城中戲水

Splashing Out in the City

多年來(lái)，有一群建筑師、設(shè)計(jì)師和藝術(shù)家一直在致力于一個(gè)富有遠(yuǎn)見(jiàn)的項(xiàng)目：修建柏林中部一條河道上的巨型游泳池。最初，這個(gè)想法似乎與市中心的正規(guī)莊嚴(yán)不相稱——但是對(duì)城市更新和修復(fù)來(lái)說(shuō)可能是很大的支持，將會(huì)改變這個(gè)標(biāo)志性區(qū)域的面貌。

博物館島是柏林城市旅游的中心，也是世界上最重要的博物館群之一。博物館島集重大建筑與文化價(jià)值于一體，其地位獨(dú)一無(wú)二，自1999年起就被聯(lián)合國(guó)教科文組織列為世界遺產(chǎn)。但是，該島不僅是高層次的文化場(chǎng)所，也是日常的娛樂(lè)天堂：庫(kù)佛爾格拉班位于島的東邊，是施普雷河一個(gè)廢棄河汊上的一條400m長(zhǎng)的運(yùn)河，天氣好的時(shí)候，成百上千的人聚集在這里狂歡。他們?cè)谶@從柏林市中心流過(guò)的原始清新的河水中游弋、戲水。

此處人稱“Flussbad”或河流泳池，有17個(gè)奧運(yùn)會(huì)游泳池那么大，主要為本地人開(kāi)放，是他們的一個(gè)重要娛樂(lè)區(qū)。在博物館島上，有攜家?guī)Э谏碇疽碌谋镜鼐用?，也有?lái)自世界各地的游客，他們和諧共處，互不相擾。這就是柏林，一個(gè)寬容、多樣化的城市，同一個(gè)空間，多用途并存。

具有耐力的理想家

但是，無(wú)論是誰(shuí)，要想體驗(yàn)德國(guó)首都中心的河流泳池，都需要耐心。因?yàn)?，這個(gè)景點(diǎn)目前仍然只在紙上。庫(kù)佛爾格拉班還只是一條運(yùn)河。要讓泳衣成為來(lái)柏林游客的必備服裝，尚需幾年的努力。但這并不意味著這個(gè)愿景無(wú)法成為現(xiàn)實(shí)。該項(xiàng)目的作者已經(jīng)證明他們有足夠的耐心：他們已經(jīng)為自己的項(xiàng)目努力了15年。這一切始于1997年，當(dāng)時(shí)，他們?cè)诎亓止餐瑒?chuàng)立了藝術(shù)團(tuán)體 “藝術(shù)和技術(shù)”。這個(gè)由藝術(shù)家、設(shè)計(jì)師和建筑師組成的非正式團(tuán)體背后，有蒂姆和揚(yáng)·埃德勒的驅(qū)動(dòng)力。這兩位建筑師是兄弟，分別出生于1965和1970年，他們都從事建筑研究，并在2000年聯(lián)合建立了實(shí)體：他們自己的藝術(shù)和建筑工作室。他們?cè)诿襟w型藝術(shù)裝置和建筑附件的發(fā)展中建立了國(guó)際聲譽(yù)；他們最知名的作品可能是格拉茨藝術(shù)館的“BIX Fa?ade”。

回到1997年，“藝術(shù)和技術(shù)”這個(gè)藝術(shù)家團(tuán)體?！爱?dāng)時(shí)，我們發(fā)起了相當(dāng)天真的項(xiàng)目，我們發(fā)現(xiàn)這些項(xiàng)目比我們以往的工作更有趣?！?蒂姆·埃德勒回憶說(shuō)。雖然這個(gè)由滿腔熱情的年輕人組成的團(tuán)隊(duì)可能沒(méi)有受到強(qiáng)烈關(guān)注，但它策劃了一系列令人興奮的項(xiàng)目，比如一個(gè)紅火的酒吧。蒂姆·埃德勒稱：“這個(gè)酒吧在財(cái)務(wù)上的成功使我們可以進(jìn)行其他項(xiàng)目?！?/p>

從生命線到廢水溝

其中之一就是這個(gè)河流泳池。這個(gè)想法在這個(gè)藝術(shù)團(tuán)體剛剛組成的第一年就產(chǎn)生了。蒂姆·埃德勒說(shuō)道：“一個(gè)靈感是，我們這個(gè)團(tuán)體的辦公室靠近水，在博德博物館正對(duì)面的庫(kù)佛爾格拉班上。我們經(jīng)常談?wù)撎M(jìn)河里涼快涼快會(huì)有多爽；令我們驚詫的是，庫(kù)佛爾格拉班已經(jīng)被閑置120年了?！痹谶^(guò)去的幾個(gè)世紀(jì)里，施普雷河有多種多樣的用途，在城市的早期主要作為運(yùn)輸路線，后來(lái)提供能源、防御手段和灌溉。從19世紀(jì)起，對(duì)這條河的需求越來(lái)越少，最后，該市開(kāi)始往廢棄河段填東西，例如，第二次世界大戰(zhàn)后，大量需要處理的瓦礫被填進(jìn)河里。這座城市過(guò)去的生命線淪落為廢水溝。這一點(diǎn)可以從柏林內(nèi)城區(qū)的混合廢水系統(tǒng)看出，它不會(huì)將雨水和廢水分開(kāi)，因此，大雨過(guò)后，溢流就直接流入施普雷河。結(jié)果，本應(yīng)在下水道里流的廢水流到了河里。這不僅大煞風(fēng)景，而且也危害健康。所以城市行政部門明確建議不要在施普雷河游泳。整個(gè)柏林連一個(gè)河流泳池都沒(méi)有，也沒(méi)有一處可以與水親近的地方；你得到市外才能找到一段沒(méi)有堤墻的河岸。

人人免費(fèi)入場(chǎng)

這些障礙并沒(méi)有阻止這個(gè)團(tuán)體發(fā)展其項(xiàng)目。他們的愿景是：一個(gè)巨型游泳池，一個(gè)在廢棄的河道上以世界著名的博物館島為背景且擁有21,400m2水面的河流泳池。從柏林大教堂前面和未來(lái)的都市城堡前面的盧斯特花園廣場(chǎng)，沿寬闊的臺(tái)階一直走到水邊。雖然設(shè)計(jì)包括威廉一世前國(guó)家紀(jì)念碑基座上的不顯眼的功能改變?cè)O(shè)施和儲(chǔ)物柜，但該河流泳池明確設(shè)定為公共設(shè)施：任何人都可以跳進(jìn)去涼快或游泳，不需付費(fèi)入場(chǎng)。

有兩項(xiàng)措施保證泳客不會(huì)在廢水中游泳。目前，有6個(gè)緊急出口的污水溢流流入運(yùn)河；本項(xiàng)目將把這些溢流引到溢流管道從泳池地下流走。此外，泳池上游的河道中還會(huì)安裝一個(gè)水過(guò)濾器：流入運(yùn)河的受控水流在經(jīng)過(guò)780m長(zhǎng)的過(guò)濾盆時(shí)將以自然方式得到凈化。

390m的過(guò)濾器

這個(gè)建筑面積為7200m2的濕地由0.8m厚的礫石過(guò)濾器組成，覆蓋平均深度約0.5m的水。這個(gè)過(guò)濾器能夠把流入的不純凈河水凈化到飲用水的質(zhì)量。過(guò)濾后的水經(jīng)收集通過(guò)砂填料下方的排水管道排出。上部被設(shè)計(jì)為線性公園，種植著各種沼澤、淺水和深水植物。最上游640m的河段將進(jìn)行改造。為此，北岸的堤墻將完全拆除，河道緩緩擴(kuò)展到漁夫島的地面。作為輔助目的，該河段用作內(nèi)城綠化區(qū)和初級(jí)凈水器。這個(gè)河道支流的主要實(shí)際目的是作為野生動(dòng)物避難所，以為柏林市區(qū)內(nèi)的施普雷河主河道河岸動(dòng)植物群落的重新安置提供支持。“總之，施普雷河就是一條飽受壓迫的河?！?/p>

蒂姆·埃德勒指出：“這條河的自我再生能力仍很脆弱，對(duì)環(huán)境變化非常敏感：例如，在高溫下很快就形成藍(lán)綠藻?！钡墙?jīng)過(guò)一定的時(shí)間，條件逐漸變得有利于項(xiàng)目：施普雷河的主要污染源——?jiǎng)谙４牡貐^(qū)的褐煤露天采礦穩(wěn)定減少，這意味著今天流到柏林的水比以前清潔了，因此，對(duì)以植物為基礎(chǔ)的廢水處理系統(tǒng)的需求將低于最初的預(yù)設(shè)。

時(shí)代的曙光

這些作者把他們的想法公之于眾的時(shí)候，他們對(duì)人們可能的反應(yīng)沒(méi)抱任何幻想?！拔覀冎篮恿饔境夭环蠒r(shí)代精神，”蒂姆·埃德勒說(shuō)。隨后，在統(tǒng)一后不到10年的時(shí)間里，柏林飛速發(fā)展。到處都在進(jìn)行大規(guī)模的建設(shè)。在蒂姆·埃德勒看來(lái)：“人們希望正在建造的建筑類型重現(xiàn)19世紀(jì)柏林黃金時(shí)代的風(fēng)貌。”通過(guò)回顧過(guò)去，對(duì)新身份的探索產(chǎn)生了極為重視威望的衍生架構(gòu)。“在這個(gè)時(shí)代，輕松的概念很難被認(rèn)可；建筑傾向于僵硬和正式。”但他認(rèn)為已有明顯的跡象表明這個(gè)時(shí)代已經(jīng)結(jié)束。漫步在城市中，你會(huì)得到一個(gè)不同的印象：到處仍在建設(shè)相當(dāng)夸張的建筑。但蒂姆·埃德勒說(shuō)，這些想法出現(xiàn)在前一段時(shí)間，現(xiàn)在正逐漸消失。他依然相信：“事情正在發(fā)生變化！例如，參議院城市新的規(guī)劃總監(jiān)對(duì)比較放松的項(xiàng)目態(tài)度更加開(kāi)放?！卑５吕绽^續(xù)說(shuō)，大型項(xiàng)目減少是因?yàn)闊o(wú)法再獲得所需的巨大空間，公眾對(duì)大項(xiàng)目的批評(píng)越來(lái)越強(qiáng)烈。他評(píng)論道：“很長(zhǎng)時(shí)間以來(lái)，大家對(duì)于地方上對(duì)建筑的態(tài)度不加質(zhì)疑。人們認(rèn)為，不同的意見(jiàn)會(huì)損害他人利益。因此，變化的力量更大。”

5 過(guò)濾水池景象/View of filter basin

6 泳池區(qū)域景象/View of pool area

7 游泳池剖面/Section of swimming pool

從愿景到項(xiàng)目

設(shè)計(jì)者們希望項(xiàng)目產(chǎn)生的影響遠(yuǎn)遠(yuǎn)超出其直接意義——河流泳池只是一個(gè)開(kāi)始。蒂姆·埃德勒指出問(wèn)題在于快速升級(jí)的內(nèi)城區(qū)密度?！霸S多非正式娛樂(lè)空間已不復(fù)存在，娛樂(lè)和運(yùn)動(dòng)空間也相應(yīng)減少。當(dāng)然，我們的河流泳池也無(wú)法提供與擁有大草坪的豪華海濱浴場(chǎng)相匹敵的場(chǎng)所供市民娛樂(lè)。但它將是一個(gè)獨(dú)特的體育設(shè)施，給人們帶來(lái)美好信息：看看你的城市有什么可能性——是時(shí)候采取行動(dòng)了！”在早年，他們的理念被視為烏托邦，如今，已受到各界的認(rèn)真對(duì)待?！澳憧梢愿杏X(jué)到柏林正在醞釀新發(fā)展，”這位建筑師說(shuō)，“這個(gè)城市正在變得更加模糊和多樣化。”在這種情況下，河流泳池提供了新的可能性，通過(guò)轉(zhuǎn)換現(xiàn)有環(huán)境，認(rèn)識(shí)到這個(gè)河流泳池所需的一切早已存在。正如埃德勒指出的那樣：“近年來(lái)，自然界在我們的生活中所起的作用愈加重要，在這個(gè)過(guò)程中，我們學(xué)會(huì)了以不同的方式看待水?！焙訛I已成為理想場(chǎng)所，咖啡館、酒吧和餐館遷到了施普雷河岸上；這個(gè)城市的昔日后院現(xiàn)在變成了它的名片。

吊胃口

蒂姆·埃德勒認(rèn)為，對(duì)這條河的興趣將繼續(xù)日益增長(zhǎng)，相信這一點(diǎn)絕對(duì)沒(méi)錯(cuò)。在此期間，他和他的兄弟把他們的項(xiàng)目提交給柏林政府參議院?！暗侥壳盀橹?，參議院一直采取非常合作的態(tài)度，”這位建筑師說(shuō)，“顯然，我們的項(xiàng)目與其他措施密切相關(guān)。畢竟，混合水下水道系統(tǒng)必須進(jìn)行一定的更新，沿河岸的所有擋土墻都必須改造，這會(huì)引發(fā)很多潛在的協(xié)同效應(yīng)。”當(dāng)然，要保持施普雷河一直潔凈，需要為新下水道系統(tǒng)投入大量金錢。但蒂姆·埃德勒?qǐng)?jiān)信：“問(wèn)題不在于金錢，而在保持清醒——有欲則變。一旦人們認(rèn)識(shí)到河流的存在意義不是僅僅為了緩解交通壓力，城市就會(huì)為其清潔進(jìn)行投資。我們這個(gè)項(xiàng)目最有價(jià)值的方面，就是它能夠激發(fā)人們的欲望?！?/p>

預(yù)料之中的異議

雖然柏林的許多人都對(duì)市中心有個(gè)河流泳池喜聞樂(lè)見(jiàn)，但設(shè)計(jì)者也預(yù)料到會(huì)遭遇異議。以植物為基礎(chǔ)的廢水處理站附近有住宅樓——那里的住戶會(huì)不會(huì)因?yàn)檫@些植物有可能滋生蚊子而反對(duì)本項(xiàng)目呢？博物館會(huì)對(duì)本項(xiàng)目有什么反應(yīng)呢？蒂姆·埃德勒認(rèn)為，柏林的保守派不可能馬上就支持一個(gè)河岸日常利用的項(xiàng)目：“如果鮮有質(zhì)疑，我會(huì)很驚訝?！北R斯特花園的一些擋土墻會(huì)受到河流泳池的影響，它們是由塑造19世紀(jì)普魯士的新古典主義風(fēng)格和柏林風(fēng)貌的杰出建筑師中最負(fù)盛名的卡爾·弗里德里?！ど昕藸栐O(shè)計(jì)的。任何有可能影響與他有關(guān)的建筑的企圖都會(huì)引發(fā)反對(duì)。博物館島是一個(gè)旅游圣地，這也使創(chuàng)新變得很棘手。蒂姆·埃德勒對(duì)此很清楚：“博物館島是柏林的圣杯，可以這么說(shuō)——你必須極其謹(jǐn)慎地提出干預(yù)?！边@位建筑師提出的另一個(gè)問(wèn)題是施普雷河的法律地位，它是聯(lián)邦水道，因此屬聯(lián)邦所有，柏林在這個(gè)問(wèn)題上沒(méi)什么話語(yǔ)權(quán)。關(guān)于這種水道的決定幾乎完全取決于船運(yùn)的需要，盡管從統(tǒng)計(jì)數(shù)據(jù)可以看出，施普雷河上的貨運(yùn)量正在銳減。

有魅力的項(xiàng)目

在豪瑞獎(jiǎng)參賽項(xiàng)目資料中，設(shè)計(jì)者將預(yù)計(jì)開(kāi)工期定為2018年。蒂姆·埃德勒承認(rèn)，“這當(dāng)然是樂(lè)觀計(jì)劃，這個(gè)日期是不確定的。不過(guò)，我認(rèn)為10年后在我們這個(gè)河流泳池里暢游還是有可能的?！睂?duì)于這個(gè)討論的政治層面很難說(shuō)什么，但蒂姆·埃德勒再次強(qiáng)調(diào)：“本項(xiàng)目特別適合柏林這個(gè)悠閑的城市。 我并非推崇過(guò)去20年中地方整治趨勢(shì)，其他許多人也有同感。”有趣之處在于這會(huì)導(dǎo)致：條條框框太多不利于大都市。每個(gè)城市都需要非正規(guī)、未完成的商業(yè)元素。矛盾也有其魅力，抹殺個(gè)性會(huì)造成嚴(yán)重后果。“Flussbad項(xiàng)目的一個(gè)偉大之處是，位置極公開(kāi)、人流量極大。我們不是填補(bǔ)邊邊角角，而是讓本就極具魅力的地方更有吸引力！”

1-蘆葦床/Reedbed2-河水道/Riverwater canal3-200cm厚卵石填埋/200cm Pebblefill4-排水管泳池道清水/Drainwater pipe clean water for pool5-密封層/Sealing6-土填埋/Soilfill7-溢水管約100cm/Spillwater pipe ca. 100cm

8 水處理及泳池詳圖/Details of water-treatment and pool

9 還原后的自然河流剖面/Section of renaturized river

A collective of architects, designers and artists has been pursuing a visionary project for years: a gigantic swimming pool on a river arm in the middle of Berlin. Initially the idea was seen as incongruent with the formal grandeur of the city center – but support for urban renewal and remediation may yet change the face of this iconic precinct.

The Museum Island is the heart of touristic Berlin and one of the most important museum complexes in the world. Since 1999 the Museum Island, a unique ensemble of architectural and cultural importance, has been a UNESCO World Heritage site. But the island could be the scene not only of high culture, but also of everyday pleasures: in good weather, hundreds of people congregate on the east side of the island, along the Kupfergraben, a 400m canal on a disused arm of the River Spree. Tey bathe and splash in the pristine water of the river, which flows through the center of Berlin.

The so-called Flussbad, or river pool, is as big as 17 Olympic-sized swimming pools, and intended primarily for locals, for whom the pool is an important recreation area. On the Museum Island families in bathing costumes mix with tourists from all over the world, without anybody being bothered by it. That is Berlin: a tolerant, diverse city offering varied uses of space alongside one another.

Visionaries with staying power

But whoever wants to experience a river pool in the heart of the German capital will need patience. As yet this attraction is still only on paper. The Kupfergraben is still just a canal. It will take years before a bathing costume is indispensable attire for a visit to Berlin. But this does not mean that the vision cannot become reality. The authors of the project have already demonstrated that patience is not something they are about to run out of: they have been pursuing their project for the past 15 years. It all began in 1997, when they co-founded the art group Kunst und Technik (art and technology) in Berlin. Among the driving forces behind the informal collective of artists, designers, and architects were Tim and Jan Edler, two architects. Born in 1965 and 1970 respectively, the brothers studied architecture and in 2000 founded realities: united, their own studio for art and architecture. They have built up an international reputation in the development of media-oriented art installations and building addons; their best-known work is probably the BIX Fa?ade of the Kunsthaus Graz.

But back to 1997 and the artists' collective Kunst und Technik. "At the time we initiated rather naive projects that we found more interesting than what we usually worked on," Tim Edler recalls. Although the collective of enthusiastic young people may not have been terribly focused, it masterminded a number of exciting projects, for instance a flourishing bar. According to Tim Edler, "The bar's financial success made it possible for us to pursue other projects."

From lifeline to wastewater canal

One of these was the river pool. Te idea arose in the art group's first year. Tim Edler recounts: "One inspiration was the fact that the collective's office was close to the water, on the Kupfergraben directly opposite the Bode Museum. We often talked about how nice it would be to jump into the river to cool off; we found it bizarre that the Kupfergraben had not been used for 120 years." Over the centuries the River Spree has had various uses, in the city's early days primarily as a transport route, and later to provide energy, a means of defense, and irrigation. From the 19th century onward fewer demands were made on the river and eventually the city started to fill in disused sections of the river, for instance after World War II, when enormous quantities of rubble needed to be disposed of. The city's former lifeline degenerated into a wastewater canal. Tis is evident from the mixed waste-water system in Berlin's inner city districts, which does not separate rainwater from wastewater, so that after heavy rainfall the overflow runs directly into the Spree. As a result, also wastewater that should flow through the sewers ends up in the river. This is not only unappetizing, but also a health hazard. This explains why the city administration expressly advises against swimming in the Spree. In all of Berlin there is not a single river pool and no direct access to the water anywhere; you have to leave the city to find a stretch of river bank without a quay wall.

Free admission for everybody

10 過(guò)濾水池功能圖解/Functional diagram of filter basin

Tese drawbacks did not deter the collective from developing its project. Their vision: a gigantic pool, a river pool, with a water surface of 21,400 square meters in the disused river arm against the backdrop of the world-famous Museum Island. A broad bank ofsteps leads from the Lustgarten, the square in front of Berliner Dom (Berlin Cathedral), and in front of the future reincarnation of the Stadt-Schloss (City Castle) right down to the edge of the water. While the design includes unobtrusive functional changing facilities and lockers in the pedestal of the former national monument for Kaiser Wilhelm I., the river pool is explicitly conceived of as a public amenity: anybody can jump in to cool off or swim without paying for admission.

Two measures will ensure that bathers do not find themselves swimming in wastewater. Currently, the sewage overflow from six emergency outlets spills into the canal; the project will channel this overflow into a spill water pipe that will run under the river pool. In addition there will be a water filter in the river above the pool: the controlled flow of water into the canal will be purified by natural means as it passes over a 780-meter-long filter basin.

A filter 390 meters long

This 7200 square meters constructed wetland consists of a gravel filter 0.8 meter thick, covered by an average of about 0.5 meter of water. The filter is able to purify inflowing impure river water to the quality of drinking water. The filtered water is collected and led away through drainage pipes below the sand packing. The upper side is planted everywhere with various marsh, shallow-water, and deep-water plants, designed as a linear public park. The 640-meter uppermost section of the river that continues from there will be renaturized. To this end, the northern shore wall will be completely removed and the course of the river gently widened into the grounds of the Fischerinsel. As an auxiliary purpose, this section serves as an inner city green area and preliminary water purifier. Te actual main purpose of this side arm of the river is as a wildlife refuge, to support the resettling of riparian flora and fauna in the channeled main arm of the Spree River in Berlin's urban area. "Te Spree as a whole is a stressed river,"

Tim Edler remarks, "its self-regenerating powers are still weak, and the river is very susceptible to environmental changes: at high temperatures, for example, blue-green algae quickly form." But time has worked in favor of the project: the steady reduction in lignite open-cast mining in the Lausitz region, which was a major source of pollution in the River Spree, means that the water that reaches Berlin today is cleaner than it was used to be, and that, in turn, means that demands on the plant-based wastewater treatment system will be lower than initially assumed.

The dawning of an age

11 河流規(guī)劃/River schemes

When the authors went public with their idea they were under no illusion about people's likely reactions. "We knew that the river pool was not in keeping with the spirit of the time," Tim Edler says. Ten, less than a decade after reunification, Berlin was caught up in a frenzy of development. Massive buildings were going up everywhere. In Tim Edler's view, "Te types of structures being built were expected to recreate the sense of what was believed to be Berlin's golden age in the 19th century." By looking back to the past, the search for a new identity produced an extremely prestige-focused derivative architecture. "Concepts of lightness found little recognition at this time; architecture tended to be stiff and formal." But he thinks that there are clear signs that this epoch is over. A stroll through the city leaves a different impression: rather bombastic building projects are still going up all over the place. But Tim Edler says that these are ideas of the recent past that are now being worked off. He remains confident: "Change is happening! For example, the new Senate's director of urban planning is more open toward lighter projects." Edler continues that colossal projects are also becoming rarer because the enormous amount of space they require is no longer available and public criticism of monumental projects is growing louder. He comments: "For a long time many people did not question the local attitude to architecture. It was thought that a different opinion would be damaging to one's interests. As a result, the force of change is all the greater."

From vision to project

The authors hope that their project will produce an impact far beyond its immediate significance – the river pool as kick-off pool. Tim Edler points to the rapidly escalating inner-city density. "Many informal recreational spaces no longer exist, with a corresponding loss of space for recreation and sport. Of course, our river pool would not offer the quality of a typical lido with a large lawn for hanging out. But it would be a unique sports facility and a wonderful message for people: just look what is possible in your city – now do something about the rest!" Whereas in earlier years their concept was regarded as utopian, today it is taken more seriously. "You can just sense that new developments are afoot in Berlin," the architect remarks. "The city is becoming more ambiguous and diverse." In this context the river pool offers new possibilities by converting an existing context – just about everything needed to realize the river pool is already there. As Edler points out, "In recent years nature has come to play a far more important role in our lives and in the process we have learned to see water differently." The river front has become a desirable address and cafés, bars and restaurants have moved onto the bank of the Spree; the city's onetime backyard is now its calling card.

12 地點(diǎn)位于柏林中心/Location in Berlin's Center

Whetting appetites

Tim Edler does not think it misplaced to believe that this growing interest in the river will continue. In the meantime, he and his brother have presented their project to the Senate, the government of Berlin. "So far the Senate has adopted a very cooperative attitude," the architect says. "Evidently our project ties in well with other measures. The mixed water sewage system will have to be renewed at some point anyway, and all the retaining walls along the riverfront will have to be rehabilitated, which speaks for a lot of potential synergies." Of course, it will cost a lot of money to put in a new sewage system to keep the River Spree clean all the time. But Tim Edler is convinced that "money is not necessarily the problem. It is about being aware: when the appetite has been sparked, changes are possible. Once people accept that the river is not there only for the declining volume of traffic, the city will also invest in its cleanliness. Te most valuable aspect of our project is that it could whet people's appetites."

Opposition expected

Even though many people in Berlin would welcome a river pool in the middle of the city, the authors expect opposition. There are residential buildings close to the plant-based wastewater treatment plants – will the inhabitants object to the project because they think the plant will attract mosquitoes? And how will the museums react to the project? Tim Edler thinks that it is unlikely that the voices of conservatism in Berlin will rush to support a project for everyday utilization of the river bank: "I would be very surprised if there was not a lot of skepticism." Some of the quay walls along Lustgarten that will be affected by the river pool were designed by Karl-Friedrich Schinkel, the master architect who more than anybody else shaped the neo-classical taste of 19th century Prussia and the appearance of Berlin. Any attempt to interfere with structures associated with him triggers opposition. Te Museum Island is a tourist magnet, which also makes innovations tricky. Tim Edler is well aware of this: "The Museum Island is Berlin's holy grail, so to speak – you have to be very careful about proposing interventions." Another problem raised by the architect is the river's legal status as a federal waterway and thus federal property; Berlin has little say in the matter. Decisions concerning such waterways are determined almost solely by the needs of shipping, although from statistical evidence it is clear that the transportation of goods on the Spree is declining.

Project with appeal

In the project data for the Holcim Awards competition the authors gave 2018 as the estimated start of construction. Tim Edler admits that "this is optimistic planning, of course, and the date is uncertain. Nevertheless, I think it is possible that we could be swimming in the river pool before the end of the decade." It is difficult to say anything about the political dimension of the discussion, but Tim Edler emphasizes once again: "Te project is right for Berlin, which is a fairly laid-back city. I am not a fan of the trend in the past 20 years of tidying up places, and many others feel the same way." Te interesting point is what this leads to: too much orderliness is harmful for a metropolis. Every city needs an element of non-conformism, of unfinished business. Contradictions also have their charm, and getting rid of character can have serious consequences. "One of the great things about the Flussbad project is that the location is exceptionally public and exceptionally accessible. We are not occupying some or other secluded niche, we are developing something with real appeal!"