Environmental Impacts before the collapse

fragmentation and destruction of swamp ecosystems

loss of filtering function of the swamp

spread of aquatic weeds

spread of European Carp
destabilisation due to changed

increased risk of hazards such as erosion and fire
increasing dredge point increases wave erosion

According to the National Parks and Wildlife Service:

Mining to date has opened up an extensive area of swamp with an extensive free water area now replacing what was a shrubland/rushland peat deposit. The free-water body now dissects the swamp and fills the basin created by the removal of a considerable depth and volume of peat.... Fragmentation and destruction of the swamp ecosystems has occurred and will be accelerated if peat mining was to continue.

Changes in water regimes in the swamp as a result of milling potentially also threaten the continued existence of the small populations of endangered plants listed on Schedule I of the Threatened Species Act, and if mining continued at increasing rates of extraction, physical destruction of the populations could result within the term of any renewed leases.

The continuation of peat mining would also contribute to the spread of aquatic weeds within the swamp, particularly willows (Salix spp) and exotic water plants such as Glyceria maxima. The latter plant has already colonised several areas of the swamp. The weed problem predictably, would be greatly increased if the filtering and nutrient storage capacity of the swamp was to be further reduced by the future peat extraction and an increase in nutrient enrichment eutrophication of the open waters created by peat mining.

The creation of future areas of open shallow water following peat extraction also poses a potential major problem if European Carp (Cyprinus carpio) were to colonise the open water areas. These fish are bottom feeders and contribute to turbidity and water quality problems.

According to the Department of Mineral Resources:

The unfortunate fact of the matter is that Wingecarribee Swamp has suffered severely from the impact of human activities since the beginning of white settlement of Australia. Adverse environmental impacts... included (most importantly) the drowning of almost half the swamp by the construction of the Wingecarribee Reservoir by Sydney Water in the early 1970's, vegetation clearance to bring surrounding farmland into cultivation, altered fire regimes, the construction of extensive and effective drainage, altered hydrology, altered fire regimes, the grazing of cattle, introduction of exotic fauna (in the case of the introduction of the mosquito fish, leading to local extinction of the native green and golden bellfrog), introduction of exotic weeds, notably blackberry and willow, peat extraction and increased nutrient loads from human activities...

We submit... that there has been a long and troubled history of sometimes catastrophic impacts of human activities on the swamp fauna but that there is no reason to believe that the continuation of mining on the basis proposed will contribute further to these impacts.

More on causes of environmental impacts...

Source:

National Parks and Wildlife Service, Submission to the Mining Wardens Inquiry into Possible Renewal of Mining Leases for the Extraction of Peat from Wingecarribee Swamp, 1997, Exhibit 23, pp. 8-12.

Geoffrey Hope, Senior Fellow, ANU, Submission to the Mining Wardens Inquiry into Possible Renewal of Mining Leases for the Extraction of Peat from Wingecarribee Swamp, 1997, Exhibit 34.