Maintenance of historic route within Tsitsikamma Nature Reserve

Asphalt construction on the Grootrivier Pass

Hatch Africa was tasked by the Western Cape Government (WCG) to do maintenance on 23 km of Trunk Road 2, Section 12 (TR2/12), also known as the R102. The route stretches between Kurland and the Eastern Cape border, traversing through the famous Grootrivier and Bloukrans passes in the Garden Route District Municipality.

Article authors:

• Craig Bradley – project manager, Hatch • Niel Claassens – project engineer, Hatch • Peter Henderson – contract engineer, Hatch • Louwrens Mostert – contract coordinator: Roads Branch, Western Cape Government • Azni November – chief engineer asset management: Roads Branch, Western Cape Government

Maintenance of historic route within

Tsitsikamma Nature Reserve

Constructed in the 1800s by Thomas Bain (a prolific roadbuilding pioneer), both the Grootrivier Pass and the

Bloukrans Pass were strategic in opening a roadway between Plettenberg Bay and Port

Elizabeth, thereby unlocking the economic development of the then Cape Colony. These iconic and highly revered passes are situated within the Tsitsikamma Nature Reserve and are historically relevant due to the early pioneering and expansion of the timber industry in this area. This is a key tourism route in the Garden Route region of the

Western Cape.

In addition to maintaining the historically significant passes, the R102 route provides the main access to the town of Nature’s Valley from the N2. Along with the village, Nature’s

Valley is a popular tourist destination and is surrounded by the Garden Route National

Park. The maintenance of the road is important in providing safe access to Nature’s Valley and in turn boosting tourism in the area.

Scope and evaluation phase

Minor structural defects were observed along the route – most notably surface cracks, ravelling and general surface fatigue due to ageing of the surfacing over time. A surface overlay with pre-treatment works to the road surface – including crack sealing, rut filling, asphalt scratch coat and asphalt base patches – was required in some areas and deemed to be the appropriate maintenance approach required to restore the integrity of the roadway.

As the road is situated on the steep slopes of the valley gorges of the Groot and Bloukrans rivers, slope failures in four specific areas were identified. This required rehabilitation to stabilise the road embankment slopes in the passes. Slip repairs would be undertaken simultaneously with the surface pre-treatment works. The project also included the upgrading of two community access roads: • upgrading of the DR1797 (also known as

Redford Road) from gravel to a surfaced standard, over a length of 4.6 km • rehabilitation of the minor road (OP7220) that provides a short access (1.5 km) for the residents of Kurland from the N2 to their town. Four rest areas and a scenic viewpoint are strategically located along the R102 to afford the public the opportunity to stop and engage with the dense indigenous forest. The rest areas had fallen into disrepair, and these will be refurbished, with furniture being replaced and repaired. This must be done without impacting negatively on the natural beauty of these environmentally sensitive areas. The upgrading of these facilities will provide the public with suitable stopping places to experience the unique offerings of the mountain passes and indigenous forest while taking in the scenic beauty of the area.

Challenges

The resurfacing of the Grootrivier and Bloukrans passes provided an interesting challenge in selecting the appropriate surfacing type. Significant sections of the road pass through timber plantations and dense indigenous forest. This keeps the road in almost permanent shade yearround. A relatively light traffic load and an undulating surface caused by the many years of differential settlement in the steep terrain created a scenario where conventional surface seal selection was not ideally suited.

This required a trade-off in terms of surfacing requirements. The relatively light traffic volumes would have indicated that a seal was perhaps most appropriate, yet the microclimate and environmental considerations, as well as the surface undulations, would have made this option difficult to implement. The anticipated future maintenance requirements and location led to the decision to use an asphalt wearing course as a resurfacing mechanism.

A rubber modified asphalt overlay was specified due to the topography and geometric alignment of the road and the existence of microclimatic areas. In particular, a 30 mm COLTO, continuously graded medium A-R2 asphalt surfacing was specified as the preferred option, as this mix type provides improved flexibility of the binder due to the presence of the elastomeric polymer in the rubber crumb.

This allowed the asphalt to tolerate higher deflections and offer greater resistance to reflective cracking. This mix was characterised by the increased resilience and toughness of the binder, and rendered the mix more resistant to deformation. It also provided reduced susceptibility of viscosity changes due to temperature, leading to improved fatigue resistance.

Safety

With the slip repairs, the existing road material and fill had to be excavated to a depth of 2.1 m. This was then replaced with three 510 mm thick reinforced earth layers, followed by 600 mm thick pavement layers and an asphalt surfacing.

In 2010, the WCG appointed Hatch to undertake slope stabilisation repairs on the Grootrivier and Bloukrans passes, where numerous slips had occurred over time. This is a delicate and sensitive area, and fortunately Hatch gained valuable insight and experience into the required repair methodology.

The slip repairs were constructed under half-width construction, with one lane closed to traffic. Concrete barriers were erected to protect construction workers inside the deep excavations. Traffic control was maintained using a Stop/Go system during the day, with traffic signals throughout the night.

On the valley side of the road, the exposed face of the reinforced earth embankment layers was protected by a 500 mm wide gabion structure that was 70 degrees to the vertical. A reinforced concrete balustrade, extending 450 mm above the final road level, was also constructed to provide a protection barrier for vehicles negotiating the notoriously winding roadway down to Nature’s Valley and up and over to the Bloukrans River. All road surface pre-treatment works were undertaken using half-width lane closures to allow the public to access Nature’s Valley. Similarly, the asphalt overlay was also constructed under half-width closures using daily short-term lane closures. No nighttime lane closures were permitted, as it was deemed a risk to have long stretches of roadway closed off at night, given the limited

Construction of reinforced concrete retaining wall

Upgrade of DR1797 in Bloukrans Pass

TR2/12 casting concrete parapet wall at slip repair Slip repair

sight distance, tight geometric constraints in the passes, and restricted roadway width.

As an aside, baboons and snakes were persistent visitors to the sites, and efforts were put in place to ensure awareness of the indigenous fauna.

Social aspects and community involvement

The employment of local labour from the local communities in the Kurland and Covie areas was a project objective. Contract participation goals – a portion of the contract value targeted towards local labour, communities and businesses – were set out. However, most of the works of this project focused on the asphalt overlay, so construction activities that required the involvement of local labour were limited.

With this in mind, the upgrades to the DR1797 and OP7220 were designed to incorporate construction activities that would maximise the use of local labour. Actophambili Roads was awarded the contract for the works and construction began in August 2021. The project is progressing according to the contractual programme and within the allocated budget. It is anticipated that construction will be completed towards the end of February 2023.

The access road (OP7220), which connects the town of Kurland with the N2, requires upgrading due to its narrow width and regular flooding, which makes access into the town difficult for the residents. Further to this, the provision and formalisation of infrastructure to accommodate the increased pedestrian movements to and from the N2 are also included in the project. This includes a surfaced pedestrian walkway with barrier kerbs for increased pedestrian safety, dedicated crossing points and road signage.

Similarly, Redford Road in The Crags (DR1797) will be upgraded to a surfaced road to provide improved access and usage, and to alleviate

Completed asphalt surfacing of Grootrivier Pass

dust pollution for the active farming communities adjacent to the road. These upgrades allow for additional inflow of expenditure into the area in terms of the employment of labour and use of local small, medium and micro enterprises.

The early engagement with the local communities and enterprises on the project is vital in mitigating possible community risks within the project. Since the onset of the Covid-19 pandemic, maintaining critical supply chains and community connections has become more important than ever.

Environmental aspects

The R102 traverses the Garden Route National Park, which puts the project in a highly environmentally sensitive area. Hatch’s internal environmental consultants were appointed to undertake a screening exercise to identify the applicability of the National Environmental Management Act (No. 107 of 1998; NEMA) EIA Regulations of 2014 to the project and to ascertain if environmental authorisation would be required.

Freshwater and botanical studies were also undertaken along the R102 to support the general authorisation application to the Department of Water and Sanitation (DWS) for the registration of the project for water use in terms of the National Water Act (No. 36 of 1998) – National Register of Water Use under the auspices of the Breede-Gouritz Water Management Area.

In terms of the NEMA regulations, the upgrade of the DR1797 triggered certain listed activities and the project thus required an environmental authorisation by means of a basic assessment process. Through this process, and together with meaningful stakeholder engagement with interested and affected parties, the EIA application was submitted. One of the major impacts identified is the upgrading of the existing pipe culvert, carrying a tributary of the Whiskey Creek under the DR1797, to a cast-in-situ portal culvert. This culvert upgrade requires significant vertical realignment to improve sight distance and increase culvert capacity, as well as registration with the DWS.

Further vertical and horizontal realignments along the route, as well as localised drainage improvements, led to the encroachment of existing properties in certain places. Land acquisition was thus required, and specific protected fauna species were identified for relocation, including a few mature milkwood trees. Following the submission of the basic assessment report to the WCG’s Department of Environmental Affairs and Development Planning, environmental authorisation was received and the project was set to go out to tender for construction.

Constant liaison with the environmental control officer appointed by the WCG ensured that the requirements of the EMP were fulfilled and that the contractor complied with the approved environmental constraints of the contract.

Conclusion

The resurfacing of the R102 will preserve and enhance access to the two historic passes for the public enjoyment of the spectacular scenery of the indigenous forests and pristine waterways located in the Tsitsikamma National Park. The OP7220 and DR1797 upgrades will provide an increased level of service, all-weather access, and safety to the surrounding communities as well as agricultural and forestry businesses.

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