Client: University of the Western Cape, Bellville
Architects: dhk Architects
Landscape Architects: OVP Associates
Environmental Site Management: Ecosense Consulting Environmentalist
Landscape Contractor: CapeScapes
The Life Sciences Department (LSD) of the University of the Western Cape in Bellville is a landmark building which, in its designed landscape context, seeks to reflect a commitment to sustainable design.
The site is located on the edge of the Cape Flats, an area which endures harsh environmental conditions. Although the endemic vegetation has adapted to these conditions, many sensitive habitats of the area are under threat due to urban growth and development. It is therefore vital that new developments take a sustainable approach to reducing their impact on the environment through environmentally responsive design interventions. It is also as important to provide comfortable and sheltered outdoor spaces for public enjoyment. In the planning, designing and detailing of the landscape that contextualises the Life Sciences development, numerous strategies were adopted to provide such comfortable outdoor spaces, whilst also facilitating micro habitats to encourage biodiversity across the site.
Site informants and responses
The site experiences cold, wet winters and hot, drought-prone summers, and plant selection had to therefore suit these climatic conditions as well as assist in the control of micro climates around the building. To this end, deciduous trees have been planted selectively to provide shade and reduce heat reflection to the lower floors of the building in summer. In winter, as these trees lose their leaves, the sun will be able to penetrate, providing light and warmth. During summer, strong, south-easterly winds are prevalent and in winter, north-westerly winds. To ameliorate these severe conditions, the landscape design has incorporated the use of hedge planting, tree belts and earth berming, particularly at entrance lobbies and outdoor terraces. Wind resistant plants were selected.
A drip irrigation system has been installed for all the formal, soft landscaped areas including the roof gardens, and has proved to be the most efficient, given the site’s climatic conditions. There has been minimal water loss to evaporation, compared to spray systems.
Land forms and tree planting have drawn attention to the site’s panoramic views of Table Mountain to the west and the Helderberg mountains to the east; this is particularly notable from the Forest Plaza on the north side of the building. The learning centre is close to Modderdam Road which generates high levels of traffic noise, and large earth berms with screen vegetation has helped to reduce noise pollution, particularly at ground level social spaces.
Biodiversity and rehabilitation
In terms of biodiversity, as many endemic plant species as possible were (prior to construction) rescued, bagged and propagated for later replanting at the neighbouring Cape Flats Nature Reserve. Across the site, the top 200mm of topsoil, with its particular mineral composition and seed stock, was collected and stockpiled nearby for re-use in the landscaping of the project.
The majority of this soil was spread across disturbed areas identified within the nature reserve for rehabilitation purposes and the remaining topsoil returned to the site for soft landscaping purposes. It was used firstly in its original state – spread across the ‘informal’ open areas – and secondly as part of the mixed growing medium – placed for ‘formal’ soft landscape areas.
The ‘informal’ area consists of the remaining open stretch of land between the Lab Block and Modderdam Road. This has been identified as a potential ‘nature area’, where only a selected mix of plants of the Cape Flats dune strandveld group have been planted and seeded. The land here has been re-shaped to create a variety of low-lying areas, mounds and level planes, a microcosm of the Cape Flats environment, which will hopefully assist with the establishment of a variety of micro-plant communities suited to these land forms.
A number of existing mature trees on the site were identified as significant, and retained before construction commenced. These included the indigenous Outeniqua Yellowwood, Podocarpus falcatus, and White Milkwood, Sideroxylon inerme. Where practical and possible, they were protected during the entire course of the project and incorporated into the landscape design. They have added immense value to the space they occupy, being the entrance plaza.
With the exception of two selected species, all plants are indigenous to South Africa and the majority of shrubs, grasses and groundcovers are endemic to the Cape. In high activity areas, indigenous plants which are known to be hardy in most conditions have been planted to create low maintenance planted borders, while at the same time used compositionally to achieve year round visual interest.
A selection of more unusual or uncommon plant species used in horticultural practices (and unique to the Cape Flats) have been planted in the ‘nature area’ and ‘display garden’ where they stand a better chance of survival and can also be enjoyed by those with an interest in plant diversity.
Six landscape precincts were identified around the site, as follows:
1 – Entrance plaza
This is a formal, hard landscaped space, framed on either side by the east elevation of the Lab Block and the Learning Centre. By virtue of their scale and stature, the existing Yellowwood and Milkwood trees have added immediate value to this space, providing ‘green’ mass, height and shade. A number of new Acacia zanthophloea trees have been planted near the existing trees to provide additional greening and shade, whilst also providing contrasting colour and texture. The theme of introducing these trees has extended through the entrance to the Forest Plaza.
The careful placement of trees, ramps and curved steps all assist in gathering and guiding visitors from any angle, upon approaching the entrance to the building. Against the east facade of the Learning Centre, a large planted embankment slopes up to the first floor where plants will provide some shade to rooms during the morning hours. A low seat wall surrounding the base of the embankment has a soft backdrop comprising a variety of plants which provide attractive scents, colours and textures.
2 – Forest plaza
This is located between the north-west junction of the Lab Block and the Learning Centre, where the flow of pedestrian movement between and out of these buildings converges. A pedestrian ramp to the north of the plaza ‘rises’ out of the landscape, providing seating and a semi-soft backdrop to the plaza, while also acting as a visual and noise barrier between the plaza and Modderdam Road.
The landscape from the north ‘nature area’ also flows into this space by means of organically shaped tree lines, a rock-lined path and the undulating planted earth banks of the ‘display garden’. The name ‘Forest Plaza’ is derived from the tree-shaped structural columns supporting the floating pergola ‘canopy’ above this space.
New large trees, placed between the column bases, further augment this tree-shaped pergola structure. Acacia zanthophloea trees were selected here as their clear trunks and well-shaped, light-leafed canopies soften and complement the architecture of this space.
The pergola canopy, together with these semi-deciduous trees provide light and cool shade in the plaza, preventing the space from becoming too dark both in summer and winter. What has been achieved here is the careful juxtaposition of formal hard and organic soft landscape.
Carefully selected and placed bluestone rocks provide another texture and natural element to the space. These locally sourced rocks converge around a rock pool water installation where they provide informal seating and opportunities for contemplation. The water installation runs on a recycling water system, requiring very little water for refilling; its design evokes a dry river bed, should the water supply be stopped for lengthy periods.
The organically shaped ‘display garden’ forms the centre of the space and opportunities to experience it are provided from all sides, with access provided by means of an informal stone path curving through the centre. The concept for the garden is that it should become a didactic showcase for local small shrubs, perennials, groundcovers and bulbs.
These gardens may be altered over the years to exhibit newly sought or popular indigenous plant species linked to botanical or environmental field studies. The gentle mounds and low lying zone provide interest and opportunity for the planting of different species suited to varying topographical habitats.
3 – Learning centre roof gardens
Both roof decks of the Learning Centre are designed as succulent plant roof gardens. From the upper floors of the Lab Block, the patterning of these gardens, highlighted by the curved pathways, can be perceived again in the Forest Plaza below, creating an integrated design experienced not only on ground level.
The roof gardens assist in moderating the building’s impact on the microclimate as the gardens absorb the heat energy of the sun, rather than reflecting it and through evaporation, help cool the air. This in turn assists in the cooling of the interior spaces below. The roof garden also acts as a temporary water retention system during rainfall, which helps to reduce the impact on the city’s storm water system. Approximately 90% of the plants for these roof gardens are succulent, low-growing species which have the following benefits for the longevity of the gardens:
- the low growing, ‘mat’-forming habit of these plants will provide resistance to the strong winds, while also binding the topsoil in place
- the succulents are extremely drought-resistant and will survive for long periods should irrigation be unavailable
- these plants do not require very deep soil to survive, which assists in reducing the structural requirements of the roofs
- the diverse variety in species will produce a wide range of colour throughout the seasons
- the majority of plants self-multiply, thus reducing the cost of replacements. With time, plants could even be cultivated for use elsewhere on the campus
- the majority of the plants are indigenous to the Cape and thus well-suited to the climatic conditions of the site
4 – Northern embankments
These enfold the northern elevation of the Learning Centre, creating a soft buffer between Modderdam Road, the Learning Centre and the Forest Plaza. From Modderdam Road, the visual impact of the built form is reduced by these planted banks and the Learning Centre appears to ‘rise’ out of the landscape rather than impose upon it.
Trees and plants have been planted in waves along the contours, which will result in bold sweeps of colour and texture. The planting of trees at various heights up the banks will assist in reducing noise and buffering winds travelling towards the Learning Centre and Forest Plaza.
The curved retaining walls facing Modderdam Road and rising out of these banks will, in time, be covered in wall creepers. These too will assist in absorbing air pollution, noise reduction, absorbing heat energy and reducing the impact of the built form experienced from the road edge.
5 – Service street and east parking
The street and parking landscape approach is one where the landscape suits the functional/service characteristic of these areas. Hardy, low maintenance plant species have been selected and will assist in softening the edge of the built form, providing interest with shrubs and groundcovers being planted in waves to achieve a variety of bold colour and form. An avenue of trees planted along the service street ties into the character of other tree-lined streets of the campus.
6 – Northern ‘nature area’
This area has been demarcated as the north open stretch of land between the Lab Block and Modderdam Road. A degree of rehabilitation of this area has taken place due to the reintroduction of endemic plant species by means of individual planting and hydroseeding.
The reshaped land has provided a series of informal detention ponds which will provide micro habitats for wildlife, at the same time reducing the impact of run-off from the hard landscape during the winter rainy season.
Construction Environmental Management Plan (CEMP)
Ecosense Consulting Environmentalists were appointed to ensure environmental standards and sustainability of the project and to comply with the relevant legislation. Its environmental control officer, Henry Davids, undertook frequent site inspections and provided monthly compliance checklist audit reports, accompanied by photographic evidence, of the environmental compliance issues that were evident during the inspections.
Good communication, understanding and compliance with the Environmental Management Plan was achieved between the consulting team and contractors, minimising any negative impacts on the environment.
CapeScapes was responsible for the landscaping and irrigation installation, which also included some minor hard landscaping. According to Glenn Norrie of CapeScapes, most of the earthworks were carried out during a very wet Cape Town winter, with the planting done at the beginning of summer when gale south easter winds are prevalent.
These challenges called for special installation measures, such as the suggestion to use pine resin extract in the hydroseeding mixture to ensure that the soil binded long enough to allow the seed to germinate and prevent windblown sand from harming the adjacent new building and landscape.
Despite the difficult site conditions (from both planning and environmental perspectives) the landscape installation was successful, inasmuch as can be ascertained at this early stage of establishment. Good maturation of plants is already evident and the overall perception of the architecture within its landscape context is a tribute to the collaborative effort of all parties involved.
A Netafim drip irrigation system (designed by Controlled Irrigation) has been installed for all the formal gardens, and a spray system for the nature area. The original specification for the hydroseeding was a turf valve and dragline system which was upgraded to an automated stand pipe and impact sprinkler system at the cost of the landscape contractor. Norrie says that the germination has been excellent and savings will be made on maintenance in the long run. “When one looks at the maturation of the hydroseeding with this system versus hose pipes being dragged over the area, the results speak for themselves,” he explains.
The project was completed in December 2009.
Information provided by Penny Unsworth of OVP Associates, Mark Sassman of Ecosense and Glenn Norrie of CapeScapes.
Visuals and plans courtesy of OVP Associates