Living on an Active Landslide: Alternative Housing on the Tahunanui Slump

Abstract

The active geological situation of New Zealand make its hillside urban environments highly susceptible to landslides. Despite this fact, the suburban architecture of these hillside areas are no different to their flatland counterparts. Traditional house designs are not fit for occupation on landslide prone sites, as their structural system are easily damaged, posing a threat to occupants safety. In addition, the design and construction of these houses can worsen site stability through extra weight on soil, excavation of soil and ecology increasing water penetration. Although these sites pose a risk to traditional houses, it does not entirely prevent human occupation of these areas. Instead it presents an opportunity for an architectural solution that allows for the living on landslide prone hillsides in a safe manor.

The Tahunanui Slump is a prime example of residential occupation on a landslide prone area within New Zealand. Located on the port hills of Nelson, the slump is an active landslide covered in typical residential suburbia, and has been occupied for the majority of the last century. The land of the Tahunanui Slump is continuously moving, and large movement events have occurred, on average, every thirty years since its occupation began. These disaster events have caused large damage to dwellings and infrastructure on the site, but even after such events people are quick to return to the site and rebuild in a similar fashion, due to its picturesque location, view and climate which make it a very desirable. The current model of housing on the Tahunanui Slump, with repetition of disasters followed by reconstruction of traditional architectures, is unsustainable and unfeasible for future.

This thesis sets out to create a way to allow continued occupation of the Tahunanui Slump, using an alternative architectural solution, that is responsive to the sites unique situation. It argues that this can be achieved by, dwellings designed to remove the risk to human life from land movement; the inclusion on landslide mitigation techniques to decrease the probility of landslide occurrence; and infrastructure designed with the aim of improving site stabilisation. In doing so the outcome of this thesis is anticipated to provide a frame work for design on other hillsides that are susceptible to landslides.