Structural damage to canals due to spilling as a result of overflows caused by aquatic vegetation .
losses were cut by 17 % and the water saved could be made available to new mines in the area , which are expected to inject more than R1-billion into the local economy — something that would have been difficult to achieve without the available water . Even better results were obtained in the Roodeplaat canal system , north of Pretoria , where water losses were cut by 19 % with ad hoc treatments of the canal with MAGNACIDE™ H Herbicide ( L8655 ). It was found that MAGNACIDE™ H Herbicide ( L8655 ) provides excellent control of both vascular-submersed aquatic vegetation and algae , providing more effective results than any other control method . A single application generally restores canal flow capacity within 24 hours after application ; nuisance vegetation disintegrates over a five to 10-day period . The product has no effect on civil canal structures and is not corrosive to irrigation equipment . Preventative maintenance plans are now implemented on local irrigation canal systems to control aquatic vegetation to levels where they cannot cause operational problems and canals will not spill as a result of biomass infestations . Integrated Aquatic Vegetation Management Plans ( IAVMPs ) are developed and implemented for each irrigation scheme with MAGNACIDE™ H Herbicide ( L8655 ) as chemical control component on the
Treatment of a canal to control aquatic vegetation .
flowing canal water , and sterile Chinese grass carp ( Ctenopharyngodon idella ) as biological control component in balancing dams , irrigation dams , and other semi-stationary impoundments on the irrigation scheme . The introduction of sterile Chinese grass carp to combat aquatic vegetation in dam structures , both in the water conveyance structures and in on-land irrigation dams , is very successful . The combination of the herbicidal control method with the biocontrol agent has made aquatic vegetation problems in irrigation canal systems something of the past . A preventative maintenance programme consists of a series of herbicidal applications to canals with MAGNACIDE™ H Herbicide ( L8655 ) at a scheduled frequency , while sterile grass carp is stocked in dams . With a preventative maintenance IAVMP in place , the irrigation scheme manager can keep the water distribution system in an optimal operational condition with minimal disruption of water delivery and maximum water savings . u
For more information , contact Kobus du Plessis of Envirokonsult Scientific Services at duplessisk @ envirokonsult . co . za . Website : http :// www . envirokonsult . co . za .
About the author
Kobus du Plessis is a professional water scientist with 30 years of experience in the water sector . He is the managing director of Envirokonsult Scientific Services , based in Hartbeespoort , North West Province . He specialises in water resource management , integrated aquatic vegetation management programmes , water loss control , urban lake management , and irrigation canal maintenance programmes . networking contributor innovations industry debate environment infrastructure municipalities
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