Brief

The site was identified by the University of Pretoria as an area to be allocated for students to spill out into from the large adjacent Thuto lecture hall and have a stong connection to this building even though it is separated by a vehicular road. The site also needed to respect the heritage building called Roosmaryn on its boundary. There were existing trees but otherwise the site was bare and the soil exposed as seen by the images below:

Stormwater

Civil Consult was appointed as the consulting engineer to address the inadequate stormwater infrastructure as the site often experienced flooding. The area serves as a catchment for water surface run-off from several adjacent parking lots and paved areas. Permeable paving options were investigated but the ultimate decision taken was to use an underwater catchpit (infiltration trench) that releases water into the surrounding soil over time with overflow going into the existing stormwater system.

Circulation

The primary focus of the design was to improve circulation through and across the site and in this way the site becomes a node for students to stop and pause while on their way to their destination. It is close to an important entrance at Prospect Street which is the main access from Hatfield and formalised pathways are used to create connections along existing desire lines.

Creating a raised pedestrian crossing over the road to connect the site to Thuto came at the expense of several parking bays, but this was an important decision as this area was meant to be strongly linked to the Thuto building and allow for easy access between these areas.

New Pedestrian Crossing Built over the Road - Improving Connections

Social Spaces

The next important requirement was to create ‘social learning spaces’ for students to sit and interact. Students are encouraged to stop, rest, study, socialise and use this space as their own through use of the seating walls, paved area and lawn area. The paved area includes a giant chess set so a game of chess can also be enjoyed in between classes. The irony that this project was built to encourage student interaction and connection during a time when social distancing is being encouraged does not escape me. I do hope that the future holds opportunities for humans to interact with one another in outdoor spaces and share the joy of being in a beautiful outdoor environment.

UP Containers

Three concrete plinths were built to activate certain areas of the site. These were built for custom designed storage containers that will serve as wifi hotspots and shelters where students can charge their laptops or cellphones. The containers are still to be installed.

Vegetation

All existing trees were maintained and incorporated into the design. Only a few new trees, namely Caledendron capense, were included which will create a unique atmosphere once mature and in flower. Several shrubs were included to create a diverse landscape that has a variety of foliage and texture such as Burchelia bubalina, Syncolostemon densiflorus, Leonotis leonorus, Bauhinia natalensis and Rhus burchelli . Anisodontea scabrosa was selected to compliment the Roosmaryn building as well as ‘softer’ plants such as Agapanthus and Scabiosa. Existing shaded areas were planted with Carissa ‘Green Carpet’, Hypoestes aristata, Plectranthus spp, Orthosiphon labiatus and Barleria ‘Rosea’.

A grass mix was used in the area that receives sun and is located behind a seating wall for when it looks less attractive during winter. The grassland plants were incorporated to provide an opportunity for the University to see how this type of landscaping can work on campus, learn maintenance techniques and also to provide education for the students. Landscaping with grasses is a relevant landscaping style and this was an opportunity to showcase the beauty of South African grasses and grassland species. Some of the species included Eragrostis gummiflua, Dimorphotheca jucunda, Melinis nerviglumis, Andropogon eucomis, Aristida junciformis, Pelargonium sidoides and Helichrysum umbraculigerum.

Future Overlays

The project lays an important foundation of circulation and structure for further activity layers to be superimposed onto it. It is hoped that future art installations, events and food trucks planned for the site will bring a send of fun and vibrancy that will enrich the students experience at the University. I will post more photographs of this project once the plants have established in a few months time.

On the of 25th of November a seminar was held at the University of Pretoria on the implementation, operation and management of Sustainable Drainage Systems (SuDS) / Water Sensitive Design (WSD). It formed part of a series of country-wide seminars hosted by the Water Research Commission, UCT Urban Water Management research unit, City of Johannesburg, City of Tshwane, City of Cape Town, eThekwini Municipality, and SAICE Amathole.

The introduction by Professor Neil Armitage included a brief overview of the conventional method of manging water in cities and how this needs to change to create cities that are Resilient, Liveable and Sustainable. Dr Kirsty Carden also shared on the water crises and how important education and stakeholder engagement is in order to change behaviour and achieve the goals of Water Sensitive Design (WSD).

The aim of Water Sensitive Design is to transform South African settlement into settlements that “mitigate water scarcity, improve water quality, thereby protecting ecosystems, through the development of water sensitive urban areas (for all) that are sustainable, resilient and adaptable to change, while simultaneously being a place where people want to live” (http://wsud.co.za/ - two important resources can be downloaded from this website, see images below)

Conventional engineering dealt with water as a waste substance to be collected and removed as quickly as possible. WSD proposes that water be managed as a precious resource through infrastructure that utilises stormwater in a way that transforms spaces into multifunctional assets with numerous benefits. The philosophy behind WSD is to keep the water in the city through establishing Blue/Green corridors which have multiple advantages to the city including: increase in biodiversity, climate control, water and flood management, human well being, increase in property value, recreation opportunities, tourism as well as the added benefit of storing carbon.

Professor William (Bill) Hunt from North Carolina State University is an expert in this field and he shared insightful information on how WSD systems work and best practice for their construction and maintenance. Practices currently being utilised worldwide include: dry ponds, wet-ponds, wet-pond with floating island, stormwater wetlands, bio-retention cells, level spreader, swales, bio-retention and swale (also termed “Regenerative Stormwater Conveyance”), permeable paving, green roof, underground device, and street trees. An innovative system using a steel grid to create a well that is installed below street trees was shown. The tree root ball grows downwards into the grid filled with a growing medium instead of lifting paving in search of surface water because of compacted soil below. A landscape architect would be able to assist in choosing the best species for street trees in this application because tree size, root growth and water requirements are all factors to consider in selecting a tree that will survive.

Professor Hunt also explained how the State of North Carolina has enforced legislation which compels new developments to reach certain hydrologic goals. Certain sites qualify as “Low Impact Developments” and these need to manage stormwater in such a way that the run-off levels are the same as the pre-developed site. Several case studies were explained and the results were not always as expected: for example a wetland filtration system with three ponds had the largest amount of filtration happening in the first pond and not much more in the second and third pond. Which suggests that it may be better to only have a system with one pond instead of three. These studies prove be very beneficial in providing the knowledge of how to build the most effective and cost efficient systems and clearly there is still much to learn.