TEDxMarin
David Sedlak: 4 ways we can avoid a catastrophic drought
大衛‧思德拉克: 四種方法避免毀滅性旱災
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全球氣候型態變化無常，以前飲用水豐富的地方，可能很快就要面臨水庫乾涸、地下水蓄水層枯竭的情況。大衛‧思德拉克身為土木及環境工程師，在這場演講中針對都市水問題，分享四個實際的解決方案。他的目標：轉變到新的、當地的水資源，並創造一套系統，能因應未來氣候變遷的各式挑戰。
David Sedlak - Civil and environmental engineer
David Sedlak’s research focuses the long-term goal of developing cost-effective, safe and sustainable systems to manage water resources. Full bio
David Sedlak’s research focuses the long-term goal of developing cost-effective, safe and sustainable systems to manage water resources. Full bio
Double-click the English transcript below to play the video.
00:12
Our grandparents' generation
created an amazing system
created an amazing system
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我們的祖父輩創造了一套
非常棒的渠道及水庫系統，
00:16
of canals and reservoirs
that made it possible
that made it possible
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讓大家能住在水不多的地方。
00:19
for people to live in places
where there wasn't a lot of water.
where there wasn't a lot of water.
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00:22
For example, during the Great Depression,
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譬如在美國大蕭條時期，
00:25
they created the Hoover Dam,
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他們建造出胡佛水壩，
00:26
which in turn, created Lake Mead
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也因而造出人工湖米德湖，
00:29
and made it possible for the cities
of Las Vegas and Phoenix
of Las Vegas and Phoenix
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能為拉斯維加斯、鳳凰城
00:32
and Los Angeles to provide water
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及洛杉磯供水，
00:34
for people who lived
in a really dry place.
in a really dry place.
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讓大家能住在很乾燥的地方。
00:37
In the 20th century,
we literally spent trillions of dollars
we literally spent trillions of dollars
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20 世紀時，
我們確實花了幾兆美元
我們確實花了幾兆美元
00:41
building infrastructure
to get water to our cities.
to get water to our cities.
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做基礎建設送水到城市。
00:45
In terms of economic development,
it was a great investment.
it was a great investment.
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以經濟發展而言，
這是一項偉大的投資。
這是一項偉大的投資。
00:49
But in the last decade,
we've seen the combined effects
we've seen the combined effects
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但是在過去十年，
我們看到氣候變遷
我們看到氣候變遷
00:52
of climate change, population growth
and competition for water resources
and competition for water resources
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與人口成長的綜合影響，
而對水資源的競爭
而對水資源的競爭
00:57
threaten these vital lifelines
and water resources.
and water resources.
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威脅到這些重要的
命脈及水資源。
命脈及水資源。
01:01
This figure shows you the change
in the lake level of Lake Mead
in the lake level of Lake Mead
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這張表顯示米德湖水位
01:05
that happened in the last 15 years.
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在過去十五年的變化。
01:07
You can see starting around the year 2000,
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大家可以看到
大約從 2000 年開始，
大約從 2000 年開始，
01:10
the lake level started to drop.
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水位開始下降。
01:12
And it was dropping at such a rate
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下降幅度之快，
01:14
that it would have left the drinking water
intakes for Las Vegas high and dry.
intakes for Las Vegas high and dry.
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讓拉斯維加斯飲用水取水口
遠高過湖水位並乾涸。
遠高過湖水位並乾涸。
01:18
The city became so concerned about this
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該市非常擔心，
01:21
that they recently constructed
a new drinking water intake structure
a new drinking water intake structure
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因此他們最近新建了
一個飲用水取水口，
一個飲用水取水口，
01:25
that they referred to as the "Third Straw"
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他們稱之為「第三根吸管」，
01:27
to pull water out
of the greater depths of the lake.
of the greater depths of the lake.
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從愈來愈低的湖中取水。
01:31
The challenges associated
with providing water to a modern city
with providing water to a modern city
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供水給現代都市所面臨的挑戰
01:34
are not restricted
to the American Southwest.
to the American Southwest.
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並非只限於美南地區。
01:37
In the year 2007, the third largest
city in Australia, Brisbane,
city in Australia, Brisbane,
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2007 年，澳洲
第三大都市布里斯本
第三大都市布里斯本
01:43
came within 6 months
of running out of water.
of running out of water.
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缺水缺了六個月。
01:46
A similar drama is playing out today
in São Paulo, Brazil,
in São Paulo, Brazil,
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今天類似的情景
也在巴西聖保羅上演，
也在巴西聖保羅上演，
01:50
where the main reservoir for the city
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該市的主要水庫
01:52
has gone from being
completely full in 2010,
completely full in 2010,
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從 2010 年滿水位狀況，
01:55
to being nearly empty today
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到今天幾乎完全乾涸，
01:57
as the city approaches
the 2016 Summer Olympics.
the 2016 Summer Olympics.
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而該市正準備舉行
2016 年夏季奧運會。
2016 年夏季奧運會。
02:01
For those of us who are fortunate enough
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對我們這些有幸住在世界
02:04
to live in one
of the world's great cities,
of the world's great cities,
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各個重大都市的人而言，
02:06
we've never truly experienced
the effects of a catastrophic drought.
the effects of a catastrophic drought.
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我們從未真正體驗過
毀滅性的旱災。
毀滅性的旱災。
02:10
We like to complain
about the navy showers we have to take.
about the navy showers we have to take.
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我們抱怨要洗戰鬥澡。
02:14
We like our neighbors to see
our dirty cars and our brown lawns.
our dirty cars and our brown lawns.
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我們喜歡讓鄰居看見
我們的髒車及枯黃的草皮。
我們的髒車及枯黃的草皮。
02:18
But we've never really faced
the prospect of turning on the tap
the prospect of turning on the tap
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但是我們從未真正面對過
打開水龍頭
卻無水可用的窘境。
卻無水可用的窘境。
02:22
and having nothing come out.
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02:24
And that's because when things
have gotten bad in the past,
have gotten bad in the past,
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這是因為過去情況變糟時，
02:27
it's always been possible
to expand a reservoir
to expand a reservoir
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我們總是有辦法擴建水庫，
02:30
or dig a few more groundwater wells.
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或挖更多口地下水井。
02:34
Well, in a time when all
of the water resources are spoken for,
of the water resources are spoken for,
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在所有水資源
都已開發殆盡的年代，
都已開發殆盡的年代，
02:37
it's not going to be possible
to rely on this tried and true way
to rely on this tried and true way
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我們不可能再依賴這種
已知可行的方法
已知可行的方法
02:41
of providing ourselves with water.
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來提供用水。
02:43
Some people think that we're going
to solve the urban water problem
to solve the urban water problem
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有些人認為我們可以
向都市四周有水源的地主借水
向都市四周有水源的地主借水
02:47
by taking water from our rural neighbors.
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以解決都市的供水問題。
02:50
But that's an approach that's fraught
with political, legal and social dangers.
with political, legal and social dangers.
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但是這個方法伴隨著
政治、法律及社會威脅。
政治、法律及社會威脅。
02:56
And even if we succeed in grabbing
the water from our rural neighbors,
the water from our rural neighbors,
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即使我們能從四周鄰居
成功搶到水，
成功搶到水，
03:00
we're just transferring
the problem to someone else
the problem to someone else
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我們只是把問題轉移給別人，
03:02
and there's a good chance
it will come back and bite us
it will come back and bite us
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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，
回頭反咬我們一口，
03:05
in the form of higher food prices
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03:07
and damage to the aquatic ecosystems
that already rely upon that water.
that already rely upon that water.
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並破壞靠此水為生的
水生生態系。
水生生態系。
03:12
I think that there's a better way
to solve our urban water crisis
to solve our urban water crisis
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我認為有更好的方法
解決都市的水危機，
解決都市的水危機，
03:15
and I think that's to open up
four new local sources of water
four new local sources of water
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而方法就是開拓四種
新的當地水資源，
新的當地水資源，
03:19
that I liken to faucets.
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我比作打開水龍頭。
03:21
If we can make smart investments
in these new sources of water
in these new sources of water
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如果我們可以明智地
投資在這些新的水資源上，
投資在這些新的水資源上，
03:25
in the coming years,
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在未來幾年，
03:27
we can solve our urban water problem
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我們就能解決都市水問題，
03:29
and decrease the likelihood
that we'll ever run across
that we'll ever run across
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並減低我們碰到
03:32
the effects of a catastrophic drought.
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毀滅性旱災後果的可能性。
03:36
Now, if you told me 20 years ago
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如果你在 20 年前跟我說
03:38
that a modern city could exist
without a supply of imported water,
without a supply of imported water,
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一個現代化都市
不用從外面引水也可以生存，
不用從外面引水也可以生存，
03:42
I probably would have dismissed you
as an unrealistic and uninformed dreamer.
as an unrealistic and uninformed dreamer.
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我大概會把你打發走，
說你是不切實際又無知的空想家。
說你是不切實際又無知的空想家。
03:47
But my own experiences
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但是依我自己的經驗，
03:48
working with some of the world's most
water-starved cities in the last decades
water-starved cities in the last decades
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在過去幾十年與世界上
幾個非常缺水的都市合作後，
幾個非常缺水的都市合作後，
03:53
have shown me that we have
the technologies and the management skills
the technologies and the management skills
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讓我知道我們的確有
科技與管理技巧
科技與管理技巧
03:57
to actually transition away
from imported water,
from imported water,
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能真的轉變到不用從外面引水，
04:00
and that's what I want
to tell you about tonight.
to tell you about tonight.
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這也是我今晚的主題。
04:03
The first source of local water
supply that we need to develop
supply that we need to develop
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我們第一個要打開的
當地供水資源
當地供水資源
04:07
to solve our urban water problem
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以解決我們的都市水問題，
04:09
will flow with the rainwater
that falls in our cities.
that falls in our cities.
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會流出降在都市內的雨水。
04:13
One of the great tragedies
of urban development
of urban development
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都市發展的大悲劇之一，
04:16
is that as our cities grew,
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就是隨著都市成長，
04:18
we started covering all the surfaces
with concrete and asphalt.
with concrete and asphalt.
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我們以混凝土及瀝青
覆蓋所有的表面。
覆蓋所有的表面。
04:22
And when we did that,
we had to build storm sewers
we had to build storm sewers
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在我們如此做的同時，
又必須蓋雨水下水道
又必須蓋雨水下水道
04:24
to get the water
that fell on the cities out
that fell on the cities out
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將降下的雨水排到都市外，
04:26
before it could cause flooding,
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不然會引起水災，
04:28
and that's a waste
of a vital water resource.
of a vital water resource.
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這浪費了我們重要的水資源。
04:32
Let me give you an example.
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舉一個例子，
04:33
This figure here shows you
the volume of water
the volume of water
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這張表顯示
04:37
that could be collected
in the city of San Jose
in the city of San Jose
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在矽谷聖荷西市
能收集的雨水水量，
能收集的雨水水量，
04:39
if they could harvest the stormwater
that fell within the city limits.
that fell within the city limits.
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只要他們能把市區範圍內的
雨水全都收集起來。
雨水全都收集起來。
04:43
You can see from the intersection
of the blue line and the black dotted line
of the blue line and the black dotted line
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從藍線與黑點線的交點可以看到
04:48
that if San Jose could just capture half
of the water that fell within the city,
of the water that fell within the city,
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聖荷西只要能收集
降在市區範圍內一半的雨水，
降在市區範圍內一半的雨水，
04:52
they'd have enough water
to get them through an entire year.
to get them through an entire year.
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就有足夠的水撐過一整年。
04:56
Now, I know what some of you
are probably thinking.
are probably thinking.
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我知道有些人可能會這麼想：
04:58
"The answer to our problem
is to start building great big tanks
is to start building great big tanks
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「那我們的解決方案就是
開始裝幾個大桶子，
開始裝幾個大桶子，
05:02
and attaching them
to the downspouts of our roof gutters,
to the downspouts of our roof gutters,
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與簷槽的雨落水管相連，
05:05
rainwater harvesting."
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收集雨水。」
05:07
Now, that's an idea
that might work in some places.
that might work in some places.
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這個想法在某些地方或許可行。
05:09
But if you live in a place
where it mainly rains in the winter time
where it mainly rains in the winter time
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但是如果你住的地方
雨季主要在冬天，
雨季主要在冬天，
05:12
and most of the water demand
is in the summertime,
is in the summertime,
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最需要水的時候卻是夏天，
05:15
it's not a very cost-effective way
to solve a water problem.
to solve a water problem.
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這就不是非常
具經濟效益的解決方法。
具經濟效益的解決方法。
05:19
And if you experience the effects
of a multiyear drought,
of a multiyear drought,
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如果你經歷多年旱災的影響，
05:22
like California's currently experiencing,
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像加州現在一樣，
05:24
you just can't build a rainwater tank
that's big enough to solve your problem.
that's big enough to solve your problem.
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你不可能蓋一個夠大的
雨水儲槽來解決問題。
雨水儲槽來解決問題。
05:28
I think there's a lot more practical way
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我想有很多更實際的方式
05:30
to harvest the stormwater and
the rainwater that falls in our cities,
the rainwater that falls in our cities,
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能收集降在市區範圍內的雨水，
05:34
and that's to capture it
and let it percolate into the ground.
and let it percolate into the ground.
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那就是要留住雨水
並滲透到地下。
並滲透到地下。
05:37
After all, many of our cities are sitting
on top of a natural water storage system
on top of a natural water storage system
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畢竟，許多城市
都位於天然儲水系統上方，
都位於天然儲水系統上方，
05:43
that can accommodate
huge volumes of water.
huge volumes of water.
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能容納大量的水。
05:46
For example, historically,
Los Angeles has obtained
Los Angeles has obtained
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舉例而言，
歷史上洛杉磯曾經
歷史上洛杉磯曾經
05:49
about a third of its water supply
from a massive aquifer
from a massive aquifer
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從聖費爾南多谷下方的蓄水層
取得約三分之一的供水。
取得約三分之一的供水。
05:52
that underlies the San Fernando Valley.
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05:56
Now, when you look at the water
that comes off of your roof
that comes off of your roof
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現在，當你看著屋頂上的水
05:59
and runs off of your lawn
and flows down the gutter,
and flows down the gutter,
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流過你的草坪，從屋簷流下，
06:01
you might say to yourself,
"Do I really want to drink that stuff?"
"Do I really want to drink that stuff?"
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你大概會對自己說：
「那種水真的能喝嗎？」
「那種水真的能喝嗎？」
06:05
Well, the answer is
you don't want to drink it
you don't want to drink it
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答案是你不想喝那種水，
06:07
until it's been treated a little bit.
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除非這水經過一些處理。
06:09
And so the challenge that we face
in urban water harvesting
in urban water harvesting
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所以我們收集都市雨水
要面對的挑戰，
要面對的挑戰，
06:12
is to capture the water, clean the water
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就是要把水留住、弄乾淨
06:15
and get it underground.
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並存入地下。
06:17
And that's exactly
what the city of Los Angeles is doing
what the city of Los Angeles is doing
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這正是洛杉磯市目前正在執行的，
06:20
with a new project that they're building
in Burbank, California.
in Burbank, California.
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他們在柏本克市興建一項新計畫。
06:24
This figure here shows
the stormwater park that they're building
the stormwater park that they're building
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這張圖是他們正在興建的
雨水處理廠，
雨水處理廠，
06:28
by hooking a series of stormwater
collection systems, or storm sewers,
collection systems, or storm sewers,
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他們將一系列的雨水收集系統
即雨水下水道連接起來，
即雨水下水道連接起來，
06:33
and routing that water
into an abandoned gravel quarry.
into an abandoned gravel quarry.
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將收集的水導入一座
廢棄的採石場。
廢棄的採石場。
06:37
The water that's captured in the quarry
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在此採石場收集到的水，
06:39
is slowly passed
through a man-made wetland,
through a man-made wetland,
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會慢慢流經一座人造溼地，
06:42
and then it goes
into that ball field there
into that ball field there
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然後進入那塊沙洲，
06:44
and percolates into the ground,
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再滲入地面，
06:46
recharging the drinking water
aquifer of the city.
aquifer of the city.
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補注該市的飲用水蓄水層。
06:49
And in the process
of passing through the wetland
of passing through the wetland
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在通過溼地
06:52
and percolating through the ground,
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及滲入地下的過程中，
06:54
the water encounters microbes
that live on the surfaces of the plants
that live on the surfaces of the plants
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水會碰到存在於植物表面
06:58
and the surfaces of the soil,
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及土表的微生物，
06:59
and that purifies the water.
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這會淨化水。
07:02
And if the water's
still not clean enough to drink
still not clean enough to drink
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如果這些水仍然
不夠乾淨到能喝的程度，
不夠乾淨到能喝的程度，
07:04
after it's been through
this natural treatment process,
this natural treatment process,
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在這項天然的處理過程之後，
07:07
the city can treat it again
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該市會再處理一次，
07:08
when they pump if back out
of the groundwater aquifers
of the groundwater aquifers
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他們從地下水層抽水出來，
07:11
before they deliver it to people to drink.
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處裡後再供水給大家喝。
07:14
The second tap that we need to open up
to solve our urban water problem
to solve our urban water problem
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我們要解決都市水問題
該開的第二個水龍頭
該開的第二個水龍頭
07:18
will flow with the wastewater
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會流出廢水，
07:20
that comes out
of our sewage treatment plants.
of our sewage treatment plants.
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從我們的汙水處理廠出來。
07:23
Now, many of you are probably familiar
with the concept of recycled water.
with the concept of recycled water.
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在座很多人大概還滿熟悉
再生水（中水）的概念。
再生水（中水）的概念。
07:26
You've probably seen signs like this
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你大概看過像這樣的標誌，
07:28
that tell you that the shrubbery
and the highway median
and the highway median
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顯示這塊灌木叢、
高速公路的中央安全島、
高速公路的中央安全島、
07:31
and the local golf course
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還有家附近的高爾夫球場
07:33
is being watered with water
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都用再生水灌溉，
07:35
that used to be
in a sewage treatment plant.
in a sewage treatment plant.
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從汙水處理廠裡流出來。
07:38
We've been doing this
for a couple of decades now.
for a couple of decades now.
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這早已行之有年。
07:41
But what we're learning
from our experience
from our experience
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但是我們從經驗得知
07:43
is that this approach is much more
expensive that we expected it to be.
expensive that we expected it to be.
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這個方式遠比我們預期的貴很多。
07:47
Because once we build
the first few water recycling systems
the first few water recycling systems
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因為一旦我們蓋了
頭幾座再生水系統廠，
頭幾座再生水系統廠，
07:50
close to the sewage treatment plant,
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位於汙水處理廠附近，
07:52
we have to build longer
and longer pipe networks
and longer pipe networks
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我們就必須接愈來愈長的管線
07:54
to get that water to where it needs to go.
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把水輸送到該去的地方。
07:57
And that becomes prohibitive
in terms of cost.
in terms of cost.
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這會讓人卻步，因為成本過高。
08:00
What we're finding is
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我們發現
08:02
that a much more cost-effective
and practical way of recycling wastewater
and practical way of recycling wastewater
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更具經濟效益
及更實際的再生廢水方法，
及更實際的再生廢水方法，
08:06
is to turn treated wastewater
into drinking water
into drinking water
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是把處理過的廢水變成飲水，
08:08
through a two-step process.
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這要透過二個處理步驟。
08:11
In the first step in this process
we pressurize the water
we pressurize the water
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第一步是將水加壓
08:14
and pass it through
a reverse osmosis membrane:
a reverse osmosis membrane:
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讓它通過逆滲透膜：
08:16
a thin, permeable plastic membrane
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那是一層可滲透的塑膠薄膜，
08:19
that allows water molecules
to pass through
to pass through
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讓水分子通過，
08:21
but traps and retains the salts,
the viruses and the organic chemicals
the viruses and the organic chemicals
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但是會抓住及留住鹽分、
病毒及有機化學物質，
病毒及有機化學物質，
08:26
that might be present in the wastewater.
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這些東西可能存在於廢水中。
08:29
In the second step in the process,
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處理過程的第二步
08:31
we add a small amount of hydrogen peroxide
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是注入少量的過氧化氫
08:33
and shine ultraviolet light on the water.
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及照射紫外線。
08:36
The ultraviolet light
cleaves the hydrogen peroxide
cleaves the hydrogen peroxide
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紫外線會分解過氧化氫
08:39
into two parts that are called
hydroxyl radicals,
hydroxyl radicals,
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成為兩個氫氧自由基，
08:42
and these hydroxyl radicals
are very potent forms of oxygen
are very potent forms of oxygen
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氫氧自由基
是非常有力的氧形式，
是非常有力的氧形式，
08:46
that break down most organic chemicals.
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會分解大部分的有機化學物質。
08:50
After the water's been
through this two-stage process,
through this two-stage process,
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水經過這兩個步驟處理後，
08:53
it's safe to drink.
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可以安全飲用。
08:54
I know,
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我知道，
08:56
I've been studying recycled water
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我利用所有現代科學
已知的測量技術
已知的測量技術
08:58
using every measurement technique
known to modern science
known to modern science
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研究再生水
09:02
for the past 15 years.
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研究了 15 年。
09:04
We've detected some chemicals
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我們偵測到某些化學物品
09:05
that can make it through
the first step in the process,
the first step in the process,
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可以通過此處理過程的第一步，
09:08
but by the time we get to the second step,
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但是到了第二步，
09:10
the advanced oxidation process,
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即高級氧化程序，
09:12
we rarely see any chemicals present.
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我們很難再看到任何化學物品。
09:14
And that's in stark contrast
to the taken-for-granted water supplies
to the taken-for-granted water supplies
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這與我們天天飲用、
視為理所當然的自來水
視為理所當然的自來水
09:18
that we regularly drink all the time.
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形成鮮明對比。
09:21
There's another way we can recycle water.
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還有一種方法可以再生水。
09:24
This is an engineered treatment wetland
that we recently built
that we recently built
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這是我們剛興建的人工溼地，
09:27
on the Santa Ana River
in Southern California.
in Southern California.
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位於南加州聖塔安娜河。
09:30
The treatment wetland receives water
from a part of the Santa Ana River
from a part of the Santa Ana River
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這座人工溼地接收
從聖塔安娜河部分河段進來的水，
從聖塔安娜河部分河段進來的水，
09:34
that in the summertime consists
almost entirely of wastewater effluent
almost entirely of wastewater effluent
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夏天時幾乎全是廢汙水，
09:38
from cities like Riverside
and San Bernardino.
and San Bernardino.
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由河濱市及聖伯那地諾市等地排放。
09:41
The water comes
into our treatment wetland,
into our treatment wetland,
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廢汙水進入我們的處理溼地，
09:43
it's exposed to sunlight and algae
189
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曝露於陽光及藻類下，
09:45
and those break down
the organic chemicals,
the organic chemicals,
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這個過程會分解有機化學物，
09:48
remove the nutrients
and inactivate the waterborne pathogens.
and inactivate the waterborne pathogens.
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去除營養物
並使水媒病原體失去活性。
並使水媒病原體失去活性。
09:51
The water gets put back
in the Santa Ana River,
in the Santa Ana River,
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該水再流放回聖塔安納河，
09:54
it flows down to Anaheim,
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往下流到安納罕，
09:56
gets taken out at Anaheim
and percolated into the ground,
and percolated into the ground,
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然後在安納罕滲透入地面，
09:59
and becomes the drinking water
of the city of Anaheim,
of the city of Anaheim,
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並成為安納罕市的飲水，
10:01
completing the trip
from the sewers of Riverside County
from the sewers of Riverside County
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3936
是一趟從河濱縣的廢汙水
10:05
to the drinking water supply
of Orange County.
of Orange County.
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轉變成橘縣飲用水的完美旅程。
10:09
Now, you might think
that this idea of drinking wastewater
that this idea of drinking wastewater
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你可能會認為
這種喝廢水的想法
這種喝廢水的想法
10:13
is some sort of futuristic fantasy
or not commonly done.
or not commonly done.
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是某種未來的幻想
或不常見。
或不常見。
10:16
Well, in California, we already recycle
about 40 billion gallons a year
about 40 billion gallons a year
200
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但是在加州，我們每年
已再生一千五百多億公升廢水，
已再生一千五百多億公升廢水，
10:21
of wastewater through the two-stage
advanced treatment process
advanced treatment process
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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，
二階段式的高級氧化處理過程再生，
10:24
I was telling you about.
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10:25
That's enough water to be
the supply of about a million people
the supply of about a million people
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3736
這個量足夠提供
大約一百萬人使用，
大約一百萬人使用，
10:29
if it were their sole water supply.
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如果這是他們唯一的水源。
10:32
The third tap that we need to open up
will not be a tap at all,
will not be a tap at all,
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4216
我們必須打開的第三個水龍頭
跟水龍頭一點關係都沒有，
跟水龍頭一點關係都沒有，
10:36
it will be a kind of virtual tap,
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它是虛擬的水龍頭，
10:38
it will be the water conservation
that we manage to do.
that we manage to do.
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3096
它就是我們能做到的節約用水。
10:41
And the place where we need to think
about water conservation is outdoors
about water conservation is outdoors
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我們要思索
如何節約的地方是戶外，
如何節約的地方是戶外，
10:44
because in California
and other modern American cities,
and other modern American cities,
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因為在加州
及美國其它現代都市，
及美國其它現代都市，
10:48
about half of our water use
happens outdoors.
happens outdoors.
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我們的水有一半用在戶外。
10:51
In the current drought,
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目前的乾旱
10:53
we've seen that it's possible
212
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讓我們看見
10:54
to have our lawns survive
and our plants survive
and our plants survive
213
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要讓草皮及植物生存，
10:57
with about half as much water.
214
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1896
只要以往一半的水就夠了，
10:59
So there's no need
to start painting concrete green
to start painting concrete green
215
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3016
所以實在不需要
把門前車道噴成綠色、
把門前車道噴成綠色、
11:02
and putting in Astroturf
and buying cactuses.
and buying cactuses.
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3096
鋪上人工草皮及買仙人掌。
11:05
We can have California-friendly
landscaping with soil moisture detectors
landscaping with soil moisture detectors
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653920
4216
我們可以用適合加州的園藝造景，
裝上土壤水分偵測器
裝上土壤水分偵測器
11:10
and smart irrigation controllers
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1896
及智慧型澆水控制器，
11:12
and have beautiful
green landscapes in our cities.
green landscapes in our cities.
219
660080
2440
就能在城市裡有美麗的綠色園景。
11:15
The fourth and final water tap
that we need to open up
that we need to open up
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663760
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我們要開的第四個
也是最後一個水龍頭
也是最後一個水龍頭
11:18
to solve our urban water problem
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以解決都市水問題，
11:20
will flow with desalinated seawater.
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會流出海水淡化水。
11:23
Now, I know what you probably heard
people say about seawater desalination.
people say about seawater desalination.
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671360
3976
我知道你們大概聽過
別人這樣說海水淡化：
別人這樣說海水淡化：
11:27
"It's a great thing to do if you have
lots of oil, not a lot of water
lots of oil, not a lot of water
224
675360
4176
「如果你有大量石油，
卻沒有大量的水，
卻沒有大量的水，
11:31
and you don't care about climate change."
225
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2376
而且你也不在乎氣候變遷，
那這是件好事。」
那這是件好事。」
11:33
Seawater desalination is energy-intensive
no matter how you slice it.
no matter how you slice it.
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681960
4336
無論你怎麼看，
海水淡化都非常耗能。
海水淡化都非常耗能。
11:38
But that characterization
of seawater desalination
of seawater desalination
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但是把海水淡化視為
11:40
as being a nonstarter
is hopelessly out of date.
is hopelessly out of date.
228
688960
3016
毫無前途
是無可救藥的過時想法。
是無可救藥的過時想法。
11:43
We've made tremendous progress
in seawater desalination
in seawater desalination
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海水淡化在過去二十年
已有長足進步。
已有長足進步。
11:46
in the past two decades.
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694800
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11:48
This picture shows you
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這張照片上面
11:50
the largest seawater desalination plant
in the Western hemisphere
in the Western hemisphere
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3976
是西半球最大的海水淡化廠，
11:54
that's currently being built
north of San Diego.
north of San Diego.
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702600
2816
目前正在聖地牙哥北邊興建。
11:57
Compared to the seawater
desalination plant
desalination plant
234
705440
2256
與另一座海水淡化廠相比，
11:59
that was built in
Santa Barbara 25 years ago,
Santa Barbara 25 years ago,
235
707720
3296
25 年前建於聖塔芭芭拉，
12:02
this treatment plant
will use about half the energy
will use about half the energy
236
711040
2656
這座處理廠生產一加侖的水
12:05
to produce a gallon of water.
237
713720
1520
只要用約一半的能量。
12:07
But just because seawater desalination
has become less energy-intensive,
has become less energy-intensive,
238
715840
3736
但是就算海水淡化
現在比較不那麼耗能，
現在比較不那麼耗能，
12:11
doesn't mean we should start building
desalination plants everywhere.
desalination plants everywhere.
239
719600
3239
也不代表我們就該在四處
開始興建處理廠。
開始興建處理廠。
12:14
Among the different choices we have,
240
722863
1736
在我們各種選項中，
12:16
it's probably the most energy-intensive
241
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2113
這大概是最耗能源、
12:18
and potentially environmentally damaging
242
726760
1936
最破壞環境的一種方法
12:20
of the options to create
a local water supply.
a local water supply.
243
728720
2920
來創造當地水資源。
12:24
So there it is.
244
732560
1216
情況就是這樣。
12:25
With these four sources of water,
245
733800
1776
開了這四個水龍頭，
12:27
we can move away
from our reliance on imported water.
from our reliance on imported water.
246
735600
3320
我們就不需仰賴外地引水。
12:31
Through reform in the way we landscape
our surfaces and our properties,
our surfaces and our properties,
247
739680
4496
透過改良我們園藝造景的方法，
12:36
we can reduce outdoor water use
by about 50 percent,
by about 50 percent,
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744200
3096
我們可以節省
約 50% 的戶外用水，
約 50% 的戶外用水，
12:39
thereby increasing
the water supply by 25 percent.
the water supply by 25 percent.
249
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3456
因而增加 25% 的供水。
12:42
We can recycle the water
that makes it into the sewer,
that makes it into the sewer,
250
750800
2524
我們可以再生廢汙水，
12:45
thereby increasing
our water supply by 40 percent.
our water supply by 40 percent.
251
753348
3080
因而增加 40% 供水。
12:48
And we can make up the difference
through a combination
through a combination
252
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2616
我們也可以透過結合
12:51
of stormwater harvesting
and seawater desalination.
and seawater desalination.
253
759520
2480
收集雨水及海水淡化補足供水量。
12:55
So, let's create a water supply
254
763280
3816
所以，讓我們創造一套
12:59
that will be able
to withstand any of the challenges
to withstand any of the challenges
255
767120
3656
能夠承受任何挑戰的供水法，
13:02
that climate change throws at us
in the coming years.
in the coming years.
256
770800
2576
在未來幾年能因應
氣候變遷帶來的挑戰。
氣候變遷帶來的挑戰。
13:05
Let's create a water supply
that uses local sources
that uses local sources
257
773400
3336
讓我們創造一套使用當地水資源
13:08
and leaves more water
in the environment for fish and for food.
in the environment for fish and for food.
258
776760
4040
並能在環境中留更多水
給魚類、給糧食用的方法。
給魚類、給糧食用的方法。
13:13
Let's create a water system that's
consistent with out environmental values.
consistent with out environmental values.
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781640
5016
讓我們創造一套能與
環境價值相符合的供水系統。
環境價值相符合的供水系統。
13:18
And let's do it for our children
and our grandchildren
and our grandchildren
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讓我們為子孫做這件事，
13:22
and let's tell them this is the system
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並告訴他們
未來他們要好好照顧這套系統，
13:24
that they have to
take care of in the future
take care of in the future
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13:27
because it's our last chance
to create a new kind of water system.
to create a new kind of water system.
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因為這是我們創造
新式供水系統的最後機會。
新式供水系統的最後機會。
13:31
Thank you very much for your attention.
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謝謝大家專心聆聽。
13:32
(Applause)
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（掌聲）
ABOUT THE SPEAKER
David Sedlak - Civil and environmental engineerDavid Sedlak’s research focuses the long-term goal of developing cost-effective, safe and sustainable systems to manage water resources.
Why you should listen
Author, Professor and Director of the Institute for Environmental Science and Engineering at UC Berkeley, David Sedlak has developed cost-effective, safe and sustainable systems to manage water resources. He is particularly interested in the development of local sources of water, and his research has addressed water reuse–the practice of using municipal wastewater effluent to sustain aquatic ecosystems and augment drinking water supplies as well as the treatment and use of urban runoff to contaminated groundwater from contaminated industrial sites as water supplies.
In recent years, Sedlak's research on the fate of wastewater-derived contaminants has received considerable attention. He began this research in 1996 when he developed simple methods for measuring steroid hormones in wastewater. Since that time, he and his students have studied the fate of hormones, pharmaceuticals, toxic disinfection byproducts and other chemicals. His research team has also studied approaches for remediating contaminated soil and groundwater by in situ chemical oxidation (ISCO) and advanced oxidation processes.
He also is the author of Water 4.0, a book that examines the ways in which we can gain insight into current water issues by understanding the history of urban water systems.
David Sedlak | Speaker | TED.com