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

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

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<strong>Chapter</strong> 5 Summary<br />

<strong>Chapter</strong> 5 · Summary 95<br />

Conventionally, three water systems in urban area, i.e. drinking water supply, wastewater<br />

disposal and rainwater elimination, are planned, designed, and managed individually. Very<br />

often water supply and wastewater disposal systems are centralized systems, where<br />

rainwater is eliminated from cities as soon as possible. It has been realised that such kind of<br />

urban water systems is neither sustainable nor optimised. Today, the water scarcity is<br />

becoming the global problem due to many man-made reasons, such as population explosion,<br />

water pollution, industrialisation and urbanisation. Hence, the better solutions of our urban<br />

water systems are desiderated.<br />

The cycle makes the world endless. The appropriate cycle makes the nature balanced.<br />

Thus, the water cycle in urban area needs to be properly closed, too. As two sides of urban<br />

water systems, water usage and water infrastructure need to be properly matched. Based on<br />

these ideas, the new conception for integrated urban water system (<strong>IUWS</strong>) is conceived. The<br />

conception is further developed into the decision support model <strong>IUWS</strong>-<strong>DSM</strong> that is a tool for<br />

planning <strong>IUWS</strong>s in the early project phase. For having the clear overview of the dissertation,<br />

the systematic structure of the dissertation is sketched in Figure 41. Following the arrows,<br />

the ideas and systems can be easily discerned.<br />

First of all, the urban water system is structured in the hierarchy, where the entire water<br />

system is divided into four levels including two types of water entities, i.e. ZONE type and<br />

GROUP type. The water entities of ZONE type cover the first two levels in the hierarchy, and<br />

the water entities of GROUP type form the third and the fourth levels. From top to bottom,<br />

four levels are: a. City Area (CA), b. Urban District (UD), c. Water Utilisation Unit (WUU) and<br />

d. Water Utilisation Cell (WUC). CA represents the whole water system or one absolute<br />

independent water system in urban area, which is going to be the <strong>IUWS</strong>. UD is the divided<br />

urban area that is contained by CA. It can either coincide with administrative canton or be the<br />

natural division. WUU is the certain functional unit or group in cities and subsequently, its<br />

water system can be managed and coordinated as one entity, e.g. a university or a hospital<br />

or two adjacent residential quarters. WUC has the same structure as WUU but on the small<br />

scale that mostly focuses on the single large buildings or mono- water end-users. The<br />

hierarchy is the base of the <strong>IUWS</strong>. (§ 2.1.3, p. 11)<br />

For constructing the <strong>IUWS</strong>s, the essential components in urban water systems are reidentified.<br />

First, the new terms are defined: Desired water has the quality that satisfies the<br />

requirements of end uses. Used water is substituted for the conventional term “wastewater”<br />

and includes different types of urban sewage. Desired water quality is further categorised.<br />

Besides drinking water quality (represented by Quality A), other two categories (represented<br />

by Quality B and Quality C) are set up in order to adapt to the variety of required water<br />

quality in cities. Based on the characteristics of used water, the source separated collection

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