9Structural Controls - Department of Water - The Western Australian ...

Figure 6. Flush kerbing to allow dispersion of
road runoff into adjacent parkland. (Photograph:
Department of Water 2006.)
The measures implemented individually could not have successfully managed the stormwater for the
catchment. However, the cumulative impact of the combination of several measures has ensured that only
large events reach receiving water bodies via overland flow.
The outcomes of the stormwater management approach implemented in this development demonstrate the
potential environmental benefits, as well as cost savings that can be achieved. Distributing management
measures throughout the catchment and utilising overland flow paths, instead of collecting and conveying
flow in one centralised system, can result in significant reductions in piping and associated infrastructure
requirements.
Located close to the high value environments of the Ramsar recognised Peel-Harvey Estuary and a
Conservation category wetland, the Bridgewater South Estate development required a sensitive approach to
stormwater management. As the Peel-Harvey Estuary is an iconic landscape that is valued by the community,
actions to protect its qualities were supported by residents. Community awareness about the importance of
protecting the estuary had been raised by their experiences of the major adverse impacts caused by water
quality degradation, such as fish kills and algal blooms.
The levels of bubble-up pits and overflows in the stormwater system required some minor adjustments to
fine tune retention and pooling times in the detention areas. These adjustments have resulted in a system
that performs well and is acceptable to the community.
Acknowledgments
Information and feedback provided by Mr Grahame Heal, Manager Infrastructure and Services, City of
Mandurah.
References
Bureau of Meteorology 2007 .
Beachridge Estate, Jurien Bay
Project description
Figure 7. Bubble-up pit located within a swale at
the downstream end of the catchment. (Photograph:
Department of Water 2007.)
Beachridge Estate is the first stage of development of a 2000 hectare coastal bushland estate south of
Jurien Bay in the Shire of Dandaragan. Jurien Bay experiences a Mediterranean-type climate, with hot,
dry summers and cool, wet winters (Figure 1). The site is characterised by sandy soils and a shallow water
Stormwater Management Manual for Western Australia: Structural Controls 27