- Created by: alisha55555
- Created on: 07-04-18 18:17
DEFINE HYDRAULIC ACTION
Water that crashes into gaps in soil and rock, exploiting them and causing wear.
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Water picking up rock sediment that smashes against river banks
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Rocks carried in the river smashing into each other, wearing them down to smaller and rounder rocks.
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Minerals are dissolved into the river water.
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Tiny particles are carried for long distances in the river.
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Sediment bouncing along the river bed.
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Bed load slowly rolling along the river bed.
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UPPPER COURSE CHARACTERISTICS.
Steep gradient. Narrow and shallow. Low velocity. Waterfalls, v shaped valleys, interlocking spurs.
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MIDDLE COURSE CHARACTERISTICS.
Gentle gradient. Wider and deeper. Faster velocity. Meanders, oxbow lakes.
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LOWER COURSE CHARACTERISTICS.
Flat gradient. Widest and deepest. Fastest velocity. Floodplains, estuaries.
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WHEN DOES DEPOSITION OCCUR?
When a river loses its energy, for example in shallow areas or slower flowing areas.
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EXPLAIN HOW V SHAPED VALLEYS ARE FORMED
Fast flowing water - vertical erosion - unstable upper valley rock - weathering - collapse/landslides
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EXPLAIN HOW MEANDERS ARE FORMED
INSIDE BEND - shallower, slower, more deposition, slip off slope.OUTSIDE BEND - deeper, faster, erosion, river cliff
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WHERE ARE MEANDERS FOUND?
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EXPLAIN HOW WATERFALLS ARE FORMED
hard rock over soft rock - soft rock erodes (hydraulic action + abraision) - hard rock stays - plunge pool formed by hyd. action, abrasion makes it receed - ledge overhang unstable - collapses - repeats
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WHERE ARE WATERFALLS FOUND?
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HOW ARE OXBOW LAKES FORMED?
tight neck meander - water flows over and takes quickest route - water stops flowing into oxbow so deposition eventually seals it of - detaches
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HOW ARE FLOODPLAINS FORMED?
river floods - up to a bluff line on either side - these remain to control where the river floods next time - fertile land
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WHERE ARE FLOODPLAINS FOUND?
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DEFINE DRAINAGE BASIN.
The area of land that is drained by a river and its tributaries
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When rainfall does not reach the ground as it is blocked by trees and buildings.
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The movement of water into soil
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The flow of water through the soil
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DEFINE GROUNDWATER FLOW.
The flow of water through rocks.
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The movement of water from the soil into the bedrock
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The boundary of two drainage basins marked by a ridge of high land.
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WHAT FACTORS AFFECT THE STORES AND FLOWS IN A DRAINAGE BASIN?
Type of rock (permeable/impermeable. Soil type (sand/clay). Urbanisation. Weather. Relief.
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WHY DO RIVERS FLOOD?
INCREASED RAINFALL (ground becomes saturated, runoff/no time to infiltrate, runoff). VEGETATION (interception reduces time for water to reach ground). GEOLOGY/URBANISATION (permeable/impermeable, runoff)
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HARD ENGINEERING STRATEGIES FOR FLOOD MANAGEMENT?
FLOOD WALLS / DAMS - effective & protect important settlements, dams can be used to generate power (profit, favoured by governments), expensive, long to build, ugly. FOR EXAMPLE FLOOD WALLS IN SHREWSBURY - effective, multipurpose and versatile
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SOFT ENGINEERING METHODS FOR FLOOD MANAGEMENT?
MANAGED REALIGNMENT / AFFORESTATION - working with environment, can help effects of flooding in some places, land becomes more fertile, good for environment / not enough space, farmers land used/destroyed.
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EXPLAIN WHY CLIFFS RETREAT THROUGH WEATHERING.
PHYSICAL - FREEZE THAW (rainwater enters cracks, freezes and expands, bigger crack, weak, collapse). BIOLOGICAL- PLANT ROOTS (cracks exploited). CHEMICAL - CARBONATION (acidic rainwater enters cracks and reacts with limestone, erosion)
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DEFINE MASS MOVEMENT (ROCKFALLS+LANDSLIDES).
When soil, rocks or stones move down a slope.
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EXPLAIN WHY MASS MOVEMENT OCCURS ON CLIFFS.
Hydraulic action and abrasion weaken the base of the cliff by weathering, rock base becomes unstable and cannot support the rock above it (CLIFF COLLAPSES, LANDSLIDES)//Hydraulic action triggers action on the cliff face, loosening smaller rocks-fall
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DEFINE LONGSHORE DRIFT.
The process by which sediment is moved along the coastline through the power of waves and wind.
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EXPLAIN HOW SPITS ARE FORMED.
Longshore drift transports sediment along coast. coast changes direction- area of calmer water- sediment loses energy- deposited in long thin ***** that is in the original direction but bends. E.G. SPURN POINT, EAST COAST.
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An area of land that juts out into sea.
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A recessed area of coastline often found in between two headlands.
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DEFINE WAVE CUT NOTCH.
A slot on the face of a cliff with an over-hang and wave cut platform out towards the sea
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EXPLAIN CLIFF COLLAPSES AND WAVE CUT PLATFORMS.
Hydraulic action + abrasion-wave-cut notch and eventually platform on face of cliff- continued erosion and weathering at high tide - unstable and collapsing cliff - sediment falling in - abrasion of platform, smooth. E.G. COLLAPSE AT BARTON ON SEA
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EXPLAN HOW ARCHES AND STACKS ARE FORMED.
Hydraulic action causes cave/arch in soft rock. rock above unstable, collapse, left with stack - eroded to form stump . FOR EXAMPLE OLD HARRY ROCKS IN SWANAGE (clear distinction)
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EXPLAIN HOW HEADLANDS AND BAYS ARE FORMED..
ocean erodes away a discordant coastline (alternating soft and hard rock) - soft rock erodes quicker by hydraulic action, curved bay. hard resistant rock does not erode as quick- headlands that jut out. E.G. SWANAGE BAY AND DURLSTON HEAD IN DORSET
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WHAT FACTORS AFFECT THE RATE OF LANDFORM CHANGE IN RIVERS AND COASTAL LANDSCAPES?
GEOLOGY (type of rock). CLIMATE (wind changes wave direction. rainfall increases discharge. extreme weather events). HUMAN ACTIVITY (management, GROYNES IN BARTON ON SEA, tourism erosion, fake beaches)
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EXPLAIN THE NEGATIVE AND POSITIVES OF GROYNES.
A low wall or barrier on a beach built at right angles to the sea to restrict longshore drift. Keep material on beach, natural absorber of wave energy protects landforms. Make other areas prone to erosion as stops longshore drift as no sediment/absor
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WHAT FACTORS MAKE A LANDSCAPE DISTINCTIVE
Geology. People and culture. Vegetation. Land use.
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GIVE AN EXAMPLE OF A DISTINCTIVE LANDSCAPE.
THE JURRASIC COASTLINE - 95 miles of coast from Devon to Dorset. Known for beautiful cliffs and beaches. Home to many fossils. Tourist attraction (car park, gift shops) leading to VISITOR PRESSURE AND EROSION.
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Other cards in this set
Water picking up rock sediment that smashes against river banks