Urbans recently constructed an erosion protection rock wall on the River Torrens, creating a reformed river path and protecting the local environment from future undermining.
The erosion protection rock wall and swale is fit for purpose and has delighted locals.
The $580,000 Battams Road Linear Park Bank Erosion Remediation Works project was conducted for the City of Norwood Payneham and St Peters over a four-month period.
Located on a 90-degree dog leg near the bend of Battams Road and Ninth Avenue, Royston Park, the embankment was suffering a severe case of undermining, requiring the erosion protection rock wall be reformed.
At peak flows the bend receives a water force that had slowly eroded the embankment, exposing drainage infrastructure and causing undermining.
The erosion prompted fears the steep embankment would collapse into the river, resulting in significant environmental damage that would not only impact the water course but also local flora and fauna.
Due to the proximity of the River Torrens Linear Park Trail and access to nearby homes and public transport options, the area is popular with local residents who frequent the location for walking and bike riding.
The river bend also provides a popular access point for families keen to enjoy the natural environment for activities such as catching tadpoles, while dogs also enjoy using the waterway.
Methodology
The experienced Urbans team planned the project to ensure a quality result for our client, the City of Norwood Payneham and St Peters, but also to ensure the safety of our workers, the public and the local environment.
The restructuring works included repairs to the Battams Road stormwater discharge outlet into the River Torrens, civil works for the embankment and rock stepping for the tiered revetment.
Seven Urbans staff using excavators, complete with rock grab, skid steers and tandem tippers were engaged to complete the project via the following processes.
Site Establishment/ Preliminary:
- Prepare Site Access via River Street and shared path alongside the Obahn
- Site Establishment, set up site compound, site fencing etc.
- Pedestrian management
- Strip vegetation on the existing sediment bar on the northern riverbank
- Create diversion trench to direct water flow away from the working area.
- Prepare scour pool area, working platform and footing rock area.
- Construction of scour pool & working platform with specified rock
- Strip vegetation to the southern riverbank
- Strip topsoil & stockpile on site
A stepped revetment rock wall was constructed in the following sequence:
- Excavate for Footing Rock
- Install 200mm diameter base rocks
- Install footing rock
- Prepare area embankment area (cut/fill)
- Install geotextile to subgrade of embankment
- Fill the embankment under level 1 supervision
- Build Stepped rock layers including geotextile and backfill with screenings
Simultaneously with the stepped revetment rock wall, the stormwater drainage outlet was constructed in the following sequence:
- Demolish existing concrete matting
- Shape to make area safe (benching/ batters)
- Excavate for drainage pit base and toe footing
- Construct concrete drainage pit base
- Install drainage pit and culvert including extension of pipe
- Backfill area
- Install footing rock, rocks to culverts and pit opening border rock
The project was completed via the following:
- Install Toe Rock in sand bar – Northern Riverbank.
- Topsoil and landscaping to Southern Embankment and Northern Riverbank.
Challenges
Natural river conditions prompted several challenges, including the requirement to create a diversion trench to maintain a dry work site for the excavators. A working platform and scour pool were created to prevent silt from entering the main river course.
A major volume of ground water also seeped into the site, which was pumped away from the work zone.
Due to the project’s position at the foot of a steep embankment, Urbans faced significant challenges in safely moving plant, equipment and materials to the work site.
To manage this, all plant and materials delivered to the worksite were escorted slowly and safely along the shared path to site.
At various times, including during summer, heavy rains delayed progress, but work was still concluded within the client’s required timeframe.
Conclusion
The result of Battams Road Linear Park Bank Erosion Remediation Works project is aesthetically pleasing with many locals dropping by to express delight at the completed structure.
Now it is finished, the erosion protection wall and swale will prevent further dangerous soil shifting that would erode the riverbank and also reduce environmental issues in the Torrens.
Check out another Urbans landscape construction project featuring a rock work, along with a project we completed in Pakapakanthi Wetland.
