Maccaferri Africa involved in the project of dam-spillway rehabilitation in the popular Emmarentia Dam in Johannesburg.
Maccaferri Africa was appointed as the sole supplier of Gabions and Castoro Mattresses for the dam-spillway rehabilitation at Emmarentia Dam in Johannesburg, South Africa.
The Johannesburg Roads Agency (JRA) in April embarked on a very important eight-month-long rehabilitation project for the old Emmarentia dam.
The dam is located on the Westdene spruit, which is a tributary of the Jukskei river and a popular recreational venue for Johannesburg residents.
This 103 year landmark was in need of maintenance following the recent floods, which damaged the aging infrastructure. While significant improvements to Emmarentia dam were undertaken in 1988, a recent comprehensive investigation conducted by the JRA showed that preventative maintenance and flood-retention protection is required to safeguard the dam’s integrity and ensure the safety of residential properties downstream. The investigation revealed some subsiding, which means that the dam wall slope stability is potentially at risk. It also revealed that urgent repairs on the return channel are required as a major flood could undermine the existing gabion and concrete walls, which could cause significant structural damage.
Further, continued erosion could expose the banks and possibly undermine existing municipal roads located next to the return channel. Also Olifants road, along the crest of the dam’s embankment, has also been affected by possible leaks within stormwater inlet structures, requiring repairs and road reconstruction. Improving Emmarentia dam’s flood-prevention facility to protect properties located downstream of the dam from flooding will include excavating and repairing the pipework and surrounding soil at the stormwater structures located along the dam. The project scope also includes altering outlet structures, repairing the box culvert outlet, widening the control section and constructing a gabion wall on the eastern side of the outlet.
The JRA will also implement protection measures to prevent future erosion caused by high volumes of flooding water, which involves reconstructing and/or repairing the gabion wall and reconstructing the bottom of the channel. A concrete wall will also be constructed where the channel comes close to the roadway to prevent damage to the roadway. Olifants road will also be reconstructed. The completion of these preventative measures will ensure that the dam has the capacity to convey a flooding event of the 25-year recurrence flood peak value. The project started in April 2015 and is envisaged to be completed by January 2016.
Maccaferri Africa, as part of the Technical Support, is assisting the contractor even by training the labour force on product installation and site management.
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