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Water Supply Options
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From the course by Johns Hopkins University
Public Health in Humanitarian Crises
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From the lesson
Module 3: Water and Sanitation
This module describes the burden of, and mechanisms of, sanitation and water-related diseases in humanitarian crises. We also illustrate the various strategies and priorities that can be used to reduce outbreaks of those diseases.
Meet the Instructors
Gilbert Burnham, MDProfessor
International Health
Mija VerversSenior Associate
Health Systems
So, just as there are variety of options available for dealing with sanitation,
there's a variety of options available for dealing with water supply.
It isn't clear to me now,
whether giving people cleaner water or more water is better.
I think that once people are in Europe, once people are living
at a really high standard, water quality issues become the dominant issue.
But I think, more or less, for most of the world, giving people
more water is probably more protective than giving people cleaner water.
That varies over space and time, but I think it's a general, general rule.
And there are several ways of getting people more water.
You will find people collecting rain water, and this is a great thing.
Rainwater falls from the sky microbiologically pure.
It may actually in the case of these Arundian huts.
It may pick up a bit of bird feces as it runs off that piece of metal sheeting.
But most people know this and actually there's dust on the roof as well.
So when it starts raining they'll wait just three minutes and
let the first flush of water come off and then they'll put their pots and
buckets out there and so you're getting microbiologically high quality water.
It is right next to the home.
They don't have to carry it, they don't have to wait in line, they don't have to
struggle with people at the well, or who's next, it's just great, in that regard.
So, here is a woman, in Burundi and
she was consuming four times more water than all of her neighbors.
And when someone brought the data form back to me I said, this is weird.
Why is this woman consuming almost 50 liters per person, per day.
Can we go back and talk to her?
So we went back and we had a little conversation and
she took us out back behind her house.
And you can see that she had taken a little bit of metal sheeting and
it's hanging up with a piece of wire, sort of like a coat hanger.
And she's now got a 200 liter barrel.
I don't think all this together cost five Euros.
This is very, very little cost of stuff and yet it was allowing
her in the rainy seasons to be consuming five times more water than her neighbors.
What a fascinating, fascinating thing.
Admittedly, in Burundi, there are only two rainy seasons and
it probably only gives her her water for 80 or
100 days out of the year but what a great benefit for those 80 or 100 days.
The more dry a place is,
the harder it is to get a significant amount of your water from rainfall.
So there are lots of places, like this clinic in Ethiopia,
where people will collect water during the water rainy season and
try to store it and keep it for some period in the dry season.
And this is completely driven by economics as to whether or not it's a good idea.
If you can run a pipe from some other source and
have a year round supply well then maybe investing in storage doesn't make sense.
If you're bringing water here by a tanker truck for this clinic,
then probably having storage vessels like this and trying to
get through a few extra months makes a lot of sense and is very, very cost effective.
Usually there's some system to it and they will allow that first little bit of
rainfall to be flushed off the roof before it starts coming into the cistern.
If this is going to go on for months and the water is going to be here for
a long time, you might need to think about controlling mosquito breeding in it.
But by and large, this is a great, great technology.
Here's a place in Zimbabwe, where there's a river and it's run dry and
people are digging in the bottom of the river to keep down to where the water is.
The engineering term for this, is a well.
A well is a hole in the ground that gets down to the groundwater.
Here's a somewhat better well in Uzbekistan.
This well is better because it
has a nice set of rings that come up above the surface so
it's preventing any rainfall from running down in the pit or anything like that.
Moreover if you look carefully,
the land is grated just a little bit away from that well.
So if one of these self-propelled fecal dispension units on the left washes off
their dirty body, and there is fecal material in water flowing onto the ground,
it's going to seep away from the well, and then percolate down in the ground.
Rather than shunting right back down into everyone's drinking water.
There are a huge variety of kinds of pumps that people use.
Having a concrete platform over it like this, compared to the last open well,
does help protect all the unsanitary things that are going to happen over there
above ground from getting down into people's water supply.
And there isn't any one kind of pump or well that's the best one.
If people have special needs, if people need to have a trough for
their cattle, well, that's what they need, that's cool.
So in terms of well technology, there is a tendency to say
the India Mark Three is the best pump, and that's what our NGO is going to install.
But just realize, doing what people want is what's going to make these
sustainable in the long haul and by and large most of the wealth that
have been made across the globe have fallen into disrepair and been abandoned.
And the ones that haven't are maintained through an ongoing
process by which money is collected and maintenance is provided.
Maybe it's collected from an NGO or a donor, but most of the time,
it's collected from the community.
And having people enthused about your structure is as important
as the advantages of one particular pump over some other.
There are places like this hillside in Congo
where the ground water naturally pops to the surface.
The phrase for this is a spring.
Springs have many advantages.
Generally, if the water has been moving through the ground for
a long period of time which is the norm.
A long period of time being months or
years It will come out relatively microbiologically pure.
There are exceptions to that of course, but by and large spring water has been
filtered by the ground already, so it's coming out clear.
There's no moving part to this, unlike a hand pump, so sometimes these springs,
in this case, they've taken a hillside here and they've sort of dug a box.
They dug a square into the hillside and created a concrete box and
we're looking at the wall where those children and
people are standing that's at the close end of that box.
And that box fills up with water, they've covered it over and
that there is a top of the box and now there is dirt on top of it as well.
And the water pops out of a pipe, so there's nothing moving.
Sometimes these will silt in and you have to sort of open up the box and
dig the silt out but often these go for years and years and
years without any need for maintenance or doing anything.
So springs, high quality water, cheap to operate, easy to maintain.
The trouble is, nature determines where you can have a spring, by and large.
And nature does that by having lots of rainfall and lots of sloping terrain.
You don't tend to find springs in very, very flat areas.
You don't find springs generally in arid areas.
Wet climates, hilly terrain, that's what's conducive to springs.
I said, by and large, there is sort of one exception to that.
There is a fascinating technology in the Middle East.
And it's called Different Things in Different Places.
So here we are, we're in Afghanistan, where they call it a kodi.
Elsewhere, they call it a canot or a carez.
And we're looking at the end of an opening of a spring, but that spring is actually
a tunnel, a shaft that's been dug into the hillside and
this one goes in over a kilometer into the hillside there.
It took hundreds of years to dig this shaft.
So someone would start digging it and their great, great, great, great,
great grandchildren would get the water from it.
There is quite a bit of cultural sophistication about who gets to sample
the water first and how the animals can only take water at the end of the flow.
So springs, nature determines it except there are a few places
where man can sort of twist nature's arms just a little bit.
If you have a population that's in any sort of settlement or
with high density, in most settings, the cheapest thing to do,
the most reliable thing to do over time is to have a piped water supply.
The trouble is it takes a lot of capital investment
to get a pipe water supply going and it takes a lot of operation and
maintenance to keep a pipe water supply running.
So many NGOs who show up in a crisis and know they're only going to be there six
months or a year are not prone to wanting to make a pipe water supply.
Because they know as soon as they go no one will be there to operate the plant and
chlorinate the water, do whatever.
Whereas with a hand pump,
there's lots of locals who know how to maintain those things.
And secondly it takes some social organization to be able to collect
fees and come up with the ongoing resources to run a piped water supply.
So it would be, you can imagine, difficult in a very corrupt society,
to have any sort of ongoing pay for
water system that maintains a piped water network.
So It's a challenge.
Just realize if people are going to be somewhere ten years
it almost always is the most cost effective solution for them.
And it will provide the safest water and the most health benefits.
When you provide piped water a whole bunch of other good things happen.
Certain economic opportunities arise.
Certain senses of permanence arise.
Which may not be to the pleasure of the host government, so pipe water supplies,
they're, they're a little tricky but the nice thing about pipe water is,
that you can easily chlorinate water for a lot of people.
And chlorination is the solution for us in emergencies when we have
a water quality problem, with regard to fecal contamination.
Here we have some folks there in the country of Malawi.
And they're ladling two milligrams per liter
of free chlorine into every bucket that people are collecting at these wells.
And that is a great, great solution to both killing any viruses or
bacteria that are coming out in that well water, or for like neutralizing
any contamination that's going to happen as the people collect that water.
Chlorine, it is a great option and a nice thing about chlorine is, if people
are chlorinating somewhere there will be a residual in the water and afterwards
you'll be able to tell did this household get chlorinated water, or did they not?
And, you'll be able to test, and, if they said, yes, I went to the well where
they're chlorinating, I'm very attentive about this.
And you test their water, you can know whether or
not they were telling the truth, and
you can tell whether or not people at the well were adding enough chlorine.
But, chlorination, it is the solution to water quality challenges.
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