Page 25 - Landscape130

LANDSCAPING SERVICES FEATURE

CE Consulting Engineers planned a Terraforce wall design
that allows appropriate interfacing with the environment, by
Kcreating space for vegetation in the near vertical terraces and
‘shelves’. Plant pockets were constructed by turning the L12 blocks’
round face outwards at regular intervals. The retaining wall acts as a
buffer between the engineered platforms on the lower level and the
protected nature conservation area to the east.
Nigel Barr of KCE Consulting Engineers says that De Aanzicht
“nestles up against a large Renosterveld reserve, where slopes of up
to 12m high and a rock outcrop created a soft interface requiring the
use of an undulating retaining system.” The Terraforce system was
chosen as it combines access, planting and stormwater management,
and the slope treatment will eventually disappear behind the
planting. This will hide the engineering of soft soil anchors, tied back
foundations and the mixed pattern Terraforce block facings.

Design
The design of the overall retaining system was such that in order
to create the embankment required within the restricted footprint
area, KCE detailed a two-part system to adequately secure the
embankment, whilst taking great care to avoid encroachment into
the environmental buffers and restricted no-go zones around the
conservation area.
A series of soil nailed terraces, the front faces stabilised with a
gunnite shotcrete, was created as the initial lateral support system
for the embankment, with a series of terraced Terraforce retaining
structures constructed in front of the lateral support, providing
the aesthetics and landscape-friendly portions for the face of the
embankment. The Terraforce walls act as a cladding for the otherwise
harsh and rustic finish of the lateral support system, whilst also
providing planting pockets, accessible terraces and maintenance
access routes throughout the embankment area.
Barr says that the aesthetic appeal of Terraforce’s rock face
finish blocks suited the overall environment and “blends into the
surrounding landscape with ease”.
Landscape design
Ankia Bormans from TERRA+ Landscape Architects says that their
brief required them to green the gunnite wall retaining structure.
At that stage, it had not yet been designed by the engineer, hence
the involvement of the landscape architects to ensure sufficient
space for the planting. The landscape design concept was to
integrate the planting with the area behind the development which
has Renosterveld fynbos, and to ensure that it becomes a visually
pleasing amenity.
The embankment along the eastern portion of De Aanzicht
is very steep and required an engineering solution. TERRA+ was
instrumental in guiding the engineering design to ensure that there
was sufficient space for planting. This ensured that the face of the
retained embankment was softened by planting and would in time
present as a green edge to the development.
Plant material was carefully considered to ensure that the correct
species were chosen to function optimally in these conditions.
In addition to the functionality of the species, it was critical that
those chosen would not threaten, but rather enhance the adjacent
green open space, which is a remnant of critically endangered
Renosterveld fynbos. Species chosen were of the Renosterveld
biome but commercially available, thus increasing biodiversity
without threatening the sensitive conservation area.
Says Bormans: “The embankment is seen as a green amenity
and a positive element, rather than detracting from the rest of the
development.”

Information and photos supplied by Terraforce Retaining Walls,
Terra + Landscape Architects and Nelson Nongwane of Balwin Properties.

The landscape design was required to ensure sufficient space for planting, and to
integrate it with the area behind the development which has Renosterveld fynbos.
Plant material was chosen so as to enhance the adjacent green open space and all
species are of the Renosterveld biome. n

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