Rivers, Floods and Management 2

merrettn
Mind Map by merrettn, updated more than 1 year ago
merrettn
Created by merrettn almost 6 years ago
27
3

Description

Landforms rejuvenation physical factors and causes

Resource summary

Rivers, Floods and Management 2
1 River Landforms
1.1 Waterfalls
1.1.1 Bands of hard and soft rock - the soft rock is eroded easier and causes a step
1.1.2 Vertical erosion of soft rock causes waterfall
1.1.2.1 Plunge pool and undercutting is caused - this causes a gorge
1.2 Potholes
1.2.1 Small circular hollows in the river bed
1.2.2 Formed by abrasion as turbulence swirls a rivers bedload in circular motion, this causes an increased erosion
1.3 Rapids
1.3.1 Steep sections of river with turbulent flow where several sections of hard rock are present
1.4 Levees
1.4.1 Natural, raised embankments formed as a river overflows its banks
1.4.2 During a flood material is deposited as energy is lost, the heaviest is dropped first closest to the river bank
1.5 Braiding
1.5.1 When a rivers velocity drops, it deposits material in the channel, this causes it to be divided into smaller winding channels
1.6 Floodplains
1.6.1 When a river overflows its banks, the friction increases, this causes it to lose energy and thus depositing its fine silt across the flood plain
1.7 Deltas
1.7.1 When a river reaches a slow moving sea or lake, the energy is absorbed and material is deposited
2 MEANDERS
2.1 ALTERNATING POOLS AND RIFFLES at equally spaced intervals
2.1.1 GREATER ENERGY IN DEEPER AREAS SO MORE EROSION OCCURS
2.1.1.1 CONCENTRATED FLOW IS CAUSED ON ONE SIDE
2.1.1.1.1 TURBELANCE INCREASES AND HELIOIDAL FLOW OCCURS ( corkscrew effect)
2.1.1.1.1.1 Erosion in deep end and deposition in shallow end due to loss of energy
3 Rejuvenation
3.1 When a river gains more energy by movement of the sea level or ground level
3.1.1 Rise in Ground level
3.1.2 Fall in Sea Level
3.2 Knickpoints - sharp change in gradient
3.2.1 Can form Waterfalls
3.3 River Terraces
3.3.1 Former flood plains which have been left above the level of present-day flooding following increased vertical erosion
3.4 Incised Meanders
3.4.1 When a river keeps its meandering course as the vertical erosion increases. Deep, winding valleys with steep sides.
4 Causes of Flooding
4.1 Sparse Vegetation
4.1.1 Less Interception occurs so more discharge
4.2 Impermeable Ground
4.2.1 Infiltration cant occur so more surface runoff an more discharge
4.3 Steep slopes means the water reaches the river channel quicker
4.4 High Drainage density
4.4.1 Short Lag time, increasing discharge
4.5 Climate Change
4.5.1 Monsoon Weather
Show full summary Hide full summary

Similar

Economic Growth
Kati Christova
GRE Prep - Reading Comprehension
Abood
An Inspector calls Themes
anya14
Data Structures & Algorithms
Reuben Caruana
EEO Terms
Sandra Reed
French Grammar
annabelmiddleton
Unit 5: Nuclear and Thermal Physics
Michael Priest
AQA Business Unit 1
lauren_binney
Grammar Rules
Sandra Yeadon
Část 3.
Gábi Krsková
CSA (115) ⊙ IITU 2017
Zhandos Ainabek