mining argued that further mining would compromise the filtering
function of the swamp as well a sits ability to retain nutrients.
This would impact on water quality in the reservoir as well as habitat
for flora and fauna in the area. The
impacts are exacerbated by the growing size of the dredge pool,
the diminishing size of the swamp and the construction of drainage
to Australian Water Technologies:
is rich in fulvic and humic
acids which impart yellowish-brown colour to water. In peat mining,
drainage and disturbance release these materials, with potential
adverse effects on the quality of waters receiving the drainage.
These effects can usually be alleviated by allowing the effluent
to flow over undisturbed peat beds, where the dissolved substances
can be adsorbed and the solids settled. Bubbles of methane formed
and trapped in peat tend to obstruct drainage, so reducing and slowing
water seeping from the swamp into the lake lacks oxygen and is highly
coloured and rich in iron, its impact appears to be relatively small
because of the low rate of flow...
of the swamp in ameliorating the impacts of flood events on the
water quality of the lake is largely due to the area of swamp
available. Further peat mining will reduce this area and so is
likely to reduce the ability of the swamp to remove contaminants.
At the same time, the volume of the dredge pool, and the probability
that a flood would displace a large volume of poor quality water
from this pool, will increase. Since sub-surface flow through
peat is impeded, there would be a progressively increasing probability
that surface flows would exceed the capacity of the residual swamp
area to ameliorate the quality of the volume displaced from the
of water quality in Lake Wingecarribee would be best served if
an extension to the lease is not granted.
Wingecarribee Reservoir was subject to algal blooms caused by concentrations
of nutrients and in the summer of 1996/97 algal concentrations exceeded
limits set by the National Health and Medical Research Council (NHMRC)
to Australian Water Technologies:
dredge pool contained high concentrations of phosphorus. Increase
in the size of the pool would be likely to increase the quantity
of phosphorus in the water, even if the concentration were to decrease.
During flood events there is the danger that this water will be
displaced into the lake, overwhelming the capacity of the remaining,
and smaller, swamp barrier to remove the contaminants, which would
mainly flow over the surface. As the volume of the dredge pool increases
the danger of the lake receiving pulses of phosphorus-rich water,
which can lead to algal blooms, will increase.
removal of peat will release phosphorus into the lake, and will
reduce the capacity of the swamp to ameliorate the effects of
flood events. It is likely that water quality will deteriorate
progressively, and the frequency and magnitude of algal blooms
to the Department of Mineral Resources:
reservoir has in fact suffered in recent times from a blue-green
algal bloom. That bloom has not yet produced dangerous toxins but
may do so... The mechanisms which determine whether such blooms
produce toxins are not well understood and the present substantially
harmless bloom could become a serious problem with little warning.
not clear at all the extent to which Sydney Water have regarded
the bloom or peat mining a problem. Until the inquiry Sydney Water
had been progressively scaling back their testing of water from
the Wingecarribee Reservoir.
channels, constructed by the peat miners, cross the swamp area and
are typically 1m deep. Their purpose is to drain surface water from
the swamp and dry it out sufficiently to enable machinery and animals
to be able to cross its surface.
to the Department of Land and Water Conservation:
drainage of the surface of the swamp by the channels alters flows
patterns resulting in alteration of the filtering capacity of the
swamp. Water travels more quickly through artificial drains than
through natural wetlands... during
low flow conditions, the channels in Wingecarribee Swamp could be
the major flow path for water to traverse the swamp from upstream
to Wingecarribee reservoir, if the volume of water flowing at that
time is within the capacity of the channels.
flows occurring at a rate and volume that could be conveyed by
the channels dug into the swamp, the capacity of the buffer zone
to manage flows during baseflow conditions is doubtful.
1997 the Environmental Protection Authority (EPA) served notice
on Emerald Peat "to take immediate steps to prevent muddy discharges
from the operation from entering Wingecarribee Reservoir".
This followed the appearance of a "muddy yellow slick"
which spread across the surface of the Reservoir, covering half
the surface at times. Emerald Peat was order to install appropriate
filters and move its boat loading location.(EPA News Release 26/9/97)
the slick had released phosphorous into the storage, the Wingecarribee
Council and the Sydney Water Corporation (SWC) were also concerned
about its potential to create an algal bloom. As a result the SWC
was conferring with Wingecarribee Council about upgrading water
treatment for the water supply. (ABC Illawarra 16/9/97) This was
estimated to cost about $600,000 by the Wingecarribee Council.
Peat proposed to install a revised water treatment arrangement to
upgrade the existing system if its leases were renewed. This upgrading
of a recycling system to avoid any discharges in the swamp of
of a floating containment boom and silt curtain around the dredge.
of peat on the dredge pontoon using return water pumped from the
of a clarifier if inadequate settlement of solids is achieved.
of the current outlet from the settling ponds to the swamp.
of any excess waters from the recycling system by spray irrigation
on the Sharp property.
of additional bunding on fuel tanks.
to Emerald Peat:
On the basis of both the theoretical and empirical assessment
there is not reasonable likelihood that continued peat extraction
as proposed will result in any deterioration in water quality or
increase the risks of algal blooms in Wingecarribee reservoir. Continued
monitoring can ensure this occur, together with the powers of the
regulatory authorities to intervene if unlikely problems arise.
Consulting Services, Report on Water Quality Issues in relation
to Peat Mining in Wingecarribee Swamp, Report No. 97/36, February
1997, Exhibit 35, pp. 7, 13-14.
Philippa Resource Officer, Catchment Planning Sydney South Coast
Region, Department of Land and Water Conservation Hydrology Comments,
Mine Warden Inquiry, May 1997, Exhibit 88.
of Mineral Resources, Submission to Inquiry into Renewal of Mining
leases 567 and 568 at Wingecarribee Swamp, 1997.