World-beating megabridges to boost Wild Coast economy

A modern highway being built along the Eastern Cape’s remote Wild Coast will feature two massive bridges, the longest and highest in Africa, which will bring much-needed investment to one of South Africa’s poorest regions.

A visualisation of the megabridge over the Mtentu River. The bridge will reach up to 220 metres above the floor of the gorge, surpassing the Bloukrans Bridge on the Garden Route and making it the highest bridge in the southern hemisphere
A visualisation of the megabridge over the Mtentu River. The bridge will reach up to 220 metres above the floor of the gorge, surpassing the Bloukrans Bridge on the Garden Route and making it the highest bridge in the southern hemisphere. (Image: Sanral)

Mary Alexander

Two massive megabridges will soon connect communities and speed up investment into the deep rural areas of the Eastern Cape’s Wild Coast.

The bridges form the backbone of the South African National Roads Agency’s (Sanral) N2 Wild Coast Toll Road construction project. The full project runs from Durban down the coast to East London. The greenfields section of new highway will extend modern road infrastructure for 110 kilometres from Port Edward on the border of KwaZulu-Natal southwards along the Eastern Cape coast to Port St Johns.

The new coastal highway will halve the distance travelled between Port Edward and Port St Johns. At the moment, the fastest route between the towns runs for some 200 kilometres inland along the R61 road.

The first megabridge will cross the Mtentu River outside Xolobeni, and the second the Msikaba River near Lusikisiki. They are essential segments of the highway.

“The bridges form part of the greenfields section of the Wild Coast highway project,” says Edwin Kruger, Sanral’s bridge network manager. “This section is a brand-new road and without the bridges we cannot complete the highway.”

Record-breaking bridges

The Mtentu bridge will be the first of its size in South Africa, and one of the longest main-span balanced cantilever bridges in the world. It will reach heights of up to 220 metres – more than two kilometres – making it the highest bridge in Africa.

The last time South Africa built a megabridge was in the early 1980s, during the construction of the N2 Tsitsikamma on the Garden Route. That was the 217-metre Bloukrans arch bridge, currently the tallest bridge in the southern hemisphere. When the Mtentu bridge is complete, it will exceed the Bloukrans record.

The second megabridge will stretch 1.1 kilometres across the spectacular and pristine Msikaba River gorge. It will be the longest cable-stayed suspension bridge in South Africa – and possibly the whole of Africa, Kruger says.

“Cable-stayed bridges are distinct in their use of towers and cables to support the bridge deck,” he says. “This single-span bridge will be anchored back into rock on either side of the gorge.” A famous example of a cable-stayed bridge – although a lot smaller – is the Nelson Mandela Bridge in Johannesburg.

The construction of these massive bridges in a remote rural area is a major undertaking, requiring specialised engineering skills and building techniques.

“No South African firm has ever built a balanced cantilever bridge of this magnitude before. As such, South African tenderers have joint ventured with international firms to bring skills and expertise into the bridge’s construction,” Kruger says.

A cable-stayed megabridge will run for 1.1 kilometres across the pristine Msikaba River gorge, making it the longest bridge of its kind in South Africa
A cable-stayed megabridge will run for 1.1 kilometres across the pristine Msikaba River gorge, making it the longest bridge of its kind in South Africa. (Image: Sanral)

Business, skills and work for locals

“Both bridges have a large concrete component, so labour will be needed for fixing steel and placing the concrete for the bridges. Semi-skilled and unskilled labour will be sourced locally,” Kruger adds.

Craig McLachlan, Sanral’s southern region project manager, says that as part of the road agency’s SMME development programme, local Wild Coast small businesses are already being given the skills needed to take part in the project. This is in the form of full learnerships teaching a combination of road construction and business skills.

“The SMME development programme will ensure that jobs created by the N2 greenfields project can be filled by local contractors,” he says.

SMME participation is an essential component of all Sanral projects. More than R1.5-billion will go to SMMEs in the construction the 110 kilometres of new roads and bridges. It is estimated that this will help create 50,000 direct and indirect jobs in the local community, both during and after construction.

McLachlan says that as wages earned typically have a multiplication effect in the local economy of two to three times, this job creation will further boost local livelihoods.

Protecting the Pondoland biome

The Wild Coast is one of South Africa’s most beautiful regions, a place of untouched grassy plateaus incised by subtropical forested ravines and gorges. Its Pondoland biome of indigenous and endemic plant life forms part of the Maputaland-Pondoland-Albany biodiversity hotspot, a unique floral region.

One environmental requirement in Sanral’s Wild Coast highway project is that it have as little impact on this precious landscape as possible. The cable-stayed Msikaba bridge was therefore designed to ensure that its construction would not damage the environment in the gorge more than 200 metres below.

Environmental lobby groups have expressed concern about the new N2 highway’s impact on the Pondoland biome. During the environmental impact assessment phase of the project, Sanral used specialist studies to ensure that its route avoids the most sensitive areas of Pondoland.

But some damage is unavoidable, so Sanral has established comprehensive environmental mitigation measures that include a search and rescue programme for threatened and protected plant species.

“Before we start any construction we will send a specialised team into the area to retrieve bulbs, succulents, and other plants that can be relocated,” says McLachlan.

“We have set up nurseries that then preserve and further propagate these plants. These plants are then used for rehabilitation, and when we have an excess they will be translocated into protected areas such as the Mkambati Nature Reserve.”

More than this, a biodiversity offset agreement with the Eastern Cape Parks and Tourism Board will ensure that the Pondoland biome is preserved for generations. The agreement sets out the declaration, rehabilitation and ongoing protection of some 15,000 hectares of new protected areas.

Pedestrian sidewalks will be constructed on each side of the bridges, and sites off the bridges will provide special viewing points for tourists. The sidewalks will also connect previously separated communities on either side of the gorges.

“The Msikaba and Mtentu bridges will become tourist attractions in their own right, and will offer opportunities for the associated tourism industry in the area,” Kruger says.

Catalyst for development

The Mtentu and Msikaba bridges, and the new section of highway constructed for the N2 Wild Coast Toll Road, will improve travel time, connect divided communities and open up investment and tourism opportunities for the rural region.

“By improving the travel time between Durban and East London by up to three hours for heavy freight and by providing a high mobility route through an area that is currently extremely isolated and underserved by road infrastructure, the route will have significant social and economic benefits and will act as a catalyst for local and regional development,” McLachlan says.

Why a highway on the Wild Coast?

The N2 Wild Coast highway will vastly improve access to the region and help develop the eco-tourism potential of the area.

Existing roads such as the N2 and R61 tend to follow “watershed alignments” to avoid crossing deeply incised gorges and river valleys. Because of this, the existing N2 runs more than 100 kilometres inland and reaches a height of some 1,700 metres above sea level at Brookes Nek before it descends to the coast at Port Shepstone.

The R61, in turn, runs almost 60 kilometres inland to Flagstaff, 1,000 metres above sea level.

Access to the coast is poor where it exists at all, and no roads run along the coast because of the deep valleys and gorges.

In many cases it is only possible to drive between locations on the coast by first returning to the R61. This can involve a round trip of more than 100 kilometres to travel between places only 20 kilometres apart.

Not surprisingly, this region is one of the most impoverished areas of South Africa.

The NT Wild Coast highway will improve access and linkages in the region, reduce road-user costs and optimise safety and socioeconomic benefits.