TEDxMarin
David Sedlak: 4 ways we can avoid a catastrophic drought
大卫•塞德拉克: 避免大旱灾的4种方法
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随着世界气候持续变化无常，那些曾经水资源丰富的地方，可能转眼间就会水库干涸，地下水资源枯竭。在此次演讲中，民用和环境工程师大卫•塞德拉克与我们分享了解决城市用水危机的4种实用方案。他的目标是：将我们的水源供应定位于新的、本地水源，并且创建新的供水系统，能够承受住未来气候变化给我们带来的挑战。
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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我们爷爷那一代人，
00:16
of canals and reservoirs
that made it possible
that made it possible
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修建了伟大的运河和水库系统，
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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让人们可以在缺水的地方正常生活。
00:22
For example, during the Great Depression,
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比如在大萧条时代，
00:25
they created the Hoover Dam,
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他们修建了胡佛水坝，
00:26
which in turn, created Lake Mead
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拦下的水形成了米德湖，
00:29
and made it possible for the cities
of Las Vegas and Phoenix
of Las Vegas and Phoenix
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为几个位于干旱地区的城市，
比如拉斯维加斯、凤凰城
比如拉斯维加斯、凤凰城
00:32
and Los Angeles to provide water
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和洛杉矶供水，
00:34
for people who lived
in a really dry place.
in a really dry place.
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让那里的市民有水可用。
00:37
In the 20th century,
we literally spent trillions of dollars
we literally spent trillions of dollars
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在二十世纪，我们花费了数万亿美元，
00:41
building infrastructure
to get water to our cities.
to get water to our cities.
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为我们的城市修建供水系统。
00:45
In terms of economic development,
it was a great investment.
it was a great investment.
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对经济发展而言，这是笔不错的投资。
00:49
But in the last decade,
we've seen the combined effects
we've seen the combined effects
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但在过去几十年间，我们看到
00:52
of climate change, population growth
and competition for water resources
and competition for water resources
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气候变化、人口增长
和水资源争夺带来的后果，
和水资源争夺带来的后果，
00:57
threaten these vital lifelines
and water resources.
and water resources.
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已经威胁到我们赖以生存的水资源。
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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这张图表显示的是米德湖的水位
01:05
that happened in the last 15 years.
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在过去15年的变化情况。
01:07
You can see starting around the year 2000,
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差不多从2000年开始，
01:10
the lake level started to drop.
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水位开始下降。
01:12
And it was dropping at such a rate
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下降的速度如此之快，
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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很快，为拉斯维加斯
供水的管道将抽不到水。
供水的管道将抽不到水。
01:18
The city became so concerned about this
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拉斯维加斯很担心这一点
01:21
that they recently constructed
a new drinking water intake structure
a new drinking water intake structure
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他们最近铺设了一条新的抽水管道，
01:25
that they referred to as the "Third Straw"
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称之为“第三吸管”，
01:27
to pull water out
of the greater depths of the lake.
of the greater depths of the lake.
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从湖的更深处抽水。
01:31
The challenges associated
with providing water to a modern city
with providing water to a modern city
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向现代都市供水的难题
01:34
are not restricted
to the American Southwest.
to the American Southwest.
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不仅仅发生在美国西南部。
01:37
In the year 2007, the third largest
city in Australia, Brisbane,
city in Australia, Brisbane,
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2007年，澳大利亚第三大城市，布里斯班，
01:43
came within 6 months
of running out of water.
of running out of water.
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整整6个月无水可用。
01:46
A similar drama is playing out today
in São Paulo, Brazil,
in São Paulo, Brazil,
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同样的情况也在巴西圣保罗上演，
01:50
where the main reservoir for the city
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圣市最主要的水库
01:52
has gone from being
completely full in 2010,
completely full in 2010,
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在2010年还几乎全满，
01:55
to being nearly empty today
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如今已几乎见底，
01:57
as the city approaches
the 2016 Summer Olympics.
the 2016 Summer Olympics.
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而他们还将举办2016夏季奥运会。
02:01
For those of us who are fortunate enough
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我们足够幸运，
02:04
to live in one
of the world's great cities,
of the world's great cities,
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能够生活在世界上最伟大的城市之一，
02:06
we've never truly experienced
the effects of a catastrophic drought.
the effects of a catastrophic drought.
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我们从未真正经历过大旱灾。
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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我们会抱怨洗澡的水不够大。
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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我们也经常不洗车，不浇草坪。
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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但我们从未经历过拧开水龙头，
02:22
and having nothing come out.
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却无水可用的状况。
02:24
And that's because when things
have gotten bad in the past,
have gotten bad in the past,
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因为在过去，如果发生这样的事情，
02:27
it's always been possible
to expand a reservoir
to expand a reservoir
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我们总是能把水库修得更大些，
02:30
or dig a few more groundwater wells.
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或者多挖几口水井。
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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但如果所有的水资源都枯竭了，
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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那这种曾经屡试不爽的老办法
02:41
of providing ourselves with water.
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可能就不适用了。
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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有些人觉得，要解决城市用水问题，
02:47
by taking water from our rural neighbors.
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从临近的农村取水就好了。
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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但这种方法充满了
政治、法律和社会风险。
政治、法律和社会风险。
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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即便我们能从农村取水，
03:00
we're just transferring
the problem to someone else
the problem to someone else
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那也不过是将问题转嫁到了别人头上，
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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而且很有可能，它会反噬到我们身上
03:05
in the form of higher food prices
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要么会抬高食品价格，
03:07
and damage to the aquatic ecosystems
that already rely upon that water.
that already rely upon that water.
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要么会破坏水生生态系统。
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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我认为可以用更好的办法
来解决我们的城市用水危机，
来解决我们的城市用水危机，
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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就是下面我将要说的4种新水源，
03:19
that I liken to faucets.
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我把它们比作4个水龙头。
03:21
If we can make smart investments
in these new sources of water
in these new sources of water
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在未来数年里，如果我们
能对这4种新水源
能对这4种新水源
03:25
in the coming years,
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进行明智的投资，
03:27
we can solve our urban water problem
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我们就能解决城市用水问题，
03:29
and decrease the likelihood
that we'll ever run across
that we'll ever run across
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使我们遭遇大旱灾的可能性
03:32
the effects of a catastrophic drought.
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大大降低。
03:36
Now, if you told me 20 years ago
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如果在20年前，你告诉我，
03:38
that a modern city could exist
without a supply of imported water,
without a supply of imported water,
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现代城市可以在没有
外来水源的情况下得以发展，
外来水源的情况下得以发展，
03:42
I probably would have dismissed you
as an unrealistic and uninformed dreamer.
as an unrealistic and uninformed dreamer.
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我可能会觉得你是痴人说梦。
03:47
But my own experiences
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但在过去的几十年里，
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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我一直在世界上最缺水的城市工作，
03:53
have shown me that we have
the technologies and the management skills
the technologies and the management skills
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这段经历告诉我，我们的技术和管理能力
03:57
to actually transition away
from imported water,
from imported water,
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已经可以不依赖于外来水源，
04:00
and that's what I want
to tell you about tonight.
to tell you about tonight.
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这就是今晚我想跟大家分享的。
04:03
The first source of local water
supply that we need to develop
supply that we need to develop
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要解决城市用水问题，
04:07
to solve our urban water problem
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我们需要发展的第一种本地新水源
04:09
will flow with the rainwater
that falls in our cities.
that falls in our cities.
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就是从天而降的雨水。
04:13
One of the great tragedies
of urban development
of urban development
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城市发展带来的最大灾难之一，
04:16
is that as our cities grew,
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就是随着城市越变越大，
04:18
we started covering all the surfaces
with concrete and asphalt.
with concrete and asphalt.
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我们将所有地面都用
水泥和沥青覆盖起来了。
水泥和沥青覆盖起来了。
04:22
And when we did that,
we had to build storm sewers
we had to build storm sewers
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这样一来，我们必须修建巨大的排水管道，
04:24
to get the water
that fell on the cities out
that fell on the cities out
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将落在城市里的雨水排出去，
04:26
before it could cause flooding,
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以免引发洪灾，
04:28
and that's a waste
of a vital water resource.
of a vital water resource.
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这对水资源是极大的浪费。
04:32
Let me give you an example.
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让我来举个例子。
04:33
This figure here shows you
the volume of water
the volume of water
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这张图表显示的是
04:37
that could be collected
in the city of San Jose
in the city of San Jose
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圣何塞市能够收集到的雨水百分比，
04:39
if they could harvest the stormwater
that fell within the city limits.
that fell within the city limits.
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与收集到的雨水总量间的关系。
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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注意看蓝线和黑虚线相交的地方，
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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如果圣何塞市能收集它降雨量的一半，
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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就足够全市用上一年。
04:56
Now, I know what some of you
are probably thinking.
are probably thinking.
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我知道，有人可能会想，
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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“那要解决用水问题，
只要做一些巨大的储水罐
只要做一些巨大的储水罐
05:02
and attaching them
to the downspouts of our roof gutters,
to the downspouts of our roof gutters,
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跟屋顶排水沟的落水管连在一起，
05:05
rainwater harvesting."
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收集雨水就行了。”
05:07
Now, that's an idea
that might work in some places.
that might work in some places.
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这方法在某些地方可能有用。
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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但如果你居住的城市冬天经常下雨，
05:12
and most of the water demand
is in the summertime,
is in the summertime,
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而夏天用水量大，
05:15
it's not a very cost-effective way
to solve a water problem.
to solve a water problem.
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这个方法就不是那么有效了。
05:19
And if you experience the effects
of a multiyear drought,
of a multiyear drought,
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而且，如果你所处的地方常年干旱，
05:22
like California's currently experiencing,
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就像今天的加利福尼亚州一样，
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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你做多大的储水罐也解决不了问题。
05:28
I think there's a lot more practical way
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我认为有更加现实的方法
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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来收集城市里的雨水，
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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那就是收集之后，让它渗入地下。
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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这样一来，我们城市的地底下
就有了一个天然的储水系统，
就有了一个天然的储水系统，
可以储存大量的水。
05:43
that can accommodate
huge volumes of water.
huge volumes of water.
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05:46
For example, historically,
Los Angeles has obtained
Los Angeles has obtained
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比如说，在过去的洛杉矶，
05:49
about a third of its water supply
from a massive aquifer
from a massive aquifer
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它的用水量的三分之一都来自
05:52
that underlies the San Fernando Valley.
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圣费尔南多谷的地下蓄水层。
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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当你看到雨水从房顶滴落，
漫过草坪，流进沟渠，
05:59
and runs off of your lawn
and flows down the gutter,
and flows down the gutter,
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你可能会犹豫，“我真的要喝这样的水吗？”
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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06:05
Well, the answer is
you don't want to drink it
you don't want to drink it
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毫无疑问，要想喝这水，
06:07
until it's been treated a little bit.
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得先经过处理。
因此，在城市里收集（雨）水有三大挑战，
06:09
And so the challenge that we face
in urban water harvesting
in urban water harvesting
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06:12
is to capture the water, clean the water
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收集雨水，清洁雨水，
06:15
and get it underground.
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灌入地下。
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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洛杉矶已经开始这么做了，
06:20
with a new project that they're building
in Burbank, California.
in Burbank, California.
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他们在加利福尼亚州
伯班克市新建了一个项目。
伯班克市新建了一个项目。
06:24
This figure here shows
the stormwater park that they're building
the stormwater park that they're building
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这是一个雨水收集园区
06:28
by hooking a series of stormwater
collection systems, or storm sewers,
collection systems, or storm sewers,
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他们将众多雨水收集系统
或者排水沟连接起来，
或者排水沟连接起来，
06:33
and routing that water
into an abandoned gravel quarry.
into an abandoned gravel quarry.
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将雨水引入一个废弃的采石场。
06:37
The water that's captured in the quarry
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采石场里的水
06:39
is slowly passed
through a man-made wetland,
through a man-made wetland,
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慢慢通过一个人造湿地
06:42
and then it goes
into that ball field there
into that ball field there
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进入旁边的一个球型区域
06:44
and percolates into the ground,
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然后渗入地下，
06:46
recharging the drinking water
aquifer of the city.
aquifer of the city.
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补充洛杉矶的地下蓄水层。
06:49
And in the process
of passing through the wetland
of passing through the wetland
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这些水在穿过湿地
06:52
and percolating through the ground,
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渗入地下的过程中，
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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会接触到生活在植物和土壤表面
06:58
and the surfaces of the soil,
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的微生物，
06:59
and that purifies the water.
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它们能净化水。
07:02
And if the water's
still not clean enough to drink
still not clean enough to drink
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如果水在经过自然净化处理后，
07:04
after it's been through
this natural treatment process,
this natural treatment process,
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还是不能直接饮用，
07:07
the city can treat it again
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管理人员会把
07:08
when they pump if back out
of the groundwater aquifers
of the groundwater aquifers
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从地下蓄水层抽出来的水
进行二次处理
进行二次处理
07:11
before they deliver it to people to drink.
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然后再供市民饮用。
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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解决城市用水问题的第二个水龙头
07:18
will flow with the wastewater
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是来自污水处理厂
07:20
that comes out
of our sewage treatment plants.
of our sewage treatment plants.
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处理过的废水。
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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大家对于循环水应该已经不陌生了。
07:26
You've probably seen signs like this
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你们也许都见过这样的牌子
07:28
that tell you that the shrubbery
and the highway median
and the highway median
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上面写着灌木丛、高速公路隔离绿化带
07:31
and the local golf course
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本地高尔夫球场
07:33
is being watered with water
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的灌溉用水
07:35
that used to be
in a sewage treatment plant.
in a sewage treatment plant.
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都来自污水处理系统。
07:38
We've been doing this
for a couple of decades now.
for a couple of decades now.
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几十年来我们都是这么做的。
07:41
But what we're learning
from our experience
from our experience
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但几十年的经验告诉我们，
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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这样做的成本比我们预期的要高。
07:47
Because once we build
the first few water recycling systems
the first few water recycling systems
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因为一旦我们在污水处理厂附近
07:50
close to the sewage treatment plant,
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建起水循环系统，
07:52
we have to build longer
and longer pipe networks
and longer pipe networks
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我们就不得不建造越来越长的管网
07:54
to get that water to where it needs to go.
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把水送到需要的地方去。
07:57
And that becomes prohibitive
in terms of cost.
in terms of cost.
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这笔开销真心不小。
08:00
What we're finding is
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我们发现，
08:02
that a much more cost-effective
and practical way of recycling wastewater
and practical way of recycling wastewater
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更加经济实惠和可行的办法
08:06
is to turn treated wastewater
into drinking water
into drinking water
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是将处理过的废水变成饮用水，
08:08
through a two-step process.
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只需要两步。
08:11
In the first step in this process
we pressurize the water
we pressurize the water
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第一步是给水加压，
08:14
and pass it through
a reverse osmosis membrane:
a reverse osmosis membrane:
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让它通过反向渗透膜
08:16
a thin, permeable plastic membrane
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——一种很薄的、可渗透的塑料膜——
08:19
that allows water molecules
to pass through
to pass through
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水分子可以通过，
08:21
but traps and retains the salts,
the viruses and the organic chemicals
the viruses and the organic chemicals
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但废水中可能含有的盐、病毒和有机化学物
08:26
that might be present in the wastewater.
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会被拦截下来。
08:29
In the second step in the process,
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第二步，
08:31
we add a small amount of hydrogen peroxide
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我们往水里加入少量的过氧化氢
08:33
and shine ultraviolet light on the water.
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然后用紫外线进行照射。
08:36
The ultraviolet light
cleaves the hydrogen peroxide
cleaves the hydrogen peroxide
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紫外线能将过氧化氢
08:39
into two parts that are called
hydroxyl radicals,
hydroxyl radicals,
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分裂成两部分，称为氢氧基，
08:42
and these hydroxyl radicals
are very potent forms of oxygen
are very potent forms of oxygen
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氢氧基是一种非常强的氧气形式
08:46
that break down most organic chemicals.
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能够消灭大部分有机化学物。
08:50
After the water's been
through this two-stage process,
through this two-stage process,
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水经过这两步处理之后，
08:53
it's safe to drink.
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就可以安全饮用了。
08:54
I know,
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过去15年里，
08:56
I've been studying recycled water
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我一直在运用
08:58
using every measurement technique
known to modern science
known to modern science
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现代科学的各种测量方法
09:02
for the past 15 years.
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来研究循环水。
09:04
We've detected some chemicals
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我们发现某些化学物质
09:05
that can make it through
the first step in the process,
the first step in the process,
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无法在步骤一被过滤掉，
09:08
but by the time we get to the second step,
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但经过第二步：
09:10
the advanced oxidation process,
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高级氧化过程之后，
09:12
we rarely see any chemicals present.
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几乎没有化学物质能残留下来。
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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这比我们一直喝的“毫无问题”的水
09:18
that we regularly drink all the time.
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可安全多了。
09:21
There's another way we can recycle water.
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还有另外一种方法来循环水。
09:24
This is an engineered treatment wetland
that we recently built
that we recently built
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这是我们最近修建的人工湿地
09:27
on the Santa Ana River
in Southern California.
in Southern California.
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位于加利福尼亚州南部的圣安娜河上。
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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圣安娜河的部分河水流入人工湿地，
09:34
that in the summertime consists
almost entirely of wastewater effluent
almost entirely of wastewater effluent
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每到夏天，圣安娜河里就全是污水，
09:38
from cities like Riverside
and San Bernardino.
and San Bernardino.
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都来自里弗赛德市和圣贝纳迪诺市。
09:41
The water comes
into our treatment wetland,
into our treatment wetland,
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河水流入我们的人工湿地，
09:43
it's exposed to sunlight and algae
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在阳光暴晒和水藻的作用下，
09:45
and those break down
the organic chemicals,
the organic chemicals,
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有机化学物被分解，
09:48
remove the nutrients
and inactivate the waterborne pathogens.
and inactivate the waterborne pathogens.
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营养物被消耗，水生病原体被杀死。
09:51
The water gets put back
in the Santa Ana River,
in the Santa Ana River,
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之后河水流回圣安娜河，
09:54
it flows down to Anaheim,
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流向安纳海姆市，
09:56
gets taken out at Anaheim
and percolated into the ground,
and percolated into the ground,
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河水在那里被抽出，
渗入地下，
渗入地下，
09:59
and becomes the drinking water
of the city of Anaheim,
of the city of Anaheim,
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成为安纳海姆市的饮用水，
10:01
completing the trip
from the sewers of Riverside County
from the sewers of Riverside County
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通过这一过程，里弗赛德郡的废水
10:05
to the drinking water supply
of Orange County.
of Orange County.
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就变成了橙郡的饮用水。
10:09
Now, you might think
that this idea of drinking wastewater
that this idea of drinking wastewater
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也许你们会觉得，将废水变成饮用水，
10:13
is some sort of futuristic fantasy
or not commonly done.
or not commonly done.
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只是天方夜谭，或者还没有得到推广。
10:16
Well, in California, we already recycle
about 40 billion gallons a year
about 40 billion gallons a year
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实际上，运用我刚刚介绍的两步处理法，
10:21
of wastewater through the two-stage
advanced treatment process
advanced treatment process
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我们每年在加利福尼亚州循环利用的水
10:24
I was telling you about.
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达到了1.5亿立方米。
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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这些水足够供应100万人，
10:29
if it were their sole water supply.
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作为他们的主要水源。
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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我们的第三个水龙头并不是实体，
10:36
it will be a kind of virtual tap,
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而是虚拟的，
10:38
it will be the water conservation
that we manage to do.
that we manage to do.
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指的是节约用水。
10:41
And the place where we need to think
about water conservation is outdoors
about water conservation is outdoors
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而且主要指的是户外用水，
10:44
because in California
and other modern American cities,
and other modern American cities,
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因为在加利福尼亚以及其他的美国都市，
10:48
about half of our water use
happens outdoors.
happens outdoors.
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差不多一半的用水发生在户外。
10:51
In the current drought,
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即使在现在的干旱状态下，
10:53
we've seen that it's possible
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我们的用水量下降了一半，
10:54
to have our lawns survive
and our plants survive
and our plants survive
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但我们的草坪，我们的植物
10:57
with about half as much water.
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还是活下来了。
10:59
So there's no need
to start painting concrete green
to start painting concrete green
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因此我们还没到把水泥地喷成绿色，
11:02
and putting in Astroturf
and buying cactuses.
and buying cactuses.
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或者改铺人工草皮，改种仙人掌的地步。
11:05
We can have California-friendly
landscaping with soil moisture detectors
landscaping with soil moisture detectors
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在土壤湿度探测器和智能浇灌系统的帮助下，
11:10
and smart irrigation controllers
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加州式园林不是梦，
11:12
and have beautiful
green landscapes in our cities.
green landscapes in our cities.
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我们的城市依旧可以绿意盎然。
11:15
The fourth and final water tap
that we need to open up
that we need to open up
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我们需要打开的第四个，
也是最后一个水龙头，
也是最后一个水龙头，
11:18
to solve our urban water problem
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来解决城市用水问题，
11:20
will flow with desalinated seawater.
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是海水淡化。
11:23
Now, I know what you probably heard
people say about seawater desalination.
people say about seawater desalination.
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也许你们听人们谈论过海水淡化，
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
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“海水淡化是很好，
前提是你石油多、淡水少，
前提是你石油多、淡水少，
11:31
and you don't care about climate change."
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而且也不在乎气候变化。”
11:33
Seawater desalination is energy-intensive
no matter how you slice it.
no matter how you slice it.
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没错，海水淡化
是一项能源密集型产业。
是一项能源密集型产业。
11:38
But that characterization
of seawater desalination
of seawater desalination
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但如果仅仅因为这样，就将海水淡化
11:40
as being a nonstarter
is hopelessly out of date.
is hopelessly out of date.
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视为没有前途，那就太落伍了。
11:43
We've made tremendous progress
in seawater desalination
in seawater desalination
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在过去20年间，我们在海水淡化上
11:46
in the past two decades.
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已经取得了巨大进展。
11:48
This picture shows you
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这张照片上
11:50
the largest seawater desalination plant
in the Western hemisphere
in the Western hemisphere
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是在建的西半球最大的海水淡化厂，
11:54
that's currently being built
north of San Diego.
north of San Diego.
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位于圣地亚哥市以北。
11:57
Compared to the seawater
desalination plant
desalination plant
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与25年前建在圣巴巴拉市
11:59
that was built in
Santa Barbara 25 years ago,
Santa Barbara 25 years ago,
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的海水淡化厂相比，
12:02
this treatment plant
will use about half the energy
will use about half the energy
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这家海水淡化厂每生产一加仑淡水
12:05
to produce a gallon of water.
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的能耗下降了一半。
12:07
But just because seawater desalination
has become less energy-intensive,
has become less energy-intensive,
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当然，海水淡化的能耗降低了，
12:11
doesn't mean we should start building
desalination plants everywhere.
desalination plants everywhere.
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并不意味着我们就该到处建海水淡化厂。
12:14
Among the different choices we have,
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在我们的众多选择中，
12:16
it's probably the most energy-intensive
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在4种新水源中，
12:18
and potentially environmentally damaging
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海水淡化依然是能耗最大，
12:20
of the options to create
a local water supply.
a local water supply.
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最有可能对环境造成危害的。
12:24
So there it is.
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综上所述，
12:25
With these four sources of water,
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有了这4种新水源，
12:27
we can move away
from our reliance on imported water.
from our reliance on imported water.
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我们不用再依赖进口水。
12:31
Through reform in the way we landscape
our surfaces and our properties,
our surfaces and our properties,
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通过改进我们绿化城市和居民区的方法，
12:36
we can reduce outdoor water use
by about 50 percent,
by about 50 percent,
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我们可以将户外用水量下降50%，
12:39
thereby increasing
the water supply by 25 percent.
the water supply by 25 percent.
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因此提高25%的供水量。
12:42
We can recycle the water
that makes it into the sewer,
that makes it into the sewer,
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我们可以循环利用废水，
12:45
thereby increasing
our water supply by 40 percent.
our water supply by 40 percent.
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以此提高40%供水量。
12:48
And we can make up the difference
through a combination
through a combination
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我们可以综合利用
12:51
of stormwater harvesting
and seawater desalination.
and seawater desalination.
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雨水收集和海水淡化。
12:55
So, let's create a water supply
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让我们来创造稳定的水源供应，
12:59
that will be able
to withstand any of the challenges
to withstand any of the challenges
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足以在未来几年承受气候变化
13:02
that climate change throws at us
in the coming years.
in the coming years.
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给我们带来的挑战。
13:05
Let's create a water supply
that uses local sources
that uses local sources
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让我们充分利用本地水源，
13:08
and leaves more water
in the environment for fish and for food.
in the environment for fish and for food.
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将更多的水留给环境，
留给动物，留给食物。
留给动物，留给食物。
13:13
Let's create a water system that's
consistent with out environmental values.
consistent with out environmental values.
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让我们创造环境友好型的供水系统。
13:18
And let's do it for our children
and our grandchildren
and our grandchildren
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让我们为子孙后代而努力，
13:22
and let's tell them this is the system
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告诉他们，在未来的岁月里，
13:24
that they have to
take care of in the future
take care of in the future
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他们也应该珍视这个系统
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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因为这是我们创建
新型供水系统最后的机会。
新型供水系统最后的机会。
13:31
Thank you very much for your attention.
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非常感谢大家。
13:32
(Applause)
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（掌声）
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