Water quality in
the Mounts Bay Catchment
The Claise Brook Catchment group made
the following submission to Landcorp on the proposed development of the Swan
River and Mounts Bay foreshore. Information about the proposed development
can be found at the following website.
www.perthwaterfront.com.au
25th
March 2008
SUBMISSION –
Perth
Waterfront
On behalf of
the Claise Brook Catchment Group I would like to make the following
submission on the proposed development of the Perth water front at Mounts
Bay.
CLAISE BROOK
CATCHMENT GROUP
The Claise
Brook Catchment Group is a community based environmental group working to
improve water quality and habitat within Perth city and the inner city. Our
group considers that it is vitally important that urban environments be
designed and managed to reduce their environmental impact. We believe that
incorporating natural features into an urban environment can have multiple
benefits including habitat for wildlife and improved water quality through
restoring natural water flows and the filtering effect of natural systems.
Our catchment
group has recently completed surveys of all parks and reserves within the
City of Perth, assessing the biodiversity values of the open spaces. We
found that Perth city is blessed with its many parks, with the river
foreshore and the Swan River being arguably the city’s greatest natural
asset. A significant benefit to protecting biodiversity in the city would be
to improve the linkage along the foreshore from Kings Park to East Perth and
Heirisson Island. We also note that traditionally Perth’s foreshore was not
developed, and consider this a point of difference with other urban
waterfronts and something to be valued.
Importantly,
the two existing sandy beaches, west of Barrack Square, and the adjacent
grassed areas, are currently used by Black Swans. The Black Swan is
emblematic of Western Australia, particularly of Perth city. Many
organisations, schools, clubs and businesses founded in Perth, feature the
Black Swan in their logo or emblem. That the Black Swan still frequents the
city foreshore, although in reduced numbers, is something of value which
should not be lost.
The location of
the proposed development is on the Swan River which flows through the heart
of Perth and is highly valued by both residents and visitors to
Perth.
The importance of the
Swan River to the Perth community was recognised when it was declared
Western Australia’s
first heritage icon in 2004.
RESPONSE TO
DEVELOPMENT PROPOSAL
Bringing the
city closer to the river and making the river more accessible to city
residents, workers and visitors is laudable, but not if it is at the cost of
degrading the river and foreshore environment. Instead, the development
should be focussed on enhancing the experience of the waterfront
environment.
This could be
achieved by restoring a natural foreshore to the area with indigenous
vegetation to control erosion and pedestrian access via boardwalks. Visitors
will have a much more interesting experience if they can sit in a café
overlooking the river and see black swans on a beach, a cormorant sunning
its wings, a large Pelican floating lazily, dolphins swimming by and closer
to hand, honeyeaters busily feeding in small trees.
While any
development on the foreshore hinders the possibility of improving a
biodiversity linkage, a nodal development on the foreshore, would be
preferable to development along the entire foreshore. Extending the proposed
development along the foreshore to the Narrows Bridge will impact negatively
on the value of the current length of protected open foreshore as well as
views to and from Kings Park. We suggest that
development on the river’s edge should be limited in extent, and no greater
than the section from Barrack Square to William Streets. Any development
towards the Narrows Bridge should be setback at least 30m, and preferably
50m, from the river’s edge, consistent with Western Australian Planning
Commission Development Control Policy 2.3 Public Open Space in Residential
Areas (2002), with revegetation works and bank stabilisation required to
accommodate the impact of higher numbers of people inhabiting the area.
Elsewhere much
of the city’s foreshore is completely hard-walled, creating an environment
hostile to wildlife. Incorporating natural areas, attractive to Black Swans,
would be of far greater interest to visitors than features such as the boat
moorings or bathing beach. The group, and we believe the general public,
would be very concerned of any development that would remove habitat for the
Black Swan on the river foreshore.
WATER QUALITY
ISSUES
The site’s
location, on the Swan River, means that the treatment of stormwater, the
choice of landscaping, design of road drainage and water management on
public and private land has the potential to impact almost immediately on
water quality within the Swan River. In addition the two small water bodies
within the project area, and the larger lake on the western side of the
Narrows Interchange, could be affected by the development of this area.
Available
information indicates that water quality within
Mounts
Bay is poor, with some accumulation of heavy metals in the sediments and
nutrient levels in Mounts Bay exceeding the Swan River Trust’s water quality
targets. This is exacerbated by the location of the Mounts Bay Main Drain
outfall and poor
flushing within the bay. Water quality is not suitable for water contact
activities. The water quality within the Narrows Interchange lakes, two of
which are within the project area, is generally poor with Health Warning
signs having to be displayed advising that contact with water is not
advised.
Our catchment
group considers that improvements to water quality, within Mounts Bay, the
Narrows Interchange lakes and the wider catchment are implicit and must be
funded and integrated with any development of the foreshore. It is not
acceptable to the public to develop an area, knowing that the poor water
quality may result in Health Warning signs and banning of water contact
activities, particularly when the proposal includes a bathing beach.
As much of the
land within the lower Mounts Bay Catchment (below Lake Monger) is under the
management of government agencies including the Department for Planning and
Infrastructure, Main Roads and the Water Corporation, we urge an
inter-agency approach to managing water movement through the area and
improving water quality. While the larger catchment extends above Lake
Monger, the upper catchment appears to only overflow to the lower Mounts Bay
Main Drain in winter, when water quality is quite likely to be relatively
good. It would appear that for much of the rest of the year, water of very
poor
quality either flows or is pumped through the lower catchment. The source of
this water is not clear but may include groundwater.
LANDSCAPING
CHOICES AFFECT WATER QUALITY
Landscaping
throughout the area is an important component of the infrastructure
contributing to amenity, aesthetics and creating a ‘sense of place’ within
the area. Inappropriate landscaping can have significant environmental
impacts, particularly on water quality. A significant source of nutrients in
urban catchments is related to the widespread use of exotic vegetation in
streets and public landscaping, particularly deciduous vegetation. Deciduous
plants drop all of their leaves over a short period and decompose quickly,
resulting in an excessive release of nutrients into water bodies. Street
trees are of particular concern since most of their foliage will end up
being washed into the stormwater drainage system.
The site’s
location on the Swan River, adjacent to the Narrows Interchange
parklands and Kings Park, 400 hectares of primarily natural bushland, gives
particular importance to the choice of species for landscaping.
We suggest that
a ‘Western Australian’ theme in the landscaping will give the area a unique
‘sense of place’. We consider that choosing Western Australian trees of
different sizes will allow shade to be provided at street scale and avenues
to be formed through the area. Lower landscaping in garden beds and planter
boxes featuring the wide variety of unique Western Australian flowering
plants would add real visual interest for interstate and overseas visitors.
Using primarily
Western Australian species will visually link the area to the natural
bushland of nearby Kings Park, while also having significant benefits for
the health of the Swan River due to lower water and fertiliser requirements.
Local Western Australian species, from the Swan Coastal Plain, particularly
the species found along the estuary and offshore islands, will also be more
able to withstand the likely impacts of climate changes such as storm surges
and occasional flooding with saline river water.
RECOMMENDATIONS:
1.
A whole of government commitment be made to improve water
quality within the broader Mounts Bay catchment, with agencies including
Main Roads, the Department for Planning and Infrastructure, the Water
Corporation working in partnership with the advice and assistance of the
Swan River Trust and Department of Water. Together these agencies will
commit to:
a.
Setting targets for water quality improvement to the Swan
River and lakes within the Mounts Bay Catchment below
Lake
Monger;
b.
Funding
a coordinated monitoring program for the
drainage system to determine the nutrient and pollutant content of the
various flows;
c.
Facilitate ongoing improvements to land and water management practices in
the Mounts Bay Main Drain (MBMD) catchment and better connect management to
data;
d.
Investigate possibilities for the treatment of MBMD water quality within the
system;
e.
Retrofit measures to remove pollutants from freeway drainage prior to
discharge into river and maximise infiltration into drainage swales;
f.
Commit adequate resources
to improving water quality
within the lower Mounts Bay Catchment including the Hamilton and Narrows
Interchanges and the Mounts Bay Foreshore, noting that supporting funding
may be available through various programs.
2.
Within the project area, design public and private spaces
according to Water Sensitive Urban Design principles, complying with best
practices for Water Sensitive Urban Design as detailed in the Department of
Water Stormwater Manual including but not limited to:
a.
Set an Environmental Objective ‘Water Sensitive Urban
Design (WSUD) will ensure that there is no environmental impact on the
Swan River from the foreshore development area”
b.
Drainage from hard surfaces including roads, footpaths and
surface parking be directed to drainage swales to maximise infiltration;
c.
Incorporate semi-landscaped hardstand areas for parking and
overflow parking spaces.
3.
Develop a ‘Western Australian’ theme in the landscaping to
give the area a unique ‘sense of place’. Develop policies to ensure the
theme is maintained in the public and the private domain.
4.
Development on the river’s edge should be limited in extent,
and no greater than the section from Barrack to William Streets. West of
William St, development should be setback from the river’s edge at least
30m, preferably 50m, consistent with Western Australian Planning
Commission Development Control Policy 2.3 Public Open Space in Residential
Areas (2002).
5.
Redesign the Waterfront foreshore to retain areas of sandy
beach with adjacent natural areas, where buildings have been setback from
the river’s edge, suitable for Black Swans. Design the natural areas to
perform multiple functions including wildlife habitat, drainage swale and
surface water filtering. Replace the proposed bathing beach and boat mooring
with areas suitable for wildlife, particularly focusing on the requirements
of the Black Swan (noting that water quality within Mounts Bay is not
suitable for water contact activities).
6.
Rather than using hard walling to edge the river, restore a
sloping bank to the river’s edge, planted with indigenous vegetation to
control erosion while also providing habitat and visual interest. Preferably
retain the existing Melaleuca cuticularis trees. Provide pedestrian
access with a boardwalk along and above the vegetated foreshore. Aim for a
continuous natural foreshore and boardwalk from William St to the Narrows
Bridge.
7.
Develop policies to require a high standard of landscaping
for all developments. A landscape plan is to be submitted with all
development applications demonstrating waterwise landscaping in accordance
with the landscaping theme of the project area. Accompanying the landscape
plan will be a maintenance plan demonstrating that no fertilisers or organic
matter (lawn clippings, mulch) will impact on surface or groundwater quality
such as through washing into stormwater drains.
8.
Aim for a high standard of water conservation in both the
public and private domain within the project area to reduce scheme water
consumption and facilitate reuse of stormwater. Any greywater reuse systems
must be designed to ensure they do not impact negatively on ground or
surface water quality.
9.
Ensure that the proposed circular pool is designed to prevent
algal blooms, botulism or other problems which may occur with the
semi-enclosing of poor quality water. Consider making the proposed ‘swan
island’ an island with habitat values, particularly for Black Swans, which
may have the additional benefit of encouraging swans to use the circular
pool.
We consider
that the recommendations above will achieve the creation of a uniquely
Western Australian waterfront environment in this important location.
Thankyou for
the opportunity to comment. We are happy to discuss our concerns and explain
these recommendations in more detail.
Regards
Sally
Lake
Coordinator
Claise Brook Catchment Group
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