The necessity for irrigation schemes. Comparison of size of global schemes. Australia is 23rd in world rank. Why so far behind? Examples of world irrigation projects. Existing Australian irrigation projects. Current Queensland projects, existing and planned – pathetic.
The groundwater at Rome was notoriously unpalatable, and water from the Tiber was unsafe to drink. Aqua Appia, Rome’s first aqueduct (312 BC) was commissioned by the censor Appius Claudius Caecus as a publicly funded major project.
By the late 3rd century AD, Roman aqueducts supplied Rome with water by a combined conduit length of 800 kilometres, of which only 47 km were carried above ground level by the familiar masonry supports. They supplied around 1 million cubic metres (ie 10,000 GigaLitres) a day; enough to supply a modern city of population of 10 million. The longest was the Constantinople (Turkey) around 500 km. Gradients for Roman Aqueduct were 1:4800 and typically around a metre wide and deep with a flow rate estimated to be about 35,000 m3 /day (or 350GL/day) depending on the season .
With the fall of the Roman Empire, some aqueducts were deliberately cut by enemies but many more fell into disuse through lack of organized maintenance. Their failure had an impact on the population of cities; Rome declined from its high of over 1 million people in the Imperial era to as low as 30,000 in the medieval era.
The New Bradfield Scheme is very similar length, capacity and function to the Roman aqueducts being totally gravity fed. With an estimated fall of 1:5000, 100m from Hell’s Gate over a distance of 500 km to the Lakes Buchanan and Galilee Storages, a wider, lined channel could easily provide the 20,000GL per annum. Harvesting the flow from streams along would be possible, or desirable helping to reduce flooding lower in the catchments and leading to potentially greater harvest rates. Spillways would dump the excess if the water level got too high.
As Sir Humphrey Appleby said about public projects (‘Yes, Minister’): “Anything is possible for government, so long as it isn’t the first time.” The Roman Empire has done a similar-sized gravity-fed aqueduct system 2000 years ago.
In Queensland, CSIRO have identified the Mitchell catchment (yellow area above) as the greatest potential to increase greenfield development opportunities in Northern Australia, and the coastal regions of the Fitzroy and Burdekin River catchments for enhancements. However, developments in these would do nothing for the water poor, rich soil areas of Clermont, Richmond, Longreach, Barcaldine, Muttaburra that already have established agricultural infrastructure that could be expanded, established human settlements (and importantly voters), and further west potentially channel water into the Murray Darling Basin.
The CSIRO studies have not, so far, evaluated the feasibility of aqueducts between catchments. Therefore, the locations they identify rely on the coincidence of good soils, dam locations and rainfall. They do not consider connected water networks with harvesting levees and high catchment dams, or aqueducts that could transfer water between high rainfall poor soil, to low rainfall good soil locations. Not considered, also, are potential higher returns from enhanced town water supplies.
The problem – very few people live in the Mitchell catchment or want to go there (see map). I am concerned the CSIRO are going down the wrong path again, potentially creating another massive ‘white elephant’ like the Ord River Irrigation Scheme that may take 100’s of years to reach the projected potential. A system of gravity-fed aqueducts from the high rainfall northern rivers of Tully and the Walsh Rivers into the existing populated outback areas with irrigation potential – aka the new Bradfield Scheme – needs to be included in the CSIRO feasibility studies.
CSIRO have investigated the potential of northern Australia’s water resources to support increased regional development as part of our engagement in delivery of the Australian Government’s White Paper on Developing Northern Australia, for which one of the key initiatives is the development of northern Australia’s water resources. They have delivered water resource assessments for three priority regions in northern Australia for the Australian Government after working with northern jurisdictions, research partners and communities over 2.5 years. An orphaned dam in the Mitchell catchment is all we get? Disappointing.
Let’s look at similar water storage and distribution systems to the New Bradfield Scheme, in California.
California is 400 km wide and 1200 km long. It has a land area of 423,970 km2 of which 36,421 km2 is irrigated. Agricultural production is $47 billion per year, a large proportion of which is irrigated or irrigation related.
California is largely desert and its population centres and agriculture watered by a number of long aqueducts exceeding 500 km in length.
For example, the California State Water Project, commonly known as the SWP, collects water from rivers in Northern California and redistributes it to the water-scarce but populous south through a 650 km length aqueduct, with pumping stations and power plants. About 70% of the water provided by the project is used for urban areas and industry in Southern California and the San Francisco Bay Area, and 30% is used for irrigation in the Central Valley.
By comparison, Northern Queensland has a land area of approximately 500,000 km². An extended Bradfield Scheme may provide irrigation for 30,000 km2 of land. This would be achieved by a system of aqueducts and dams, of similar length to similar to those in California. In return, we would expect agricultural production of $50 billion per year, similar to California.
In some ways Queensland is more suited than California, as due to good luck or blessing, the new Bradfield Scheme may entirely gravity fed through tunnels and aqueducts. The cost of water may therefore be considerably less than the cost of water in the SWP in California.
The construction of the aqueducts in the new Bradfield Scheme could be staged, developing first those areas that are closer to population centres and prepared for irrigation, and releasing the excess water into parched river systems. However, the irrigation of large areas black soil plains in the central state would open up the largest areas to new agriculture.
The new Bradfield Scheme could provide 30 thousand km2 of new irrigated land in inland Queensland, more than doubling the land under irrigation, and catapulting Australia from 23rd place by irrigated land area (between Peru and Japan) to 8th place (between Brazil and Thailand).
The Deputy Prime Minister, Michael McCormack speaking at the National Press Club in Canberra announcing, if re-elected, the LNP government would introduce a new statutory authority called the National Water Grid tasked to managed water infrastructure around Australia (with Bradfield Schemes as a first order of business).
We need to better store, better harvest, and better use water— our most valuable asset.
Our country community is some of the most inventive minds, finest engineers, smartest entrepreneurs, willing people prepared to have a go try things.
Let us have a vision. Show some courage of the scale of the Murrumbidgee Irrigation Area and the Snowy Scheme to again show the world what a mighty nation of thinkers and builders we are.
That’s why today I’m proud to announce that the Liberals and Nationals in government will establish a National Water Grid.
The National Water Grid will be a statutory authority responsible for the strategic planning and project management for water infrastructure right across the Nation.
The National Water Grid will bring together the world’s best scientists to take the politics out of the way water is captured and stored in Australia.
No longer will states be able to hide behind political games as to why they will or won’t allocate water to a particular valley or region.
No longer will future federal governments be able to strip funding from vital water infrastructure projects because they believe they don’t stack up purely based on politics.
No longer will our communities’ ability to unlock their own potential merely exist in and around election cycles.
It’s been too long since we built a dam. You all know that. We can’t even raise a dam wall. Enough is enough.
This is not about pitting states against states, catchments against catchments, communities against communities.
This is about the Commonwealth providing real leadership and real vision.
Right across the country, we are building the water infrastructure our communities expect and deserve and the National Water Grid will be responsible for developing the water grid and to identify the missing links.
I can also announce one of the National Water Grids first orders of business will be able to use the best available science to examine how large scale water diversion projects could be established to deliver reliable and cost-effective water to farmers and regional communities.
A re-elected Liberal and Nationals government will also seek agreement for States and Territories to co-invest to make this a truly a national initiative based on science, not politics.
And we are going to put a down payment of 100 million dollars for projects supporting states to better understand their own water resources and kick start investigation to water diversion projects.McCormack announces a national water authority
How do gravity fed systems work? Examples of Gravity fed systems. Yeomans Keyline system. Permaculture. Colorado River. Climate variability, rainfall sources monsoon in northern Queensland, flood flows vs regular flows, soil types suitable for irrigation, water tables. Economics of pumping and gravity fed methods. Crop selection and processing facilities. Market proximity.
Pause to think about why farmers dam water. Usually, it is to store intermittent or seasonally variable rain until the optimal growing season of the crop when water becomes limiting.
When it is most needed, the rainfall deficit coincides with a deficit going into the dam. When raining and the dam is filling, the local need is low. At high rainfall events, storages are filled to overflowing when the local demand is lowest, so most of the water goes over the spillway.
Conveyance of water via long aqueducts provides water from sources that are far away. Either the source is less correlated with the sink, or the supply and demand are in sync, such that the water is most in demand when it is the most available, and least in demand when least available.
Long Conveyance of water in the Bradfield Scheme not just about the supply of water from less correlated regions. It is about transfer between climates with reliably different rainfall patterns. Large local dams need to store water over from the winter period in order to water during summer, losing considerable amounts due to evaporation. Conveyance of monsoonal water during the summer period would minimize the storage and associated evaporative losses.
In a summer crop such as cotton, water may be limited in the hot dry growing season. Therefore the transfer of water from a monsoon climate in Northern Queensland to climates with uniform rainfall such as southern Queensland and Northern NSW makes sense.
Annual average rainfall varies from more than 1800 mm along the coast with peak rainfall in summer (Jan to April). Southern districts receive average rain in the hot summer, making agriculture particularly reliant on rainfall during the winter growing season – unless water was conveyed from the reliable monsoon falls of the north.
As an example, cotton is a perennial plant grown commercially as an annual, summer crop. It prefers hot summers with low humidity and a maximum amount of sunshine. Cottonseed is planted in the spring as soon as the soil is warm enough to be sure of satisfactory seed germination and crop establishment. On irrigated cotton farms the initial irrigation (watering) is usually followed by a further four to five irrigations, at two to three-week intervals, from mid-December to late-February.
Thus the northern wet season is long enough for the fourth months of growth needed from germination to when the cotton bolls to ripen and split open. When mature, timing is critical in cotton. The controlled watering ensures dry conditions on the heavy soils that are needed for mechanical harvesting, placing into large modules, and transferring to cotton gins for processing and shipping to overseas markets.
Local water storage doesn’t last through Australian droughts.
The South Burnett is located on top of Australia’s Great Dividing Range just two hours drive north-west of Brisbane, Australia and directly west of the Sunshine Coast. The South Burnett is Queensland’s largest wine region, home to the State’s biggest vineyards and more than 20 wineries and cellar doors. The South Burnett is also home to two of Queensland’s biggest inland waterways (Lake Boondooma and the Bjelke-Petersen Dam), the Jurassic-era Bunya Mountains and some of Australia’s prettiest agricultural country.
With the water level at Lake Barambah currently 8%, irrigation of these agricultural business has been severely restricted.
Lake Barambah has irrigation, camping and recreational facilities handled by Murgon Shire Council. Facilities for caravans, cabins, camping and day-trippers are extensive. Under normal conditions there are no boating restrictions, except near the dam wall. In 2006, drought conditions reduced dam levels to 5% of total capacity. With such low levels, visitors numbers dropped significantly and local councils were concerned about maintaining drinking water for local towns. With the water level at Lake Barambah currently 8%, recreational users and visitors must be aware of exposed and submerged hazards.
An integrated water scheme such as the new Bradfield Scheme would allow storages such as these to be refilled by the abundant flows from the recent coastal wet season that saw widespread above average rainfalls and flood from Cairns to Townsville.
Read the full-alert here: https://bit.ly/2DdOiN0
Through control of the supply of water to certified producers including mines and farmers, the Bradfield Scheme can drive the environmental and humane animal husbandry outcomes that consumers seem to increasingly demand.
Sustainability branding is the process of creating, maintaining and adding value to the products of the scheme through certified environmental and social benefits. In contrast to existing green, organic brands which mainly focus on farming practices, the sustainability brand entails health and safety issues, conditions under which a particular product is produced, and adheres to the triple bottom line of ecological (environmental), social (equity), and financial (economic) sustainability.
Certification may require demonstration of such practices as Integrated Pest Management, free-range animal husbandry, environmental offset and reserves, indigenous employment to name a few. In this way, there will be the likelihood of identification and loyalty amongst consumers associated with social and environmental added value.