Saturated zones - a success story

2.10.2014 - Posted by Alexa McAuley
Recently, David Knights and I helped run some bioretention design training for Blacktown City Council in Sydney. As part of the training workshops, I met the participants at the Blacktown Showground and talked to them about the bioretention system there, which we designed a couple of years ago. We talked about the design and construction process, focusing on the challenges and key lessons from this project. Despite its fair share of challenges, the bioretention system is looking great today and appears to be functioning well. This system has a saturated zone and this feature has helped it thrive despite a long dry spell over the previous months. The participants told me they had visited several other bioretention systems earlier in the day, and vegetation was struggling in all of the others.

Blacktown Showgrounds

Research on saturated zones has shown that one of their key benefits is that they provide resilience through dry spells. While fully drained systems can take some time to recover their treatment performance after a long dry spell, systems with a saturated zone have shown very little loss of performance, as long as some water remains within the system. Anecdotally we have seen much better vegetation establishment in systems with saturated zones in Sydney.

The ultimate design challenge: aesthetically appealing + cheap + resilient in extremes

30.09.2014 - Posted by Steve Skull
The holy grail for councils dealing with urban waterways is how to balance the need for urban water channels that meet community expectations (who prefer natural and vegetated channels), are easily maintained, cope in extremes, and deliver the best outcome over from a life cycle perspective.

Alluvium and the Mackay Regional Council have been exploring the lifecycle costs and resilience of a range of urban waterway drainage channel designs (traditional channel design and more natural channel designs.

The needs of the Council, which we captured through a series of interviews and workshops, included:
  • designs must have adequate channel capacity in flood events
  • designs must have a low lifecycle cost
  • the channels must be easy to maintain
  • the Council must acquire more expertise in the areas of design and maintaining
  • the designs must be resilient in the face of cyclones and droughts.

Traditional channel design 

Our results showed that:
  • the capital cost is similar for all types of water drainage channel designs
  • the overall lifecycle cost for operation and maintenance in normal circumstances cost is similar for all types of water drainage channels (i.e., traditional designs were only 5% cheaper than the naturalised water drainage channel, and 10% cheaper than the vegetated channel)
  • However, when the impacts of extreme events (particularly cyclones) are included, the lifecycle costs of a traditional water drainage channel can be between 30% (compared to naturalised waterway) and 50% (vegetated waterway) cheaper.
How much value does the community place on natural/vegetated channels over other attributes? The next challenge will be to consider these lifecycle costs in the context of the significant additional community and environmental outcomes these systems can provide compared with the traditional drainage approaches.

Natural channel design

Alluvium sponsors healthy waterways awards

27.06.2014 - Posted by Kane Travis Congratulations to all the finalists and winners of the 2014 Healthy Waterways Awards!

Alluvium was the proud sponsor of the Rural and Agricultural Award category, which was won by the Wild Mountains Trust for their great work on the Camp Creek Headwaters Renewal Project. This project is designed to help people understand their vital connection to water and to motivate personal action. Last year, volunteers involved with the project cleared many hectares of weeds and planted thousands of trees.

From our experience working at the forefront of understanding the major issues facing our waterways in rural and agricultural settings, we know first-hand that solutions require a collective approach from government, industry and the rural community. The Wild Mountains Trust project was a great example of the community’s contribution to river health.

It would be remiss not to mention the other finalists in this category: the Maroochy Landcare Group for their work on Maroochy FarmFLOW Program, and SEQ Catchments for their work on the Laidley Valley Flood Recovery Project.

Restoring the health of our waterways requires long term investment and the energy of passionate people. The Healthy Waterways Awards night, with over 300 people focused on improving river health in attendance, bodes well for the future of the waterways in southern Queensland.

L to R Susan Zommers and Lizz Hills from the Wild Mountains Trust collecting the Rural and Agriculture Awaard for the Camp Creek Headwater Renewal project, with Steve Skull from Alluvium.

Our lifeblood – online river atlas for Victoria

25.03.2014 - Posted by Leonie Duncan
By the time marathon swimmer Tammy van Wisse had swam the entire length of the Murray River she had knocked herself unconscious twice on submerged timber and eaten more than her fair share of that other type of snag, the barbequed variety. Yet she emerged from the experience more passionate than ever about the Murray River.

Tammy calls herself a human water quality tester. A day in the “office” can result in bouts of gastro and ear infections. But her epic journey along the Murray also gave Tammy a fish-eye view of many majestic sights, such as Gunbower Forest, and the chance to meet scores of locals who cheered her along and hosted barbeques in her honour. When Tammy reached the Murray Mouth – after 2438km and 106 days (yes, that is over three months in the water) – she achieved one of the six swimming world records she currently holds. That was back in 2000, but Tammy still talks about it with such energy that she might have well just completed the trip.

I heard Tammy van Wisse tell her story at the Sustainable Living Festival in Melbourne last month, by the banks of the Yarra River. Tammy was there to help launch Environment Victoria’s new online river atlas. This project was the vision of Healthy Rivers Campaigner, Juliet Le Feuvre, and was brought to life by some dedicated volunteers.

The atlas is designed as an educational resource. It provides catchment-by-catchment information on river values, conditions, threats and priority actions to improve stream health, as well as photos, stories and links.

Image of the Goulburn River near Seymour from Environment Victoria's online river atlas

Community completes Alluvium rain garden

27.02.2014 - Posted by Alexa McAuley
On Sunday, Alexa McAuley and Andrew McMillan from Alluvium attended a community planting day at Marrickville Council’s newest stormwater treatment system – the Bruce Street rain garden at Marrickville Golf Club in Sydney.

Alexa and Andrew completed a detailed concept design for the rain garden in 2012, and Council finalised the construction drawings in 2013. Construction was recently completed and everyone is very happy with the result. Council did a great job organising the event; the rain garden was opened by the Mayor and around 45 community members attended the planting day. The volunteers planted around 1,200 plants and Marrickville Golf Club put on a BBQ for all the participants.

Volunteers planting native grasses on the edge of the rain garden

View of the completed rain garden. Council’s contractors planted out the filter area and left the edges for the community planting day.