3.4 The human impact

Question 1

mining

Answer 1

• removes underlying and/or lateral support
• large amount of waste left: increased stress

Question 2

construction

Answer 2

• change in topography
• increased weight : stress
• undercutting slopes
• groundwater effected by sewage, drainage system and water demand
• water erosion: decreased internal strength
• hydraulic engineering can cause saturation in surrounding slope: mudslides

Question 3

tourism

Answer 3

• prevalent in hillslope, alpine areas : increasing stress
• eg skiing
• erosion: vegetation, heavy machinery: damages, compacts soil
• seasonal melting: dramatic increase of water triggers mass movement on degraded slope

Question 4

agriculture

Answer 4

• soil compacted with heavy machinery and animals
• vulnerable to erosion, changes in water flows, less vegetation
• overgrazing and trampling: less veg, soil degradation, soil creep more likely

Question 5

deforestation

Answer 5

• soil strength enhanced by roots
• less interception: more overland flow and faster infiltration
• less taken up by roots: ground more saturated
• erosion + mass movement
• clearcutting: vulnerable to wind
• forest roads (transporting timber) interrupt natural flows of water: channel run offs are highly erosive
• unstable slope

Question 6

afforestation

Answer 6

• roots increase internal strength: can take more stress
• reduce saturation of soil by interception: less mass movement and erosion
• cheap + advantegous but takes time

Question 7

netting

Answer 7

• netting or mesh over for stability
• catches falling debris : limits hazard
• collect fragments of scree: safely removed:maintenance
• especially rock slopes to prevent rock falls
• help contain loose material
• contoured to prevent larger movement
• stabilise by allowing other

Question 8

pinning

Answer 8

• attach wire nets
• soil nailing: steel rods drilled in, can carry weight
• rock bolting: bolts drilled in rock slopes in a specific patters: transfers load from weaker exterior to the stronger interiors of slope
• knit together: stronger

Question 9

grading

Answer 9

• more uniform topography
• building, controlling surface runoff and minimising erosion
• reinforces slope
• reduces downslope influence og gravity as reduces overall angle

Question 10

managing falls

Answer 10

• flattening slope: subsoil built from bottom of slope
• benching the slope: cutting slopes in steps: gentle fall
• drainage
• rock walls, anchor bolts into bedrock under soil
• steel mesh

Question 11

managing slides and flows

Answer 11

• grading, benching, flattening
• drainage
• sealing surface cracks to prevent infiltration
• rock/earth buttresses
• retaining walls
• pilings through potential land mass