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Displaying items by tag: drought

Sunday, 24 November 2019 16:07

Water Desalination

As this is being written in late-August, Sydney is enjoying another near cloudless day. There’s been no rain for weeks and none is forecast. Rainfall at the observatory has been 3.2 mm for the month so far.

This is not unusual for August. August 2018s total was 7.8 mm; 2017s 24.2 mm. But it can be very variable; 2014s was 215 mm. Sydney’s record daily rainfall was on 6 August 1986 – 328 mm with a total of 448 mm with the inclusion of the day before and the day after.

It has been dry and the dams are about 50% full and falling rapidly. As a result the desal plant at Kurnell is in operation to provide about 15% of Sydney’s water. Consequently our water bills are being increased from $2.11 to $2.24 per kL on 1 October.

Desal means desalination; i.e. the process of converting sea (saline) water to drinking water by the removal of salt. This is done by a process of filtration (reverse osmosis) but requires the water to be subject to massive pressure. It is very expensive in terms of energy consumption.

Brisbane (Gold Coast), Sydney, Melbourne and Adelaide all got their desal plants as a result of the millennial drought in the early years of this century. They are only operated fully in drought periods – but see our update on Adelaide.

The Melbourne operation is quite marginal as the plant is located near Wonthaggi south-east of Melbourne not far from Phillip Island. It was impossible to locate it on Port Phillip Bay as water circulation in the bay is too low. So an 85 km pipeline had to be built as well and this of course gives rise to extra energy for pumping.

What about Perth you ask? This is the standout situation as this city depends on desal for about 40% of its supply year on year. Only about 10% comes from the dams in the Darling Ranges near Perth as most of this water is piped to the Eastern Goldfields (Kalgoorlie). One suspects that much of it is used by the gold mines.

The remainder is supplied by groundwater and recycling. The groundwater in future might become saline in which case it will be subject to desal too. This is also an issue in outback NSW.

The environmental impact of desal in Perth is somewhat mitigated by the use of natural gas to generate electricity.

Do Perth residents pay more than Sydney residents given that their water costs more to provide? The answer appears to be yes but it is not as simple as it might be. Perth has a sliding scale of charges. Like Sydney there is quarterly billing but the Perth charge depends on one’s annual consumption and can cost up to $4.442 per kL.

Sydney Water claims that its desal power is provided in an environmentally friendly way in that they have a contract with the 67 turbine Capital Hill Wind Farm, near Canberra.

This is a furphy. When the desal plant isn’t operating the wind farm feeds the NSW power grid. So when it is operating this feed is reduced and we have more reliance on gas and coal so increasing greenhouse gas emissions over what they otherwise would be.

A contrary view might be reasonable if we knew the pricing/contractual arrangements between Sydney Water and Infigen Energy, the owner of the Capital Hill Wind Farm. It may be that the farm would not have been developed without the desal requirement or not developed to the same extent.

Desal

CityLab article

Here are some excerpts from an article entitled A Water-stressed World Turns to Desalination.

The first large-scale desal plants were built in the 1960s, and there are now some 20,000 facilities globally that turn sea water into fresh. The kingdom of Saudi Arabia, with very little fresh water and cheap energy costs for the fossil fuels it uses in its desal plants, produces the most fresh water of any nation, a fifth of the world’s total.

Israel, too, is all in on desalination. It has five large plants in operation and plans for five more. Chronic water shortages there are now a thing of the past, as more than half of the country’s domestic needs are met with water from the Mediterranean.

Ecological impacts: It takes two gallons of sea water to make a gallon of fresh water, which means the gallon left behind is briny. It is disposed of by returning it to the ocean and - if not done properly by diffusing it over large areas – can deplete the ocean of oxygen and have negative impacts on sea life.

Another problem comes from the sucking in of sea water for processing. When a fish or other large organism gets stuck on the intake screen, it dies or is injured; in addition, fish larvae, eggs, and plankton get sucked into the system and are killed.

Contributed by Jim Wells

Update on Adelaide – November 2019

In another example of policy on the run like Snowy 2.0, PM Scott Morrison announced a drought relief package in early November. This includes a deal to crank up Adelaide’s desal plant in order to provide water for farmers to grow fodder for livestock.

Lin Crase, Professor of Economics and Head of School, University of South Australia in an article in The Conversation points out that this is not such a brilliant idea.

The plan involves the federal government paying the South Australian government up to $100 million to produce more water for Adelaide using the little-used desalination plant. Adelaide has continued to mostly draw water from local reservoirs and the River Murray, which on average has supplied about half the city’s water (sometimes much more).

But with federal funding, the desal plant will be turned on full bore. This will free up 100 GL of water from the Murray River allocated to Adelaide for use by farmers upstream in the Murray Darling’s southern basin.

The federal government expects the water to be used to grow an extra 120,000 tonne of fodder for livestock. The water will be sold to farmers at a discount rate of $100 per ML. That’s 10 cents per 1,000 litre.

The production cost of desalinated water is about 95 cents per 1,000 litres, according to a cost-benefit study published by the SA Department of Environment and Water in 2016. That means the total cost for the 100 GL will be about $95 million. So the federal government is effectively paying $95 million to sell water for $10 million: a loss to taxpayers of $85 million.

The discounted water provided to individual farmers will be capped at no more than 25 ML. The farmers must agree to not sell the water to others and to use it to grow fodder for livestock.

The amount of hay that can be grown with 1 ML of irrigation water depends on many things, but 120,000 tonne with 100 GL is possible in the right conditions. In the Murray-Darling southern basin lucerne hay currently sells for $450 to $600 a tonne. That would make the market value of 120,000 tonne of lucerne $54 to $72 million.

It means, on a best-case scenario, the federal government will be spending $85 million to subsidise the production of hay worth $72 million to its producers. One question is how will the government distinguish between the fodder grown with the megalitres provided at low cost and any other fodder harvested on the same farm that has been grown from rainfall or other irrigation water? How much will it cost to monitor and enforce such arrangements?

It seems a long way from the type of national drought policy Australia needs. It’s hard to see how a policy of this kind does anything other than waste a large amount of public money and disrupt important market mechanisms in agriculture in the process.

Contributed by Jill Green

Published in STEP Matters 203
Thursday, 07 February 2019 02:27

Murray-Darling Basin Plan: Too Little, Too Late

murrayWe have all been shocked by the mass killing of fish in the Menindee Lakes and other areas in January, the loss of wildlife and the poor water quality and quantity for communities along the Darling River. Murray Cod and other native species believed to be up to 100 years old that have survived numerous droughts have not survived this one. The politicians are blaming the drought but the causes of the severe degradation of the Darling River go back a long way stemming from the over exploitation of the water and the lack of political will to solve the problem.

The Murray-Darling Basin covers a massive area of southeast Australia inland from the Great Dividing Range, from southern Queensland through to the mouth of the Murray in South Australia (see map).

Water extraction for irrigation commenced late in the 19th century along the Murray River with the creation of schemes by the Caffey brothers near Mildura and Samuel McCaughey in the Murrumbidgee Valley. Regulation of the Murray River system was one of the first issues addressed after Federation.

With a severe drought in the late 1960s, environmental impacts were starting to emerge as water quality had deteriorated and salinity was apparent. From the 1970s state governments undertook initiatives to manage water diversions including the definition of water entitlements, development of water markets and salinity management, but there was no interest in the fundamental issue of too much water being used.

By 1995, in response to increasing evidence of deterioration of the Basin’s river system including a massive blue-green algae outbreak in 1991–92, the Murray–Darling Basin Ministerial Council directed that a water audit be prepared to investigate the current levels of water use and potential increases across the Basin if infrastructure was developed so that all available entitlements were taken up.

The audit showed that between 1988-89 and 1992-93 the average total diversion from the Basin was 10,780 GL/year. Of this amount, over 95% was diverted for irrigation.

The report modelled the hypothetical flows of water at the mouth of the Murray. With no diversions drought conditions would have occurred in 1 in 20 years, but with the current level of diversions drought conditions would occur in 60% of years, and under full development it would occur in 3 out of 4 years.

graphThis graph shows the massive increase in the water used for irrigation and agriculture as revealed in the audit report. It showed that growth even in the previous 8 years had been 8%, mostly in the north for cotton growing. Not only that, there was the potential under the current management regime for usage to grow by a further 14.5% if the infrastructure capacity were installed. However use of the full entitlements would reduce the overall security of the system for individual irrigators because the levels of reserves in storages would be reduced. The full entitlements equated to diversion of 12,344 GL per year.

Environmental Impact of Current Extractions

The 1995 audit reported that the changes to the natural flow regime from the current water diversions and extractions had had a significant impact on river health. There was a reduction in the areas of healthy wetland, native fish numbers had declined in response to the reduction in flow triggers for spawning and salinity levels had risen. Algal blooms had increased in frequency in line with more periods of low flow leading to increased water temperatures and nutrient levels. The fish kills occur when the temperature changes and the algae die off and the bacteria increase reduces oxygen levels available to fish and other aquatic life.

First Plan to Control Extractions, the Cap

In 1995, the Murray–Darling Basin Ministerial Council introduced the Murray–Darling Basin Cap on Surface Water Diversions (the Cap):

to protect and enhance the riverine environment and protect the rights of existing water users.

The Cap introduced long-term average limits on how much water could be taken from rivers in 24 designated river valleys. The total Cap was 12,100 GL per year based on possible extractions in the 1993-94 year under infrastructure then available with some adjustment for the development of new diversions outside the main states of NSW and Victoria. This total extraction each year was to be adjusted to allow for actual rainfall. With the Cap in place, new developments were allowed, provided that the water for them was obtained by improving water use efficiency or by purchasing water from existing developments.

The Cap made water in the Basin a more valuable resource as it gave entitlements to its diversion more value and saw increased trade in these entitlements. The Cap was meant as an emergency measure to prevent further disasters while a long-term policy was worked out. Nearly 25 years later, it is still in effect.

The Cap is too High

The millennium drought from the late 1990s to 2010 in much of the Basin highlighted the need for continuing reform. Too much water was still being used and the environment was suffering.

In 2007, Prime Minister John Howard announced a $10b plan to improve water efficiency and to address over-allocation of water. The Water Act was passed that set up the Murray–Darling Basin Authority (MDBA) with the purpose of developing the Basin Plan. The Act’s primary objective is:

to bring water extractions back to sustainable levels in order to protect, restore and provide for the ecological values and ecosystem services of the Murray–Darling Basin

The Act should give effect to Australia’s international agreements such as the Ramsar wetlands. The ultimate source of conflict in implementation of the Act was the provision that management should optimise economic, social and environmental outcomes.

Contents of the Plan

In October 2010, as part of the preparation of the Basin Plan, the MDBA produced a report for discussion entitled Guide to the Proposed Basin Plan. The scientific evidence described in the report stated that achieving an ecologically sustainable level of take would require the recovery of between 3,856 GL ± 20% (high uncertainty of success) and 6,983 GL ± 10% (low uncertainty of success) of surface water from the current baseline development level of consumptive use of 13,623 GL. 10,900 GL of this baseline development level was extracted for irrigation and the remainder was run off stored in on farm dams.

The irrigation communities objected violently to the idea that their allocations could be reduced by so much. The MDBA and politicians buckled and in 2012, the Basin Plan passed by parliament was for a water recovery target of only 2,750 GL (by June 2019), with a program to recover an additional 450 GL of water (by 2024) to benefit South Australia through ‘efficiency measures’ (reducing water losses via infrastructure improvements rather than buying back entitlements), bringing the total to 3,200 GL.

What about Climate Change?

In preparing the Plan in 2010 the MDBA also asked CSIRO to prepare a report modelling water availability in the Murray–Darling Basin including a projection of the effects of climate change.

The assessments for climate change scenarios were made for the median model at 2030 and for the ‘dry extreme’ and ‘wet extreme’. The median projection was of a 10% reduction in Basin-wide water availability with a range of –27% (dry extreme) to +9% (wet extreme).

So not only was the Plan the bare minimum with great risk of not achieving the necessary improvement in environmental flows, there was no allowance for adjustment for the impacts of rainfall reduction from climate change.

Unwinding of Water Recovery Targets since 2012

As has become apparent the Basin Plan is too little, too late. To make matters worse the state and federal governments have been fudging the implementation of the Plan that was always going to require dedication and strict administration.

There are several instances of improper governance and attempts to water down (pun, sorry!) the Plan. A few are outlined below.

In July 2017 ABC’s Four Corners aired a story of water theft and lack of proper oversight allowed by the NSW government. Some prosecutions followed but the administration has been laissez faire.

The Four Corners report prompted the South Australia government to hold a Royal Commission. The report just released condemns the MDBA and governments for maladministration of the Water Act and calls for a separation of management and compliance.

A series of policy changes since 2012 are threatening to further undermine the possibility satisfying the objectives of the Basin Plan. The Australian government intends to amend the Basin Plan by increasing surface water extraction limits for irrigation by 70 GL in the northern Basin. After NSW and Victoria threatened to abandon the Plan water extraction limits in the southern Darling Basin were increased by 605 GL on the basis of 36 projects that improve water efficiency but so far the MDBA has failed to demonstrate that they will achieve genuine water saving. Progress in getting the extra 405 GL to South Australia seems non-existent. Water buy-backs have been halted in favour of these so-called efficiency projects.

The Menindee Lakes fish kill is another story relating to a plan to change the water flow and reduce evaporation, too complicated to explain here but another example of mismanagement. Read a report on this from the Australian Institute.

The federal and state government ministers responsible for the success of the Act have actively undermined the Plan.

Fish Strategy Killed Off

Another concerning demonstration of disregard for science is the treatment of the Native Fish Strategy. This was developed in 2001 and lays out a plan for helping the Basin’s fish communities to recover. The MDBA produced a report in 2009 showing fish stocks were at 10% of pre-European levels (0% in some parts) and the objective of the strategy was to bring this back to 60% over 50 years. It was visionary and forward-thinking – contributed to by a multitude of scientists, managers, indigenous groups and Basin communities.

But direct funding ceased in 2012 when NSW pulled out 60% of its funding. Since then, implementation of its recommendations has been opportunistic and without central coordination. Science ignored again!

Conclusion

Even before the Plan is due to be fully implemented it has been shown to be totally inadequate. Taxpayers that have already paid billions of dollars for water buybacks now have to bear the cost of river rehabilitation, clean up of fish kills and assistance to river communities. The politicians must have the fortitude to strengthen the water take restrictions. We hope the recent events will convince the sceptics and vested interests that stronger action is needed for the common good.

Published in STEP Matters 199

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