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

1.3 Scope of the research
1.3.1 Research objectives
Chapter 1 · General Introduction 7
This research work comprises three water systems, i.e. drinking water, wastewater and
rainwater systems, into one integrated urban water system (IUWS) and subsequently,
establishes a decision support model (DSM) that is specially for planning IUWS in the early
project phase. Instead of generating concrete and absolute values, the model provides more
orientation sense with appropriate comparison in selecting the sustainable and reasonable
urban water systems. The model is designed for water consultants and city planers, as well
as concerned authorities.
Cost is selected as the main criterion for evaluating the systems. Energy consumption is
another independent and optional criterion for evaluating and comparing IUWS. Certainly,
the energy consumption can be represented by the cost.
1.3.2 System Boundaries
Factually, the system boundaries equal to the boundaries of the object-city. If it is a
megacity, like Hamburg, Shanghai and New York, it can be physically one independent
district of the city. As the objective, water enters the system from the water intake and leaves
the system after it is discharged into the natural water bodies. The natural processes, such
as precipitation and evaporation, etc., are not included, as this work focuses on urban water
usage and water infrastructure. Within the area of the object-city, water users, water sources,
water infrastructure including water intake, treatment, transmission, distribution and collection
facilities are considered.
1.3.3 Application fields
In urban area, two kinds of situation are usually confronted:
1. planning of a new water system,
2. expansion of an existing water system.
In the first situation, the new water system can be designed for the whole city, but more
often, it is for the new spread urban districts that have no water infrastructure at all. The
second situation can also include two different situations. The upgrade of the water system is
either for the whole city or for certain district(s) only. Moreover, there can be the mixed
conditions, i.e. the water systems needs to be planned for both the new spread districts and
existing area simultaneously. All situations need to be properly dealt with.
Thereby, the new conception is conceived and created. The decision support model is
subsequently developed, which is used to plan and design the IUWS in those different
situations.