soft engineering and hard engineering Flashcards
5 soft engineering techniques?
- beach nourishment
- cliff regrading
- cliff drainage
- dune stabilisation
- managed retreat
-beach nourishment-what is it, positives and negs
replaces beech sediment
+uses natural sediment so beach looks natural
-doesn’t last long, may have come from dredging
-cliff regrading-what is it, positives and negs
lithology of a cliff may be unstable so it is cut back at an angle
+creates natural looking slope
+should remain stable
-costly (£1 mil)
-engineers may get their calculations wrong
-cliff drainage-what is it, positives and negs
cliff my be unstable so drains with gravel inserted into a cliff to drain water out to prevent landslides and slumping.
+looks natural
+reduces mass movement
- difficult to implement-carryout
-dune stabilisation-what is it, positives and negs
replanting grasses onto sandunes
+ looks natural
+provides ecosystem
-powerful storms may destroy efforts so may only be a temporary fix
-managed retreat-what is it, positives and negs
areas set aside to flood
+allows natural processes to take place
+ecosystems can be formed
-doesn’t prevent land from being lost
6 hard engineering techniques?
- groynes
- seawalls
- rip-rap
- revetments
- offshore breakwaters
- gabions
-groynes-what is it, positives and negs
wooden walls on a beach at right angles
+maintains size of a beach
-expensive
-obstacle to peopl-terminal groyne sydrome
-seawalls-what is it, positives and negs
recurved walls, reduce wave energy \+tops can be used as promenades \+long lasting - the most expensive -unsightly
-rip-rap-what is it, positives and negs
boulders resistant to erosion
+ long lasting
- unsightly
-may contrast with local geology
-revetments-what is it, positives and negs
sloped walls often made of wood \+absorb wave energy \+cheaper than sea wall -unsightly - may need constant maintenance
-offshore breakwaters-what is it, positives and negs
rock boulders deposited in shallow areas parallel to shore
+effective
+keep beach in place for recreational use
-costly
-unsightly at low tide
-gabions-what is it, positives and negs
pebbles in wire baskets to make a wall \+cheap \+easy to maintain -unsightly -needs frequent repair
what are the 4 choices made through the ICZM
- advance the line
- hold the line
- managed retreat
- no active intervention
whats advance the line
Build new coastal defences on the seaward side of the existing coastline.
Usually this involves land reclamation.
whats hold the line
maintenance of defences across coastline and buildng new coastlines
whats managed retreat
allowing flooding but monitoring it
whats no active intervention
no monitoring- flooding occurs
