4 ways we can avoid a catastrophic drought | David Sedlak

Prevodilac: Vojislav Gavrilov Lektor: Mile Živković

Our grandparents' generation created an amazing system

Generacija naših baba i deda stvorila je neverovatan sistem

of canals and reservoirs that made it possible

kanala i rezervoara koji su omogućili

for people to live in places where there wasn't a lot of water.

da ljudi žive na mestima gde nije bilo previše vode.

For example, during the Great Depression,

Na primer, za vreme velike depresije

they created the Hoover Dam,

izgradili su branu Huver

which in turn, created Lake Mead

koja je kao posledicu stvorila jezero Mid

and made it possible for the cities of Las Vegas and Phoenix

i omogućila gradovima Las Vegas i Feniks

and Los Angeles to provide water

i Los Anđeles da obezbede vodu

for people who lived in a really dry place.

za ljude koji su živeli na jako suvom mestu.

In the 20th century, we literally spent trillions of dollars

U 20. veku smo bukvalno potrošili bilione dolara

building infrastructure to get water to our cities.

gradeći infrastrukturu da dovedemo vodu u gradove.

In terms of economic development, it was a great investment.

U smislu ekonomskog razvoja, to je bila odlična investicija.

Ali u poslednjoj deceniji svedoci smo toga da kombinovani efekat

But in the last decade, we've seen the combined effects

of climate change, population growth and competition for water resources

klimatskih promena, rasta populacija i trke za vodenim resursima

threaten these vital lifelines and water resources.

ugrožava ove vitalne linije života i vodene resurse.

This figure shows you the change in the lake level of Lake Mead

Ovaj grafik pokazuje promene nivoa vode jezera Mid

that happened in the last 15 years.

koje su se desile u poslednjih 15 godina.

You can see starting around the year 2000,

Vidi se da je oko 2000. godine

the lake level started to drop.

nivo jezera počeo da opada,

And it was dropping at such a rate

i opadao je takvim tempom,

that it would have left the drinking water intakes for Las Vegas high and dry.

da bi grad Las Vegas ostao bez vode za piće.

The city became so concerned about this

Grad se toliko zabrinuo zbog ovoga

that they recently constructed a new drinking water intake structure

da su izgradili novu strukturu za dopremanje vode u grad,

that they referred to as the "Third Straw"

koju su nazvali "Treća slamka",

to pull water out of the greater depths of the lake.

da bi izvaličili vodu sa većih dubina jezera.

The challenges associated with providing water to a modern city

Izazovi povezani sa dopremanjem vode modernom gradu

are not restricted to the American Southwest.

nisu ograničeni samo na jugozapad Amerike.

In the year 2007, the third largest city in Australia, Brisbane,

Godine 2007, trećem najvećem gradu u Australiji, Brizbejnu

came within 6 months of running out of water.

je bilo ostalo samo 6 meseci da nestane vode.

A similar drama is playing out today in São Paulo, Brazil,

Danas se slična drama odigrava u Sao Paolu u Brazilu

where the main reservoir for the city

gde se glavni gradski rezervoar

has gone from being completely full in 2010,

u periodu od 2010. kad je bio potpuno pun

to being nearly empty today

skoro potpuno ispraznio do danas

as the city approaches the 2016 Summer Olympics.

kako se grad približava Letnjim Olimpijskim igrama 2016.

For those of us who are fortunate enough

Mi koji imamo dovoljno sreće

to live in one of the world's great cities,

da živimo u jednom od najboljih svetskih gradova,

we've never truly experienced the effects of a catastrophic drought.

nikad nismo doživeli prave efekte katastrofalne suše.

We like to complain about the navy showers we have to take.

Volimo da se žalimo na hladna tuširanja.

We like our neighbors to see our dirty cars and our brown lawns.

Sviđa nam se da komšije vide naš prljav automobil i braon travnjake.

But we've never really faced the prospect of turning on the tap

Ali se nikad nismo suočili sa situacijom da kada otvorimo slavinu,

and having nothing come out.

ništa ne ističe.

And that's because when things have gotten bad in the past,

Sve zbog toga kada su u prošlosti stvari krenule po zlu

it's always been possible to expand a reservoir

uvek je bilo moguće proširiti rezervoar

or dig a few more groundwater wells.

ili iskopati još koji bunar.

Well, in a time when all of the water resources are spoken for,

Pa, u vremenu kada su svi izvori vode zauzeti,

it's not going to be possible to rely on this tried and true way

neće biti moguće osloniti se na ovu uspešnu i isprobanu metodu

of providing ourselves with water.

dopremanja vode.

Some people think that we're going to solve the urban water problem

Ljudi misle da probleme sa vodom u urbanim sredinama možemo rešiti

by taking water from our rural neighbors.

uzimanjem vode od ruralnih suseda.

But that's an approach that's fraught with political, legal and social dangers.

Ovakav pristup je pun političkih, zakonskih i socijalnih opasnosti.

And even if we succeed in grabbing the water from our rural neighbors,

Čak i da uspemo da ugrabimo vodu od naših ruralnih suseda,

we're just transferring the problem to someone else

samo prebacujemo problem na nekog drugog

and there's a good chance it will come back and bite us

i vrlo je verovatno da će nam se taj problem vratiti

in the form of higher food prices

u obliku većih cena hrane

and damage to the aquatic ecosystems that already rely upon that water.

i u obliku oštećenja ekosistema koji se već oslanjaju na tu vodu.

I think that there's a better way to solve our urban water crisis

Milsim da postoji bolji način da se reši kriza u urbanim sredinama

and I think that's to open up four new local sources of water

i mislim da je to otvaranje 4 nova lokalna izvora vode

that I liken to faucets.

koje poredim sa slavinama.

If we can make smart investments in these new sources of water

Ako pametno investiramo u ove nove izvore vode

in the coming years,

u godinama koje slede,

we can solve our urban water problem

moći ćemo da rešimo probleme u urbanim sredinama

and decrease the likelihood that we'll ever run across

i smanjićemo šanse da cemo se ikad susresti

the effects of a catastrophic drought.

sa efektima katastrofalne suše.

Now, if you told me 20 years ago

Da ste mi pre 20 godina rekli

that a modern city could exist without a supply of imported water,

da moderan grad može da postoji bez zaliha uvezene vode,

I probably would have dismissed you as an unrealistic and uninformed dreamer.

verovatno bih vas okarakterisao kao nerealnog i neinformisanog sanjara.

But my own experiences

Ali moja iskustva,

working with some of the world's most water-starved cities in the last decades

u radu sa gradovima kojima je najpotrebnija voda decenijama unazad,

have shown me that we have the technologies and the management skills

su mi dokazala da posedujemo tehnologiju i menadžerske sposobnosti

to actually transition away from imported water,

da se udaljimo od uvezene ovde

and that's what I want to tell you about tonight.

i to je ono o čemu želim da vam pričam večeras.

The first source of local water supply that we need to develop

Kroz prvi izvor lokalne vode koji moramo da razvijemo

to solve our urban water problem

da bismo rešili problem urbanih voda

will flow with the rainwater that falls in our cities.

će teći kiša koja pada u našim gradovima.

One of the great tragedies of urban development

Jedna od velikih tragedija urbanog razvoja je

is that as our cities grew,

kako su gradovi rasli

we started covering all the surfaces with concrete and asphalt.

počeli smo da prekrivamo sve površine betonom i asfaltom.

And when we did that, we had to build storm sewers

Zatim smo morali da napravimo kišnu kanalizaciju

to get the water that fell on the cities out

da bismo izbacili vodu iz naših gradova

before it could cause flooding,

pre nego što se desi poplava,

and that's a waste of a vital water resource.

a to je bacanje vitalnih izvora vode.

Let me give you an example.

Evo primera.

This figure here shows you the volume of water

Ova slika pokazuje količinu vode

that could be collected in the city of San Jose

koja se može skupiti u gradu San Hoze

if they could harvest the stormwater that fell within the city limits.

kada bi mogli da skupe kišnicu koja pada u granicama grada.

You can see from the intersection of the blue line and the black dotted line

Na preseku plave i crne isprekidane linije se može videti

that if San Jose could just capture half of the water that fell within the city,

da kada bi San Hoze uhvatio samo polovinu vode koja pada u granicama grada,

they'd have enough water to get them through an entire year.

imali bi dovoljno vode za celu godinu.

Now, I know what some of you are probably thinking.

Znam šta neki od vas sada verovatno misle.

"The answer to our problem is to start building great big tanks

"Rešenje naših problema je gradnja ogromnih rezervoara

and attaching them to the downspouts of our roof gutters,

i spajanje ih sa izlazima krovnih oluka,

rainwater harvesting."

skupljanje kišnice."

Now, that's an idea that might work in some places.

Ovakva ideja bi uspela na nekim mestima.

But if you live in a place where it mainly rains in the winter time

Ali ako živite u mestu gde kiša uglavnom pada zimi,

and most of the water demand is in the summertime,

a većina potrebe za vodom je leti,

it's not a very cost-effective way to solve a water problem.

ovakvo rešenje nije finansijski isplativo.

And if you experience the effects of a multiyear drought,

I ako ste pod uticajem višegodišnje suše,

like California's currently experiencing,

koja je trenutno u Kaliforniji,

you just can't build a rainwater tank that's big enough to solve your problem.

ne može se izgraditi dovoljno velik rezervoar da reši problem.

I think there's a lot more practical way

Postoji mnogo praktičniji način

to harvest the stormwater and the rainwater that falls in our cities,

prikupljanja kišnice koja pada u naše gradove,

and that's to capture it and let it percolate into the ground.

a to je uhvatiti je i dopustiti da se premesti u zemlju.

After all, many of our cities are sitting on top of a natural water storage system

U ostalom, mnogi naši gradovi su iznad prirodnih skladišta vode

that can accommodate huge volumes of water.

koja mogu da smeste ogromne količine vode.

For example, historically, Los Angeles has obtained

Na primer, kroz istoriju Los Anđeles je dobijao

about a third of its water supply from a massive aquifer

trećinu svoje potrebe za vodom iz masivnog izdana

that underlies the San Fernando Valley.

koji je ispod doline San Fernando.

Now, when you look at the water that comes off of your roof

Kada pogledate vodu koja silazi sa krova

and runs off of your lawn and flows down the gutter,

i otekne preko travnjaka do kišnog odvoda,

you might say to yourself, "Do I really want to drink that stuff?"

možda ćete pomisliti: "Da li stvarno želim da pijem ovo?"

Well, the answer is you don't want to drink it

Pa, odgovor je da ne želite to da pijete

until it's been treated a little bit.

dok se malo ne obradi.

And so the challenge that we face in urban water harvesting

Izazov kod prikupljanja vode u urbanim sredinama

is to capture the water, clean the water

je uhvatiti vodu, prečistiti vodu

and get it underground.

i smestiti je pod zemlju.

And that's exactly what the city of Los Angeles is doing

Upravo to se radi u Los Anđelesu

with a new project that they're building in Burbank, California.

na novom projektu u Burbanku u Kaliforniji.

This figure here shows the stormwater park that they're building

Ova slika pokazuje park za kišnicu koji se gradi

by hooking a series of stormwater collection systems, or storm sewers,

tako što se povezuju nizovi sistema za kišnicu, ili kišnih kanalizacija,

and routing that water into an abandoned gravel quarry.

koji sprovode tu vodu u napušteni kamenolom.

The water that's captured in the quarry

Ova voda, skladištena u kamenolomu

is slowly passed through a man-made wetland,

se polako odvodi kroz veštačku močvaru,

and then it goes into that ball field there

i potom odlazi na ovo polje ovde

and percolates into the ground,

gde se sliva u zemlju

recharging the drinking water aquifer of the city.

i puni izdan pijaće vode u gradu.

And in the process of passing through the wetland

U procesu prolaska kroz močvaru

and percolating through the ground,

i slivanja kroz zemljište,

the water encounters microbes that live on the surfaces of the plants

voda dolazi u dodir sa mikrobima koji žive na povrišini biljaka

and the surfaces of the soil,

i na površini zemljišta

and that purifies the water.

i ovo pročišćava vodu.

And if the water's still not clean enough to drink

Ako voda i dalje nije dovoljno čista za piće

after it's been through this natural treatment process,

nakon što je prošla prirodni proces čišćenja,

the city can treat it again

može se ponovo obraditi

when they pump if back out of the groundwater aquifers

prilikom ispumpavanja iz podzemnog izdana

before they deliver it to people to drink.

pre nego što se dostavi ljudima za piće.

The second tap that we need to open up to solve our urban water problem

Kroz drugu slavinu koju treba otvoriti da bi se rešio problem u urbanim sredinama

will flow with the wastewater

će teći otpadna voda

that comes out of our sewage treatment plants.

koja teče iz fabrika za preradu otpadne vode.

Now, many of you are probably familiar with the concept of recycled water.

Većina vas je upoznata sa principima reciklirane vode.

You've probably seen signs like this

Sigurno ste videli ove znakove

that tell you that the shrubbery and the highway median

koji vas obaveštavaju da se grmlje i sredina autoputa

and the local golf course

i lokalni teren za golf

is being watered with water

zalivaju vodom

that used to be in a sewage treatment plant.

koja je bila u fabrici za preradu otpadnih voda.

We've been doing this for a couple of decades now.

Ovo radimo već nekoliko decenija.

But what we're learning from our experience

Ali kroz ovo iskustvo učimo da je ovaj pristup

is that this approach is much more expensive that we expected it to be.

mnogo skuplji nego što se očekivalo.

Because once we build the first few water recycling systems

Jer kada jednom izgradimo prvi sistem za reciklažu vode

close to the sewage treatment plant,

blizu fabrike za preradu otpadnih voda,

we have to build longer and longer pipe networks

moramo potom da gradimo sve dužu mrežu cevi

to get that water to where it needs to go.

da bismo dopremili ovu vodu gde je potrebna.

And that becomes prohibitive in terms of cost.

Troškovi ovakvog prisutpa su preveliki.

What we're finding is

Nalazimo da je

that a much more cost-effective and practical way of recycling wastewater

mogo jeftiniji i praktičniji način recikliranja vode

is to turn treated wastewater into drinking water

taj da se obrađena otpadna voda pretvori u vodu za piće

through a two-step process.

kroz proces u dva koraka.

In the first step in this process we pressurize the water

U prvom koraku vodu izlažemo pritisku

and pass it through a reverse osmosis membrane:

i guramo je kroz membranu za obrnutu osmozu:

a thin, permeable plastic membrane

tanku membranu od propustljive plastike

that allows water molecules to pass through

koja dopušta molekulima vode da prođu

but traps and retains the salts, the viruses and the organic chemicals

ali zaustavlja soli, viruse i organske hemikalije

that might be present in the wastewater.

koje voda možda sadrži.

In the second step in the process,

U drugom koraku,

we add a small amount of hydrogen peroxide

dodajemo malu količinu vodonik peroksida u vodu

and shine ultraviolet light on the water.

i obasjamo je ultraljubičastom svetlošću.

The ultraviolet light cleaves the hydrogen peroxide

Ultraljubičasto svetlo cepa vodonik peroksid

into two parts that are called hydroxyl radicals,

na dva dela koji se nazivaju hidroksil radikalima,

and these hydroxyl radicals are very potent forms of oxygen

ovi hidroksil radikali su veoma potentan oblik kiseonika

that break down most organic chemicals.

koji razlaže većinu organskih hemikalija.

After the water's been through this two-stage process,

Nakon što je voda prošla kroz ovaj proces,

it's safe to drink.

bezbedna je za piće.

I know,

Ovo znam

I've been studying recycled water

jer sam izučavao recikliranu vodu,

using every measurement technique known to modern science

koristeći sve tehnike merenja poznate modernoj nauci,

for the past 15 years.

u prethodnih 15 godina.

We've detected some chemicals

Našli smo neke hemikalije

that can make it through the first step in the process,

koje uspeju da prođu kroz prvi korak procesa,

but by the time we get to the second step,

ali kad prođu kroz drugi korak,

the advanced oxidation process,

napredni proces oksidacije,

we rarely see any chemicals present.

retko nailazimo na bilo kakve hemikalije.

And that's in stark contrast to the taken-for-granted water supplies

Ovo je u suprotnosti sa izvorima vode koje uzimamo zdravo za gotovo

that we regularly drink all the time.

iz kojih redovno pijemo vodu.

There's another way we can recycle water.

Postoji još jedan način na koji recikliramo vodu.

This is an engineered treatment wetland that we recently built

Ovo je veštačka močvara za preradu koju smo nedavno izgradili

on the Santa Ana River in Southern California.

na reci Santa Ana u južnoj Kaliforniji.

The treatment wetland receives water from a part of the Santa Ana River

Močvara za preradu prima vodu iz dela reke Santa Ana

that in the summertime consists almost entirely of wastewater effluent

koje se tokom leta uglavnom sastoji od otpadnih voda

from cities like Riverside and San Bernardino.

iz gradova kao što su Riversajd i San Bernandino.

The water comes into our treatment wetland,

Ova voda dolazu u močvaru za preradu

it's exposed to sunlight and algae

gde je izložena algama i suncu

and those break down the organic chemicals,

koji razlažu organske hemikalije,

remove the nutrients and inactivate the waterborne pathogens.

uklanjaju hranljive sastojke i deaktiviraju patogene iz vode.

The water gets put back in the Santa Ana River,

Voda se vraća u reku Santa Ana,

it flows down to Anaheim,

teče do Anahajma,

gets taken out at Anaheim and percolated into the ground,

izdvaja se iz reke i sliva se u zemlju,

and becomes the drinking water of the city of Anaheim,

i tako postaje voda za piće u Anahajmu,

completing the trip from the sewers of Riverside County

završavajući put od kanalizacionih voda iz okruga Riversajd

to the drinking water supply of Orange County.

do vode za piće okruga Oranž.

Now, you might think that this idea of drinking wastewater

Možda mislite da je ideja ispijanja otpadne vode

is some sort of futuristic fantasy or not commonly done.

neka vrsta fantazije ili da se ne praktikuje.

Well, in California, we already recycle about 40 billion gallons a year

Pa, u Kaliforniji, se već reciklira oko 152 milijarde litara godišnje

of wastewater through the two-stage advanced treatment process

otpadne vode kroz napredni proces obrade u dva koraka

I was telling you about.

o kom sam vam pričao.

That's enough water to be the supply of about a million people

Ovo je dovoljno vode za oko milion ljudi

if it were their sole water supply.

kad bi to bio njihov jedini izvor vode.

The third tap that we need to open up will not be a tap at all,

Treća slavina koju moramo otvoriti u stvari neće biti slavina,

it will be a kind of virtual tap,

biće to vrsta virtualne slavine,

it will be the water conservation that we manage to do.

u pitanju je štednja vode koju uspevamo da ostvarimo.

And the place where we need to think about water conservation is outdoors

Mesto na kome moramo da razmislimo o štednji vode je napolju

because in California and other modern American cities,

jer u Kaliforniji i ostalim modernim gradovima u Americi,

about half of our water use happens outdoors.

oko polovina upotrebe vode se dešava napolju.

In the current drought,

U aktuelnoj suši,

we've seen that it's possible

shvatili smo da je moguće

to have our lawns survive and our plants survive

da naši travnjaci i biljke prežive

with about half as much water.

sa pola količine vode.

So there's no need to start painting concrete green

Tako da nema potrebe da se beton farba u zeleno

and putting in Astroturf and buying cactuses.

i da se postavlja veštačka trava i kupuju kaktusi.

We can have California-friendly landscaping with soil moisture detectors

Može se zadržati kalifornijski stil uređenja

uz pomoć detektora za vlažnost zemljišta

and smart irrigation controllers

i pametnih kontorolera navodnjavanja

and have beautiful green landscapes in our cities.

i da samim tim imamo lepe zelene površine u gradu.

The fourth and final water tap that we need to open up

Četvrta i poslednja slavina koju moramo da otvorimo

to solve our urban water problem

da bismo rešili urbane probleme sa vodom -

will flow with desalinated seawater.

kroz nju će teći desalinirana morska voda.

Now, I know what you probably heard people say about seawater desalination.

Pretpostavljam da ste čuli šta ljudi pričaju od desalinizaciji vode:

"It's a great thing to do if you have lots of oil, not a lot of water

"Odlično je ako imate puno nafte, a malo morske vode

and you don't care about climate change."

i ne marite za klimatske promene."

Seawater desalination is energy-intensive no matter how you slice it.

Desalinizacija morske vode uvek zahteva puno energije.

But that characterization of seawater desalination

Ali okarakterisati desalinizaciju vode

as being a nonstarter is hopelessly out of date.

kao neisplativu je apsolutno zastarelo.

We've made tremendous progress in seawater desalination

Ostvaren je ogroman napredak u desalinizaciji vode

in the past two decades.

u prethodne dve decenije.

This picture shows you

Na slici je prikazano

the largest seawater desalination plant in the Western hemisphere

najveće postrojenje za desalinizaciju na Zapadnoj hemisferi

that's currently being built north of San Diego.

koje je u izgradnji severno od San Dijega.

Compared to the seawater desalination plant

U poređenju sa postrojenjem za desalinizaciju

that was built in Santa Barbara 25 years ago,

izgrađenom u Santa Barbari pre 25 godina,

this treatment plant will use about half the energy

ovo postrojenje će koristiti oko polovinu energije

to produce a gallon of water.

da proizvede pet litara vode.

But just because seawater desalination has become less energy-intensive,

To što je desalinizacija morske vode postala manje energetski zahtevna

doesn't mean we should start building desalination plants everywhere.

ne znači da treba da počnemo svuda da gradimo ova postrojenja.

Among the different choices we have,

Među svim izborima koje imamo

it's probably the most energy-intensive

ovo je verovatno energetski najzahtevniji

and potentially environmentally damaging

i potencijalno najopasniji za okruženje

of the options to create a local water supply.

od svih opcija koje stvaraju lokalni izvor vode.

So there it is.

To je to.

With these four sources of water,

Sa ovim izvorima vode

we can move away from our reliance on imported water.

možemo da se udaljimo od zavisnosti od uvezene vode.

Through reform in the way we landscape our surfaces and our properties,

Kroz reforme načina na koji uređujemo površine i privatne posede

we can reduce outdoor water use by about 50 percent,

možemo da smanjimo potrošnju vode za oko 50%,

thereby increasing the water supply by 25 percent.

time bismo uvećali snabdevanje vode za 25%.

We can recycle the water that makes it into the sewer,

Možemo da recikliramo vodu koja završi u kanalizaciji

thereby increasing our water supply by 40 percent.

i time povećamo snabdevanje za 40%.

And we can make up the difference through a combination

Ostatak možemo da nadomestimo kombinacijom

of stormwater harvesting and seawater desalination.

prikupljanja kišnice i desalinizacije morske vode.

So, let's create a water supply

Hajde da stvorimo snabdevanje vodom

that will be able to withstand any of the challenges

koje može da izdrži bilo koji od izazova

that climate change throws at us in the coming years.

koje će nam klimatske promene postaviti u godinama koje slede.

Let's create a water supply that uses local sources

Hajde da stvorimo snabdevanje vodom koje koristi lokalne izvore

and leaves more water in the environment for fish and for food.

i ostavlja više vode u okolini za ribu i hranu.

Let's create a water system that's consistent with out environmental values.

Hajde da stvorimo sistem vode koji je u saglasnosti sa ekološkim vrednostima.

And let's do it for our children and our grandchildren

I uradimo ovo za našu decu i za naše unuke

and let's tell them this is the system

i kažimo im da je ovo sistem

that they have to take care of in the future

koji moraju da čuvaju u budućnosti

because it's our last chance to create a new kind of water system.

jer je ovo poslednja šansa da stvorimo novi sistem snabdevanja vodom.

Thank you very much for your attention.

Puno vam hvala na pažnji.

(Applause)

(Aplauz)