Stories from the Field

South Africa

Sixty percent of South Africa’s water supply is used in the agricultural sector, but 35 percent of this water is lost in the river and canal conveyance system alone.

Addressing Water Wastage in South Africa’s Irrigation Schemes

The Vaalharts Irrigation Scheme, in operation for more than 75 years, is the largest of its kind in South Africa. With more than 1,100 kilometers of concrete-lined canals, it irrigates almost 40,000 hectares. Like all national irrigation schemes, Vaalharts receives a quota each year stipulating the amount of water it may distribute, so the ability to accurately track water usage and reduce losses is of paramount importance.

Over 25 years of research funded by the Water Research Commission went into the creation of the Water Administration System (WAS). In 2011, the Strategic Partners Water Network (SWPN) South Africa, supported by the 2030 WRG, funded research to select the best data logger and internet platform for optimal data tracking and management, and has subsequently supported the roll out of the system across multiple irrigation systems.

“Before WAS, most irrigation schemes could only estimate the amount of water they had left and how much was wasted. Now, with a touch of a button they have access to information which helps them better manage their distribution and minimize water wasted.”

Following the implementation of the WAS, Vaalharts has already decreased annual water losses by 5 percent, equivalent to 17.5 million m3. The WAS is an innovative decision-support program that allows water user associations on irrigation schemes to manage water accounts and supply and demand through rivers, canal networks, and pipelines. This allows Vaalharts to track water distribution in real time.

According to Kobus Harbron, Chief Water Control Officer of the Vaalharts Water Users Association, “The WAS has helped streamline a once laborious process, susceptible to human error, and has decreased administrative time from three days to half a day per week, allowing staff to spend more time on other important tasks, such as infrastructure maintenance.

Once Vaalharts is able to make further repairs to its canal network, an additional 5 to 8 percent in annual water savings is expected.” The WAS also helps farmers, who manage about five plots each, make informed decisions on crop management based on water availability. Automation has allowed the scheme to operate seven days a week as opposed to five and a half, enabling farmers to take advantage of low off-peak energy rates. Today, the award-winning WAS is used on almost all major irrigation schemes in South Africa and saves an average of 10 percent of water that was previously lost.

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