In the previous post I outlined the basis of the Water
Stress Index and how it can provide an idea of sanitation levels around the
world. However, as I said, there are many components that the Index fails to
take into account: spatial and temporal variations, quality and access to
water, all of which hugely affect sanitation.
Lack of access to water is not necessarily a consequence of
a national shortage; in fact, very often significant numbers face inadequate
access to clean water despite living in a country that is not water stressed. This
is because of economic and physical barriers affecting availability, which vary
from place to place. Affordability and infrastructure play a major role, and
differences are especially marked between urban and rural areas. For instance,
in sub-Saharan Africa only 5% of the rural population has a piped water supply
in their homes, in contrast to 35% of urban residents (UNEP 2012). The
most important factor that affects urban water usage in East Africa is whether
households have access to a functioning piped system. During the 1960s, a
person in a piped household consumed eight times as many litres as someone in
an unpiped household. In 1997, the latter walked on average about 300m to
unprotected sources to obtain water, increasing the risks of poor hygiene and water-borne
diseases (Thompson et al. 2000). This demonstrates that although an area may physically
have sufficient water (especially when considering water storage and
groundwater, not accounted for in the Index calculation), it is not
inexpensively, easily and safely available to all. It is access to and quality
of water that define sanitation.
Water quantity in a country changes over the course of the year;
seasonal differences are not taken into account by the Water Stress Index. As
an annual national average, the Index does not take into account that at some
times of year there are great quantities of water present, whilst at others
there are severe shortages. Rainfall and river flow (especially the upper
course) can have strong seasonality in sub-Saharan Africa and is more and more
variable between years as a consequence of global climate change. In Namibia,
though renewable water resources are plenty (at 45.5km3 per year, or an average
of 26,300m3 per year), river flow is extremely seasonal (Taylor 2004). In the
month of February rainfall is around 66mm, but in July it is roughly 0.6mm
(World Bank – see graph). The changes in water availability force individuals
to ‘draw water from a mix of sources through the year’. This is not
investigated at all by the Water stress index, suggesting that it cannot represent
the ‘spatial and temporal variability in the supply and demand of water’ (Taylor
2004: 14).
Average monthly rainfall for Namibia 1960-1990. Source: World Bank |
A question that must be addressed is: what do we actually
mean by ‘water scarcity’? According to Frank Rijsberman (2006: 6), it is when
many people in an area are ‘water insecure’ (do not have access to safe,
affordable water to meet drinking, washing and livelihood needs) for a
‘significant period of time’. In truth, there is actually no widely accepted
definition, since it must be considered very much on a case-by-case basis. What
can be deemed “scarcity” depends on how needs are defined, the potential
proportion of the resource that could be made available, and temporal and
spatial scales. A vital element of good sanitation is full and constant access
and use of safe water sources. Nevertheless, in some of the most water scarce
countries in North Africa, sanitation levels are high. This is because of other
factors also affect sanitation, such as the prevention of food contamination
and access to sewage infrastructure or flush toilets. In 2004, Morocco had a
coverage of improved drinking water resources of 56% in rural areas, but the improved
sanitation rate in these same areas was almost 75% (UNICEF 2006). It is
extremely questionable whether there is truly a relationship between water
stress and low levels of sanitation.
A measure as one-dimensional as Falkenmark’s Water Stress Index
does not capture the essence of water scarcity, let alone what this means for
sanitation. To use the Index as a main indicator for sanitation would be to say
that sanitation is principally affected by water quantity in a country, without
looking at other factors that determine sanitation: affordability, quality,
infrastructure for water provision, investments in sanitation facilities,
health literacy… The Water Stress Index does not illustrate access to clean water,
nor how this varies over time and space, and therefore fails to indicate how
sanitation and water truly correlate.
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