Water quality in
the Mounts Bay Catchment
The Mounts Bay Drain is part of a
drainage system which connects Lake Monger to the Swan River at Mounts Bay,
in front of Perth city. The Mounts Bay Drain was constructed in 1909
to allow water levels in Lake Monger to be regulated.
Prior to this, Lake Monger was part of the chain of lakes north of the city
which were interconnected
during the wet season and drained into the river through Claise Brook.
Overflow from Lake Monger, flows via the Mounts Bay Main
Drain (MBMD), discharging into the Swan River at
Mounts Bay through an outlet west of Barrack Square.
The Claise Brook Catchment Group has
been concerned for some years about water quality
within this catchment and within the receiving waters which is the Swan
River and particularly Mounts Bay.
Due to the urbanisation of the catchment
and other reasons, the water quality is poor and pollutants tend to get
trapped in Mounts Bay which is poorly flushed by tides or river flow. Water
quality is also of concern in the water bodies within the catchment
including the lakes within the Narrows Interchange which are an important
recreational area for visitors to the city as well
as the increasing number of city residents.
The area between Lake Monger and the
Swan River has been highly modified since 1829. Firstly the wetlands were
used for market gardens, then the railway line was built (opened 1880) and
Perth’s first industries developed along the railway line before drainage
and sewerage were extended through the area. More recently the Narrows
Bridge was built, followed by the freeway and the Narrows and Hamilton
Interchanges which required additional drainage. Most recently the
Northbridge tunnel was constructed and the Perth Mandurah railway, which
passes through the narrows interchange, was recently completed.
Future development of the river
foreshore in the Narrows Interchange area is proposed and the catchment
group considers it important that water quality problems are addressed as
part of any future development within this catchment.
Many managers
There are many Stakeholders in the MBMD
system. The MBMD is a declared main drain and is owned and operated by the
Water Corporation. In the upper catchment the City of Subiaco manages Mabel
Talbot Lake, which feeds into Lake Monger. The Town of Cambridge manages Lake Monger and controls
the outlet weir which allows water to enter the MBMD from Lake Monger. The
Hamilton Lakes and Narrows Interchange Lakes and associated pumps and pipes
are managed by the Main Roads Department with the City of Perth.
The City of Perth manages the Narrows
Interchange area as parkland for passive recreation
and tourism purposes and water from
one of the lakes is used to irrigate the parkland.
The Swan River Trust is working to
reduce nutrient and pollutant inputs to the river and improve water quality
as well as foreshore habitat through a number of programs. The Narrows
Interchange area and the outlet from the MBMD are located within the Swan
River Trust Development Control Area. The Department of
Water provides technical advice and policy direction for stormwater
management.
There have been several proposals for development of the Mounts Bay area of
the Swan River and the Narrows Interchange lakes. The Department for Planning
has responsibility for major development proposals
through advice to the Western Australian Planning Commission and is
currently working on the final plans to develop the
Perth Waterfront.
Perth Region NRM is the regional
natural resource management group and are interested in ensuring that the
relevant stakeholders are involved in resource management issues. They are
working with light industry and local governments to reduce pollutants from
this activity.
The Claise Brook Catchment Group is the
local catchment group with an interest in this area. We
are primarily concerned with water quality and habitat and the better
connection of people with their urban ecosystems. With our local knowledge
of the area we are able to provide a community perspective to the project.
Improving water quality
In May 2006 the
Claise Brook Catchment Group brought
together many of the stakeholders mentioned above to
discuss the issues and identify whether proposed future works in the area
provide opportunities to implement changes which could improve water
quality within the catchment. All Stakeholders affirmed
that they are concerned with water
quality and recognise the need to make some improvements to the system to
improve the water quality in the lakes and entering the Swan River.
Download the Report of the 4th May 2006
workshop
here.
Subsequent workshops were held to assist
in the preparation of a Water Quality Improvement Plan (WQIP) which was
completed in September 2009. The WQIP is supported by the Swan River Trust
through the Healthy Rivers Action Plan to provide local councils and
communities with guidance to improve water quality in their catchment.
Download the Mounts Bay Catchment WQIP
here.
The catchment group is continuing to
liaise with stakeholders within this catchment to identify ways of improving
water quality in this catchment as the area becomes a vibrant community
connecting the city to the river. Through the development of a Memorandum of
Understanding the key stakeholders are committed to working together to
implement actions of the Mounts Bay Catchment WQIP.
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