign in this respect. One can evidently also see the archeological sites, monumentally taken over by vegetation,as indications of how nature takes revenge without any unduly respect for the Icarian water engineering endeavors of the past. A substantial part of the massive water works of the Khmer Rouge are undergoing the same fate, as are colonial infrastructures. Interestingly, human occupation continues in the shadow of the majestic ruins. It has done this without unduly respect (to such a point that the French colonizers once claimed discovery of the sites), but in hindsight in a way that is not so much rewriting and re-engineering nature, but rather inscribing itself again within and respecting the logics of this constructed nature.

Recently, there has been a resurgence in the importance of TEK in relation to conserving biological diversity. On the whole, indigenous peoples strove to increase their territories’ biological diversity in order to both increase resources at their disposal and reduce risks associated with fluctuations in the abundance of individual species. Customary management practices evolved over time and “what is ‘traditional’ about traditional knowledge is not its antiquity, but the way in which it is acquired and used” (emphasis in original)[23]22. For millennia, there has been collective resource management of the basin — originally with collective labor of local water management organized by elders and notables[1]10.A number of the local irrigation systems in the plains, including the large barays of Angkor, has fallen into disrepair and could perhaps be eventually reutilized as Molyvann proposed. This reuse clearly could not be a pure reconstruction of the Icarian water engineering system of the Khmer Empire,but a recuperation of elements that can sustainably function as a neo-natural structure, a result of the iterative constructions of nature and man. There is probably a no more telling example than Angkor of where art conservation techniques can literally be the means of ecological restoration[24], while simultaneously supporting agricultural and settlement redevelopment. As well, the interdependency of forests and riparian vegetation to the healthy functioning of the water system must be prioritized.The return of broad-based resource stewardship in community forestry and fisheries management is clearly indicated as a reversal of merely extractive practices, which were primarily induced since colonialism and re-emphasized with the neoliberal turn of the last decades.

It remains a question if the systemic reactivation of TEK suffices to deal with the contemporary impressive challenges arising from strong demographic growth, the consequences of climate change and severe poverty. The systemic re-activation of TEK implies de-activation of the extreme inequality of access rights through the successive privatization programs and campaigns and other privileges that liberal policies have enforced since the late 19thcentury. As such, various concepts of nature have been forcefully projected and imprinted on the Cambodian landscape over centuries, ranging from massive engineering by the Khmer Empire to the Khmer Rouge’s drastic deurbanization strategies to widespread scars resulting from colonial extractive operations and privatization of common land and its neoliberal successors, to the exploits of military war operations and civil war guerrillas and finally, also to various protection, preservation and conservation concepts that are enforced to various degrees. It seems that various ethnic groups whose traditional beliefs steer social practices towards the establishment of harmony between people, nature and the spirits of the village, anchor themselves rather freely upon these imposed and disruptive structures. As such,they seem to mimic nature, which constructs itself without too many duties or respect to its own new succession. In Henneghan’s understanding,restoration is that that inevitably builds upon rather than literally reconstructs a past state[24].

The growing recognition, lived realities and reinvigoration of TEK in many parts of the globe point to the acute necessity of alternative methods of engaging humankind’s settling with and in the world — ways to very specifically engage with locational assets — natural resources in the first place — culture and the particularities of context.As such TEK offers a leitbild in the double meaning of this German notion: a guiding image (as in a policy strategy or in a governance model) as well as a mission statement (the vision that defines actions,plans, programs). The resurgence of interest in TEK challenges notions of nature and culture, modern and traditional, hard-engineered and ecologicalengendered. It reveals the wisdom of age-old systems of environmental stewardship prompted by successive experiences over long periods of time and encounters with various circumstances, possible sustainable livelihoods, and restorative justice. In the context of the global warming crisis, TEK offers a tangible and inspirational opening to renewed forms of environmental ethics and responsibility for healing massive disturbances of human and non-human habitats. Indigenous science and TEK reveals complex and sophisticated relationships to land, much of which actively resists the neoliberal development paradigm, while embracing commons. TEK is a welcomed set of worldviews and ethics to challenge Western Scientific Ecological Knowledge (SEK). The case study of the Tonle Sap demonstrates how TEK defined and continues to define settlement (as settling with and settling in nature) in a particular context that historically iterated between monumental engineering and ecological embeddedness, and, which since colonialism, accommodates contradictory extractive and self-sufficient oriented models of development.

Note:

① the first monarch installed during the French colonial administration (1863—1953).

Sources of Figures:

Fig. 1, 9, 11 ? K. Shannon ；Fig. 2, 3, 5, 7, 8, 10, 12～15 are drawn by the authors based on 2021 fieldwork, Mekong Delta Regional Plan and Open Development Cambodia information；Fig. 4, 6 ? Archives Nationales d’Outre Mer,Aix-en-Provence, OF-TOL-17010983, OF-TOL-17010974.

(Editor / LI Qingqing)