Rising seas and, more importantly, increased storm intensities and magnitudes are already on their way. Building higher and more massive bulwarks against the waves might seem to be an obvious response, but is it, really?
Look at the images in the slideshow above…
In the news we witnessed huge hurricane driven waves hammering the seawalls at Chesil Beach in the UK. Waves crashed into the seawall, over-topping them and flooding the historic town of Portland… and hurling rocks and other ‘bombs’ into the streets. After the storm an inspection of the beach below the seawall revealed that the shingle beach below the wall is…gone. Meanwhile, the un-armoured portion of beach – just to the north of the old town – dissipated the wave energy without damage. The beach profile steepened but sustained only minor damage – and has been subsequently re-contoured to its pre-storm condition with excavators.
There are many similar local examples. Counter-intuitively, heavy, steep armouring contributes to overtopping and the dangerous launching of airborne rocks, logs and debris – onto roadways, parks and patios. And yet, immediately adjacent undeveloped beaches absorb and dissipate that same storm wave energy through run-up, gravity drainage, energy transfer to shifting logs and gravel, etc.
It’s all about how to manage the energy in the waves. In new and existing development that energy can be managed.
Pioneering Soft Shore Protection On the Salish Sea
In 2004-5 JPH identified a severe shoreline erosion problem while designing Dick Murphy Park in Campbell River. An existing seawall had collapsed and stop-gap stone armouring was failing as well. The problem was being caused by development encroachment onto the upper beach by the former trailer park – which truncated the natural run-up of waves during storms.
We proposed applying a different method of shoreline protection to our City of Campbell River Parks clients – one that restored the natural function of the sand-and-gravel beaches common along the shores of the Salish Sea. The wall was removed; the beach surface was graded back to its pre-development slope; and the back of the beach was planted with native species typical of the backshore.
Benefits of this approach include:
- Erosion abatement and enhanced shoreline resilience
- Elimination of harm – caused by armouring – to nearshore habitats – e.g. forage fish spawning areas and eel grass beds
- Walk-on beach access
- Restoration of beautiful native shoreline vegetation – for both people and wildlife
- An inexpensive alternative to heavy armouring solutions
- Easily adjusted to rising sea levels
JPH scores Gold with Green Shores
This project was subsequently peer-reviewed by the Green Shores Technical Work Group – as a pilot application of their new stewardship-oriented rating system – and was awarded “Gold”. The project figures prominently on their website both, as a case study, and in their “Learn About Green Shores” video.
Since 2005, JPH has designed and overseen the implementation of several similar soft shore beach restorations.
We also provide assessments and advice to public and private sector clients on shoreline protection and habitat enhancement.