1. Disaster: Global Fresh/Potable Water Shortage
Objective: Disaster prevention
Kristijan Bevc
Department of Geography, Faculty of Arts, University of Ljubljana, Slovenia

2. Reasons for selection
Source: (2) Source: (2)
 I have chosen this type of disaster since, in my opinion, it represents the biggest
threat to humanity
 The first signs are already here  40 % of the world population already have water
shortages (1)
 Water is essential for life; we cannot exist without it
 The more water we use and as of result pollute, the less of it will be available for us
and future generations
 This presentation presents some simple but concrete data on how fresh water is
(mis)used and gives possible solutions how to reduce fresh water usage or
completely remove it where it is not needed.
 Where there is no source listed, those values have been calculated by myself and
compared to “official” ones.
(1) http://www.lenntech.com/specific-questions-water-quantities.htm
(2) http://www.unwater.org/statistics_res.html

3. How, why, when?
 Human population is growing rapidly
 Earth’s resources are limited, water is no exception Source: (1)
 If the trend continues there will not be enough water to
sustain the entire human population
 The question is not IF, but WHEN will it happen if we
continue with wasteful and unsustainable use
 By 2025, 1,8 billion people will be living in regions with
absolute water scarcity and 2/3 of world population could be
under stress conditions (1)
 More populationmore foodmore irrigation=less water
(1) http://www.unwater.org/statistics_use.html

4. Problems already exist
 6 billion people already used 54 % of accessible fresh water (1)
 2,5 billion people suffer at least moderate shortage and 1-2 billion
high level of water scarcity (2)
 Today over a billion people do not have access to clean drinking
water (4)
 During the last century water consumption rose twice as fast as the
population did (1, 3)
 Toilet flushing uses at least 25 % of all the water used in a day by
a person
 If 4 billion people out of 6,5 (2,6 estimated to be without even the
basic sanitation facility (4)) use 40 liters a day (4 to 6 flushes) = 58
km3 of water in 1 year, which is roughly about 15 % of all fresh water
distributed for domestic use
(1) http://www.unwater.org/statistics_use.html
(2) Charles J. Vo ro smarty, Christian Le veˆque and others: Fresh water, URL: www.maweb.org/documents/document.276.aspx.pdf
(3) Deborah Zabarenko , Oct 25, 2011: Water use rising faster than world population, URL: http://www.reuters.com/article/2011/10/25/us-
population-water-idUSTRE79O3WO20111025
(4) WHO/unicef: Water for life (2005)

5. A simple model of what can be
done at home. Source: K. Bevc
Ideas for
conservation
 Without decreasing the world population growth this solution would
only postpone the inevitable.
 The idea is focused on preventing the disaster by changing the ways we use
water now, finding new solutions and potential ways of averting the disaster
 Conserving fresh water, dual water supply, drip irrigation are just a few of
the ideas how to optimize and reduce fresh water usage
 Potable/fresh water should only be used for cooking, drinking, showering,
washing clothes and dishes as depicted in the above picture
 Toilet flushing, car cleaning, watering the garden, fire-fighting, irrigation
etc., is a WASTE of fresh/potable water or uses too much of it.

6.  Dual water supply is essential if we want to conserve potable water. Toilets,
car washes, watering the garden and other household chores, industrial
companies that don’t need clean fresh water for production and firefighters
should use recycled water or filtrated storm water.
 Dual water piping needs to be built; one supplying clean potable/fresh
water and the other filtrated storm water or recycled waste water; regions
located near a salt water source can even use salt water too
 Construction of the dual water piping would cost the same as the regular
one, but costs can be reduced if both systems are installed at the same time.
 Since this can only be done when constructing a new building, existing
buildings and structures would be hard to modify for the dual piping
system, thus, at least all future buildings yet to be constructed would have
to have this system implemented.
 Agriculture is the biggest user of fresh water, water conservation should be
applied there first; with new techniques like drip irrigation to minimize
evaporation and maximize water delivery efficiency
 FAO estimates this system can reduce water usage by 30-60 % (1)
(1) http://www.fao.org/ag/magazine/0303sp3.htm

7.  Another simple way of conserving water, where dual water
supply cannot be implemented, is the dual-flush toilet; an
option to either flush using the entire water tank or just flush
with half the amount, depending on the “situation”.
 A dual-flush toilet can use up to 40 % less fresh water
 Simple calculation: using 10l and 8l tank; 4 times liquid waste and one
solid waste (1 to 2 full flushes) per day
 Full flush: 4x10l+10 to 20=50 to 60l ; 4x8l+8 to 16=40 to 48l
 Half flush for liquid waste: 4x5l+10 to 20= 30 to 40l ; 4x4l+8 to 16 =
24 to 32l  40 to 30 % less fresh water
 All industrial companies should have a closed water loop for
production  the same amount of water in the system all the time,
no use for additional fresh water or should use recycled/filtered
water instead of fresh where the loop in not possible.
 Since city population is increasing, storm water should be filtered
and reused for purposes already mentioned above, getting cities one
step closer so self-sustainability

8.  The proposed solutions are pretty straight forward, making fundamental
changes at the heart of the problem. Toilets are a big problem but at the
same time the easiest to solve.
 Large scale projects like dual water supply, storm water filtration and drip
irrigation require a lot more planning and even more funding.
 Instead of governments giving subsidies for water to farmers, giving
subsidies for drip irrigation implementation would be a lot more
beneficial (where applicable).
 Fresh water usage needs to be cut by all sectors by providing new
technology solutions that can greatly optimize and reduce use of fresh
water, especially in agriculture.
 Humanity is driven by innovation and all the solutions presented are a
product of it. Dual pipeline from Hong Kong since the 1950’s (1), refined
drip irrigation idea from Israel, storm water filtration from various cities
in the world, dual-flush toilets from all over the globe.
 All these solutions are already integrated in some parts of the world and
are being considered more and more. The results of their effect are
encouraging, giving the humanity the opportunity to use its innovation to
avert a potential disaster. Immediate implementation is crucial.
(1) http://www.southtravels.com/asia/hongkong/traveltips/hk_watersupply.html

9. Goals and targets
 The proposed solution is aimed to reduce the quantity of used fresh water in all
sectors (agriculture, industrial and domestic sector), to optimize its usage or to
completely remove it from operations that do not need fresh/potable water.
 By eliminating fresh water usage by toilets, firefighters and all other mentioned
proposals, we can save a huge amount of fresh water that can be distributed to
households, hospitals and other locations that desperately need it. Estimation: 100
% less fresh water usage by substituting fresh water with recycled/filtered for
toilets or 30 % by only implementing dual-flush toilets.
 With dual water supply and storm water filtration, cities can become more self-
sustainable, since world trends show a continuous increase in urban population, most
of the solutions in the future will be focused on urban areas.
 By implementing drip irrigation in agriculture, huge amounts of fresh water can be
saved and allocated elsewhere. Estimation: 30-60 % less fresh water usage
 To prevent world population from using 75 % or more of all accessible fresh water
sources in 2025 and more than 90 % in 2050, bringing both % numbers down.
 To prevent an even greater fresh water scarcity in regions where the problem already
occurs or is starting to manifest, thus preventing desertification and decreasing the
number of population infected with water-related diseases.

10. Impact and arguments
 Fresh water usage should drop significantly and be diverted where it is
needed most. Regions under water stress could receive more fresh water.
 Cities would pump less water, because of storm water filtration which would
be used for toilets and firefighters, thus being more self-sustainable.
 By reducing fresh water usage future generations are given a chance for
better living conditions. More recycled and filtered water means less
depletion of it=larger bodies of water=higher regeneration ability=less
polluted=less water-related diseases
 The questions whether the solution will work will undoubtedly arise. The
presented arguments about that are clear, with the right technology and
implementation; good results are inevitable, global examples of good
practice confirm that.
 Since the solution is aimed at the biggest fresh water users it should have the
maximum effect.
 Israel, using water treatment and recycling, recycles more than 80 % of
household water and half the water for irrigation is from recycled water (1).
(1) http://www.reuters.com/article/2010/11/14/us-climate-israel-idUSTRE6AD1CG20101114