Senix Water Level Sensors Drive Irrigation Automation Project
Australia’s Water Crisis
Irrigation management is serious business in Australia especially within the Murray-Darling Basin, a 1,000,000 square kilometer watershed that is home to Australia’s most productive agricultural land. The basin’s 23 rivers have some of the lowest and most variable flows in the world. A massive system of dams, lakes and canals stores water from mountain snowmelt and seasonal rains and distributes it to farms and communities throughout the growing season.
The Murray-Darling watershed has been under pressure since the 1960s, but a series of environmental and economic crises in the 1990s created momentum for changing the way water resources were managed. In 1991, a 1,000-kilometer outbreak of blue-green algae on the Murray River became a vivid symbol of the environmental stress associated with reduced river flows. Reduced flows were threatening sensitive wetlands, protected species and salinity levels throughout the watershed. Water shortages threatened everyone, including farms, industry, municipalities and tourism.
Australia’s response was one of the most sweeping water management reforms ever enacted. The Murray-Darling Authority was created in 2007 to develop the first cross-border water resource management plan. In 2012 the Murray-Darling Basin Plan became law. Once implemented, the plan would return 2,750 gigaliters of surface water to the environment. An additional $1.7 billion was appropriated in 2012 to provide an additional 450 gigaliters to the environment. The total 3,200 gigaliters to be returned would be provided in two basic ways: (1) modernization and automation of irrigation infrastructure from one end of the watershed to the other and (2) government-authorized selective water rights purchases on behalf of the environment.
Murray Irrigation Limited
Murray Irrigation, Australia’s largest privately owned irrigation company, manages irrigation along the upper reaches of the Murray River in southeastern New South Wales. Their system distributes water to more than 2,300 farms covering approximately 750,000 hectares through almost 3,000 kilometers of gravity-fed earthen channels. This highly productive agricultural region has had its share of drought crises. The most recent major drought, the “millennium drought” from 2005 to 2009, resulted in a 63% reduction in water deliveries to farms and devastated agricultural production.
Managing this decades-old irrigation system has been a complex undertaking. Farm customers requested seasonal allocation of water based on the weather, crop maturity, soil conditions and other factors. Water orders had to be placed up to seven days in advance to allow for coordination, but a lot can change in a farm field in seven days. Delivering water through a spider web of surface channels is a complex manual process. Water levels and releases in each channel had to be balanced so that each customer received their water allotment regardless of their location in the distribution system. Murray Irrigation had to balance the requests of 2,300 farms as well as the needs of industrial and municipal customers on a day-to-day basis all while staying within Murray’s allocation within the greater Murray-Darling Basin Plan.
Historically, the system was managed manually through a system of channel control gates and mechanical water meters. Irrigation staff would travel to channel control points and raise gates a certain height for a specified duration to release water to downstream channels. Dozens of people positioned throughout the 3,000 kilometers of channels would attempt to coordinate water levels so that each farm customer received their requested water allocation when they wanted it. Customer water usage was typically measured with mechanical meters that had to be visited periodically to monitor consumption. Large contingency releases of water were necessary to make sure that end-of-the-line customers received the water volume they were entitled to with sufficient flow to make consistent field irrigation possible. The system was labor intensive and imprecise, but it was cost effective as long as water was plentiful. With devastating droughts and routine water scarcity, a more efficient system is critical.