Decision support system for managing stormwater and greywater quality in informal settlements in South Africa
Date
2009-07-09T10:45:14Z
Authors
Owusu-Asante, Yaw
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Abstract
Managing the quality of stormwater and greywater in informal settlements are essential to
their growth. In this thesis, methodologies are developed for the assessment and
management of stormwater and greywater quality based on the analysis of both nonstructural
and structural control interventions.
The objectives of the research were as follows:
· Review stormwater runoff quality and treatment practices and the extent of runoff
and greywater management in rural and peri-urban areas of South Africa. The
review was to also determine the extent of quality control awareness and
experience among stormwater management professionals and collate information
upon which present and future needs can be assessed and addressed.
· To develop a methodology to identify factors causing water quality management
issues in low-cost, high-density settlements.
· To develop a methodology to characterize storm and grey water quality as well as
setting ambient water quality and management objectives.
· To develop a methodology to identify and select potential non-structural and
structural control interventions to manage storm and grey water quality.
· Based on the above, to develop a decision support system for evaluation of
potential interventions for storm and grey water management at planning level.
The methodologies used to achieve the above objectives consisted of: literature review;
consultations with stakeholders; data analysis and computations; model development; and
model application.
The current status of managing water quality pollution in urban areas is outlined and the
related problems, specifically those applicable to developing areas are discussed.
Management interventions employed to date in the management of water quality effects
are set out and the applicability of such interventions to developing areas is identified.
The potential of expert systems is evaluated and the application of this system to
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stormwater quality management models is assessed. A decision support system (DSS)
was developed for rapid assessment of various water quality management interventions.
The model is primarily targeted at those who are involved or are likely to be involved in
stormwater quality management including catchment managers, local governments or
municipalities, catchment management agencies, private consultants and researchers.
The DSS and the related methodologies have been shown through Alexandra Township
(north of Johannesburg) case study, to be useful and to satisfy all the objectives set out
for the research. The results of the research are summarised and the merits and limitations
of the decision support systems are discussed. Recommendations for the direction of
future research and the development of the existing model are detailed. Specifically, it is
recommended that:
· Extensive monitoring be undertaken in order to improve the defaults in the model
· A research be undertaken into the extent to which GIS can be integrated to the
DSS to select appropriate management interventions and their sites
· A research be undertaken into privatization and partnership in the ownership and
operation of stormwater management systems.
· Selection of least cost strategy with the DSS is presently achieved by trial and
error process. The selection process can be improved if the DSS can be linked to
an optimizer.