//The Work Of Rivers

Question 1

Youthful stage of a river:

Answer 1

-Steep slope, erode downwards
-V-Shaped Valleys erode downwards. Steep sides, narrow floors
-Interlocking Spurs stick out across a Vshaped valley. High ground
-Waterfalls (erosion) river falling over a vertical slope eg. Niagara Falls
>Band of hard rock on soft rock
>River erodes soft rock, then hard = vertical drop where soft and hard rock meet
>Plunge pool= soft rock abrasion + hydraulic action = hard rock undercut and collapses

Question 2

Mature stage of Rivers:

Answer 2

-Gentle slope, erode sideways
-Flood plains= river deposits fertile mud called alluvium
Meanders= large bends and loops (erosion and deposition)
>Outer side= water flows quickly + erodes
>Inner side = water flows slowly + deposition

Question 3

Features of Old River Stage

Answer 3

Features of Old rivers
-Flood plains
-Big meanders
-Deltas: fan-shaped areas deposited alluvium (smaller= distributaries)
-Ox-Box Lakes- deposition= closed meanders
-Levees- narrow raised banks of alluvium (deposition)
>River floods = water spreads over flood plain = looses energy = deposit alluvium
>Heavier load deposited next to river bank + build up = levees

Question 4

Case Study: Flooding in Clonmel

Answer 4

-Flood plain of the Suir
-More buildings=rapid draining of river
-Farm drainage=rapid water flow to river
Prevention: Flood barriers, clearing rubbish from rivers, planting trees

Question 5

Hydroelectric Power Station

HEP dams Case Study

Answer 5

Positives: generates electrify, provides reservoirs, lakes from recreation
Negative: lakes Flood valleys, expensive, salmon stock threatened

Question 6

Erosion in Rivers

Answer 6

• Hydraulic Action- moving water breaking materials
• Abrasion- river load hits against rivers
• Attrition- load bounce off each other = smooth and worn
• Solution- acids dissolve limestone

Question 7

Transportation in rivers

Answer 7

• Solution- dissolved rock eg. Limestone
• Bouncing small and rolling large pebbles
• Mud particles suspended

Question 8

Deposition in rivers

Answer 8

• Slow down/lose energy
• Enters lake/sea
• Reaches flat ground
• Inner sides of meanders

Question 9

River course features

Answer 9

River source: begins
Tributary: stream/river joins
Confluence: where two rivers join
Estuary: Tidal