Sand Sausages on the Shoalhaven River
Sand Sausages on the Shoalhaven River
Shoalhaven Riverwatch - Battling bank erosion, one long sausage at a time
Making a Difference -
LLCI024-003
The issue
The beauty of the Shoalhaven River attracts large numbers of recreational river users. But increased activities have degraded the river banks due to a number of factors. To maintain the beauty and health of the Shoalhaven River, Shoalhaven Riverwatch has undertaken riverbank restoration using different techniques since 1980. Sandbagging combined with replanting shoreline vegetation in many areas has proved cost effective. Unfortunately, sandbagging is a slow and labour intensive method.
Is there another way?
The solution
Shoalhaven Riverwatch, led by Peter Jirgens, designed an alternative to individual sandbags - the low cost Shoalhaven Sand Sausage. The Sausage is one long continuous sandbag placed along the toe of the bank, and constructed on-site with removable frames, geotextile fabric and a sewing machine. Volunteers fill the sausage from sand or mud on-site, sew it in place and then remove the frame to the next section.
The Sausage prevents wave action from eroding the bank as well as trapping sediment from eroding banks. Over time, additional Sausages can be added on top of the earlier Sausage to further build up a stable riverbank. The Sausage is also inexpensive to construct, costing only 1/5 of the cost of conventional sandbagging. Unlike sandbags, it is not moved during flood events due to its length, flexibility and weight.
The impact
The impact of the Shoalhaven Sand Sausage has been immediate – 100 metres of the riverbank are protected against erosion in hours, whereas once it would have taken days. Riverwatch has been successfully using the Sausage at a number of tidal sites on the Shoalhaven River. Bank stabilisation has multiple benefits for the river, improving fish habitat, improving water quality as well as protecting riparian vegetation and valuable farmland.
The effective impact of the Shoalhaven Sand Sausage and other Riverwatch activities has seen an increase in volunteers who are enthusiastic to be involved in immediate outcomes as well as the opportunity to work alongside like-minded volunteers. A sense of pride and comradeship encourages the volunteers.
Monitoring of Sausage sites shows a build-up of sediment on both sides of the Sausage, even during flood events. This demonstrates the effectiveness of the Sausage which, coupled with its construction efficiency, proves that it is a valuable tool to restore riverbanks.
Key facts
- Innovative new design for riverbank erosion control
- The work is done in hours, and not days
- Time and cost effective
- Increase in volunteer numbers
- www.riverwatch.org.au