Australian Water Management Review Vol. 1 2014 | Page 54

Wicking up a Storm –
wicking beds delivering
resilient urban parklands
Innovation is often born when ideas are
brought together from different applications.
The recipe for this idea came from a base
knowledge in soil-water science, mixed with
a historical Ethiopian farming technique
and a sprinkling of sports field drainage
technology. The result is an admirably
simple but integrated solution that delivers
everything you could ask for in a sustainable
landscape scheme; passive irrigation,
stormwater treatment, an alternative water
source and improved soil profiles for healthy
turf and active use spaces.
The Gladstone Coal Exporters Maritime Precinct
parkland, currently under construction, is a major
new civic parkland for the City of Gladstone located
on the foreshore of Auckland Inlet. The integrated
parkland design features an innovative application of
‘wicking bed’ technology to store locally harvested
stormwater runoff for passive irrigation of two high
use open lawn areas.
The wicking beds use the natural process of soil
capillary rise, driven by evapotranspiration, to draw
water reserves held in shallow artificial aquifers to
the active root zone thereby ensuring optimal soil
moisture conditions for healthy turf growth. This noimported energy, low maintenance irrigation system
will help sustain the lawn areas between rainfall
events and increases the usability and resilience
of these areas after heavy rainfall events through
improved sub-soil drainage.

48 | Australian water man age m e nt re v ie w

Responsive design

Educate and inspire

The parkland location and context, being adjacent
to Auckland Inlet and located primarily on reclaimed
land, drove the parkland design to meet a number
of important outcomes – to recreate a soil profile to
support a healthy landscape; to manage site runoff
to protect Auckland Inlet; and to build resilience by
reducing the reliance on potable water supplies.

The Precinct plans include an Interpretive Centre
and site tours that will feature this novel, large scale
application of wicking bed technology to educate
and inspire local and regional visitors. The potential
of this scalable no-energy, stormwater harvesting
technology is endless and its benefits wide-ranging.

Biomimicry in action
Stormwater runoff from the site is collected and stored
within a 300mm deep sand layer creating a sub-surface
aquifer. The pore spaces in the sand layer provide the
storage space for the stormwater. Water slowly wicks
upwards via the process of ‘capillary rise’ to the root
zone of the turf above, acting like a large sand sponge.
As the turf removes water from the soil it is replaced by
water replenished from the storage below by capillary
action. An overflow system ensures that the turf layer
and growing media above won’t be submerged during
rainfall events and also facilitates enhanced drainage
of the turf soil layer.
Knowledge generation
The wicking bed is integrated with the parklands
broader automated irrigation control system enabling
real time monitoring of performance. Data from soil
moisture probes located in the turf growing media and
from a water level sensor for the sub-surface aquifer is
received though the central control system. A fail-safe
automated ‘top-up’ system is also in place for extended
dry periods. The operating philosophy is to only
‘top-up’ the wicking bed storage with potable water
when a trigger water level is reached or for adaptive
management based on the real time data.

Multiple benefits – what’s not to like?
• Reduced stormwater and pollutant loads to
the environment
• Reduced potable water use
• Reduced energy requirements for irrigation
• Reduced fertiliser application
• Retention of soil moisture
• Increased turf resilience to dry periods
• No water logging or boggy fields
• Quick return to play following rainfall
• Ease of maintenance and mowing
• Deep root system and healthy turf
• Supporting healthy lifestyles and active play