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ABSTRACT
This thesis attempts to explore alternative solutions to the
conventional drainage system which has now been realized that the
drastic discharge of rainwater resulted in significant ecological
damage. The detrimental effects mainly concern the reduction in the
natural ground water recharge, the increase in flood discharge and
the considerable pollution of surface water. Since these
disadvantages resulted in high costs for subsequent remedial
measures (flood control, etc) widely applicable alternatives were
needed.
This thesis outlines the national approach to stormwater management
in Malaysia, and evolving implementation practices by State and
Local government authorities. In response to the needs for paradigm
shift the way the stormwater is managed, the Malaysian Government
has introduced a new approach of planning and design of urban areas
through the New Stormwater Management Manual for Malaysia (MSMA)
that offers a sustainable solution for integrating the land
development and urban water cycle. The research focused on new
concepts for the urban stormwater runoff and the water quality
management based on integrated stormwater solutions. The USM
Engineering campus is a pilot project for urban stormwater
management strategy as an example of an ecologically sustainable
development based approach to urban stormwater management. The
concept is based on open and natural drainage systems integrated
into multipurpose open space/environmental corridors or greenways,
is the most promising approach in newly developing or urbanizing
areas.
This thesis aims to introduce such an alternative - the "Principle
of Control-at-Source" based on Storage-Oriented Approach. With
respect to its technical implementation the term "Bio-Ecological
Drainage Systems”), further in this text referred to BIOECODS) has
prevailed. The BIOECODS combines four engineering techniques to
manage stormwater based on “Control-at-Source” approach namely
infiltration, storage, conveyance and treatment by integrating the
drainage components (i.e. ecological swales, on-line sub-surface
detentions, and dry ponds) with the ecological pond components (i.e.
detention pond, constructed wetland, wading stream and recreational
pond). In combination, this approach increases runoff lag time,
increase opportunities for pollutant removal through settling and
bio-filtration, and reduce the rate and volume of runoff through
enhanced infiltration opportunities. With this new approach, the
main bulk of stormwater is collected and stored at its source to
allow natural cleaning to occur prior to infiltration or controlled
release to watercourses to reduce impact on river capacity.
Bio-Ecological Drainage System (BIOECODS) is an example of an
innovative sustainable urban drainage system consists of different
stormwater drainage facilities suggested in MSMA that designed to
restore the natural environment implemented at USM's Engineering
Campus with the following objectives:
• Promotion of stormwater infiltration from impermeable areas (e.g.
roof tops, car parks) by using bio-ecological swales
• Gradual release of stormwater through the use of bio-ecological
swales, on-line underground bio-ecological detention storages and
bio-ecological dry ponds
• Treatment of stormwater quality using treatment train concept by
utilising bio-ecological swales and bio-ecological ponds (e.g. wet
pond, wetland) as the storm water moves downstream.
This thesis first introduces the survey study on the current
stormwater management practices in Malaysia. The preliminary study
has shown that the Urban Stormwater Management Manual (MSMA) was
written based on overseas experience with limited local data and
information of local conditions. In order to understand the current
stormwater management practices in Malaysia and the deficiencies and
errors in the MSMA manual, the surveys were conducted in order to
evaluate the status of the stormwater management practices in
Malaysia such as issues on public awareness, design aspect, best
tools of stormwater facilities, errors or deficiencies in MSMA
manual, cost, maintenance and public acceptance towards the MSMA
manual.
In order to understand the behaviour of on-site source control
facilities, this thesis also investigated the small scale pilot
project of subsurface infiltration and storage tank system (on-site
retention/detention system) to control stormwater quantity in
Engineering Campus Universiti Sains Malaysia, Tronoh, Perak. The
objective of the project is to implement the on-site source control
and distributed storage systems to attenuate the peak flood
hydrograph and volume by using three different infiltration and
storage techniques namely module infiltration system, loose rock
infiltration system and module storage tank system. The results were
used as basis for the development of full scale pilot project of
BIOECODS.
The basic principles of the design and concept of BIOECODS are
discussed in detail in this thesis followed by a description of
technical and constructions of BIOECODS. The objectives of the study
for BIOECODS are focused on the hydraulic performance, water quality
treatment train performance and the economic evaluation. In order to
study the effectiveness of the full scale pilot project BIOECODS in
treating the stormwater runoff, a storm water quality monitoring
programme is being carried out by two methods namely grab sampling
and automatic sampling method at ten sampling stations along
ecological swales and at eight sampling stations along ECOPOND. The
hydraulic performance of the BIOECODS system is focused on the
ecological swale, dry pond and ecological pond. The effectiveness of
an ecological swale is considered from the aspect of quantity
control in terms of peak flow attenuation. The operational
functional of a dry pond is calculated in terms of its capability to
retain and drain the storm water. Dry pond is an off-line storage
designed with the function to reduce peak discharge at the
downstream by infiltrating through the layer of topsoil and river
sand into the storage module underneath before flowing to the
downstream of the sub-surface module of the swale. In addition, the
Storm Water Management Model (XP-SWMM) is used to model and simulate
the hydrologic and hydraulic performance of BIOECODS. Finally, the
economic aspect of BIOECODS is studied by developing a simple method
to conduct life cycle cost (LCC) analysis of BIOECODS. The simple
LCC method was applied to a pilot project of USM Engineering Campus
and it is found that the BIOECODS method has a lower capital cost
but due to higher maintenance cost, its life cycle cost is little
higher than the traditional method. However, the study has shown
that the little increase in life cycle cost associated with the
BIOECODS method can be balanced with the long term benefits gained
from this innovative urban drainage system as part of sustainable
approach in the new development area.
Overall, the outputs of this thesis give a useful insight into the
status of stormwater management practices and effectiveness in
Malaysia that will help with the development and delivery of new
updated version of MSMA manual. Moreover, the results obtained from
small scale project for on-site retention/detention systems and full
scale project for BIOECODS have confirmed the good performance of
the systems in attenuating the peak runoff and treating the
stormwater runoff. Finally, the results can be used to support the
MSMA manual with a local data for the updated version of MSMA manual
in the next five years.
Effective new concept of Stormwater Management Manual for Malaysia (MSMA)
is not easy to achieve and requires an innovative approach and
commitments from all the key stakeholders. Furthermore, developing
technologies or new approaches of stormwater management to improve
the environmental protection and enhancement will always lead to
temporary spatial and procedural inconsistencies. These issues can
be seen as areas for development: addressing them allows the overall
approach to be improved. It is only by methodically evaluating
progress and barriers, and strengths and weaknesses at the grass
roots level that these valuable lessons can be learnt and shared for
the benefits of the nation.
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