BLESSING OR CURSE SERIES? ( #2 ) “VERTICAL DROP” EarthCache

Your response provides a way of monitoring the changes in the level of the sands. There is uncertainty regarding climate change and the validity of current predictions but general consensus amongst coastal scientists is that there will be an increased incidence of storm surges and a general rise in sea level.

The beach erodes because the supply of sand to the beach can not keep up with the loss of sand to the sea.

Sand may be transported from beach to beach along a shoreline but this is mostly just a redistribution of sand that is already on the coast. The problem of beach loss can be exaggerated if sea level rises relative to the land (either due to true sea level change or geological sinking of the coast line).

The situation is made worse by the extraction of sand from the Severn Estuary and Bristol Channel. This however has for a century been vital to the construction industry and almost 90% of the sand supplied in South Wales, comes from marine sources (Bellamy, 1999). This sand is ideal for construction and there is no other viable alternative.

On an uninhabited shoreline, new beach can be created further inland. But, when the encroaching sea comes against people's property, the tendency is for people to try and stop the encroaching sea.

Often the shoreline is reinforced with seawalls, revetments, jetties, etc.. But these have a negative effect on beaches because once sea water reaches them, it "bounces" off them with more energy than a wave washing back off a normal sandy beach.

More sand is carried off shore, promoting beach loss. Additionally, jetties placed perpendicular to the beach, disrupting along-beach currents and causing sand loss downstream of the jetty. (Demonstrated well at the eastern end of the beach)

National and local government policy is hold the line, maintaining, upgrading and replacing defences in response to future climate change/ sea level rise, subject to the availability of public funding for coastal erosion and flood risk management. There are a large number of socio-economic assets at risk from coastal erosion and flooding along this frontage along with the risk that potentially contaminated fill could be released into the coastal zone.

Coastal managers may need to adopt techniques that work with the natural processes rather than simply implement traditional hard engineering responses. Beach nourishment is increasingly used as a soft engineering solution

Beach erosion is becoming a more common and destructive process and can have significant and costly effects on human populations. With 50 to 70% of the global human population living in coastal zones and rising sea levels caused by global warming speeding up beach erosion, researchers need a way to monitor what is happening.

In an attempt to understand this phenomenon data has largely been obtained by observations and measurements of exposed coastal areas, such as beaches, to quantify the effects of coastal erosion.  

AN OBJECTIVE MEASURE WOULD BE THE EXTENT OF THE EXPOSURE OF STEEL PILING, WHICH WAS COVERED WHEN THE SEA WALL WAS BUILT.

Hard engineering structures such as seawalls, groynes, piers, etc. have traditionally been used to manage storms and tides for the protection of developments within the coastal zone. These structures are expensive and tend to promote erosion, possibly by the formation of rip currents.

A few miles along the coast at Porthcawl, the Esplanade seawall of 1887 was replaced in 1906 and again in 1934 as erosion continually undermined the previous constructions. Beach levels continued to fall and in 1984 the beach was paved with bitumen macadam


DO GO to the coordinates and assess the problem for yourself. Log the cache, and email you response to the following. will reply as quickly as possible. (Please don’t post photos which would allow others to complete the cache from home!!)

1.   The sand was originally level with the top of the last step. How much can you see of the steel pilings which were formally covered? (Estimate in metres or parts there of)

 ( This equals the depth of sand lost)

2.   How far along does this vertical drop carry?  Answer in metres and “between letters”  (You will see what I mean when you look at the sea wall)

3.   What can you see being done to alleviate the problem?

4.   Was the development a blessing or a curse? What do you think? What might be the best solution today?

5. If you have the time visit the other end of the beach. Try to visualise the depth of sand that has been replaced by other materials since the sea wall was built. You can see the massive impact of a jetty built perpendicular to the beach.

Well done Plasma Wave on your FTF