Repairs to gabion revetment under way

The gabions in the revetment between Big Bay and Small Bay are being replaced with sand bags.

The City of Cape Town is replacing the gabions in the revetment between Big Bay and Small Bay with sandbags.

According to Mayco member for spatial planning and environment, Marian Nieuwoudt, the renovated revetment will fall within the footprint of the existing one, negating the need for environmental authorisation.

“However, the City will have environmental oversight of the construction via a designated environmental control officer to ensure compliance,” Ms Nieuwoudt said.

The damaged gabions in the revetment will be replaced with 3-ton sandbags the City refers to as “geo containers”.

The bags, according to Ms Nieuwoudt, are made of reinforced material suited for marine conditions and the outer layer is designed to be resistant to abrasion and UV rays.

The work should be finished in 10 weeks, weather-permitting, she said.

The full length of the gabion revetment will be removed and replaced with the bags. The bags will also replace the damaged toe protection in front of the gabion wall to provide scour protection.

Ms Nieuwoudt said the June 2017 storm had a severe impact on the coastline south of Big Bay up to the northern end of Small Bay. The continued loss of sand and beach levels, along with successive wave action over the past two years had seen the gabion revetment collapse she said.

“This gabion revetment was built 30 years ago to protect and defend this short section of exposed coastline and has lasted longer than expected. However, once the ‘toe’ of the gabion was exposed by loss of sand levels, the continual abrasion by stones and pebbles being thrown against it by the wave action has caused the wire baskets to begin to break, fail, and collapse.”

Once the wire baskets started collapsing, the pedestrian walkway between Big Bay and Small Bay also started collapsing.

Last year’s winter storms had aggravated the situation, Ms Nieuwoudt said.

The only part of the new revetment that would be higher that the current one was where the edge of the southern portion tied into the beach access stairs, she said.

“However, the crest of structure at that portion is not higher than the natural ground level and therefore will not have an impact on views.”

In March Blouberg resident Agi Orfanos complained about the collapsing pathway, broken gabions as well as the collapsing sea barrier at the end of Popham Street.

“When you allow things to deteriorate they do so to a point of disrepair,” he said.

The City needed to identify problems continuously and repair them timeously such as the brick paving, log fencing and build-up of sand dunes, he said.

“The roadway and concrete paths from Small Bay to Blue Peter have also remained closed as waves have sucked out much of the underlying sand below the foundations.

“This needs to be underpinned and sealed before that whole section collapses which will result in devastating expensive even unaffordable consequences, which can be saved now if this work is undertaken,” Mr Orfanos said at the time.

Ms Nieuwoudt said the walkway between Small Bay and Big Bay would be repaired once the revetment had been installed.

During the construction, the walkway between Big Bay and Small Bay will be closed to the public for safety reasons and the parking area at De Mist Street will be closed and used for a construction site camp. Alternative parking is available at Popham Street and Pelegrini Street, or at Eden on the Bay during this period.

The public are urged to not access the beach between De Mist Street and the lifesaving ramp for their own safety.