Tasmanian Sites

Transend Store

Transend Store,
Bridgewater Tasmania

Susan Small Landscape Architects

          
The brief was to provide a landscape solution that satisfied planning conditions for the construction of an electrical parts supply facility for the electricity provider Transend.  The project design was for a large building and an even larger concrete apron for storage of transformer parts.

The site abuts an existing rural residential precinct, so an important requirement was to provide privacy, and to ‘landscape’ the perimeter of the concrete apron.

The hydraulics engineers had designed for runoff from the extensive hardstand area to enter a straight, relatively steep, evenly graded, grass swale. The volume of water was potentially very large during high rainfall events and likely to exceed the capacity of the discharge drain in extreme events.

The landscape architectural input provided for a swale solution that would dramatically slow down water flows, and trap pollutants arising from the runoff from the slab. During consultation it emerged that very large boulders were to be excavated on site, and which were being costed for removal. The LA proposed to use these boulders in construction of the swale and in parts of the landscaping on the site. These ideas were accepted by the client and integrated into the project.

The result is a dramatic and cost effective landscape solution which also creates a magnificent habitat for a variety of fauna in this rapidly developing precinct, otherwise characterized by tilt-up slab sheds and concrete-sealed landscapes.

Special Factors

• The swale comprised the construction of 6 basins separated by low weirs. Each basin had a gradient between 1:80 to 1:100. The top basin was fully stone-lined, and each succeeding basin incorporated more plantings and less stone, through to the lowest being almost 100% fully planted with sedges.

• The swale is working very successfully, with capacity for greater than a 100+ year flood event.  In fact some storm events in the last 3 years have been very large, with high peak flows, so the vigorous plant growth in the lower 3 basins and the minimal silt in the grated pit at the end of the system clearly indicates that the system is working very effectively.

• Proximity to the extensive development of the Brighton Industrial Hub, affords an excellent opportunity to demonstrate alternative approaches to managing stormwater and the extent landscape design can ameliorate the heat island effect that large industrial zones like the Hub can cause.

• Aspects of the design approach which exemplified sustainable practices include the retention of construction materials within the site, modification of stormwater discharges (overall volume, peak flows and water quality), choice of local native plant species and avoidance of potential weed invaders. The swale, when established will require much less maintenance than the proposed grass swale.  Other plantings are irrigated by tank water collected from the building roof. Separate irrigation stations have been provided for different plant species to allow for managing irrigation frequency as plants become established, thereby minimizing water use and maintenance cost

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