Storms in South Africa are becoming more severe leading to flooding and swollen rivers, especially in the country’s downstream fertile growing regions where it can cause havoc with river pumping and storage dam irrigation systems.
Entire pump stations being washed away and dam wall collapses are not the least of a farmer’s worries as rising sediment levels in rivers and dams can be equally destructive over the course of a rainy season. As the severity of storms increases so has the rush of sediment-laden water become a major issue and a significant challenge for irrigation.
Hugo Du Plessis from KSB Pumps and Valves explains that when sediment levels rise to just 10 grams per litre or more, the risk of pump wear and dam silting increases dramatically. In these circumstances it is best to have an action plan and either stop pumping or adapt to prevailing conditions. Simultaneously, river extraction becomes more difficult and the management of systems entails moving equipment and infrastructure. Early warning systems are critical and as waters subside the farmer can test for sediment and wait until river flow settles and the water clears before resuming pumping.
Where water is extracted to a storage dam the design is critical and work done at the design stage is preferable to interventions after the fact. Things like inlet/outlet points need to be scientifically calculated to prevent deposits near points of extraction to avoid ingestion of silt and mud into the field irrigation pumps. Poorly designed storage dams with insufficient capacity may also exacerbate the issue as they force farmers to pump during heavy rainfall periods and risk equipment damage as a result of either being washed away or getting badly damaged by silt.
“We recommend the use of high-quality KSB ETAnorm, ETA C&D, WKLn pumps, which are locally manufactured and supported to provide farmers with reliable pumps that won’t leave them high and dry after the rains. With the ability to pump heads of up to 300 metres and low running costs, we also provide options to ensure dam placement can be located exactly where it is required, regardless of the terrain. Proper placement of storage dams takes numerous factors into consideration such as elevation and distance of fields, proximity to required infrastructure and geological factors.
“With regard to the pumps, our range of irrigation pumps is manufactured with materials suitable for river water, and can be adapted locally with local conditions in mind. They have a higher level of durability integrated into the designs to ensure longevity in African conditions. Even the best pumps need maintenance under trying conditions and that is why we also recommend more regular scheduled maintenance during the rainy season, as well as the adaptation of both irrigation and extraction infrastructure to suit changing weather patterns,” Hugo says.
He points to the importance of proper design and maintenance of systems as a means of ensuring the success of an irrigation scheme as the company’s representatives regularly see pumps lasting over 20 years which are standing alongside farms where the pumps can only last a mere year or two. The difference in these instances is that the long-lasting pumps belong to systems that have been properly designed and maintained according to the circumstances while the ones that need regular replacement simply weren’t.
When developing or upgrading irrigation systems, farmers − particularly those operating medium to large farms − can greatly benefit from the expertise of specialist firms accredited by SABI. These professionals bring a wealth of experience and an in-depth understanding of local waterways, enabling them to design tailored solutions that align with the unique needs of specific catchments and individual farms.
“KSB Pumps and Valves has been a cornerstone of South African agriculture since 1959 and works closely with companies like Agrico, Valley Irrigation and Valmont Industries among other KSB partners to provide high-quality irrigation solutions. With the proper design and preparation and the right pumping equipment local farmers have the ability to thrive in the face of adversity. With service and support from KSB Pumps and Valves experts our farmers can face all eventualities from flooding to droughts with confidence,” says Hugo.
For more information contact KSB Pumps and Valves South Africa,
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