The need for modernisation
The Connections Project is a $2b investment in the Goulburn-Murray Irrigation District.
Ten years ago, northern Victoria was struggling through the crippling millennium drought.
In 2006, inflows into Goulburn-Murray Water’s (GMW) storages hit an all-time low. Just 200 GL of water flowed into Lake Eildon – the key storage supplying irrigators on the Goulburn system – in this year.
GMW’s ageing infrastructure was inefficient. When the full water allocation could be supplied, an estimated 900GL of water was wasted each year to leakage, seepage and evaporation. In 2008 the Victorian Government committed $1 billion in funding to the Northern Victorian Irrigation Renewal Project (NVIRP) to ensure a once-in-a-lifetime upgrade of the irrigation infrastructure in the Goulburn-Murray Irrigation District (GMID).
The upgrade would secure annual water savings of 225GL per annum which would be shared equally between local farmers, Melbourne Water and the environment.
On October 18, 2011 the Victorian and Commonwealth governments signed the contract for Stage 2 of the project (then NVIRP2). As part of the agreement the Federal Government announced it would provide $953M and the Victorian Government $106M.
The project would generate an additional 204GL of annual water savings, to be split equally between the funders. On this day it was also announced Victoria would sell its 102GL of water savings to the Commonwealth. The proceeds from this sale would be used to fund Victorian irrigators’ contribution to Stage 1 of the project, meaning irrigators would not have to face price rises to cover their share.
When the business case was written there were a number of assumptions made. Because of the drought conditions the project funding assumed about 3,000 landowners would no longer want to be part of irrigated agriculture and would terminate 45 per cent of delivery share in the GMID. But four years later things were changing. The drought was over and the project would soon be integrated into GMW. In 2010, GMW recorded 1944 GL of inflows into Lake Eildon.
This was followed by strong inflows from 2011 to 2014. Farmers received 100 per cent of their water allocation during these years. The change in weather, combined with solid market conditions meant farmers wanted to be part of irrigated agriculture in the GMID.
The Connections Project is a key part of Victoria’s contribution to the Murray Darling Basin Plan. The water savings are provided to Environmental Water Holders who protect and improve our waterway health to support fish, vegetation and water quality. When the project is complete – and the channels that waste water through leakage, seepage and evaporation are upgraded or rationalised – it’s estimated an average annual water savings of 429GL will be achieved and irrigation water use efficiency will be increased from about 70 per cent to at least 85 per cent.
The Connections Project is one of the largest infrastructure projects in the country. It creates hundreds of jobs for local contractors, designers, manufacturers and other water related industries. The project is critical to the sustainability of our region.
Modernising irrigation infrastructure
To move from a manually operated channel system to a fully automated irrigation delivery system, we’re creating a channel system with better measurement and management of water flows.
Automatic regulation gates are controlled by the Total Channel Control system, which was developed through research by Rubicon Systems Australia and Melbourne University.
This is implemented in many parts of the system. Flume Gates are also being installed to provide precision control and accurate flow measurement.
The gates control the flow of water onto the farm by varying their position according to upstream and downstream water levels and the farmer’s flow requirements.
This involves remodeling channel banks, piping sections of channel and lining channels with clay or plastic to minimise water lost to the system.
These works are targeted toward seepage and leakage water losses, which account for up to 45 per cent of overall losses when using an open channel system.
Electronic flow meters are being installed to provide accurate electronic flow rate and volume measurement data to the main GMW office, via a radio system in most cases.
These meters provide greater accuracy and are compliant with national metering standards, unlike the dethridge wheel.
As part of the Connections program, GMW replaces existing open channels with pipelines. These pipelines include gravity, pressurised options and in some cases a hybrid of both gravity and pressurised. The material used to date is HDPE (High Density Polyethelene) of varying wall thicknesses. Pipelines are often considered highly efficient and able to provide a high level of service.
About 70 per cent of our pipeline works are carried out during the winter works period each year.