Coastal case studiesPRAA SANDS AND PORTHLEVEN

CORNWALL

PRAA SANDS

WOODEN STEPS TO PREVENT EROSION OF THE CLIFFS AND DUNES

ANCIENT PEAT BED

MARRAM GRASS –A XEROPHYTE THAT THRIVES UNDER CONDITIONS OF

SHIFTING SANDS AND HIGH WINDS

Blowouts are sandy depressions in a sand dune ecosystem (psammosere) caused by the removal of sediments by wind A blowout forms when a patch of protective vegetation is lost, Causes of vegetation loss include extended droughts, fire, trampling by humans, cattle, horses, etc.SAND DUNES AND BLOWOUTS

COASTAL MANAGEMENT

SOME MEASURES TO PREVENT FURTHER EROSION OF THE SAND DUNES HAVE BEEN

UNDERTAKEN

PLANT SUCCESSION INCLUDING HEATHER HEATHS AND GORSES TAKES PLACE. WHEN THE SOIL IS BOUND BY THE MARRAM GRASS.THESE PLANTS TOO ARE ADAPTED TO THE LOW SOIL WATER CONTENT AND HAVE SMALL, PRICKLY LEAVES WHICH REDUCE TRANSPIRATION.

SEA SPURGE

THE MARRAM GRASSES ADD NITROGEN TO THE SOIL, MEANING OTHER, LESS HARDY PLANTS CAN THEN COLONIZE THE DUNES.

TREE MALLOW

FENCING AND PARTIONING TO PROTECT

AGAINST FURTHER EROSION

RIPRAP— IS ROCK OR OTHER MATERIAL USED TO ARMOUR SHORELINES RIPRAP WORKS BY

ABSORBING AND DEFLECTING THE IMPACT OF A WAVE BEFORE THE WAVE REACHES THE DEFENDED STRUCTURE.

CLOSE UP OF GABION

GABION IN SITU TO MANAGE EROSION

SEA WALL WITH DRAINAGE HOLESAND

REVETMENT REINFORCED WITH STEEL

RIP RAP AND FENCING TO PREVENT EROSION

VEGETATION TO BIND SOILS

CLOSE UP OF COASTAL EROSION

VEGETATION BINDING SOIL TO PREVENT EROSION AS WELL AS THE RIP RAP (BOULDERS).

WAVE CUT PLATFORM RIP RAP TO ABSORB WAVE

ENERGY

GEOLOGY AT PRAA SANDS (REGIONALLY IMPORTANT GEOLOGICAL / GEOMORPHICAL SITE) ALSO SSSI (SITE OF SPECIAL SCIENTIFIC INTEREST).

RHYOLITE DYKE CONTACT IN METASEDIMENTS, PRAA SANDS,

CORNWALL.

ADIT FORMED BY EROSION

CAVES

EROSIONAL LANDFORMS AT PRAA SANDS

HOE POINT SEA STACK AT PRAA SANDS

SECTION OF ROCKY BEACH

GRANITE PIER AT PORTHLEVEN

BEACH STRETCHING OUT TOWARDS LOE

BAR

THE COST EFFECTIVE SEA WALL CONSTRUCTED AT PORTHLEVEN TO PROTECT THE HOUSES AND

THE ROAD BEHIND THE COAST

CURVED SEA WALLS REFLECT THE ENERGY OF THE WAVES BACK TO THE SEA.