A proposal to drastically slash the annual intake of saline water into Wellington Dam is part of the Griffin Group’s billion-dollar plan for the Collie region, based on an integrated industrial estate at nearby Coolangatta.
A proposal to drastically slash the annual intake of saline water into Wellington Dam is part of the Griffin Group’s billion-dollar plan for the Collie region, based on an integrated industrial estate at nearby Coolangatta.
The centerpiece of the 120-hectare Coolangatta Industrial Estate, situated on land owned by Ric Stowe’s private Griffin Group subsidiary W R Carpenter Agriculture, will be the $250 million, 200-megawatt Bluewaters coal-fired power station.
Bluewaters, which Griffin Energy intends to have commissioned by September 2008, is the first of three such state-of-the-art coal-fired power stations planned to be based near the company’s Ewington 1 coalmine to service the estate’s industries.
Electricity will also be sold into the South-West Integration System (SWIS).
Griffin argues that development of Bluewaters and the other two proposed power stations will not only improve the efficiency of SWIS, but also reduce the state’s dependence on the Dampier-to-Bunbury National Gas Pipeline.
Early this month, Griffin signed an engineering procurement and construction contract with Mitusi & Co and Ishikawajima-Harima Heavy Industries Co of Japan to build the station.
Griffin also signed the go-ahead for a pulp mill feasibility study with Hong Kong-based ARC International of China to demonstrate Coolangatta Estate’s potential to host major energy intensive industries.
In addition to these developments, Griffin has spent more than four years working with Water and Rivers Commission (WRC) experts and Harvey Water officers on a trial involving diversion of between 1.5 gigalitres and 3gL of saline water from the East Collie River.
It’s hoped the trial will take place this winter.
The proposal, likely to cost about $30 million in state and federal funds, is part of a bigger project that envisages diverting up to about 10gL, which is expected to be announced after conclusion and assessment of this trial.
Griffin says the diversion plan concept involves construction of a weir to divert the first major winter waters of the East Collie River – when the river is carrying the highest ratio of salt – into the company’s network of coal mining voids or pits.
The diversion plan, which has been developed by Griffin and WRC experts since 2001, is being undertaken initially to improve the quality of irrigation water that has been steadily becoming less useable.
WRC’s salinity researchers quickly identified the East Collie River as the main source of saline water flowing into Wellington Dam, particularly with flows generated by the first winter rains.
Griffin has agreed to make its farm the site of diversion and its coal mining voids or pits available to divert and store this early winter saline water to ensure this water doesn’t reach the dam and mix with other less saline water taken from other streams.
A Griffin spokesman said that, although it would naturally be desirable for the diverted saline water to be used in the power generating process by the company’s planned power stations, this was not feasible at present but could be in the future.
Wellington Dam’s current salinity level of more than 1,000 milligrams per litre (mg/L) is to be reduced to 550mg/L.
Currently, to reduce salinity in Wellington Dam the Government releases about 450,000 tonnes of saline water into the sea during the winter months.
This wasteful procedure, called dam scouring, simply involves opening a large gate valve at the base of the dam and discharging the saline water out to sea.
Since saline water is denser that fresh, or potable, water it sits at the bottom of the dam and can be relatively easily discarded by scouring.
Wellington Dam’s saline water component has been estimated at up to 40gL, with the dam’s annual average annual supply standing at about 140gL.
However, as scouring the dam involves discharging about a tonne of water for every Perth household, it is a major waste of a potentially useable supply.
This has prompted a Perth-based group, Agritech Smartwater, to propose desalinating the scoured water and diverting the potable product into the metropolitan area’s network.
If the water diversion experiment is shown to dramatically slash the dam’s salinity level, as Government experts predict it will, then the next stage would be to treat a further 8gL of saline East Collie River water in the same way.
The 72-year-old Wellington Dam has a capacity of about 186gL and an annual inflow of nearly 145gL, which is now used to provide irrigation water to farmers along the South West coastal region.
Because Wellington Dam is situated well south of Perth it reaps the benefit of being in a high rainfall zone, making its one of the state’s most reliable recipients of water.
Salinity levels began rising after 1960, forcing the then government to commission the nearby Harris Dam, the intake of which does not include waters from the East Collie River, in 1989 to provide water to towns under the Great Southern Towns Water Supply Scheme.
Presently, Wellington Dam is only being used to supply around 68gL of irrigation water annually.
Over the past decade government hydrological and other experts have made ongoing measurements and compiled computer models that show the East Collie River is the main supplier of saline water into the dam.
Some are believed to have registered salinity levels of more than 1500mg/L.
The idea of diverting salt-laden early winter East Collie River water into Griffin’s coal voids or pits was unveiled in November 2002 at Darkan by the WRC and the Collie Salinity Recovery Team.
The WRC had launched a long-term plan to lower the dam’s salinity level to 500mg/L by 2015, meaning the water diversion proposal is seen as a medium-term solution to Wellington Dam’s salinity problem.
In the longer term it is intended that the cleared lands to the east of Collie will continue to be revegetated to bring these tracts back to their pre-1960 state.
GRIFFIN PLANS
- $250 million, 200-megawatt Bluewaters coal-fired power station to be built on 120ha Coolangatta Industrial Estate.
- Engineering procurement and construction contract signed with Japanese companies.
- Go-ahead for pulp mill feasability study also signed with Chinese group.
- Hopeful of winter trial of plan to divert between 1.5 gigalitres and 3gL of saline water from the East Collie River into the company’s network of coal mining voids or pits.
- Proposal requires $30m in state and federal funds.
