human activity at coast

Created by

olivia thorley

Cards (25)

intentional management case study 
holderness coastline
key stats/ideas - holderness 
europes fastest eroding coastline
2m/yr disappearing
retreated 4km since roman times
29 villages lost
geology of holderness coast
composed of soft boulder clays deposited by ice sheets
structurally weak lithology
surrounded by chalk - stronger lithology
influence of fetch/waves at holderness
fetch = 800km
amplified by currents from atlantic increasing energy
intense weather systems and winter storms
deep sea floor = no friction to slow waves
lsd at holderness 
boulder clay erodes fast into small particles = easily transported by LSD and so doesnt accumulate infront of cliffs = no layer of protection
beaches = narrow so fail to absorb wave energy
why manage? - holderness (ECONOMIC)
number of visitors declining
some villages cant sustain shops due to low population
gas terminal at Easington at risk - 25% of britains gas
80,000km squared of farmland lost annually
why manage? - holderness (SOCIAL)
properties at risk have no equity so owners receive no financial aid as compensation
why manage? - holderness (ENVIRONMENTAL) 
wildlife behind spurn head losing diversity due to lack of sediment
certain sites of special scientific interest are threatened
management at easington  
£4.5 million rock armour at cliff foot to protect gas terminal
? doesnt protect villages
management at mappleton 
2 rock groynes - 1991 £2million
cliff face regraded = less steep
!! groynes prevent removal of beach = locally affected
!! cliff more stable
? cliffs slumping again
? large rocks behind 2nd groyne undermined
? cliff face below car park undermined
? groynes = sediment deficit at Cowden = increased erosion rates 2.5-3.8m/yr 1991-2007
management at hornsea 
groynes repaired + new ones constructed - £5.2 million
sea wall raised
sea dunes replanted
beach nourishment
!! sand dunes stabilised
!! groynes locally effective at lower cost
? groynes rarely effective on their own
? beach nourishment easily undone by storm events
? costs limit length of wall
unintentional management case study
mangawhai - pakiri coastline
key ideas/statistics - mangawhai pakiri
mining rates of 75,000m3 at pakiri
1994-2004 = 165km/yr3 extracted
extraction rates 5x higher than inputs
1978 = 28m breach of spit
sand mining at pakiri
used for replenishing auklands beaches and construction industry
impacts of sand mining at mangawhai - pakiri
movement of sediment between stores decreased
beaches experiencing sediment deficit = wider/flatter = less effective at absorbing wave energy
dunes and spit vulnerable = 2 breaches of spit altered tidal currents leading to increased sedimentation of harbour
little input from rivers
coastal retreat is evident and long term retreat estimated at 35metres by end of century
management at mangawhai - pakiri 
dredging of harbour and groynes on spit
2years of monitoring occurs before mining can begin
push to ban sand mining
positive impacts of coastalisation - australia
main port/industry = jobs
house prices cheaper in small towns nearer coast
positive impacts of coastalisation - florida 
value of property = $1.9 trillion
positive impacts of coastalisation - bournemouth
growth of service sector
positive impacts of coastalisation - boscome surf reef
attracts surfers - spend 8% more than average tourists
negative effects of coastalisation - florida
wetlands shrunk by 80% so providing freshwater is hard
more people at risk from hurricanes, flooding, storm surges
negative impacts of coastalisation - bournemouth
coastal squeeze as city is squashed between coast and rural green belt
negative impacts of coastalisation - jurassic coast 
problems with traffic congestion, littering and dune tramping
fossil hunters disturb rocky shore
jet/water skiing is noisy + swash impacts plant life
negative impacts of coastalisation - boscome surf reef 
noisy for locals
car parking shortages
negative impacts of coastalisation - fawley oil industry 
salt marsh decreases in size