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

2.3 Integrated Urban Water System (IUWS)
Chapter 2 · New Conception 41
As an integrated system, all five subsystems are joined and considered at the same time.
The system options for IUWS are developed. In the hierarchy, the planning process of IUWS
is completely different, whereby a procedure is newly developed. A demonstration is
presented in order to provide a comprehensive image of IUWS.
2.3.1 Options
If rainwater and/or water reuse systems are added in, the IUWS will be systematically
changed. Both rainwater and reclaimed water can be used in either direct or indirect way.
The key difference between direct and indirect utilisation/reuse is that the direct utilisation/reuse
system changes the system structure and the infrastructure sizes, where the
indirect utilisation/reuse only influences the arrangement of water sources. Correspondingly,
four types of water system are identified (Table 14).
Table 14: System types of water entities in IUWS
no. type abbreviation specification
1 basic system
only use conventional water sources
2 adding rainwater utilisation systems
1. surface runoff utilisation AND
2. roof-water utilisation
3 adding water reuse system
1. indirct potable reuse OR
2. direct non-potable reuse
4 adding both rainwater
and reuse systems
Sys. Base i.e. conventional system
Sys. +Rainwater two options can occur at
the same time
Sys. +Reuse two options are mutual
exclusive through all
levels in the hierarchy
Sys. +Both it follows the above roles
As an integrated system, all components of WIS need to be taken into account in the
same time. In the WIS, seven parts are identified:
i. abstraction & transmission
ii. raw water treatment
iii. distribution (networks)
iv. collection (sewage sewer + storm drain)
v. used water treatment
vi. rainwater utilisation (surface runoff)
vii. rainwater utilisation (roof-water)
In Part iv, collection includes both sewage sewer and storm drain, as they can be either
separate or combined. Part vi and vii are both for rainwater, as the utilisation of surface
runoff and roof-water are two parallel independent systems. On the contrary, water indirect
potable reuse and direct non-potable reuse are mutual exclusive through all levels in the
hierarchy because in one system the water can be reused only once (in one time of water
cycle). Water reuse system consists of treatment and distribution, which are included by Part
v and Part iii respectively.