10 - impacts of humans on coastal processes Flashcards
what is integrated shoreline management
integrated shoreline management plans consider the coast holistically rather than on local scale
consider large scale sediment cells rather than just protecting one area
how do conservation schemes protect
- global frameworks (world heritage sites eg great barrier reefs)
- establishment of marine reserves at national scale
- development of sites of special scientific interest
factors affecting success of managed realignment
- estuary size and shape
- degree of wave exposure
- tidal regime
- current land use
- public perception
- research of the site ‘science’
- positive site management
what is managed realignment
allows sea to flood areas that were previously protected
areas serve both flood defence and for wildlife conservation
seen as new way of adapting to rising sea levels
positives of managed realignment
- more sustainable , produces new salt marshes and mudflats
- encourages natural protection
- provides possible reduction in cost of protection relative to employing hard engineering schemes
positives of managed realignment 2 (increased…)
- increased intertidal width
- increased conservation potential
- retained naturalness of estuaries
- increased protection against sea level rise
- cheaper as lower value land flooded visit income potential rises
problems of managed realignment
- danger of modifying tidal processes
- experimental technique that may fail
- complexity of compensation issues
- uncertainty about hydrological processes
- poor public perception of ‘giving up’
- can only be used on certain estuaries
- environmental values can be over estimated
what is dredging and how does it impact the coast
- dredging for aggregates, sands and gravels taking place on variety of scales for shoreline protection and to improve shipping lanes and port access
- fine grain particles are released during dredging and these settle and affect turbidity of water and suffocates filter feeders
- when harbours dredged of mud it is taken out to sea and dumped offshore affecting ecosystems
what can lead to sand dune erosion
- highly fragile environments
- human impacts eg urbanisation, golf courses, agriculture, forestry, mining, and tourist activities lead to sand dune erosion
how can sand dunes be utilised
- conversion (new land use)
- removal (of sand for other uses)
- utilisation (using current resource for activities eg tourism)
- external (outside influence, eg removal of sediment supply from hard engineering)
how does urbanisation influence sand dunes
urbanisation puts a layer of tarmac over the sand rendering the dunes immobile
campsites, barbecues, sand mining lead to dune break down
what are the three main management approaches for dunes
- heavily degraded areas require complete reconstruction
- less severely degraded dunes can be restored and repaired
- cause of problems tackled with holistic solutions
what is the main objective of medmerry management as a positive impact of humans on coasts
to combat flooding coastal realignment has been used by surrendering land to sea
what is involved in the medmerry realignment
costing £28m in West Sussex, 7km of new sea walls will be built up to 2km inland
by letting waters in it reduces risk of flooding for hundreds of homes and surrendered land provides new habitats for many species
what was the scale of the medmerry coastal realignment
450,000 cubic metres of earth dug up
7km of new earthen defences built from soil
60,000 tonnes of rocks imported by ship to reinforce works
10km new drainage ditches/ponds installed
2 carparks, 4 viewpoints and 10km of cycle paths been constructed
350 homes, 2 holiday parks and water treatment works increasing protection
what are the three key objectives of medmerry
1) sustainable flood risk management
2) creation of compensatory intertidal habitat
3) involvement of local communities
what are some benefits of medmerry to humans
- around £90m direct economic benefit expected
- maintenance costs less than old shingle bank
- local economy received boost from increase in green tourism
- extended season for caravan parks generating income and jobs
how does the great yarmouth demonstrate a negative impact of humans on coasts
- coastal erosion increased by dredging as it removes important sediment
- sediment starvation occurs
- in some cases dredging by modifying water depth induces wave refraction resulting in modifying longshore and crossshore sediment transportation patterns
how has medmerry affected places further down
Winterton beach has suffered from increased quicker coastal erosion and sea defences have also affected regular replenishment as more is drawn down from shoreline
what is the zandmotor project in the netherlands and what does it do
- mega nourishment of large artificial sand bank up to 5m above sea level, ‘building with nature’
- supports dune flood defences
- gradually supplies sediment to both sides using natural processes
- large scale experiment for innovative coastal management
- new habitat above and under water
- eco dynamic design as natural processes transport sediment downdrift
what are facts and figures involved with zandmotor
21.5 million m3 of sand
2 miles by 1/2 mile above water
1 year construction designed for 20 year life
cost £60m
how is zandmotor good for nature
- depositing a large amount of sand in one operation reduces repeated disturbance as natural forces (waves, tides, wind) transport sand to right place
- it also builds up stronger dunes to withstand inevitable rising waters
- leads creation of unique natural and recreational area that wind and sea currents will transform continuously
- area is an appealing habitat for a range of flora and fauna.