Chapter 3 Decision Support Model (IUWS-DSM) - Tubdok

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Chapter 3 · Decision Support Model (IUWS-DSM) 83
Total Water Demand vs. Water Sources in IUWS
(as demonstration)
situation 1: planning of new area situation 2: expansion of existing area
Scenario 1 Scenario 2 Scenario 3 Existing
status
Scenario 1 Scenario 2 Scenario 3
ext.src.
wa.reuse
rf.wa.
srfc.runoff
loc.src.
wa.demand
Figure 38: Strategic view of total water demand vs. water sources in IUWS (demonstration)
3.5.2 Water infrastructure
In the hierarchy of the IUWS, the system options of WIS are diverse, whereby the general
comparison methods are developed. It can be further progressed by model users according
to their situation and special requirements.
After deciding the system sizes based on the water usage, the comparison can be
categorised into three cases:
1. different system options of WIS with the same type of water usage,
i.e. comparison within water usage scenario;
2. the same system options of WIS with different types of water usage,
i.e. comparison between water usage scenarios;
3. different system options of WIS with different types of water usage,
i.e. comparison in the mixed situation.
In general, there are certain system alternatives that are interested mostly, so they shall
be involved in any case. Such alternatives are the conventional system, the system with the
lowest water demand, with the lowest costs, and with lowest energy consumption, etc.
As shown in Table 15, one complete set of WIS in one water entity includes seven parts
and the comparison focuses on two aspects that are costs and energy consumption.
Different system options may only effect changes of some parts in WIS, which are exactly
the portion that needs to be compared. The comparison thereby falls into two classes:
1. within the water entity;
2. crossing levels among water entities.
So the most general comparison between system options with the specified system parts
are given in Table 33 and Table 34. Besides, two classes of comparison may need to be
combined. One typical example is the comparison of water reuse: direct non-potable reuse in