Recent storms have brought dramatic erosion even closer to the freeway edge. While the City tries to patch up the river bank protection with ratepayer funds, storms endanger the freeway, a vital link in our State's economy. You can see more photos and details by clicking here.
Further along the shore there is a line of palm trees with almost no visible means of support. The palms are as tall as their distance from the freeway and are due to fall over in the next decent westerly wind, possibly falling into freeway traffic.
As with many other parts of the Swan River banks, significant work is required. In this and many other cases the work is important to the State, not just local residents. It is time we made this clear so that high- level funding is made available for protective works.
The older style of protection, with visually attractive vertical walls, has been ineffective, these being undermined and falling over after construction. What is required is an appropriate set of structures that dissipate wave energy. Different methods will be needed in each area.
Where the natural river banks still exist there is often not much of an erosion problem. Where we have moved the river, to accommodate developments such as the freeway, we see significant erosion.
Unless we do something soon the winter storms will be likely to cause much more damage.
7 comments:
Pete,
If some of Como beach was retained and those sections of the Como foreshore with river walls were planted with river reeds, would the reeds offer the wave dissipation needed to prevent erosion ?
This seems like a low embodied energy solution (no concrete or limestone cut and transported to site) that also promotes wildlife at Como.
Are there historical, cultural, or social reasons why Como couldn't have a small (sandy) beach for swimming and recreation only around the jetty area ?
Harry
Pete -
Good summary and a pretty scary situation; would specific types of trees help to stabilise the soil. I like Anonymous comment about reed planting and the concept of a sandy beach around the jetty area. The shore has been enhanced and landscaped and its a waste not to be used.
Presumably the Swan River Authority know about this. Are they planning any action? It's beyond the scope of the City of South Perth to deal with it I guess.
Diane
Pete,
Thanks for your concern. When they were building the new wall near to Canning Bridge I wondered why they had not raised the height of the land as well because any water escaping the wall would inevitably enter the Freeway.
We really need a proper study of the whole of that part of the River as it seems with the piecemeal repairs and wall replacements within a short time they erode and we are back to square one.
It is such a popular stretch of River what with walkers and bikies that there should be an awareness that safety is an issue for a lot of the users.
The section North of Preston Street has always been a problem as it directly faces the full force of any River surges and it is protected by pieces of wood.
In the event of several Winter storms I fear we could lose the Freeway and footpath accesses.
Tony
"Good heavens, that's where we used to go prawning in the 70s & 80s until it was denuded by over-zealous restauranteurs...
There was at least 20 - 25 meters of beach past those palms at that time. "
Thanks Peter. Thoroughly agree with you. Natural vegetation such as reeds and rushes, paperbarks and taller trees e.g. casuarina etc will do much to stabilize the banks (will need to be recreated) and dissipate the wave energy as well as provide habitat for fauna such as waterbirds. It is interesting to see along the freeway that Pelicans sit on the light poles in the evening because they have no other place to roost. Elsewhere along the river there is a dearth of places for birds such as cormorants and darts to roost and dry their wings while waiting to fish. If you look at the trees in the lakes at the freeway interchange you will notice that there are quite a few trees and these are well used by cormorants etc. The other thing I have noticed is the significant increase in Swans in the river. But again I not aware of anywhere nearby where they can nest. This is a wonderful opportunity to return the Como foreshore to its natural condition and functionality which could be a real showcase.
The historical time series is probably the best illustration of management for Como foreshore.
From what I have been able to make out, the initial reclamation works was supposed to be followed with regular renourishment. One large exercise was conducted within a few years, but it was then scaled down quite a bit.
The Swan River Trust continued to provide “backpassing” of material from the Narrows, but they were placing it in the vicinity of the sea scouts. From the wave climate analysis, this is on the south side of a “zone of separation”, which means that it gets pushed southwards, and does not feed back into Como Beach – which is where it was intended to go. I suspect they may have stopped transporting material, as last time I heard they were trying to use the material dredged out of the Narrows at another location.
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