In Australia, irrigation management is crucial, particularly within the Murray-Darling Basin, which is a 1,000,000 square kilometer watershed. It is home to Australia’s most productive agricultural land. The 23 rivers in the basin possess some of the most variable and lowest flows in the world. A huge system of lakes, dams, and canals store water from seasonal rains and mountain snowmelt and distribute it to communities and farms during the growing season.
Since the 1960s, the Murray-Darling watershed has been under pressure, but in the 1990s a series of economic and environmental crises generated momentum for altering the approach by which water resources were managed.
Environmental Stress Due to Decreased River Flows
A 1000 km-outbreak of blue-green algae on the Murray River in 1991 became a powerful representation of the environmental stress related to decreased river flows. The reduced flows were threatening protected species, sensitive wetlands, and salinity levels throughout the watershed. Water shortages endangered everyone, including industry, municipalities, farms, and tourism.
Figure 1. The Murray-Darling Basin covers 14 % of Australia. It is Australia’s most important environmental and agricultural asset.
Figure 2. The Hume weir at Albury during the Millennium drought. These conditions prompted massive public investment in irrigation automation.
Australia’s reaction was one of the most extensive water management reforms that have ever happened. In 2007, the Murray-Darling Authority was formed to create the first cross-border water resource management plan. The Murray-Darling Basin Plan became law in 2012. The plan would return 2750 gigaliters of surface water to the environment once implemented.
In 2012, a further $1.7 billion was commandeered to supply an additional 450 gigaliters to the environment. The overall 3200 gigaliters to be returned would be dispensed in two basic ways:
- Automation and modernization of irrigation infrastructure from one end of the watershed to the other.
- Government-authorized selective water rights purchases on behalf of the environment.
Figure 3. Murray Irrigation manages 3,000 km of surface irrigation channels along the upper reaches of the Murray river in New South Wales.
Figure 4. Dethridge wheels measured water use by counting revolutions on mechanical counters that were read manually each month. They are being replaced by modern digital water meters.
Operations of Murray Irrigation
The biggest privately-owned irrigation company in Australia, Murray Irrigation, handles irrigation across the upper reaches of the Murray River in southeastern New South Wales. Covering around 750,000 hectares through nearly 3000 kilometers of gravity-fed earthen channels, their system distributes water to over 2,300 farms.
This highly productive agricultural region has had its share of drought crises. A 63% reduction in water deliveries to farms was recorded in the “millennium drought” from 2005 to 2009, which is the most recent major drought, and it devastated agricultural production.
It has been a complex task to manage this decades-old irrigation system. Based on the weather, soil conditions, crop maturity, and some other factors, farm customers requested seasonal allocation of water. Water orders had to be assigned up to seven days in advance to enable coordination, but a lot can change in seven days in a farm field.
Transporting water through a spider web of surface channels is a complicated manual process. So that every customer received their water allotment regardless of their location in the distribution system, water levels and releases in each channel needed to be balanced.
Murray Irrigation had to balance the requests of 2,300 farms in addition to the requirements of municipal and industrial customers daily - all while staying within Murray’s allocation set out in the greater Murray-Darling Basin Plan.
Historically, the system was managed manually via a system of mechanical water meters and channel control gates. To release water to downstream channels, irrigation staff would travel to channel control points and raise gates a certain height for a specified duration.
Dozens of people located over 3000 kilometers of channels would try to coordinate water levels so that each farm customer acquired their requested water allocation when they needed it. Typically, to monitor consumption, customer water usage was measured using mechanical meters that had to be visited periodically.
To ensure that end-of-the-line customers received the water volume they were entitled to, large contingency releases of water were necessary with enough flow to make consistent field irrigation viable. The system was imprecise and labor-intensive, but as long as the water was plentiful, it was cost-effective. With routine water scarcity and devastating droughts, a more efficient system is vital.
Figure 5. Modern bridge gate with remote power and communications. A ToughSonic REMOTE 14 ultrasonic sensor is mounted on top of the stilling tubes beside the gate.
Murray Irrigation started their Private Irrigation Infrastructure Operators Program (PIIOP) in 2013, intending to decrease water distribution losses across the almost 3000 km channel length.
Described as a “once-in-a-generation opportunity to modernize our irrigation infrastructure and supply system,” the $169.2 million PIIOP is intended “for the benefit of all our irrigation customers and to provide improved water efficiency and productivity for our customers’ farm businesses.”
Senix ToughSonic REMOTE 14 Used to Upgrade Regulatory Channel Structures
The project calls for upgrading over 1,300 regulatory channel structures and over 2200 water meters and integrating them through an enhanced telemetry and SCADA system. Senix ToughSonic REMOTE 14 ultrasonic sensors supply real-time water level measurements to guide semi-autonomous and autonomous channel control structures in this new system.
Since work started in 2013, over 1,000 irrigation control points have been replaced. Around 1,200 more channel control points will be replaced with sensor-driven, automated gates utilizing ToughSonic water level sensors during this next phase of the project.
Murray Irrigation is applying two levels of system automation. Irrigation control points are controlled remotely in Standard Level of Service (SLOS) areas. ToughSonic ultrasonic sensors mounted near each gate supply water level measurement data to Murray’s SCADA system.
To release water based on known time and volume parameters, control center operators monitor water orders and channel levels and issue remote gate movement commands. This system is responsive and accurate, while it permits farmers to adjust their water orders every 12 hours.
Irrigation control points are automatically controlled based on determined parameters in High Level of Service (HLOS) areas. Irrigation customers submit water orders online and the irrigation management system issues gate manipulation commands.
To establish the quantity of water delivered, the system monitors water level data from the ultrasonic level sensors and other sensor inputs. HLOS systems enable irrigation customers to order water as often as four times per day, overall system flow permitting.
Water is distributed with precision and with no need for large and potentially wasteful contingency releases in both of these service areas. Farmers benefit from more stable flows and shorter lead times, enabling them to water crops more precisely, maintain healthy crop yields, and decrease overall water consumption.
Figure 6. Senix ToughSonic REMOTE 14 is installed in irrigation automation systems around the world.
To decrease energy consumption and enhance surge protection during lightning storms, Senix modified the ToughSonic 14 sensor. Enhancements made for Murray Irrigation were later incorporated into the recently released ToughSonic REMOTE sensor product line.
“We also now offer REMOTE versions of our longer range ToughSonic 30 and ToughSonic 50 sensors for flood management customers, like those used in the Iowa Flood Warning System and the Philippines Tsunami Early Warning System,” says founder and President of Senix, Doug Boehm.
“When we received the first order for modified ToughSonic 14 sensors from Murray Irrigation, we decided to formally introduce it as the first model of our ToughSonic REMOTE product line.”
Population growth combined with changing weather patterns is creating crippling droughts all over the globe. Australia is meeting these challenges with major investments in irrigation automation technology and effective policy change.
The more precious water supplies become, the more carefully they must be managed. Murray Irrigation is implementing one of the most sophisticated irrigation distribution systems in the world with state-of-the-art sensors, gates, and SCADA technology, all designed to improve customer service and decrease waste. Irrigation officials from all over the globe are visiting the Murray-Darling Basin to learn more about the future of irrigation automation and irrigation policy.
This information has been sourced, reviewed and adapted from materials provided by Senix Corporation.
For more information on this source, please visit Senix Corporation.