Our grandparents' generation created an amazing system of canals and reservoirs that made it possible for people to live in places where there wasn't a lot of water. For example, during the Great Depression, they created the Hoover Dam, which in turn, created Lake Mead and made it possible for the cities of Las Vegas and Phoenix and Los Angeles to provide water for people who lived in a really dry place.
我們的祖父輩創造了一套 非常棒的渠道及水庫系統, 讓大家能住在水不多的地方。 譬如在美國大蕭條時期, 他們建造出胡佛水壩, 也因而造出人工湖米德湖, 能為拉斯維加斯、鳳凰城 及洛杉磯供水, 讓大家能住在很乾燥的地方。
In the 20th century, we literally spent trillions of dollars building infrastructure to get water to our cities. In terms of economic development, it was a great investment. But in the last decade, we've seen the combined effects of climate change, population growth and competition for water resources threaten these vital lifelines and water resources.
20 世紀時, 我們確實花了幾兆美元 做基礎建設送水到城市。 以經濟發展而言, 這是一項偉大的投資。 但是在過去十年, 我們看到氣候變遷 與人口成長的綜合影響, 而對水資源的競爭 威脅到這些重要的 命脈及水資源。
This figure shows you the change in the lake level of Lake Mead that happened in the last 15 years. You can see starting around the year 2000, the lake level started to drop. And it was dropping at such a rate that it would have left the drinking water intakes for Las Vegas high and dry. The city became so concerned about this that they recently constructed a new drinking water intake structure that they referred to as the "Third Straw" to pull water out of the greater depths of the lake.
這張表顯示米德湖水位 在過去十五年的變化。 大家可以看到 大約從 2000 年開始, 水位開始下降。 下降幅度之快, 讓拉斯維加斯飲用水取水口 遠高過湖水位並乾涸。 該市非常擔心, 因此他們最近新建了 一個飲用水取水口, 他們稱之為「第三根吸管」, 從愈來愈低的湖中取水。
The challenges associated with providing water to a modern city are not restricted to the American Southwest. In the year 2007, the third largest city in Australia, Brisbane, came within 6 months of running out of water. A similar drama is playing out today in São Paulo, Brazil, where the main reservoir for the city has gone from being completely full in 2010, to being nearly empty today as the city approaches the 2016 Summer Olympics.
供水給現代都市所面臨的挑戰 並非只限於美南地區。 2007 年,澳洲 第三大都市布里斯本 缺水缺了六個月。 今天類似的情景 也在巴西聖保羅上演, 該市的主要水庫 從 2010 年滿水位狀況, 到今天幾乎完全乾涸, 而該市正準備舉行 2016 年夏季奧運會。
For those of us who are fortunate enough to live in one of the world's great cities, we've never truly experienced the effects of a catastrophic drought. We like to complain about the navy showers we have to take. We like our neighbors to see our dirty cars and our brown lawns. But we've never really faced the prospect of turning on the tap and having nothing come out. And that's because when things have gotten bad in the past, it's always been possible to expand a reservoir or dig a few more groundwater wells. Well, in a time when all of the water resources are spoken for, it's not going to be possible to rely on this tried and true way of providing ourselves with water.
對我們這些有幸住在世界 各個重大都市的人而言, 我們從未真正體驗過 毀滅性的旱災。 我們抱怨要洗戰鬥澡。 我們喜歡讓鄰居看見 我們的髒車及枯黃的草皮。 但是我們從未真正面對過 打開水龍頭 卻無水可用的窘境。 這是因為過去情況變糟時, 我們總是有辦法擴建水庫, 或挖更多口地下水井。 在所有水資源 都已開發殆盡的年代, 我們不可能再依賴這種 已知可行的方法 來提供用水。
Some people think that we're going to solve the urban water problem by taking water from our rural neighbors. But that's an approach that's fraught with political, legal and social dangers. And even if we succeed in grabbing the water from our rural neighbors, we're just transferring the problem to someone else and there's a good chance it will come back and bite us in the form of higher food prices and damage to the aquatic ecosystems that already rely upon that water.
有些人認為我們可以 向都市四周有水源的地主借水 以解決都市的供水問題。 但是這個方法伴隨著 政治、法律及社會威脅。 即使我們能從四周鄰居 成功搶到水, 我們只是把問題轉移給別人, 這個問題很有可能 會以高漲的食物價格 回頭反咬我們一口, 並破壞靠此水為生的 水生生態系。
I think that there's a better way to solve our urban water crisis and I think that's to open up four new local sources of water that I liken to faucets. If we can make smart investments in these new sources of water in the coming years, we can solve our urban water problem and decrease the likelihood that we'll ever run across the effects of a catastrophic drought.
我認為有更好的方法 解決都市的水危機, 而方法就是開拓四種 新的當地水資源, 我比作打開水龍頭。 如果我們可以明智地 投資在這些新的水資源上, 在未來幾年, 我們就能解決都市水問題, 並減低我們碰到 毀滅性旱災後果的可能性。
Now, if you told me 20 years ago that a modern city could exist without a supply of imported water, I probably would have dismissed you as an unrealistic and uninformed dreamer. But my own experiences working with some of the world's most water-starved cities in the last decades have shown me that we have the technologies and the management skills to actually transition away from imported water, and that's what I want to tell you about tonight.
如果你在 20 年前跟我說 一個現代化都市 不用從外面引水也可以生存, 我大概會把你打發走, 說你是不切實際又無知的空想家。 但是依我自己的經驗, 在過去幾十年與世界上 幾個非常缺水的都市合作後, 讓我知道我們的確有 科技與管理技巧 能真的轉變到不用從外面引水, 這也是我今晚的主題。
The first source of local water supply that we need to develop to solve our urban water problem will flow with the rainwater that falls in our cities. One of the great tragedies of urban development is that as our cities grew, we started covering all the surfaces with concrete and asphalt. And when we did that, we had to build storm sewers to get the water that fell on the cities out before it could cause flooding, and that's a waste of a vital water resource. Let me give you an example.
我們第一個要打開的 當地供水資源 以解決我們的都市水問題, 會流出降在都市內的雨水。 都市發展的大悲劇之一, 就是隨著都市成長, 我們以混凝土及瀝青 覆蓋所有的表面。 在我們如此做的同時, 又必須蓋雨水下水道 將降下的雨水排到都市外, 不然會引起水災, 這浪費了我們重要的水資源。 舉一個例子,
This figure here shows you the volume of water that could be collected in the city of San Jose if they could harvest the stormwater that fell within the city limits. You can see from the intersection of the blue line and the black dotted line that if San Jose could just capture half of the water that fell within the city, they'd have enough water to get them through an entire year.
這張表顯示 在矽谷聖荷西市 能收集的雨水水量, 只要他們能把市區範圍內的 雨水全都收集起來。 從藍線與黑點線的交點可以看到 聖荷西只要能收集 降在市區範圍內一半的雨水, 就有足夠的水撐過一整年。
Now, I know what some of you are probably thinking. "The answer to our problem is to start building great big tanks and attaching them to the downspouts of our roof gutters, rainwater harvesting." Now, that's an idea that might work in some places. But if you live in a place where it mainly rains in the winter time and most of the water demand is in the summertime, it's not a very cost-effective way to solve a water problem. And if you experience the effects of a multiyear drought, like California's currently experiencing, you just can't build a rainwater tank that's big enough to solve your problem.
我知道有些人可能會這麼想: 「那我們的解決方案就是 開始裝幾個大桶子, 與簷槽的雨落水管相連, 收集雨水。」 這個想法在某些地方或許可行。 但是如果你住的地方 雨季主要在冬天, 最需要水的時候卻是夏天, 這就不是非常 具經濟效益的解決方法。 如果你經歷多年旱災的影響, 像加州現在一樣, 你不可能蓋一個夠大的 雨水儲槽來解決問題。
I think there's a lot more practical way to harvest the stormwater and the rainwater that falls in our cities, and that's to capture it and let it percolate into the ground. After all, many of our cities are sitting on top of a natural water storage system that can accommodate huge volumes of water.
我想有很多更實際的方式 能收集降在市區範圍內的雨水, 那就是要留住雨水 並滲透到地下。 畢竟,許多城市 都位於天然儲水系統上方, 能容納大量的水。
For example, historically, Los Angeles has obtained about a third of its water supply from a massive aquifer that underlies the San Fernando Valley. Now, when you look at the water that comes off of your roof and runs off of your lawn and flows down the gutter, you might say to yourself, "Do I really want to drink that stuff?" Well, the answer is you don't want to drink it until it's been treated a little bit. And so the challenge that we face in urban water harvesting is to capture the water, clean the water and get it underground.
舉例而言, 歷史上洛杉磯曾經 從聖費爾南多谷下方的蓄水層 取得約三分之一的供水。 現在,當你看著屋頂上的水 流過你的草坪,從屋簷流下, 你大概會對自己說: 「那種水真的能喝嗎?」 答案是你不想喝那種水, 除非這水經過一些處理。 所以我們收集都市雨水 要面對的挑戰, 就是要把水留住、弄乾淨 並存入地下。
And that's exactly what the city of Los Angeles is doing with a new project that they're building in Burbank, California. This figure here shows the stormwater park that they're building by hooking a series of stormwater collection systems, or storm sewers, and routing that water into an abandoned gravel quarry. The water that's captured in the quarry is slowly passed through a man-made wetland, and then it goes into that ball field there and percolates into the ground, recharging the drinking water aquifer of the city.
這正是洛杉磯市目前正在執行的, 他們在柏本克市興建一項新計畫。 這張圖是他們正在興建的 雨水處理廠, 他們將一系列的雨水收集系統 即雨水下水道連接起來, 將收集的水導入一座 廢棄的採石場。 在此採石場收集到的水, 會慢慢流經一座人造溼地, 然後進入那塊沙洲, 再滲入地面, 補注該市的飲用水蓄水層。
And in the process of passing through the wetland and percolating through the ground, the water encounters microbes that live on the surfaces of the plants and the surfaces of the soil, and that purifies the water. And if the water's still not clean enough to drink after it's been through this natural treatment process, the city can treat it again when they pump if back out of the groundwater aquifers before they deliver it to people to drink.
在通過溼地 及滲入地下的過程中, 水會碰到存在於植物表面 及土表的微生物, 這會淨化水。 如果這些水仍然 不夠乾淨到能喝的程度, 在這項天然的處理過程之後, 該市會再處理一次, 他們從地下水層抽水出來, 處裡後再供水給大家喝。
The second tap that we need to open up to solve our urban water problem will flow with the wastewater that comes out of our sewage treatment plants. Now, many of you are probably familiar with the concept of recycled water. You've probably seen signs like this that tell you that the shrubbery and the highway median and the local golf course is being watered with water that used to be in a sewage treatment plant. We've been doing this for a couple of decades now. But what we're learning from our experience is that this approach is much more expensive that we expected it to be. Because once we build the first few water recycling systems close to the sewage treatment plant, we have to build longer and longer pipe networks to get that water to where it needs to go. And that becomes prohibitive in terms of cost.
我們要解決都市水問題 該開的第二個水龍頭 會流出廢水, 從我們的汙水處理廠出來。 在座很多人大概還滿熟悉 再生水(中水)的概念。 你大概看過像這樣的標誌, 顯示這塊灌木叢、 高速公路的中央安全島、 還有家附近的高爾夫球場 都用再生水灌溉, 從汙水處理廠裡流出來。 這早已行之有年。 但是我們從經驗得知 這個方式遠比我們預期的貴很多。 因為一旦我們蓋了 頭幾座再生水系統廠, 位於汙水處理廠附近, 我們就必須接愈來愈長的管線 把水輸送到該去的地方。 這會讓人卻步,因為成本過高。
What we're finding is that a much more cost-effective and practical way of recycling wastewater is to turn treated wastewater into drinking water through a two-step process. In the first step in this process we pressurize the water and pass it through a reverse osmosis membrane: a thin, permeable plastic membrane that allows water molecules to pass through but traps and retains the salts, the viruses and the organic chemicals that might be present in the wastewater.
我們發現 更具經濟效益 及更實際的再生廢水方法, 是把處理過的廢水變成飲水, 這要透過二個處理步驟。 第一步是將水加壓 讓它通過逆滲透膜: 那是一層可滲透的塑膠薄膜, 讓水分子通過, 但是會抓住及留住鹽分、 病毒及有機化學物質, 這些東西可能存在於廢水中。
In the second step in the process, we add a small amount of hydrogen peroxide and shine ultraviolet light on the water. The ultraviolet light cleaves the hydrogen peroxide into two parts that are called hydroxyl radicals, and these hydroxyl radicals are very potent forms of oxygen that break down most organic chemicals.
處理過程的第二步 是注入少量的過氧化氫 及照射紫外線。 紫外線會分解過氧化氫 成為兩個氫氧自由基, 氫氧自由基 是非常有力的氧形式, 會分解大部分的有機化學物質。
After the water's been through this two-stage process, it's safe to drink. I know, I've been studying recycled water using every measurement technique known to modern science for the past 15 years. We've detected some chemicals that can make it through the first step in the process, but by the time we get to the second step, the advanced oxidation process, we rarely see any chemicals present. And that's in stark contrast to the taken-for-granted water supplies that we regularly drink all the time.
水經過這兩個步驟處理後, 可以安全飲用。 我知道, 我利用所有現代科學 已知的測量技術 研究再生水 研究了 15 年。 我們偵測到某些化學物品 可以通過此處理過程的第一步, 但是到了第二步, 即高級氧化程序, 我們很難再看到任何化學物品。 這與我們天天飲用、 視為理所當然的自來水 形成鮮明對比。
There's another way we can recycle water. This is an engineered treatment wetland that we recently built on the Santa Ana River in Southern California. The treatment wetland receives water from a part of the Santa Ana River that in the summertime consists almost entirely of wastewater effluent from cities like Riverside and San Bernardino. The water comes into our treatment wetland, it's exposed to sunlight and algae and those break down the organic chemicals, remove the nutrients and inactivate the waterborne pathogens. The water gets put back in the Santa Ana River, it flows down to Anaheim, gets taken out at Anaheim and percolated into the ground, and becomes the drinking water of the city of Anaheim, completing the trip from the sewers of Riverside County to the drinking water supply of Orange County.
還有一種方法可以再生水。 這是我們剛興建的人工溼地, 位於南加州聖塔安娜河。 這座人工溼地接收 從聖塔安娜河部分河段進來的水, 夏天時幾乎全是廢汙水, 由河濱市及聖伯那地諾市等地排放。 廢汙水進入我們的處理溼地, 曝露於陽光及藻類下, 這個過程會分解有機化學物, 去除營養物 並使水媒病原體失去活性。 該水再流放回聖塔安納河, 往下流到安納罕, 然後在安納罕滲透入地面, 並成為安納罕市的飲水, 是一趟從河濱縣的廢汙水 轉變成橘縣飲用水的完美旅程。
Now, you might think that this idea of drinking wastewater is some sort of futuristic fantasy or not commonly done. Well, in California, we already recycle about 40 billion gallons a year of wastewater through the two-stage advanced treatment process I was telling you about. That's enough water to be the supply of about a million people if it were their sole water supply.
你可能會認為 這種喝廢水的想法 是某種未來的幻想 或不常見。 但是在加州,我們每年 已再生一千五百多億公升廢水, 都由這種我剛剛提到的 二階段式的高級氧化處理過程再生, 這個量足夠提供 大約一百萬人使用, 如果這是他們唯一的水源。
The third tap that we need to open up will not be a tap at all, it will be a kind of virtual tap, it will be the water conservation that we manage to do. And the place where we need to think about water conservation is outdoors because in California and other modern American cities, about half of our water use happens outdoors.
我們必須打開的第三個水龍頭 跟水龍頭一點關係都沒有, 它是虛擬的水龍頭, 它就是我們能做到的節約用水。 我們要思索 如何節約的地方是戶外, 因為在加州 及美國其它現代都市, 我們的水有一半用在戶外。
In the current drought, we've seen that it's possible to have our lawns survive and our plants survive with about half as much water. So there's no need to start painting concrete green and putting in Astroturf and buying cactuses. We can have California-friendly landscaping with soil moisture detectors and smart irrigation controllers and have beautiful green landscapes in our cities.
目前的乾旱 讓我們看見 要讓草皮及植物生存, 只要以往一半的水就夠了, 所以實在不需要 把門前車道噴成綠色、 鋪上人工草皮及買仙人掌。 我們可以用適合加州的園藝造景, 裝上土壤水分偵測器 及智慧型澆水控制器, 就能在城市裡有美麗的綠色園景。
The fourth and final water tap that we need to open up to solve our urban water problem will flow with desalinated seawater. Now, I know what you probably heard people say about seawater desalination. "It's a great thing to do if you have lots of oil, not a lot of water and you don't care about climate change." Seawater desalination is energy-intensive no matter how you slice it. But that characterization of seawater desalination as being a nonstarter is hopelessly out of date. We've made tremendous progress in seawater desalination in the past two decades.
我們要開的第四個 也是最後一個水龍頭 以解決都市水問題, 會流出海水淡化水。 我知道你們大概聽過 別人這樣說海水淡化: 「如果你有大量石油, 卻沒有大量的水, 而且你也不在乎氣候變遷, 那這是件好事。」 無論你怎麼看, 海水淡化都非常耗能。 但是把海水淡化視為 毫無前途 是無可救藥的過時想法。 海水淡化在過去二十年 已有長足進步。
This picture shows you the largest seawater desalination plant in the Western hemisphere that's currently being built north of San Diego. Compared to the seawater desalination plant that was built in Santa Barbara 25 years ago, this treatment plant will use about half the energy to produce a gallon of water.
這張照片上面 是西半球最大的海水淡化廠, 目前正在聖地牙哥北邊興建。 與另一座海水淡化廠相比, 25 年前建於聖塔芭芭拉, 這座處理廠生產一加侖的水 只要用約一半的能量。
But just because seawater desalination has become less energy-intensive, doesn't mean we should start building desalination plants everywhere. Among the different choices we have, it's probably the most energy-intensive and potentially environmentally damaging of the options to create a local water supply.
但是就算海水淡化 現在比較不那麼耗能, 也不代表我們就該在四處 開始興建處理廠。 在我們各種選項中, 這大概是最耗能源、 最破壞環境的一種方法 來創造當地水資源。
So there it is. With these four sources of water, we can move away from our reliance on imported water. Through reform in the way we landscape our surfaces and our properties, we can reduce outdoor water use by about 50 percent, thereby increasing the water supply by 25 percent. We can recycle the water that makes it into the sewer, thereby increasing our water supply by 40 percent. And we can make up the difference through a combination of stormwater harvesting and seawater desalination.
情況就是這樣。 開了這四個水龍頭, 我們就不需仰賴外地引水。 透過改良我們園藝造景的方法, 我們可以節省 約 50% 的戶外用水, 因而增加 25% 的供水。 我們可以再生廢汙水, 因而增加 40% 供水。 我們也可以透過結合 收集雨水及海水淡化補足供水量。
So, let's create a water supply that will be able to withstand any of the challenges that climate change throws at us in the coming years. Let's create a water supply that uses local sources and leaves more water in the environment for fish and for food. Let's create a water system that's consistent with out environmental values. And let's do it for our children and our grandchildren and let's tell them this is the system that they have to take care of in the future because it's our last chance to create a new kind of water system.
所以,讓我們創造一套 能夠承受任何挑戰的供水法, 在未來幾年能因應 氣候變遷帶來的挑戰。 讓我們創造一套使用當地水資源 並能在環境中留更多水 給魚類、給糧食用的方法。 讓我們創造一套能與 環境價值相符合的供水系統。 讓我們為子孫做這件事, 並告訴他們 未來他們要好好照顧這套系統, 因為這是我們創造 新式供水系統的最後機會。
Thank you very much for your attention.
謝謝大家專心聆聽。
(Applause)
(掌聲)