Admiral Island, an upmarket housing develop-ment with a nautical theme, has been built on a man-made island in the Berg River estuary on the Cape West Coast, a short drive north of Cape Town. The island is connected to the mainland via a bridge leading onto the marina of Port Owen and was formed in 1986 by dredging out low-lying canals of a wetland to create a 20ha land mass.The brief to landscape architect Jaco Jordaan of Planning Partners was to create a sustainable and low maintenance landscape that would assist in the marketing phase of the project.
The brief also called for the landscape to be attractive and useful for the inhabitants of the island. Linked to this was the design philosophy which was to create a landscape which was sensitive to the West Coast’s unique social character. It should be “soft and natural enough for people to enjoy,” according to Jordaan.
Developers: Atterbury Cape
Architects: Smuts de Kock
Landscape Architects: Planning Partners
Landscape Contractor: Vula Environmental Services
Main Contractor: Power Construction Western Cape
Local Authority: Berg River Municipality
The area is environmentally sensitive due to its close proximity to the estuary of the Berg River and an environmental management plan (EMP) was carried out. An environmental control officer monitored civil works and on completion of the development, commented that it was the best run project he had encountered in his career.
The EMP prescribed that local, indigenous plants be used where possible, and this occurred with the exception of the trees; there are no large trees that occur naturally so close to the ocean on the West Coast.
Climatic conditions and planting
The Cape West Coast has a harsh climate – it is very dry in summer and the strong south-easterly wind causes mechanical damage to plants. In winter the north-westerly, salt-laden winds cause chemical damage to plants. These conditions impacted on the plant choice and tough, locally indigenous plants, specially grown by Vula Environmental Services, were used. Very few of these species were commercially available and Vula staff were involved in the final plant selection as they are familiar with the difficult growing conditions of this area. They were also responsible for the final grouping and layout of plants.
Landscape contractor Deon van Eeden says: “The landscaping comprises typical West Coast indigenous planting and can best be described as a blend of informality and rehabilitation. The use of mixed colours helps to create interest in larger areas.” Colour schemes give a feeling of continuity between the individual gardens, which have a stylish West Coast feel. Mixed flower colour also helps to increase interest and diversity in the landscape and has attracted birdlife to the site.
Landscaped areas are made up of public open spaces and green belts between the residential housing areas. Meandering brick-paved pathways lead through the landscaped gardens, with berms and slopes giving the areas a three-dimensional feeling.
Informal cluster planting took place and is effective in creating areas of interest in the larger landscape. It also helps to increase impact when the plants are in flower.
Planting densities were higher than for inland projects to com-pensate for the slow growth in harsh conditions and to achieve 100% coverage. Specific plants species were used to create a more favourable micro-climate for people using the parks, where it was necessary to provide wind shelter and shade. Throughout the development, most of the plants are local, indigenous and low maintenance, the obvious choice for this area due to the harsh conditions, salt-laden air and strong seasonal winds. This helps to reduce maintenance costs. The use of indigenous plants also made sense due to the low annual rainfall.
Soil conditions in the area are generally very poor and when the canals were dredged, the silt was deposited on the island, further increasing the calcium and salt content of the soil. Sterile compost was used in soil preparation to control weeds and prevent loss of moisture. Compost was mixed into the topsoil.
The irrigation system was installed by Vula Environmental Services and is made up of a 63mm HDP ring main line with 25mm full flow pipes and fittings in the garden areas. Each garden area has its own controller.
Gear drive pop-ups were used in the larger lawn areas, with fixed head pop-ups in the smaller areas. Riser pipes with static heads were used in the back of flower beds and static pop-ups with rotary heads were used in the front and along the walkways, as they are not visible. Palm trees in the centre island are the only exotic plants used for the project. They are watered by drip irrigation which is on its own dedicated line as they have different watering requirements to the rest of the landscape.
Once the irrigation system had been installed, the lawn areas were planted using roll-on lawn.
Two types of parks were created: firstly, small pocket parks which act as storm water servitudes and also serve as passive parks. Here a paved walkway meanders down to the water’s edge through rehabilitated strandveld fynbos. A paved, outdoor patio was created on the concrete structured canal edge and benches were placed here for residents to sit on and watch the yachts and water craft activity. The benches also overlook the wetlands. These parks were spaced in such a way that they are close to each residential property.
The second type of park consists of large lawned play areas which were spaced at the entrance and end of the island. They contain children’s play structures which have been set in sand and surrounded by organically shaped lawned berms.
The road design was work-shopped with the client and civil engineer to provide a ‘safe’ zone for planting, where it could take place before any development commenced. This was done for marketing purposes. The client, Atterbury Cape, saw the value in landscaping and the positive impact it would have on the marketing and sales component of the project. They agreed to create a central median for the total length of the road transversing the island – a costly decision because double the amount of kerbing is used and storm water attenuation becomes complicated. However this created a safe place for ‘upfront’ landscaping and it was necessary for the planting to break the flatness of the island. A decision was made to use Washingtonia robusta transplants all along the median and Phoenix canariensis palms in the traffic circles. A total of 42 palm transplants were planted by Fast Fell and when the order was placed, they had to run adverts in all Western Cape newspapers to obtain the required quantity. This was a ‘nailbiting’ exercise as the palm planting had to fall within the civils programme. Palm positions were pegged out and the palms planted before the road was built.
The irrigation system, shrub and infill planting was completed after the road works. Fortunately the planting time fell in the middle of the wet winter season and this helped to establish the new plants.
The client also requested that the main entrance area be completed upfront and that an attractive landscape be provided here. Planting again occurred in a central median, flanked by shrubs, groundcovers and trees in the road reserves on either side.
In addition to the palms, instant vertical elements were provided to further break the flatness of the island – masts with flags were positioned at the main entrance to celebrate the arrival and to complement the nautical/marine theme. Most people who bought properties on Admiral Island own a water craft as the canals are deep enough for yachts. The design guideline document gave specifications for timber jetties where yachts could be moored directly in front of homes.
A tall mast was provided at the end of the island in a traffic circle to act as the ‘bookend’ of the island. This structure was oriented on the magnetic compass directions and continued into the paving design where granite discs were engraved with the eight main compass directions. In addition, flags are flown from the mast, strengthening the nautical theme.
The roads are a combination of asphalt and paving, the latter placed at intersections and decision points. This assists with traffic calming on the island.
Taking care of the environment
The fact that cognizance and due care of the environment was taken early on in the development has led to good sales and excellent returns on investment. From a ‘green’ point of view, however, taking care of the environment is in itself the primary consideration.
The project received a silver award in the 2006 SALI Awards of Excellence. It was entered in the category of landscape construction with design by others.
Information provided by Jaco Jordaan of Planning Partners and Deon van Eeden/Theo Benskin of Vula Environmental Services.
Photography provided by Atterbury Cape and by Theo Benskin of Vula Environmental Services.
Photographers for Atterbury: Gerhardt Jooste and Rutger Bok