The original Lake Pedder was 10 square kilometres in area. By contrast, the Huon-Serpentine impoundment (which now covers Lake Pedder) occupies 242 square kilometres in area.
Its famous quartzite beach was 1km wide and 3km long.
The protection provided by the Lake Pedder National Park status, granted in 1955, was revoked by the Tasmanian government in 1967.
Lake Pedder was submerged by the Hydro Electric Commission in 1972 in order to provide part of the water inflow to the Gordon River power scheme being constructed at that time.
The Huon-Serpentine impoundment is a vast diversion pond. It captures the waters of the Serpentine and upper Huon Rivers and elevates those waters so that this water feeds by gravity into the Lake Gordon impoundment.
The volume of water that is sitting 15 metres above the original Lake Pedder is static and never used. It is only the top one metre that flows through the McParland Pass canal into Gordon. The other 14 metres of water only purpose is to elevate the impoundment level to flow into the pass.
Energy generation implications
The Gordon Power Station has a maximum generating capacity of 432 Megawatts – i.e. when all of its three turbines are spinning.
The Gordon scheme’s actual sustained output (this is based on average water inflows in any year) is approximately 140 Megawatts average, which equals about 10% of the state’s hydro-electric output.
Of this, the Huon-Serpentine impoundment supplies 40 percent of water inflow.
Lake Pedder’s flooding thus provides 4% of the state’s hydro-electric output. This translates to 3.2% of the state’s total electricity demand (from all power sources).
In the context of alternative supply, withdrawing total energy from Pedder waters would be equivalent to the electricity output of a large wind farm such as is currently being built at Cattle Hill (50 – 60 turbines).
Twenty large industries consume 60% of Tasmania’s power demand.
Five bulk power industries consume 50% of Tasmania’s electricity demand.
Nyrstar zinc smelter uses 11%. The Bell Bay aluminium smelter uses 31%. Temco uses more than 5%. Temco’s future is uncertain.
The Gordon Scheme was implemented in order to provide electricity to cater for a planned expansion of the Comalco furnace potline at the time.
Restoration of Lake Pedder would be the largest ecological restoration project in Australia and the world. There is a growing number of significant dam removals and restorations in other parts of the world.
An area of 15,000 hectares (equivalent in area to 6,000 MCG ovals) would need to be restored to its pre-flooded state in order for this to happen.
Scientific research (based on depth sounding and diving) has found that the original Lake Pedder beach and associated dune system remain intact, largely undisturbed by the flooding.
In 1995 a federal House of Representatives Committee of Inquiry found restoration to be technically feasible.
Australia. Parliament. House of Representatives. Report of Standing Committee on Environment, Recreation and the Arts. Inquiry into the Proposal to Drain and Restore Lake Pedder. The report was tabled 26 June 1995 and is Parliamentary Paper Number 113/1995. The Standing Committee was in existence 1987-1998. The report is still available on the Parliament of Australia website but you may have difficulty finding it. A scanned copy (118 pages, file size 4.9 MB) can be viewed or downloaded at house_reps_committee_report_lake_pedder_1995.
Dam deconstruction is a relatively new concept in Australia, it has actually been done before in Tasmania. Lagoon of Islands, like Pedder was a globally unique ecosystem sacrificed for a hydro scheme. When the water quality at LOI degraded to the extend of being completely unusable the decision was made to deconstruct the dam and restore the ecology of the site. Read about Lagoon of Island Project here as featured in the January 2021 Ecological Management and Restoration Journal.
The Future of Lake Pedder – Interim Report, Commonwealth Government’s Lake Pedder Enquiry ReportThe Future of Lake Pedder’ was first printed in an interim format for the Australian Government Publishing Service, Canberra. This book, which includes that report was published by the Lake Pedder Action Committees throughout Australia in September 1973.
Lake Pedder: Values and Restoration. The Proceedings of a Symposium held on 8th April 1995 at the University of Tasmania, Hobart. Edited by Chris Sharples. Occasional Paper No. 27, Centre for Environmental Studies, University of Tasmania, 2001. The proceedings consist of the following papers:
- FLANNERY, T. – Foreword (and title page, bibliographic details, table of contents and front piece illustration)
- SHARPLES, C. & SAWYER, N. – Introduction and overview
- KIERNAN, K. – The geomorphology and geoconservation significance of Lake Pedder
- TYLER, P. – Lake Pedder – a limnologists lifetime view
- PEMBERTON, M. – Soils in the Lake Pedder area
- BALMER, J. & CORBETT, E. – The vegetation of the Lake Pedder area prior to flooding
- LAKE, P.S. – The fauna of Lake Pedder – changes after the flooding and thoughts on restoration
- McCONNELL, A. – The cultural heritage of the Huon–Serpentine Impoundment, and an assessment of the effects of restoration of Lake Pedder
- GEE, H. – Social and cultural grounds for the restoration of Lake Pedder
- DUCKETT, T. – Practical cost effective rehabilitation of the current Lake Pedder impoundment
- SANGER, A. – Prospects and problems for the restoration of the Pedder galaxias
- LIVINGSTON, A. – Hydrological and engineering issues associated with draining and restoring Lake Pedder
- KIERNAN, K. – Restoring Lake Pedder: a geomorphological perspective on recovery prospects and likely time scales
Pedder 2000 Campaign Submission. Pedder 2000 submission to the House of Representatives Standing Committee on Environment and Heritage Inquiry into the proposal to restore Lake Pedder.
Dr Andrew Blakers Submission. Submission and Supplementary Submission to Lake Pedder Inquiry by Dr Andrew Blakers, Senior Research Fellow, Engineering Department, The Australian National University.
Dam Financing in Tasmania. Dr Andrew Blakers’ Analysis (1995).
Header Photo Credit : Dennis Garrett