Beach Nourishment

During the post on what NASA was doing to protect their property from rising sea level I briefly touched on beach nourishment as a possibility that they were trying out to protect themselves from sea level rise. I want to have a look at this in a little more detail because, as I mentioned last week, it is a hybrid defence solution that makes a compromise between cost and effectiveness. It is a commonly used method of trying to mitigate against sea level rise, storm surges, and coastal erosion (Trembanis et al, 1999).

Beach nourishment in action (GreenfieldGeography)

Beach nourishment is a really simple concept - more sand or pebbles are added to the beach - either from other beaches further along the coast, or material dredged from offshore. It is a form of soft protection as opposed to hard protection methods like building walls or more man-made barriers (Hanson et al, 2002).  Soft protection can be advantageous because as well as reducing erosion, maintaining beach profiles and protecting inland areas from flooding(Hanson et al, 2002), it has the added benefit of also being more aesthetically pleasing, and is an attempt to fit in better with the local environment (Peterson et al, 2005). However, it's not all good news, even with the best intentions in mind, beach nourishment can have a negative impact on the local environment by burying habitats, reefs, and wildlife (Peterson et al, 2005).

'Please don't bury me' beach nourishment can be very bad news for sea turtles (ABCNews)

But most importantly for this blog - how effective is beach nourishment at protecting coastal communities from the effects of sea level rise?


As we saw last week in the Resilience to Extreme Weather report, beach and dune nourishment is the most effective of the non-engineered solutions, but it is also very expensive solution. And it's not a one off cost - beach nourishment is very far from permanent - from the moment the beach is fed the sand is being eroded again. It is important to look at the rate of erosion from the beach first to see if the repeated cost of replacing sand or pebbles is worth it in the long run. Because of this, nourishment, especially on long beaches, is usually combined with more permanent harder protection, such as groynes to try and reduce constant erosion (SNH).


I think it's becoming very obvious that there is no final solution to sea level rise - even the most engineered solutions which take into account future sea level rise projections still have a shelf life. To me, beach nourishment is a bit like trying to evade the truth - by extending the beach you can imagine that sea level rise is not happening  - you still live by the sea and your view has not been obscured by a dam or sea wall. I think that there are also some serious issues with ecosystem disruption at both ends of the process. First when removing material from another beach or from offshore, and then secondly when burying the ecosystem on the beach where you are performing nourishment. Unlike sea level rise, covering all these organisms with sand or pebbles doesn't give them time to adapt or move on.