Systems Analysis of Zaragoza Urban Water - SWITCH - Managing ...

Systems Analysis of Zaragoza UWS
Guillermo Penagos
network. There are online meters at most facilities, but there is no data base.
Therefore it is not possible to differentiate actual leakages at the distribution network
from other factors contributing to unaccounted water, which has been reducing
during the last decade, but still continues to be considerably high.
In 2002, starting point of the water supply improvement plan, unaccounted water was
as high as 34 million m 3 a year, nearly 45% of total withdrawal. Municipality
estimated by that time approximately 17 million m 3 to be actual leakage in the
distribution system, but this is just a rough estimation. In 2006 unaccounted water
was around 32% of total withdrawal (see table 2). The goal is to reduce it below 15%.
The main demonstration activity for Zaragoza within SWITCH project is to carry out a
complete water balance for one sector of the city in order to improve the current
knowledge about water consumption and leakage in order to reduce the percentage
of unaccounted water.
4.2.4 Water use
As it can be seen in figure 2, domestic use accounts for approximately the 62% of
metered consumption. Industrial activities represent the 36% and public facilities plus
landscaping consume only 2%.
Data concerning water withdrawal and water consumption from 1997 –when
campaigns for rationalizing water use at households and industries started– to 2006
are shown in table 2. Along this period water withdrawal has been reduced by 20
million m 3 year -1 due to both consumption reduction and infrastructure upgrading.
Along the last decade domestic consumption has gone down from 140 to 110 l
person -1 day -1 , leading to 6 million m 3 year -1 less withdrawal; even with population
increasing with around 50 thousand people during the same period. Thus
infrastructure upgrading accounts for 14 million m 3 year -1 reduction.
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