4 ways we can avoid a catastrophic drought | David Sedlak


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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Thank you very much for your attention. (Applause)

Comments 50

  • I would like to see one catastrophic drought so we can start to give the resource the respect it deserves.

  • Ever here of the 'dust boul" or here in Canada they called it the dirty 30's. It was a much greater state of 'climate change' then we are facing now. The US government had the largest tree planting program in history. The planted 250 million trees, in a few years the water come back. You want water, plant trees. They don't call them rain forest for no reason!

  • He doesn't devote nearly enough time to gray water systems under the "Water Reuse" section. You can create very low-tech systems that simply return most of the water in your home to the ground to replenish aquifers. Specifically:
    —All my laundry water goes to my lawn. Soap doesn't hurt it (I use liquid detergent; powdered detergent contains sodium, so don't use that).
    —Additionally, I flush the toilets with recycled bath water.
    —Excess bath water also goes out with the laundry water into the lawn.
    —I've never calculated the water saved from toilet flushes, but it's 1.5 gal per flush, so conservatively I'd say 1.5 x 2/day x 365 = About 1100 gallons per year.
    —I did keep track of laundry. My machine uses 26 gal/load * 349 loads = More than 9000 gallons last year.
    —If everyone on my block did the same, we'd be talking about millions of gallons of water saved or reclaimed.

  • we can recycle our own darn pee like NASA did. We can boil seawater and create condensation.

  • This channel is dying….

  • 1 like= Im a good person
    1 sub= I Love God
    Ignore= God will know…

  • Next on Ted Talks: How to Stop The Government or Military from creating psyop's and fake news to make law changes.
    Next on Ted Ta;lks: How to approach people that are clueless about information they need to know, without calling them asleep or sheeple.
    Next on Ted Talks: How to handle approaching a drug addict and how to show them they need to get help and how to get them that help.
    Next on Ted Talks: How to make Ted Talks more important to the current real life problems people are currently facing.

  • I don't like method two. I don't like drinking treated pee.

  • Plenty of water for fracking though. Funny that eh?

  • 13.37 long, now thats the interesting part

  • and how about stop chemtrailing and messing around with HAARP?!!!

  • Plant forests on high places and make sure there will be earthworms in soil and you will have enough water.

  • How bout stop deforestation, mono cultures, fracking, and start trying to keep the water ON the land, with keyline berms etc. The answers are there, you just cant get past big business. Use permaculture. Ahh but that would upset monsanto and the fertiliser people..

  • Damn I got thirsty after watching this

  • the best part of this Ted talk was the as before it. sorry Ted. sorry.

  • مافيه ترجمه با العربي

  • Yeah you might as well have named this 'a talk about Murica'

  • 5:56 actually the water that comes off your roof is ussually pretty clean, i wouldnt mind drinking it. just make sure your gutters are clean and whatnot.

  • Way 5: Catch Groudon

  • Reservoirs???? where we fracked all those fucking chemicals!!!!!!!!!!!!!!!! TO get OIL

  • Wow, a TED talk, nay, a TEDx talk that's actually about a real topic? And whose presentation isn't mired with personal story or anecdote? What is happening here?

  • The four faucets of the hydrocolypse.

  • Why can't we use the extreme pressures deep in the ocean to power the reverse osmosis system? Say you run a pipe down to the ocean debts that has a tank at the bottom with walls lined in a fine, semi-permeable membrane. At the surface you can have a large container or ship that holds the fresh water. As long as you keep pulling filtered water out, the deep water pressure will keep forcing water though the membrane<the membrane being at the bottom of the pipe>
    It'll be like oil drilling but the the water pumps itself. The pressure depends on the level of fresh water at the surface of the pipe/container . So a ship can just pump the fresh water into it's hull or into a large bag floating in the ocean and ship it and the deep sea pressure will just force more water into the pipe to replace the water that was removed.
    Even more, you can run this pipe to the shore and have it pumped onto the land and collected in reservoirs.
    I don't see what could be wrong with this idea, anyone think otherwise? Please comment.

  • Drought is called supply versus demand. Population increases need more water. This is not from lack of rain. Predicting End Days catastrophic drought is just shamanism. Give this man a rattle and feather hat to chant.

  • Instead of focusing on preventing climate, he should focus on preventing earthquakes and volcanoes. Then a cure for all cancers. Then he will convince me he is a God, and I will worship him. Until then, quack, quack.

  • In this candid talk, David Sedlak gives some pragmatic ideas for how to replenish our water resources. The climate change is causing doom all around the world. This is the right time to discuss the subject like this. I hope the politicians, policy makers and people who are associated with the 'water resource management' will take note of this kind of ideas to stabilise the woefully disturbing 'climate change.'

  • Watch the movie 'Slingshot'. There is technology right now able to filter water for everyone. The UN and its socialist idiot leaders didn't want anything to do with it. Wasn't part of Agenda 21. We have the technology right now.

  • How about this for an idea, don't build mega cities in the dessert.

  • Maybe California should stop growing produce for all of North America, and grow only its own food, with other US states providing for themselves as well…

  • Stop washing your cars and watering your lawns.

  • Singapore has put all of these ideas in good use since 10 years ago. Why is this guy talking like he has got some brilliant ideas?

  • His 4 sources of water , is a complete ripoff of Singapore's 4 national tap! Do google about Singapore and you can see the stark similarity! Cleaning of water through his 2 advance step and desalination has been done for the past 15 years in Singapore.

  • Amazing how many geniuses and experts who have all the answers posting comments here.

  • The meat industry needs 2-10 times more water than plants. Also the meat and diary industry uses about 46% of the total land mass.

    Just saying.

  • how about we fucking take countries with water over and ship it here kinda like oil…send in the troops already

  • Fascinating talk.

  • Hello people, I'm looking for a specific ted talk video in which the speaker does a biography about Muhammad Ali. I know its on this channel but i cant find the speaker or the video. Thanks for the help.

  • hmm, I don't know about the details but I think that the first two ideas are used in germany for 50 years or so?

  • How to avoid a catastrophic drought? Easy: Stop eating meat.

    A large portion of this potable water is being fed to livestock directly and to the feed that the livestock will consume. Animal agriculture is also the causing desertification and deforestation which likely affects rainfall as vegetation and rainfall are tightly correlated.

    A low estimate states that a single pound of beef requires 600 gallons of water to produce! That's enough for 25 days of 10-minute showers (2.5gallon/min)! This has been estimated to be the 3-day consumption of an average meat-eater in the US.

  • Here's a thought LA. Move out of the desert.

  • Shine UV light on the water. This is called RADIATION!?! Do you really want to drink water that has been treated with radiation?

  • Many people (especially vegans) like below is repeat a lot of misinformation especially about water use since they clearly doesn't understand how water footprint numbers are derived or what those numbers actually represent. The vast majority 98% of the water in a water footprint number for meat is the GREEN water (primarily RAIN) it takes to grow the feed, forage or grasses that livestock eat over their lifetimes. Very little of a water foot print number is consumption (around 1%). In a pastured based system (e.g. grass fed and finished cattle) grasses don't require as much water as crops. In reality again with cattle (cow/calf/stocker/and grass finished operations) as an example, these animals are raised on land not suitable for crop production without massive blue water diversion like in California. BLUE water is what's critical NOT green water. Diverting river water, and pumping aquifers is what's not sustainable. So for water usage you have to look at appropriate land use, meaning what's the most effective use of the GREEN rain water that falls from the sky especially on land that isn't well suited for crop production.

    Here's a paper I wrote on this topic that goes into more detail: http://www.examiner.com/article/la-chef-editorial-understanding-numbers Numbers claiming 56% of water is used for AG are completely bogus as well in part for the reasons I noted, and also because a lot of water is diverted for ecological uses. In California, the total number for Ag bantered about is 80% but the real number is closer to 40% when accounting for things like diverting water to keep salt water out of the Delta river basin

  • Why is he putting so much effort into avoiding to mention Singapore ? I have heard about the exact same talk from Singapore authorities, except that they talked in the past tense, because the whole system is already in place. This is a case worth mentioning if you're trying to convince a crowd about a solution.

  • the answer is veganism

  • 6:17 Burbank CA

  • 10:30 Water Conservation

  • 11:11 Seawater Desalination

  • 12:23 Summary

  • if this interests you, check out Israels superb efforts on water management. They now have a surplus.
    Also check out Fog Nets in the Atacama desert which are very inspiring.
    Greetings from the UK.

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