MAIN BUILDING RAMP RAIN GARDEN
The garden bed project outside the main building reception ramp is well under way to be completed.
This bed is a new design concept for Burnley, as it is the first rain garden to be installed at the Campus. Created on the north side of the ramp, the side facing the roundabout Lawn, this former bitumen area has been dug up and reshaped over the last few months to create a new teaching resource for students and the public.
Rain gardens are designed to collect and store rainfall runoff from a roof or roadway into a free draining, sand based growing medium.
An overflow outlet, above the level of the growing medium, allows excess water from heavy rainfall events that overwhelms the capacity of the rain garden, to discharge into the existing stormwater system.
Four inlet grates will disperse rainfall events from the approx. 180 square metre main building roof catchment area and the fifth slightly higher grate will act as the outlet.
This will enable rainfall events to filter through the sandy growing medium to irrigate the plants, instead of it running directly into the stormwater system as is presently the case. Plants will be carefully chosen to allow for prolonged periods of drought or water inundation, depending on the climate conditions. A slotted drainage pipe at the bottom of the growing medium (on top of the clay layer) can be opened to drain away excess water into the stormwater system during low transpiration winter months. Plants currently being considered include a range of native species such as Kangaroo Paws and Bottlebrushes, as they are highly adaptable to this water excess and deficit existence.
Many thanks to Tim Fletcher for his advice and assistance in getting this rain garden built.
RAIN GARDEN UPDATE 5.12.14
The new rain garden bed has now been planted up. Choosing the 20 plant species that have winter wet and dry summer tolerance required a different way of thinking to most other aesthetically orientated garden planting projects. The tall ‘Big Red’ Kangaroo Paw cultivar has certainly caught everyone’s attention and many of the other species will provide a long- flowering display for this front entrance of the Campus. (Click on the images for a bigger view.)