公眾健康和幸福感考量的城市藍(lán)色空間
——城市景觀研究新領(lǐng)域

著：（英）西蒙·貝爾 譯：陳奕言 校：陳箏

在可被視為構(gòu)成區(qū)域景觀系統(tǒng)環(huán)境的所有方面中，水文系統(tǒng)無疑是關(guān)鍵要素之一。 所有的景觀，甚至沙漠，都可以被分解成一個個匯水盆地（hydrological basins），這些匯水盆地是可持續(xù)評估絕佳的分析單位，因為它們在許多方面都是獨立的景觀單元。流域（watershed，美國使用）或河流匯水區(qū)（river catchments，英國使用）跨越了多個尺度，一個個小的匯水區(qū)組合成更大的匯水區(qū)，形成了嵌套的分形（fractal）結(jié)構(gòu)[1]。侵蝕和沉積的持續(xù)地質(zhì)過程以及河岸生態(tài)過程有助于流域形成一種蜿蜒分支又不斷變化的獨特模式[1]。因此，在區(qū)域水文系統(tǒng)的上游地區(qū)發(fā)生的如泥沙沉積、森林砍伐或污染，會不可避免地向下游發(fā)展，并對下游地區(qū)的功能產(chǎn)生影響。同時，隨著系統(tǒng)支流逐漸向某條河流通往的地點匯合，這些支流會集中到一起。

如果我們回顧全球人類聚居的歷史，可以看到絕大多數(shù)聚居地和城市都位于水域——包括臨江臨海的港口城市、河流交匯的要塞居民點、因水利發(fā)展起來的工業(yè)城鎮(zhèn)群、漁村、海濱度假區(qū)等[2]。從最初在美索不達(dá)米亞（兩河流域）、尼羅河流域、黃河和印度河流域的城鎮(zhèn)雛形開始，河流沿岸不僅聚集了村落和城市，而且也因河建設(shè)了一系列包括灌溉系統(tǒng)、運河和港口等航運水利工程。為方便運輸和控制洪水，現(xiàn)代城市進(jìn)一步建立了大量的河流調(diào)節(jié)系統(tǒng)，使城市建設(shè)得以突破自然洪泛區(qū)的限制發(fā)展，但同時也增大了因上游匯水區(qū)管理不善引起的災(zāi)害風(fēng)險?？梢?，人類對河流匯水區(qū)的利用和濫用給人類和生態(tài)健康都造成了嚴(yán)重困擾。

縱觀全球，每個大陸上的城市都在經(jīng)歷著規(guī)模、結(jié)構(gòu)、人口密度和生活節(jié)奏的迅速變化。沿海城市人口在不斷擴(kuò)大[3]，這些城市往往把水岸當(dāng)作消極空間并限制其可達(dá)性。然而在過去20～30年中，許多這樣的城市被重新開發(fā)，水資源成為人們旅游和休閑娛樂、商業(yè)和新住宅開發(fā)的主要吸引力。這些重新開發(fā)包括港口設(shè)施（被遠(yuǎn)離市中心的集裝箱港口所取代）、河濱地區(qū)（綜合考慮洪水管理和自然軟化岸線成為新主流）以及全球貿(mào)易格局變化后的其他類型濱水空間[4]。盡管濱水再生（waterside regeneration）帶來的生態(tài)、社會和經(jīng)濟(jì)影響已得到一定關(guān)注[5-6]，但它對公眾健康和幸福感的潛在影響直到最近才開始有一些科學(xué)研究[7]。藍(lán)色空間健康價值研究的滯后和城市綠地（如城市公園、林地和行道樹等）在保健和疾病預(yù)防方面的大量實證形成了鮮明對比[8]。20世紀(jì)和21世紀(jì)初，世界各地沿海地區(qū)城市化和人口均呈現(xiàn)出增長趨勢，研究表明這種增長趨勢很可能持續(xù)下去[3]。因此，隨著越來越多的人發(fā)現(xiàn)自己工作和休閑娛樂時都在直接或間接地與城市水域接觸，“藍(lán)色基礎(chǔ)設(shè)施”（blue infrastructure，水體及其臨近濱水空間）開始在城市規(guī)劃和景觀設(shè)計中發(fā)揮越來越重要的作用。

近幾十年來，人們對與水相關(guān)的健康危害和風(fēng)險有了更全面的科學(xué)認(rèn)知。其中一類風(fēng)險是人類通過水可能會接觸到導(dǎo)致傳染?。ㄈ缁魜y、傷寒等）的微生物[9]、一系列化學(xué)污染物，在某些特定的水生生境中，還可能因接觸到瘧疾、黃熱病和登革熱等疾病的媒介而患病。而水本身也是一個重大的風(fēng)險，溺水是全球第三大最常見的意外死亡原因[10]。同時，洪水也是部分地區(qū)的主要災(zāi)害之一，該問題因洪泛區(qū)建設(shè)和透水地面硬化的增加而進(jìn)一步惡化，為洪水消退后埋下健康隱患[11]。此外，在藍(lán)色空間（水中或海灘上）進(jìn)行的許多娛樂活動也帶來了與水無關(guān)的健康影響，如增加了曬傷和患皮膚癌的風(fēng)險等。環(huán)境退化、城市微氣候（城市熱島）和極端天氣（如熱浪）等進(jìn)一步放大了上述風(fēng)險。然而，藍(lán)色空間及其基礎(chǔ)設(shè)施所帶來的公共健康福祉和個人幸福感提升，我們卻知之甚少。

那么，居住在水域附近或使用水域進(jìn)行娛樂活動對健康有哪些益處？越來越多的流行病學(xué)證據(jù)表明，在海岸附近或有海景可觀的居民通常更加健康，有更少的精神損害（mental distress）癥狀，并且比內(nèi)陸居民對生活更加滿意[12]。長期證據(jù)顯示，在海邊生活或曾在海邊生活的人們的身心健康狀況通?？赡芨肹13]。這些影響是否僅限于海濱環(huán)境，河流、湖泊、運河等其他藍(lán)色空間是否有類似的健康效益，目前尚不清楚。

藍(lán)色空間如何有助于改善大眾健康和幸福感？早期證據(jù)表明，某些影響機(jī)制或可解釋接觸藍(lán)色空間與公眾健康之間的積極關(guān)系。首先，研究指出藍(lán)色空間環(huán)境較其他戶外場所，更容易讓人們感到快樂，壓力更小[14]。其次，丹麥的一項研究發(fā)現(xiàn)，附近居民在藍(lán)色空間停留的時間通常比住得較遠(yuǎn)的市民長[15]。再者，英國的一項研究表明，海岸附近居民似乎比內(nèi)陸居民更符合英國國家體育活動指導(dǎo)方針中身體素質(zhì)的相關(guān)要求[16]；而另一項英國研究表明，藍(lán)色空間被視為與朋友和家人進(jìn)行積極社交活動的重要場所之一[17]，與綠色空間相比，藍(lán)色空間更廣泛地用于改善公眾健康和提升幸福感[18]。最后，水體的比熱容較高，更有助于緩解局部城市熱島效應(yīng)。如果對夏季氣溫及熱相關(guān)疾病的發(fā)?。ㄋ劳雎剩┥仙念A(yù)測準(zhǔn)確的話，這一作用可能今后會越來越重要[19]。

當(dāng)前城市呈現(xiàn)多元發(fā)展趨勢，其中全球面臨的一個主要問題是城市蔓延（urban sprawl）：低密度城市化占用了大面積的綠地[20]。為了應(yīng)對這類問題，越來越提倡城市緊湊發(fā)展，尤其是棕地置換[21]。這同時也給城市綠地帶來了壓力，如果不加以保護(hù)，這些綠地的數(shù)量和面積將會減少，質(zhì)量會降低。 雖然一方面城市不斷地在填海造陸拓展開發(fā)空間，但隨著濱水城市的人口不斷增加，城市藍(lán)色空間將會成為越來越重要的生活和娛樂場所。因此，在城市規(guī)劃和城市基礎(chǔ)設(shè)施規(guī)劃建設(shè)中綜合考慮藍(lán)色空間的健康實證效益，可有助于解決現(xiàn)今公共健康面臨的關(guān)鍵挑戰(zhàn)，包括減少與生活壓力、久坐的生活方式相關(guān)的非傳染性疾病的發(fā)病率，降低與溫度升高相關(guān)疾病的發(fā)病率和死亡率等[22]。

目前對藍(lán)色空間健康效益的研究遠(yuǎn)不如對綠色空間的研究成熟[23]，對海岸線以外其他藍(lán)色空間的研究尤為薄弱。歐洲只有少數(shù)幾個國家進(jìn)行了研究，并且由于統(tǒng)計功效（statistical power）偏低的緣故，結(jié)論統(tǒng)計上并不顯著，在世界其他地區(qū)的研究進(jìn)展也類似[24]。因此，對藍(lán)色空間在預(yù)防不良生活方式引發(fā)的疾病、改善人類健康和幸福感方面的潛在作用亟待深入研究?！八{(lán)色健康研究項目”①的首要目標(biāo)就是填補(bǔ)這方面研究的空白。從2016年啟動到2020年截止，這個泛歐洲項目旨在更深入地研究接觸藍(lán)色空間與公眾健康和幸福感之間的關(guān)系，通過大規(guī)模、系統(tǒng)的跨學(xué)科研究，調(diào)查在歐洲不同的地理、氣候、社會經(jīng)濟(jì)和文化背景下 ，接觸藍(lán)色空間對健康和幸福感的影響。本研究的一個重要目的在于改善城市藍(lán)色空間的規(guī)劃和設(shè)計，以幫助規(guī)劃者最大限度地提高效益、降低風(fēng)險。有關(guān)項目和所用研究協(xié)議的概述，可以進(jìn)一步查閱Grellier等人的相關(guān)研究[25]。

本研究旨在介紹藍(lán)色健康項目部分工作的初步成果，尤其是關(guān)于如何評價城市藍(lán)色空間規(guī)劃設(shè)計質(zhì)量和有效性的問題。這里總結(jié)并評價了一系列全球范圍內(nèi)已實施的項目，這些項目通常位于曾經(jīng)的工業(yè)區(qū)，目標(biāo)是重新開發(fā)藍(lán)色空間并增加娛樂休閑的功能和發(fā)揮有益健康的潛力。由于“藍(lán)色健康研究項目”還沒有結(jié)束，所有的調(diào)查結(jié)果尚未得到充分的分析和討論，在這里僅對現(xiàn)有進(jìn)展進(jìn)行概述。筆者之所以在此次“區(qū)域景觀系統(tǒng)”（regional landscape system）主題會議②中向大家介紹藍(lán)色健康項目，是因為這可能是個極其重要的研究領(lǐng)域，應(yīng)當(dāng)被納入針對水文功能恢復(fù)的政策、計劃或?qū)嵺`系統(tǒng)中；通過使用可持續(xù)的城市排水規(guī)劃或者中國的海綿城市戰(zhàn)略[26]來降低城市洪水風(fēng)險，以實現(xiàn)藍(lán)綠基礎(chǔ)設(shè)施、基于自然的解決方案（nature-based solutions ）③和其他專題城市規(guī)劃概念等綜合需求。本研究將以案例的形式，介紹項目評議（project review）的概念并總結(jié)其主要成果。

1 項目評議的概念

項目評議即系統(tǒng)地對項目投入使用的現(xiàn)狀進(jìn)行考察評議，項目評議并不像常規(guī)科研論文那么常見，但從科學(xué)的角度來看并非沒有先例。使用后評價（post-occupancy evaluations）在建筑和風(fēng)景園林行業(yè)已經(jīng)越來越普遍，但通常是針對單個場地或建筑，而非對多個項目進(jìn)行評估對比。評價（自然或社會）科學(xué)發(fā)表的同行評議學(xué)術(shù)論文相對比較容易，因為其質(zhì)量（在同行評議審核其能否發(fā)表的過程中）得到了控制。那么在考察風(fēng)景園林項目時，有沒有類似的等效程序？文學(xué)評論在藝術(shù)和設(shè)計學(xué)科中起到了類似同行評議的作用，在風(fēng)景園林學(xué)科中也是如此。

最近有一些出版物（主要是書籍）從不同角度對特定類型的藍(lán)色空間進(jìn)行了研究和評述[27-30]。雖然其中包括了一些優(yōu)秀案例，但它們都沒有從改善大眾健康和幸福感的角度論證。筆者首次嘗試對廣泛的項目類型進(jìn)行更為全面和綜合的總結(jié)評議。

2 項目挑選方法

納入評議的項目采用以下標(biāo)準(zhǔn)進(jìn)行挑選，（在第一輪挑選時）這些標(biāo)準(zhǔn)相對寬泛而包容，而非嚴(yán)格限制[31]。

1）規(guī)劃和設(shè)計項目應(yīng)在城市范圍內(nèi)（可以包括城市邊緣的農(nóng)村地區(qū)），并為公眾提供達(dá)到和使用各種類型各種規(guī)模水體的機(jī)會。

2）項目不受國家或地區(qū)限制，但須主要是在近10～15年內(nèi)建成（不過也包括了一些建成時間更長的項目，因為它們被期刊批判性地重新審視，并提供了更長遠(yuǎn)視角的經(jīng)驗教訓(xùn)）。

3）項目滿足以下條件中的一點或多點：①曾在學(xué)界普遍認(rèn)可的專業(yè)期刊上發(fā)表；②曾在競賽中勝出；③曾獲專業(yè)組織頒發(fā)的獎項；④曾被作為高質(zhì)量設(shè)計項目在網(wǎng)站列出并獲得高度評價。

4）鑒于大多數(shù)項目不可能進(jìn)行實地考察，應(yīng)當(dāng)有足夠的資料可供評估（部分項目小組成員有實地考察過，且/或非常著名）。

5）通過衛(wèi)星圖像搜索引擎，特別是谷歌地球（GoogleEarth，尤其是其中的街景功能），可以看到項目的現(xiàn)狀和項目剛建成及使用后的狀況（以避免設(shè)計師提供的完美照片影響項目給人的客觀印象）。

表1是用于確定納入評議項目的主要期刊和網(wǎng)站、它們的出版商、所屬國家和報道重點。最初發(fā)現(xiàn)了近400個潛在項目，隨后減少到172個最具代表性的，作為本評議的實證數(shù)據(jù)庫。完整的項目集合會在之后整理成一個可供查詢的數(shù)據(jù)庫，在此不再單列。

3 評議考察方法

評議考察的分析方法包括定性和定量兩種。通過閱讀各個競賽和獎項的評審委員會給予這些項目的評論和評語、頒獎詞、相關(guān)文章和論文以及在線評論網(wǎng)站上的評論，可以了解到業(yè)內(nèi)對這些項目的評價。研究人員（愛沙尼亞生命科學(xué)大學(xué)風(fēng)景園林系主任下屬有風(fēng)景園林資質(zhì)的員工）對上述內(nèi)容進(jìn)行了檢索，并使用谷歌地球及其街景功能對項目進(jìn)行了考察。在對項目進(jìn)行專題分析時，將一些現(xiàn)有的評價標(biāo)準(zhǔn)，例如綠旗獎（the Green Flag Awards）④、公共空間計劃（Project for Public Space， 簡稱PPS）⑤、空間塑造（SpaceShaper）設(shè)計委員會⑥等進(jìn)行整合，從而形成了本研究項目考察和評議的標(biāo)準(zhǔn)體系。從評議的項目中提煉出若干專題，并針對這些專題對每個項目進(jìn)行比較，形成一份定性的總結(jié)報告。筆者也將主要圍繞介紹這份定性的總結(jié)。定量研究詳細(xì)的研究方法及結(jié)果將在分析完成后另行介紹。圖1～3展示了調(diào)查項目的基本特征——所在國家/地區(qū)、藍(lán)色空間類型以及水陸界面的類型。

4 分析和結(jié)果

4.1 總體設(shè)計層面

決定項目是否出色、是否更具審美吸引力的因素主要包括：對水和水陸分界面的理解；如何將水這一元素融入設(shè)計中去；設(shè)計（包括設(shè)計元素和材料）對當(dāng)?shù)刂苓叚h(huán)境的適宜性和可供性（affordability）等。此外，設(shè)計的創(chuàng)新性和可持續(xù)性也是評判的重要因素。每一個被考察評議的項目都有某種或某一系列的具體特征，構(gòu)成該項目的獨特性，例如對場地曾經(jīng)用途的考慮（例如過去的港口），并將相應(yīng)元素納入設(shè)計中去（例如起重機(jī)、鐵路軌道、系船柱及其他要素）。除此以外，一個有力的、大膽的焦點特征（盡管有例子采用藝術(shù)品形式，但并不限于此）也可以給予場地新的定義和令人印象深刻的形象（這也有助于建立品牌），從而創(chuàng)造出一個新的場所。

許多項目將水作為創(chuàng)造或恢復(fù)地域特色的一種手段，例如設(shè)計師在設(shè)計中運用創(chuàng)造性的設(shè)計方法將陸地與水在空間上或視覺上聯(lián)系起來，從而最大限度地提高審美感受和感官影響；或是運用設(shè)計來弱化城市背景，使人們的注意力聚焦到水體上。

我們也可以看到，在形式、顏色、材料和紋理的使用上，許多項目呈現(xiàn)某種特定的當(dāng)代“外觀”。這是因為設(shè)計師們在尋找先例進(jìn)行借鑒的時候，一些特定的風(fēng)格不可避免地會影響他們的設(shè)計，甚至在設(shè)計師們試圖表現(xiàn)個人主義和獨特性的時候也是如此。

值得注意的是，相比綠色空間項目，藍(lán)色空間項目為了滿足濱水區(qū)更高的建設(shè)要求，常常會有更獨特的解決方案。比如藍(lán)色空間的構(gòu)筑物往往從美學(xué)和結(jié)構(gòu)工程角度綜合考慮，以發(fā)揮水岸防護(hù)和親水活動的雙重作用。

表1 用于挑選和確定需要考察評議項目的專業(yè)雜志和網(wǎng)站Tab. 1 Selected professional magazines and websites used for sourcing projects to be reviewed

1 評議項目所在的國家Countries where reviewed projects are located

較大的場地通常被細(xì)分為不同的功能區(qū)和景觀區(qū)。有些設(shè)計師把正式（如各種體育活動）與非正式的活動分開設(shè)置，或根據(jù)不同類型的兒童游戲、植被或水進(jìn)行分區(qū)。這種分區(qū)通過提供不同審美體驗或不同生境以提升場地的吸引力和趣味性，通過視覺上的空間分隔創(chuàng)造空間層次、減少擁擠感。

4.2 促進(jìn)身心健康和幸福感的潛力

除了一些非常小的設(shè)計（如水景），所有濱水場地都可以促進(jìn)體力活動，即使僅限于陸上運動。其中最主要的是散步和慢跑，器械運動以及其他正式或非正式的運動也非常普遍。

這些場所基本都設(shè)計得很好，人們可以在其中欣賞風(fēng)景、獨自靜坐、沉思，等等。但由于臨水區(qū)域往往很受歡迎，除了一天中的特定時刻，很難找到可以在濱水區(qū)獨處的機(jī)會。如果在稍微大一些的項目中想找可以獨處的地方，需要避開濱水區(qū)，比如緊鄰水岸的植被區(qū)域。

大多數(shù)場地具有明顯的城市化特征，因此很難不考慮城市環(huán)境及其視覺影響。比起開闊水面，即使觀賞者背對城市，可能城市環(huán)境也會削弱濱水空間的壓力緩解效果。

4.3 可達(dá)性和無障礙設(shè)計

在絕大多數(shù)情況下，場地可以很容易通過步行、騎自行車或公共交通到達(dá)。由于項目場地提供了停車場，即使在市中心地區(qū)自駕車也可以方便地到達(dá)。與德國或中國相比，美國和澳大利亞因其對于汽車依賴性更大，它們的項目場地通常都配置了停車場。

在極少數(shù)的情況下，設(shè)計師會考慮讓人們從水域進(jìn)入到場地。有些案例游客可以通過客輪到達(dá)新公園旁邊的碼頭；另一些案例游客可通過游船經(jīng)小型碼頭?？窟M(jìn)入。

大多數(shù)項目場地都有考慮無障礙設(shè)計——即使在地形相當(dāng)陡峭的情況下，也設(shè)置了帶坡道的臺階提供親水機(jī)會。只有不多的幾個例子，由于條件實在不允許而沒有進(jìn)行無障礙設(shè)計，但這顯然是極少數(shù)。在并非十分狹窄的長條形場地內(nèi)，內(nèi)部的無障礙聯(lián)系就非常重要——通過這種聯(lián)系將場地內(nèi)不同區(qū)域聯(lián)系起來，并串聯(lián)起其他各種各樣的小路。

2 評議項目涉及的藍(lán)色空間類型Blue space types associated with the reviewed projects

3 評議項目中涉及的水陸分界面類型The types of water/land interface encountered in the reviewed projects

一般情況下，盡管場地內(nèi)基本都可以騎自行車，但許多場地存在或可能存在自行車停車位不足的問題。這取決于不同國家的自行車騎行文化，荷蘭和丹麥在這一問題上處理得較好。

海濱和湖岸區(qū)域開發(fā)的時候往往都將濱水直接可達(dá)性作為重要考慮之一。大部分項目考慮提高可達(dá)性，尤其是老年人和殘疾人的可達(dá)性，并為生態(tài)敏感地區(qū)設(shè)置對生態(tài)系統(tǒng)更安全、更小破壞的游覽路徑。城市中心河流和碼頭的設(shè)計難度更大，設(shè)計師往往會提供通過視覺及其他感官的間接親水體驗，但出于水文或水質(zhì)考慮沒有提供讓人們直接進(jìn)入水的機(jī)會。同樣的考慮，也常見于公園中結(jié)合水處理工藝的植被過濾系統(tǒng)。人們雖然不能直接接觸水，但所有其他體驗都非常好，也能看到水生棲息地及相應(yīng)的野生動物（圖4）。

有一些項目的坡道和臺階的設(shè)計非常有特點，通過獨特的設(shè)計形式融入到場地整體審美體驗中，成為項目的核心。除了坡道和臺階，扶手在人們使用臺階和坡道時也十分必要——如果有老年人經(jīng)常使用，有沒有扶手會有很大的不同。

從一個地點到另一個地點的路徑聯(lián)系也非常重要，例如曼哈頓的前碼頭（former docks of Manhattan），設(shè)置了多條人行道將一系列獨立的小公園聯(lián)系起來形成一個公園系統(tǒng)。此外，沿海景觀步道、長步行道以及濱河步道都有助于連接不同的區(qū)域，給人們提供更系統(tǒng)的游憩體驗。

因此可以總結(jié)出上述項目成功的關(guān)鍵點之一是它們都擁有一個經(jīng)過深思熟慮的可達(dá)性和無障礙設(shè)計策略。要做到這些，不僅要考慮場地本身的規(guī)劃設(shè)計，還要考慮人們?nèi)绾蔚竭_(dá)。這也要求設(shè)計師與負(fù)責(zé)交通運輸、道路管理的機(jī)構(gòu)緊密合作，有時還需要和管理鐵路、地鐵以及港口的機(jī)構(gòu)合作。能否步行、能否騎車、場地周圍街道和十字路口的分布情況等，以及公交車站、地鐵站和停車場的位置和步行距離，都需要設(shè)計者仔細(xì)進(jìn)行考慮。

4.4 與水的互動

被考察的所有項目的另一個關(guān)鍵是都最大限度地挖掘與水互動的潛力。雖然一些項目出于實際或安全的考慮不讓人們直接接觸水，但所有項目都非常重視視覺和其他感官等與水產(chǎn)生互動的方式，有些處理得非常具有創(chuàng)造性。

一些項目的場地靠近堤防和運河或碼頭，所以人們不可能直接接觸到水。但它們很巧妙地在臨近的碼頭或堤岸上設(shè)置了水景，創(chuàng)造了人們與噴泉的互動機(jī)會——孩子和成人都把在炎熱的天氣里被噴泉淋濕甚至淋透當(dāng)作一種享受。另一些項目的場地雖不靠近自然水體，但噴泉或其他水景設(shè)施的吸引力如此之強(qiáng)，致使它們成為新公園或城市廣場的焦點。這在一定程度上是由于作為流體的水有著運動變化的特質(zhì)——噴射、薄霧、鏡面、急流、沖擊波、潮汐等，造成靈動的水與靜止的地面形成了鮮明的對比。

在有碼頭垂直護(hù)岸或防洪堤的場地，濱水區(qū)往往高于水體。在很多項目中，如何使人們能夠下來親水是設(shè)計的關(guān)鍵。這可通過設(shè)計在洪水期間漂浮或淹沒的親水設(shè)施實現(xiàn)。也可以將船只捆綁在較低的梯田或碼頭上，這些措施可以在水質(zhì)較差的濱水區(qū)增加親水和水上游憩活動（圖5）。

如果想和水更親近些，還可以通過可坐的碼頭或駁岸，這類手法可結(jié)合到河流自然化項目中。這類河流可能非常湍急，但即便有一點危險，靠近水面也能給人帶來一種特殊的體驗——一種壯美的體驗，這可能幫助人們從城市環(huán)境中脫離出來，從而實現(xiàn)精神恢復(fù)。

4 中國哈爾濱的群力雨洪公園，是俞孔堅和北京土人景觀規(guī)劃設(shè)計研究院設(shè)計的一個城市濕地公園獲獎范例。公園由于雨洪管理和生態(tài)保護(hù)等原因，對可達(dá)性進(jìn)行了限制。公園具有獨特的現(xiàn)代構(gòu)圖，為一個人口密集的城市提供了接觸自然的多重可能Qun Li Stormwater Wetland Park in Harbin, China, a prizewinning example by Yu Kongjian and Turenscape of an urban wetland forming a park, although with limited access to the interior of the territory due hydrological purposes. It has a distinct contemporary look and many possibilities for getting close to nature in a densely built up city

無論是在海邊還是湖邊，人們都很喜歡與水的互動。許多項目都會考慮海灘和海濱設(shè)施的修復(fù)，甚至包括填沙和使用結(jié)構(gòu)物防止海灘沙子流失。此外，很多項目也會重視植被修復(fù)。這說明，雖然設(shè)法使人親水仍然是設(shè)計的重點，但構(gòu)筑物在調(diào)節(jié)人與水岸空間之間的互動中也發(fā)揮著重要作用。

4.5 座位和社交機(jī)會

所有被考察的項目都特別注意座椅的設(shè)置。一些場地配備了大量的標(biāo)準(zhǔn)長椅，這些長椅看上去使用頻率很高。在有些項目中野餐和燒烤活動很受歡迎，通常這些區(qū)域會設(shè)置餐桌，在喜歡燒烤的地方餐桌旁往往還會有燒烤架。長椅可以采購現(xiàn)成的商業(yè)成品（價格經(jīng)濟(jì)、易維護(hù)等），也可以為項目定制。

還有一種常見的形式是將座椅以一種更基本的設(shè)計元素嵌入到設(shè)計中——就是用露臺、臺階和低墻作為靈活的多用途構(gòu)筑物，它們維護(hù)要求低，同時避免了過多設(shè)施帶來的雜亂，使場地顯得更加簡潔。

一些有潮汐的溫暖海域項目，設(shè)置了通向水中的臺階，可以在潮汐中提供半在水中、半在水外的座位，這對于老年人或殘疾人來說是非常理想的，他們可以享受在水中浮動的感覺。水面上的漂浮座位也可以提供類似將腳浸入水中的體驗，不同的是這些座位能夠隨水位的變化而變化。

另一種受歡迎的座位類型是固定的或可移動的日光浴床，它們有斜面可供坐、躺、斜倚等不同使用方式。它們在內(nèi)陸的人工“海灘”尤其受歡迎，這些“海灘”為城市居民提供日光浴的機(jī)會。它們還可以用于那些沒有沙灘或沙灘存在侵蝕問題的礁石海岸。

4.6 改善小氣候

濱水地區(qū)經(jīng)常暴露在強(qiáng)烈的陽光、狂風(fēng)暴雨或冰凍的環(huán)境條件下。如何讓它們在一年四季都能被舒適地使用，存在一定難度。由于市區(qū)內(nèi)的許多場地缺乏植被或只有有限的植被（如以前的港口和工業(yè)區(qū)），這些地點往往特別容易受到自然因素的影響，由于土壤缺乏和排水不良，樹木較難成活。無論是易于還是不易于植物成活的場地，喬木和灌木都需要一段時間才能長到能夠提供良好遮陰的冠徑，因此即使是一些以種植為特色的項目，也會使用構(gòu)筑物來代替樹木。

很多成功項目都會考慮場地的微氣候——當(dāng)然，在不同的地方有不同的解決方案。很明顯，許多場地在這方面進(jìn)行了大量的思考和創(chuàng)新。晴雨傘、可以收放的頂篷、帶攀緣植物的廊架，以及緊密間隔的樹苗（為了獲得即時效果）都是很好的解決策略。

對于現(xiàn)狀植被良好的地方，設(shè)計師需要在設(shè)計中盡量保留這些植被并且考慮到后期的養(yǎng)護(hù)管理，同時長期不斷地豐富植被。由于鹽、風(fēng)、石質(zhì)土等原因，海濱地區(qū)不利于樹木和其他木本植物的生長，因此選擇合適的植物品種來進(jìn)行配置可能不像普通公園那么簡單。

還需要注意利用臨時設(shè)施來夏季遮陽、冬季避寒，有時一個臨時設(shè)施可以兼具上述雙重功能，比如一些項目中采用的棚架。

4.7 場地管理和維護(hù)

幾乎對所有考察過的項目來說，良好的場地管理和維護(hù)十分重要。場地中幾乎沒有任何地方有損壞、故意破壞或植被破敗的跡象，所有的垃圾箱都配備齊全，同時得到了良好的使用，并有定期的垃圾收集。

在很多項目中，充分考慮材料的設(shè)計、使用以及施工質(zhì)量，可以更好地提高管理和維護(hù)環(huán)節(jié)的性價比。這類設(shè)計往往比較簡潔，使用標(biāo)準(zhǔn)化元素構(gòu)件，如果需要可以很輕松地對其進(jìn)行維修或更換。

良好的維護(hù)告訴使用者場地被精心管理著，這也意味著該場地是安全的，歡迎使用。損壞和破壞行為通常更有可能發(fā)生在衰敗的社區(qū)和那些晚上較少有人使用的地方（或晚上有反社會活動的地方）。在我們考察的項目中，很少出現(xiàn)這類問題。

4.8 安全感和安全性

與水相關(guān)的安全問題顯然十分重要。在美國的項目中，沿著水岸邊緣一般都會設(shè)置欄桿，但在其他國家很少設(shè)計這樣的欄桿，理論上來說人會有落水的風(fēng)險。這意味著設(shè)計師必須尋找一個合適的風(fēng)險平衡。

大部分項目極少配置救生圈、救生員、救生船等水上安全設(shè)備，即使那些設(shè)置了海上游泳活動的項目也是如此?？赡苤皇俏覀儧]有找到證據(jù)，但大量照片顯示在盛夏的場地上也很少有或幾乎沒有提供上述水上安全設(shè)備。

人身安全（如犯罪）并非主要問題?，F(xiàn)在設(shè)計師知道通過改善夜間照明，減少可能發(fā)生反社會或違法活動的場地，增加人群使用實現(xiàn)場所監(jiān)督等設(shè)計手段使場地變得更加安全（圖6）。

大多數(shù)場地都有良好的后勤通道，便于維修、也便于救護(hù)車或其他應(yīng)急車輛通行，確保了任何事故發(fā)生后都能夠被迅速處理。

4.9 食品銷售和餐飲機(jī)會

在所有的場地，游客通常都愿意花時間吃點心。野餐既可以是非正式的，也可以用桌子，在燒烤更受歡迎的地方可以考慮設(shè)置較多的燒烤架——這需要結(jié)合當(dāng)?shù)匚幕?xí)慣。很多地方也可以通過餐飲來吸引游客，如設(shè)置冰激凌攤、大型的餐廳、酒吧和咖啡館等。

5 討論和結(jié)論

從上面的分析可以看出，自20世紀(jì)80年代以來，在去工業(yè)化、新港口技術(shù)開發(fā)后，以及隨著人們對于雨洪管理的日益關(guān)注，針對濱水開發(fā)和無障礙水上項目的考慮越來越多，現(xiàn)已成為風(fēng)景園林和城市設(shè)計實踐的主要組成部分。規(guī)劃者和設(shè)計師清楚地意識到，有必要使這些地方具有吸引力、標(biāo)志性和可達(dá)性，也需要考慮它們的無障礙、安全性、易于維護(hù)，并在實際和其他限制條件下，提供盡可能多與水的接觸機(jī)會。筆者考察的所有項目都旨在通過提供體育活動、社交、放松、親近自然、沐浴陽光和減壓的機(jī)會，促進(jìn)身心健康并提升幸福感。此外，可以清楚地看出，絕大多數(shù)的項目都被很好地使用，無論它們位于哪里。在綠色空間很少的密集城市中，藍(lán)色空間提供了一個補(bǔ)充性的或者說替代性的環(huán)境。

當(dāng)然，這項研究也有局限性。雖然研究樣本量大（172個），但這只代表了能找到的最受好評或關(guān)注的項目。那些在出版物或網(wǎng)站上看不到信息的項目，則不可能納入本次考察評議。此外，同行評議過程主要由其他風(fēng)景園林師進(jìn)行，他們也許不會評估可能對項目產(chǎn)生負(fù)面影響的因素，如生態(tài)破壞等。同時研究人員無法親自視察絕大部分項目，這意味著許多與場地相關(guān)的細(xì)節(jié)可能被忽略。但采用谷歌地球和谷歌街景等工具，采用游客上傳的照片、“大數(shù)據(jù)”以及社交媒體開源數(shù)據(jù)等新型數(shù)據(jù)形式來開展研究，將變得越來越普遍。這些手段提供了在今后一段時間進(jìn)一步考察評估項目的可能，這是一個令人振奮的研究機(jī)會，尤其對于風(fēng)景園林類項目。因為它們往往需要一定時間去成長和發(fā)展達(dá)到最佳狀態(tài)，所以時間對評價非常重要。

項目的設(shè)計者在進(jìn)行規(guī)劃設(shè)計時，可能會考慮到大眾的健康和幸福感，也可能不會。然而，在這些備受贊譽(yù)的項目中，可以清楚地看到，哪些主要因素已被納入其中，哪些研究已確定為對促進(jìn)健康和幸福感的重要因素。因此，本研究涉及的這種在項目投入使用后再進(jìn)行評價的嘗試已經(jīng)揭示了一些關(guān)鍵點，它們可以成為規(guī)劃者和設(shè)計師的指導(dǎo)方針，無須在其他地方再做進(jìn)一步深入的分析。

綜上，可以認(rèn)為，城市藍(lán)色空間有可能在促進(jìn)城市居民的健康和幸福感方面發(fā)揮著重要作用。同時，作為河流、湖泊和海洋等區(qū)域景觀系統(tǒng)的一部分，城市規(guī)劃者和設(shè)計師應(yīng)當(dāng)考慮對城市藍(lán)色空間進(jìn)行更多的研究并加以合理利用。

（本文以作者在2018世界風(fēng)景園林師高峰講壇上的發(fā)言稿為基礎(chǔ)進(jìn)行補(bǔ)充。）

致謝：

感謝同事們，特別感謝Himansu Sekhar Mishra，在選擇和評估本研究所涉及的項目時所提供的幫助。

注釋(Notes)：

①www.bluehealth2020.eu.

② 譯者注：此處指的是2018年9月22—23日在北京舉辦的世界風(fēng)景園林師高峰講壇的主題。

③ IUCN Nature based solutions（www.iucn.org/commissions/commission-ecosystem-management/our-work/nature-basedsolutions最后訪問日期為2019年3月30日）。

④ http://www.greenflagaward.org.uk/ 最后訪問日期為2019年3月30日。

⑤ www.pps.org/最后訪問日期為2019年3月30日。

⑥ www.designcouncil.org.uk/resources/guide/spaceshaperusers-guide最后訪問日期為2019年3月30日。

圖表來源：

圖1～3 ? Himansu Sekhar Mishra；圖4、6 ? 西蒙·貝爾；圖5通過Creative Commons授權(quán)使用；表1由Himansu Sekhar Mishra整理。

Of all the aspects of the environment which can be considered as comprising a regional landscape system, surely that of the hydrological system is one of if not the key element. All landscapes — even deserts — can be broken down into hydrological basins and these make excellent units for assessing sustainability since in many ways they make separate and discrete landscape units.Watersheds (American usage) or river catchments(English usage) occur at ranges of scales, with smaller catchments forming sub-sections of larger ones and so on in a fractal structure[1].The continuing geological processes of erosion and deposition as well as the riparian ecological processes contribute to the formation of a distinct pattern of meanders and branches which remain dynamic[1]. As a result, what happens upriver in the higher parts of a regional system — such as sediment capture, deforestation or pollution — inevitably works its way downstream and has consequences for functions along the lower reaches and, as the tributaries of a system gradually combine towards the point where a single river results, these may be concentrated.

If we look at the history of human settlement globally and, in particular, the location of cities,we can see that the vast majority are located on water — harbour and port cities on river sea or lake coasts, bridging and defensive points, industrial concentrations using water power, fishing villages and towns, seaside holiday resorts and so on[2].From the earliest times of city development in Mesopotamia, the Nile valley, the Yellow River or the Indus valley, for example, not only have settlements and cities been located on rivers but the rivers and hydrological systems have been modified and engineered with irrigation systems, transport canals, dams and excavated harbours. Extensive river regulation systems to facilitate transport and to try to control flooding have been more recent features, enabling cities to expand onto flood plains and as a result to render them prone to extreme events exacerbated by upstream catchment mismanagement. Human use and misuse of river catchments has also caused major problems for human as well as ecological wellbeing.

All around the world, on every continent, cities are experiencing rapid changes in extent, structure,population density and pace of life. Populations of coastal cities are expanding[3]and many such cities, which often turned their backs on the water and restricted access to it, have, over the last 20-30 years, been extensively redeveloped and the water has become a major attractor for tourism and recreational use as well as for new residential development and business. This includes port facilities (as container harbours have taken over and moved out from city centres), riversides — where new approaches at flood management and re-naturalisation have become trends — and other types of waterfront,following changes in global trading patterns[4].While the environmental, social and economic implications of waterside regeneration have received some research attention (e.g., Jones[5], 1998 or, more recently Sairinen and Kumpalainen[6], 2006), the possible impact of this activity on public health and well-being have only recently seen scientific investigation (eg., V?lker and Kistemann[7], 2011).This contrasts with the extensive evidence base for the role of urban green spaces (such as urban parks,woodlands and street trees), in health protection and disease prevention[8]. The trends in urbanisation and population growth seen over the 20th and early 21st centuries in coastal areas around the world are forecast to continue[3]. Therefore, as more and more people find themselves in direct or indirect contact with urban water spaces through work and recreation, “blue infrastructure” — the waterbodies and their associated terrestrial margins which often provide the access to the water — starts to play an increasingly important role within urban planning and landscape design.

The scientific understanding of a range of health hazards and risks associated with water has been well-developed over several decades. One class of risks relate to sources of human exposure to microbes responsible for infectious diseases like cholera and typhoid[9], to a range of chemical pollutants and in the case of certain aquatic habitats the support of vectors of diseases like malaria,yellow fever and dengue. Water itself is also a significant hazard, drowning being the third most common global cause of unintentional death[10]. Flooding, too, is a major hazard in some areas (and getting worse in part because of increased construction in flood plains and increased surface sealing) leading to a range of health risks following flooding (eg. Alderman et al.[11], 2012). In addition, many recreational activities taking place in blue spaces (in the water or on beaches) are associated with non-water-related health impacts, such as increased risk of sunburn and skin cancer. Many of these risks are amplified by the effects of environmental degradation and the urban micro-climate (urban heat island) and extremes of weather such as heatwaves. Far less is known about the public health and individual wellbeing benefits of interactions with blue spaces and infrastructures built in, on and around them.

What about the positive health benefits associated with living near or using water spaces for recreation?Increasing epidemiological evidence suggests that people living near — or having views of — the sea coast are generally healthier, experience fewer symptoms of mental distress and are more satisfied with their lives than those living inland (eg. Wheeler et al.[12], 2012). Longitudinal evidence supports the idea that physical and mental health are typically better in people who spend or spent time living near the sea[13].Little is known of the extent to which these effects are specific to coastal environments or whether similar benefits for health would be conferred by rivers, lakes,canals or other blue spaces.

How might blue space contribute to better health and well-being? Early evidence suggests several pathways which may account for the positive relationship between exposure to blue space and health and well-being. Firstly, several studies found that people feel happier and less stressed in blue space settings than in other outdoor locations[14].Secondly, a Danish study, found that people living near blue spaces typically spend more time there than those living further away from them[15]. Thirdly, in a UK study, people living near the coast seem to be more likely to meet national guidelines for physical activity than those inland[16]while another UK study showed that blue spaces are seen as particularly important places to spend time in positive social interactions with friends and family[17]and are more widely used for health and well-being purposes than green spaces (e.g. Barton et al.[18], 2016). Finally,water bodies, with their greater thermal mass, can contribute to moderating the urban heat island effect locally, which is expected to be increasingly important if forecasts of hotter summers and increased heat-related morbidity and mortality turn out to be true (e.g. Hajat et al.[19], 2014).

Trends in city growth take several forms.One main problem faced globally is that of urban sprawl which sees lower density urbanisation take up large areas of green land[20]. As a means to counteract this urban densification has been widely proposed, especially focusing on the redevelopment of brownfield sites (eg. Fatone et al.[21], 2012).However, this places pressures on urban green spaces which may be reduced in size and number as well as area and quality if not protected. While infilling of former harbours to make land for development still takes place, with populations near large water bodies increasing in size, urban blue spaces may become increasingly important sites for living and recreation. Thus, the incorporation of evidence on the salutogenic effects of certain exposures to blue spaces into urban planning and development of urban infrastructure has the potential to help to resolve key public health challenges, ranging from reducing the incidence of non-communicable diseases associated with sedentary lifestyles and stress to reducing morbidity and mortality related to increasing temperature[22].

Research on relationships between exposure to blue spaces and health is less well-established than that conducted on green spaces and health(e.g. Niewenhuisen et al.[23], 2014) and particularly for the effects of blue spaces other than coastlines.In Europe, research has been conducted in only a few countries and results have been inconclusive,largely due to low statistical power, while worldwide the same phenomenon is true (eg. Triguero-Mas et al.[24], 2015). Thus the time is right to conduct deeper research into the potential role of blue space in promoting human health and well-being and preventing lifestyle diseases. The overarching goal of the BlueHealth project①is to fill these gaps. Starting in 2016 and running until 2020,this pan-European project aims to understand better the associations between exposure to blue space and health and well-being through a largescale systematic programme of interdisciplinary research that investigates exposure to blue space and its effects on health and well-being in various geographical, climatic, socioeconomic and cultural contexts across Europe. A significant part of this research aims to improve planning and design of urban blue spaces so as to help planners to maximise the benefits and minimise the risks.For an overview of the project and the research protocols being used see Grellier et al. (2017)[25].

The aim of this paper is to present some preliminary results of part of the BlueHealth project work, in particular focusing on the question as to how to evaluate the quality and effectiveness of planning and design of urban blue spaces. Here a summary of a critical review of a sample of projects which have been implemented worldwide with the aim of redeveloping blue spaces, frequently former industrial areas, and increasing recreational and salutogenic potential is presented. As the BlueHealth project is not yet concluded and all results are yet to be fully analysed and conclusions to be drawn, this paper provides a kind of progress overview in this particular aspect. Its relevance to the theme of the “regional landscape system”②is to introduce this as a potentially extremely important field of research which needs to be incorporated within any policies,plans or practices which aim to restore hydrological functioning, to work on reducing urban flood risks through the use of sustainable urban drainage or, in China, the implementation of the Sponge City concept[26]and to address the combined needs of green and blue infrastructure, naturebased solutions③and other topical urban planning models. The overview will present the concept of the project review and a summary of its main outcomes, illustrated with a number of examples.

1 The Concept of the Project Review

A systematically-undertaken review of evidence from projects, as opposed to scientific articles, is an unusual but not unheard of activity(from a scientific perspective). Post-occupancy evaluations are becoming common in architecture and also in landscape architecture but these are usually of single sites or buildings, not a large selection of projects. While in sciences (natural or social) which publish results in peer-reviewed academic papers it is relatively easy to carry out a review since the evidence has been quality controlled(through the process of peer review) during the publication process, what is an equivalent system for reviewing landscape architecture projects? In the art and design disciplines it is the role of criticism to perform the equivalent of peer-review and in landscape architecture this is also the case.

There have been several recent publications —books mainly — which have examined and reviewed certain specific types of blue spaces from different perspectives (eg. Prominski et al.[27], 2012; Rottle and Yocom[28], 2011; Macdonald[29], 2013; Smith and Ferrari[30], 2012) but none through a health and well-being lens, although they also contain some excellent examples which were in some cases included in the review. This is the first attempt at a wider and more comprehensive review of an extensive range of project types.

2 Project Search Method

5 德國漢堡哈芬市改造后的碼頭。碼頭可以到達(dá)登船，但是由于污染不可能進(jìn)行水上體育活動。即便如此，這里已經(jīng)成功建成了一個集居住、商業(yè)、娛樂和旅游為一體的場所The redeveloped docks in the Hafen City in Hamburg,Germany. Access down to the places where boats can be boarded is possible but due to pollution no water-based physical activities are possible. Nevertheless, a new residential, business, recreational and tourist destination has been successfully created

6 中國深圳的一條新的海濱長廊，沿著濱水區(qū)連接著許多新住宅區(qū)旁的區(qū)域。晚上光線充足，供安全使用A new promenade in Shenzhen in China, running along the waterfront and linking many sectors near new residential areas. It is well-lit at night and feels quite safe to use

Projects to include in the review were sourced by applying the following criteria, which are broad and inclusive rather than narrow and exclusive (for the first collection)[31]:

1) Projects should have been planned and designed to give access to water of any type and at any scale broadly within an urban setting (but could include more rural locations on the edge of a city).

2) They could be from anywhere in the world but have been constructed mainly within the last 10-15 years (although some older major projects were included since they were critically revisited by some journals and provided many lessons from a longer term perspective).

3) They should have appeared as① a critical article in a respected professional journal, ② have been a competition winner,③ have won a prize awarded by a professional organisation, ④be listed on websites presenting high quality design projects which have received critical acclaim, or a combination of any or all of the above.

4) There should be sufficient information available for assessment — given that no site visits were possible for most projects (although some examples had been visited by team members and/or were quite well known directly).

5) Be visible as built projects in recent photographs and, especially, via GoogleEarth(especially through StreetView), showing them some time after they were first constructed and in use (in order to avoid perfect photos from the designers affecting the impression given).

Table 1 shows the main journals and websites,their publisher, country of origin and focus of coverage used for identifying the projects. An initial trawl led to the identification of almost 400 potential projects which was then reduced to 172 examples which really stood out. This number became the database of evidence for the review.The complete set of projects will eventually be made available as a searchable database but there is no space in this paper to list them individually.

3 Method of Critical Review

The review was undertaken both qualitatively and quantitatively. Reading the comments written in jury decisions, in the articles, award citations and on the review websites, revealed how each was appraised by peers. This was checked by the researchers (landscape architecture-qualified staff at the Chair of Landscape Architecture at the Estonian University of Life Sciences) as well as examining the projects using GoogleEarth and Streetview. Thematic analysis of the projects was undertaken using a set of pre-defined factors which formed criteria for site assessment in a number of tools (such as the Green Flag Awards④, Project for Public Space⑤, SpaceShaper⑥and so on). From each of these projects a number of themes was derived and comparison made between each project in relation to these themes. This was prepared as a qualitative overview. It is a summary of this which is presented in this paper. The detailed method and results of the quantitative study will be reported elsewhere once analysis has been completed.

Figures 1-3 show some basic characteristics of the samples — the range of countries/regions where they are located, the type of blue space they occupy and the type of land/water interface.

4 Analysis and Results

4.1 General Design Aspects

The view to the water, the land-water interface, how the design incorporates the presence of water, the suitability of the design (including elements and materials) to the place context and place affordances are the main factors determining the outstanding and the most aesthetically appealing projects. The design innovation and design sustainability are also important factors. Each of the reviewed projects included some specific feature or set of features as a major part of the design concept which contributed to their unique character, such as a reference to the former use of the site, for example ports or harbours, and the incorporation of elements into the design such as cranes, railway tracks, bollards and other structures large and small. In other examples a strong, bold focal feature — not necessarily art as such, though this could also be found — gave a new identity and focal point, a strong image (which also helped with the brand) and means of creating a new place.

Many examples used the water as a means of establishing the new or restored identity of the place, for example the imaginative ways in which designers brought land and water together physically or visually, maximised the aesthetic and sensory impact or used design to screen out the urban background in order to focus on the water.

It was also possible to see a certain contemporary“l(fā)ook” to many projects in the way that forms, colours,materials and textures were used. This is because designers look to precedents and there are stylistic movements which inevitably affect what people do,as in all design professions, even when designers try to be individualistic and unique.

It is notable that, compared with green space projects, owing to the often high degree of construction required at waterfronts, unique solutions are more common in blue space projects.It is often found that structures perform dual roles as edge protection and water access provision using interesting combinations of aesthetically designed and structurally engineered solutions.

Larger sites are normally subdivided into different functional and aesthetic zones. Some may divide formal (e.g. sports) from informal activities,different types of children’s play, different types of vegetation or different types of water. This can also increase the attraction and interest of the site by providing a variety of aesthetic experiences,different wildlife and also reduce the sensation of crowding by visually separating spaces so that the site cannot be seen all at once.

4.2 Potential for Increasing Physical and Mental Health and Wellbeing

All sites, apart from the very small interventions such as water features, offer good potential for increased physical activity, even if this is solely landbased. Foremost among these is walking and jogging/running while other exercise facilities and formal or informal sports are also very widespread.

The sites are almost all well-designed for providing opportunities to gaze at the view, to sit alone, to contemplate and so on but owing to the popularity and draw of the water’s edge solitude is often a problem except perhaps at certain times of the day. In the larger sites the main places for solitude are away from the water’s edge, perhaps in the vegetation immediately behind the waterfront(where this is the case).

Most sites were found to be rather urban in character so that the possibility to put the urban context out of sight and mind is less possible,perhaps with less potential for stress reduction than when the views to the water are open to the horizon, even if the city is right behind the viewer.

4.3 Accessibility

In the vast majority of cases the site was easily accessible on foot, by bicycle and from public transport. Car access was also often good, even in inner city areas, due to the provision of car parking.Car parking was more of a standard feature in projects in the USA and Australia — where there is more of a car-borne society — than in eg Germany or China.

In a significant minority of cases access to the area from the water is also part of the design. In some cases, this was from passenger ferries which have terminals next to the new park, in others there are marinas or small docks where pleasure boats can tie up and allow people to disembark in safety.

Accessibility within the site was also a strong feature of most projects — even in situations where the terrain was quite steep, ramps supplemented steps in gaining access down to the water. In a few limited examples it was not physically possible to make everywhere universally accessible but these were a clear minority. In sites which are not narrow and linear in form internal circulation is important — connecting different areas or zones within the site as well as offering a range of different paths around the site.

Bicycle access was generally possible although cycling within many sites was not and there seemed,from the evidence available, to be inadequate cycle parking in many sites. This depends on the cycle culture of different countries and it was not an issue in eg the Netherlands or Denmark.

Seaside and lakeside areas are mainly developed with direct access into the water as a key objective — and many are there to enhance access, especially for older or disabled people or to create safer and less damaging access in ecologically sensitive areas. Inner-urban rivers and former docks pose greater challenges and the designers tend to try to give opportunities for closer proximity and visual and sensory access but cannot, due to hydrological or water quality reasons, allow people to get into the water directly. The same is true of projects which combine water treatment through vegetation filtration systems with a park. People cannot be allowed direct contact but in all other respects the area is a wonderful place, especially to see water-based habitats and wildlife (Fig. 4).

In some projects ramps and steps have been incorporated as key features of the design and made the central concept of the project, with a form which is integral into the aesthetic quality evoked by the project. Handrails are also necessary items to help people use both steps and ramps — they can make a real difference when older people are frequent users.

Linkages from one site to another featured quite often — in some areas, such as the former docks of Manhattan, a number of small individual parks have been designed which are linked by walkways, forming a more extensive system.Coastal promenades, long distance paths and riveredge walks are also found to help in connecting different areas and also offer ways for people to connect into the larger structures.

Thus we can conclude that a key feature of success is a well-thought out accessibility strategy.This involves not only the planning and design of the site but how to get there. This involves planning together with authorities responsible for transport, road management, occasionally railways or metros and sometimes harbour authorities. The walkability or cycle-ability or streets around sites and aspects such as safe road crossings play a role as does the location and walking distance of bus stops, metro stations and car parking.

4.4 Interaction with Water

A key aspect of all projects reviewed was to maximise the potential for engagement or interaction with water. While in a number of cases it is not possible for people to come in direct contact with water for practical or safety reasons,visual and other sensory contact is an extremely important part of any project and in some cases it is very creatively achieved.

In some projects the site lies next to an embanked or canalised river or dockland where it is impossible to gain physical access. On the adjoining quayside or embankment water features have been installed which provide interaction with water jets or fountains — children and adults both enjoy splashing or being soaked by the jets in hot weather. In other cases, the site is nowhere near a natural waterbody but the appeal of a fountain or water feature is so strong that installations feature as focal points in a new park or urban square. This is in part due to the movement and changing nature of water as a result of its fluid state — jets, mists,mirror-like surfaces, swift currents, crashing waves,tides and so on demonstrate the dynamic quality of water which is such a contrast to the land.

In situations where there are vertical dock walls or flood retention embankments the site is often high above the waterbody. Opportunities to enable people to descend down towards the water are key aspects of the design in a number of projects. This may include installing structures which float or else may be submerged during flooding episodes. It may also be possible for boats to tie up and use the lower-level terraces or quays,so increasing the interaction with the water and water-based activities even in cases where the water itself is not too clean (Fig. 5).

Closer access obtained by siting piers or other decking structures down by the water can also be incorporated in projects with river re-naturalisation as an aim — the river may be swift and volatile but the chance to get close, even if a bit risky, can provide a special experience — akin to the sublime— which may contribute to a feeling of escape from the city and help in mental restoration.

Interaction with water at the beach —whether at the seaside or lake side — is clearly a long-standing and popular activity. Many projects incorporate restoration of beaches and beachfront facilities, even to the extent of importing sand and using structures to prevent the beach washing away.Vegetation restoration is also a feature of many projects. This means that, while going into the water is still the main focus, built structures play a more important role in mediating between people and the land/water interface.

4.5 Seating and Opportunities for Social Interaction

All projects reviewed pay special attention to seating provision. Some sites are equipped with large numbers of standard benches and from the visual evidence these are well-used. In some places picnics and barbecues are popular and tables, often supplied with grills, are also placed for this — which is associated with some cultures more than others. Bench designs may be off-the-shelf units (cost effective, easy to maintain etc) or made specially for the project.

There is also a major trend for seating to be built into the design in a more fundamental way — using terraces, steps and low walls as flexible structures with many affordances and with a lower need for maintenance as well as keeping sites simpler and less cluttered by lots of objects.

In some examples, where there are tides and a warm sea, steps leading down into the water can provide seating which is half-in and half-out of the water at any time of the tide, ideal for older or disabled people to enjoy the feel of water on their bodies. Floating structures may also provide the same seating and dipping of feet into the water but they respond to changes in water level.

Another popular type of bench is a fixed or moveable sun-bathing bed with a sloping section for sitting, lying, reclining etc. These are especially popular in a number of inland artificial “beaches”which provide sunbathing opportunities in the middle of the city. They are also useful in places where the beach is rocky, where there is no beach or where damage and erosion are problems.

4.6 Microclimate Amelioration

Waterfront areas are frequently exposed to strong sun and wind, to rain storms or to freezing conditions. Keeping them comfortable to use all year round can be a challenge. Since many sites in inner urban areas are devoid of vegetation or only have limited planting (such as former ports and industrial areas) they are often particularly exposed to the elements but, due to the lack of soil and drainage problems, pose problems for tree establishment. In any case, since trees or bushes take time to grow to a size where they can provide good shade or shelter, many project, while featuring planting, also use constructed elements to do the job instead or as well as trees.

Micro-climate sensitive design is a feature of a number of successful projects — of course, with different solutions in different places. It is clear that much thought and ingenuity has gone into this aspect in many sites. Shade (and rain) umbrellas,canopies which can be furled and unfurled, slatted overhead frames with climbing plants and closely spaced semi-mature trees (in order to get an instant result) are examples of good solutions.

Where there is adequate vegetation already then the designers have recognised that keeping it and managing it while adding to it for the longer term is important. Coastal sites offer challenges for growing trees and woody plants due to salt, winds,rocky soils and so on so the solution of planting and the selection of the correct species or varieties may not be as simple as for a regular park.

Temporary installations can be used to create shade in summer or shelter in winter, for example, or the same structures can perform dual functions, such as some types of shelters fond on a number of sites.

4.7 Site Management/Maintenance

For almost all the projects reviewed, good site management and maintenance was an important factor. There was little evidence of damage,vandalism or worn out vegetation in any sites and almost all were well-equipped with litter bins, which appeared to be well-used and regularly collected.

In many projects the design, use of materials and quality of construction helps towards ensuring that management and maintenance is likely to be cost effective and straightforward. Simplicity is often a feature of the design as is the use of standardised elements which can easily be replaced or repaired if necessary.

Good maintenance is one signal to users that a place is cared for and this translates into a message that the site is safe and welcoming to use.Damage and vandalism are usually more likely in run-down neighbourhoods and in places where there is little use at night (or where anti-social activities take over at night). Few of the sites which were to be found in such conditions showed any such problems.

4.8 Safety and Security

Safety in relation to the water is clearly an important issue. In projects in eg the USA, railings along edges are normal but in other countries there are fewer of these and it is theoretically possible to fall off edges. This means a balance has to be struck between too little and too much risk.

Provision of water safety equipment such as life-rings or equipping beaches with lifeguards and boats etc is surprisingly minimal in many projects,even those with sea swimming access. It may be that the evidence is not available, yet we found plenty of photos of sites at the height of summer with little or no equipment.

Personal safety, eg from crime, did not appear to be a major problem. Designers are now aware of how to make sites feel safer by reducing the availability of locations within the design where anti-social or illegal activity can take place, by good lighting at night, by ensuring that places police themselves as a result of plenty of people using them and so on (Fig. 6).

Most sites had good vehicular access for maintenance purposes which would also facilitate access by ambulances or other emergency vehicles.This ensures that any accidents can be dealt with quickly.

4.9 Food Sales and Eating Opportunities

In all sites visitors are generally more likely to spend more time there by taking refreshments.Picnicking is available either informally or using tables,while in a number of sites grilling and barbecuing are popular and well-provided for — this is somewhat culturally dependent. Food sales, ranging from ice cream stalls to full-blown restaurants, bars and cafes are also popular features of many sites.

5 Discussion and Conclusions

We can see from the results presented above that waterfront developments and water-accessibility projects form a major part of landscape architecture and urban design practice at the moment and this has been a rising trend since the initial projects were started following de-industrialisation and new port technologies for example, in the 1980s onwards,as well as the need to introduce better means of dealing with storm water and other factors. Planners and designers are clearly aware of the need to make such places attractive, iconic, accessible, safe, easy to maintain and offering as close a contact to water as is possible given practical and other constraints. All the sites we reviewed aim to increase the potential for physical and mental health and wellbeing improvement by offering opportunities for physical activity, for socialising, relaxing, getting closer to nature, soaking up the sun and de-stressing. It is also clear from the evidence that the vast majority of the sites are extremely well-used wherever they are located and that in dense cities with little green space, blue space offers an additional or substitute environment.

Of course, there are limitations in this study.While the sample of sites is large, at 172, this represents only the best and most critically acclaimed projects we could find. It is impossible to collect information on all projects which exist if they are not visible in publications or websites. Furthermore,the peer-reviewing process is mainly carried out by other landscape architects who may not evaluate factors which may have negative impacts on the project sites, such as ecological damage. In addition,the fact that the vast majority of the projects could not be visited in person by the researchers means that potentially a lot of subtleties associated with many sites might have been missed. With the availability of tools like GoogleEarth and Google StreetView as well as the photographs uploaded by visitors, the use of “big data” and social media as a means of obtaining data for use in research is becoming increasingly acceptable. The ability to look at sites over time also offers fascinating possibilities for examining projects, especially landscape architecture projects where their growth and development over tine is important.

The designers of the projects may or may not have had human health and well-being at the forefront of their minds when developing their plans. However, in these highly acclaimed examples we can see quite clearly what main elements have been included which research has identified as being important for facilitating health and wellbeing benefits. Thus this attempt at post-occupancy evaluation has already revealed, without the further in-depth analysis being carried out to be reported elsewhere, a number of key aspects which can form guidelines for planers and designers.

We can say, therefore, that urban blue spaces have the potential to play an important role in the health and well-being of urban residents and that, as part of the regional landscape systems of rivers, lakes and the sea, more research needs to be undertaken and such spaces need to be properly taken into account by urban planners and designers.

(This paper is revised on the basis of the speech delivered by the author at the International Landscape Architecture Symposium in 2018.)

Acknowledgements:

The author wishes to acknowledge the help of his colleagues,especially Himansa Sekhar Mishra, in selecting and assessing the projects reviewed in this paper.

Sources of Figures and Table：

Fig. 1-3 ? Himansu Sekhar Mishra; Fig. 4, 6 ? Simon Bell;Fig. 5 licensed under Creative Commons; Tab. 1 ? Himansa Sekhar Mishra.