“Water” observed John Thorson, “links us to our neighbour in a way more profound and complex than any other."
The beauty of a new place is that we can understand the way water flows, irrigates and sustains the area long before we break ground. We can also understand the likely impact of heavy rainfall and the drainage required to cope.
At South Canterbury, this will be achieved through SUDS, or Sustainable Urban Drainage Systems, one of the starting points for our masterplan. In simple terms, SUDS are features built into the landscape that slow down, store and guide rainwater safely.
The challenge
Building new homes changes how rainwater moves across land. Roofs, roads and paving allow water to run off more quickly than open fields. If this is not carefully managed, it can increase pressure on surrounding land and watercourses.
At South Canterbury, the challenge begins with the ground itself. The soils are clay-rich, which means rainfall does not easily soak into the earth. Instead, during sustained or heavy rain, water naturally moves across the surface – known as “overland flow”, a part of the site’s existing character – towards the north-east corner which is the lowest point of the land. From there, it passes beneath the railway through existing culverts. Any drainage strategy must respect this natural pattern.
Our approach
The consented planning scheme sets out clear parameters informed by the site’s topography, physical setting and underlying ground conditions. In simple terms, we begin by understanding how water already behaves within the natural contours of the land.
Because absorption into the ground is limited, provision for large volumes of temporary rainwater storage is located in the south-east corner of the site. This creates space for water to be stored safely during periods of heavy rain, until the excess can drain naturally over time as water levels drop.
Across the wider masterplan, additional areas will be allocated for SUDS features. These will be integrated into the detailed design so that water is slowed, stored and guided through the landscape, rather than directed quickly into pipes.
This is a landscape-led approach. The new place is shaped around the site’s natural contours, working with the direction of flow rather than attempting to override it.
What happens next
Ground condition surveys planned for 2026 will provide further evidence to refine the detailed scheme. As with all drainage strategies, proposals will be carefully tested with regulators before being finalised and published.
SUDS can sound technical, but at heart, the principle is straightforward. We start with how rainwater already moves across the land, planning around the lowest points, creating space to hold the water temporarily, and making sure it leaves the site in a controlled and responsible way.
If you’d like to explore how water management shapes South Canterbury, feel free to get in touch or participate in discussions at any of our future events. For more general information on SUDS, please visit “How we manage water drainage” or Susdrain’s explanation.