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

Systems Analysis of Zaragoza UWS
Guillermo Penagos
% of Impact regarding upstream
concentrations
500
400
300
200
100
Current impact
2020
2060
0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Month
Figure 27. Seasonal variability of impact percentages of Zaragoza UWS on the Ebro River taking
TP as example. Current and future scenarios.
If the differences between upstream concentrations and the predicted ones are
converted into percentages, then these can be called impact percentages on the river
and might possibly be used as indicators for sustainability. Figure 27 shows such
percentages, again with reference to TP as an example.
Current scenario shows an impact below 20% from November to May. Again in June
it begins increasing and it goes up to 110% in August. For the 2020 scenario the
peak impact also in August is nearly 150%, and finally the seasonal impact peak for
the 2060 scenario goes up to 350%.
Table 7 shows the values of these seasonal impact peaks for BOD, COD, TN, TP
and Heavy Metals at: 1) current, 2) 2020 and 3) 2060 scenarios. Interestingly the
highest value goes to TP with 110% for present scenario, followed by COD with 50%,
TN with 33%, Heavy metals with 17% and finally BOD with 13%.
Considering these results it would be possible to say that priorities for Zaragoza
UWS to increase its environmental performance, at least with regard to the receiving
water body are as follows:
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