IGCSE - Geography P.1: River environments

how do industries use water

generating electricity through hydro-electric power + acts as a coolant for infustrial processes

water abstraction

water removed from any sources (commonly: lakes, rivers, aquifers, reservoirs)

aquifers

rock and/or sediment that holds water

groundwater

water that is held in aquifers

reservoir

large natural or artificial lake used as a source of water supply

water demand

volume of water requested by users to satisfy their needs

water consumption

volume of water that is no longer available for use

water supply

portion of abstracted water that is delivered to users (excluding any losses that occur during storage, transport, or distribution)

water stress

volume of freshwater extracted as a percentage of available freshwater resources

hydrological cycle definition

continuous movement and circulation of water on earth

stores

places where water is held for a period of time

transfers/flows

the ways in which water is moved around the hydrological cycle

evaporation

Water is converted from liquid to a gas (water vapour) by the heat of the sun.
This takes place in areas such as the sea, lakes, rivers and soil.
The water vapour is stored in the atmosphere.

infiltration

Water moves vertically into the surface of the land.

evapotranspiration

This is the combined transfer of water from the earth’s surface (through evaporation) and plants (through transpiration)

condensation

Water vapour cools and changes into its liquid form (water). This can happen in the atmosphere (eg: clouds are formed as a collection of water droplets) or at ground level (eg: dew).

transpiration

Plants take up liquid water from the soil and release this water as water vapour from its leaves to the atmosphere

precipitation

Liquid or solid water that falls to Earth as a result of condensation in the atmosphere. This includes rain, snow, and hail.

groundwater flow/base flow

Horizontal movement of water through rocks in the aquifer. The water can eventually reach rivers, lakes and the sea.

overland flow/runoff

There is more water than the soil can absorb so the water moves over the surface of the soil. This water can move faster down slopes due to gravity and is eventually absorbed by nearby rivers, lakes or sea.

throughflow

Horizontal movement of water through the soil. It can eventually reach a stream or river through the soil.

percolation

Movement of water vertically through the soil itself. This can be, for example, through the soil and into the groundwater store / aquifers.

canopy drip

Precipitation drips off the leaves and branches of trees and plants onto the ground or plants below.

channel flow/river flow

Water enters a river or stream and moves through this.

stem flow

Precipitation (eg: rainfall) reaching the ground in a forest by draining down the trunks of trees or stems of plants.

drainage basin

area of land drained by a river and its tributaries

watershed

boundary between drainage basins

confluence

place where two or more streams/rivers meet

tributaries

streams/rivers flowing into larger streams or rivers

channel network

consists of the main river channel and all of its tributaries

low/high drainage density

high = lots of tributaries
low = few tributaries

formula = total length/ total area

river regime

record of changes in the river discharge over a year

river discharge

the amount of water passing a specific point on the river at a given time

lag time

difference in the peak rainfall and peak river discharge

convectional rainfall

rainfall formed when the sun hits the water on the surface which then evaporates, cools, condenses and form clouds

weathering

The breakdown and decay of rock by natural processes without the involvement of any moving force

mass movement

large scale movement of weathered material down a slope

physical weathering

rock is broken down into smaller pieces by freeze-thaw and exfoliation

chemical weathering

rocks disintegrate and dissolve in slightly acidic rainwater

biological weathering

rocks are broken apart by the root of plants

slumping

when the slope is eroded by the river
process - river undercuts the slope, causing large-scale movement of material down the slope causing the softer less resistant material to slowly move down the slope towards the river

soil creep

when the influence of gravity causes weathered material to slowly move down the slope towards the river

erosion

wearing away and movement of material

hydraulic action

when the force of the water removes material from the banks and bed of the river

abrasion ( corrasion )

occurs when materials carried by the river scrape away at the banks and bed

attrition

when the material being carried by the river hits each other where the pieces become rounder and smoother

corrosion (solution)

occurs when some rocks are dissolved by the slightly acidic water

vertical erosion

increases the depth of the river and valley as the river erodes downwards

lateral erosion

increases the width of the river and valley as it erodes sideways

traction

when larger rocks and materials are rolled along the riverbed

saltation

when smaller material is lifted by the water and bounces along the riverbed

suspension

occurs when lighter material is carried within the river flow

solution

when materials are dissolved in the water

deposition

when a river does not have enough energy to carry materials, so it drops them

bedload

heaviest material that is deposited first

alluvium

deposited silt from floods