water Flashcards
whats surface runoff
water that runs across the land into rivers/lakes/oceans
whats transpiration
water that is released as a gas into the atmosphere from leaves in plants
whats groundwater flow
the flow of water deep underground through porous rock into aquifiers
whats interception
trees and plants catch the precipitation and slows surface runoff
whats throughflow
the lateral transfer of water downslope through the soil
whats condensation
water vapour turns back into a liquid and forms clouds
most water is stored in…
the oceans
the biggest store of freshwater is…
glaciers
order where the most water is stored for rivers, atmosphere and soil
most=soil
atmosphere
least= rivers
what is blue water
the amount of water that enters lakes, rivers and groundwater.
what is green water
the amount of rainfall that is either intercepted by the vegetation, or enters the soil and is picked up by plants and evaporated back into the atmosphere
whats groundwater storage
water held within permeable rocks
whats channel storage
water held in rivers and streams
whats surface storage
any surface water in lakes, ponds and puddles
whats percolation
the downward seepage of water through rock under gravity, especially on permeable rock e.g. sandstone and chalk.
whats stem flow
water flowing down plant stems or drainpipes
whats base flow
( also known as groundwater flow)- slow moving water that seeps into the river channel.
whats channel flow
the volume of water contained within a river channel (also called discharge and runoff)
whats surface runoff
flow over the surface during an intense storm, or when the ground is frozen, saturated or on impermeable clay. Also called overland flow
annual fluxes
the movement of water between stores over the course of a year.
store definition
all the elements of the hydrological cycle where something remains for a period of time (elements= oceans, atmosphere, biosphere, soil… etc..)
whats the cryosphere store
water stored in glaciers and ice sheets
whats residence time
the average length of time that water remains in each store within the hydrological cycle.
whats fossil water
untapped ancient stores of freshwater. These are often non-renewable stores (no water recharging this store= a non-renewable store)
oceans lose more water through _______ than they gain from _______
evaporation
precipitation
whats the global water budget
the balance of water between the stores in the hydrological cycle
whats a drainage basin
an area of land drained by its rivers and tributaries (river system). It includes water found in a water table and surface run-off. There is an imaginary line separating drainage basins called a watershed, usually this is a ridge of land.
what are the factors affecting drainage basins ( inputs)
-the rain-shadow effect
-convectional rainfall
-frontal rainfall
-orographic (or relief) rainfall
what is the rain-shadow effect
the eastern side of the UK receives less rainfall than the west, because the western hills force moist air to rise as it approaches from the Atlantic- leading to orographic rainfall in the north and west.
what is convectional rainfall
this is typical of the eastern and south-eastern UK in summer. During periods of high temperatures, the rainfall created is often intense and associated with electrical storms and thunder.
what is frontal rainfall
this is where a cold airmass reaches a warm air mass. This brings most rainfall to the UK over a year. fronts are formed as part of a low pressure area (called a depression). When warm air meets polar air, the warmer air is forced to rise over the denser colder air- forming rain along both warm and cold fronts.
what is orographic (or relief) rainfall
the western side of the UK receives the highest rainfall totals. Warmer, moist Atlantic air ( from the couth west) is forced to rise as it reaches the western uplands. as it rises, it cools over the high ground - producing heavy rain over western and northern parts of the UK
what are the physical factors that affect drainage basins
-relief of the land. steep slopes= fast flowing surface runoff
-interception
-infiltration and throughflow
-direct runoff
-percolation and groundwater flow
-evaporation and transpiration
-large drainage basins collect more precipitation
-permeable soils and rocks allow for infiltration and percolation
what are the human factors that affect drainage basins
-over abstraction-> abstracting too much water from groundwater reserves leads to rivers drying up in times of low rainfall.
-deforestation-> the tropics are fragile, deforestation disrupts the drainage basin cycle by accelerating natural processes- with deforestation, surface runoff is increased***
-reservoirs-> interrupts the natural flow of water, dams reduce river flow leading to the loss of vegetation- reservoirs delay the flows through a drainage basin adding to amounts lost via evaporation.
changing land use-> urbanisation. To satisfy increasing water demands, new reservoirs are built or more water is abstracted. permeable vs impermeable surfaces.
do kenya case study
……
talk about parts of the natural water cycle
-evapotranspiration
-lots of infiltration
-high groundwater flow
-some runoff
-evaporation
-constantly flowing stream
talk about parts of the urban water cycle
-much less infiltration
-low groundwater flow
-roofs and roads stop infiltration
-more runoff (if raining)
-if there is no rain, streams dry up but if there is rain then streams may flood
do Amazonia case study
………
physical factors affecting drainage basins: what affects inputs
-orographic
-frontal
-convectional
physical factors affecting drainage basins: what affects flows
-interception:
where raindrops are prevented from falling directly on to the ground surface by a layer of vegetation. (go ovr)
-infiltration and through flow:
infiltration is the movement of water vertically downwards through pores in the soil. Once in the soil it can move laterally or vertically via throughflow- this is the downslope influence of gravity towards the stream or river.
-direct runoff (overland flow):
this is water flowing over the surface of the ground
there are 2 types: saturated overland flow and infiltration (excess overland flow). saturated overland flow is when water is already accumulated in the soil, this causes further rainwater to run off the surface. excess overland flow occurs when rainfall exceeds the infiltration capacity**
-percolation and groundwater flow:
this occurs lower down in the rock. Percolation occurs when infiltrating water reaches permeable underlying bedrock and it continues to move slowly downwards into the rock, the water will fill the pores in the permeable rock creating groundwater storage and an aquifer, this occurs when the permeable layer lies above an impermeable layer so water can percolate no further.
physical factors affecting drainage basins: what affects outputs
-evaporation and transpiration:
evapotranspiration is the total amount of moisture removed from a drainage basin by the process of evaporation and transpiration together, this is a significant output.
-channel flow:
the discharge of a river is the volume of water passing a gauging station
what is the water balance/ budget
its the balance between precipitation, evaporation and runoff. It’s a tool to assess the current status and trends in water resources over a specific period of time
whats water surplus
areas that have a positive water balance ( more inputs than outputs)
whats water deficit
areas that have a negative water balance (less inputs than outputs)
what do water balance graphs show
shows the balance between inputs and outputs
water balance graphs:
state what happens in…
-wet seasons
-drier seasons
-back to wet seasons
-wet seasons
precipitation exceeds evapotranspiration= water surplus
ground stores fill with water
-more surface runoff
-higher discharge= river levels rise
-drier seasons
evapotranspiration exceeds precipitation= ground store depletion
some flows into the river channel
this ground store depletion is not recharged by precipitation
plants rely on soil moisture
-back to wet seasons
ground stores start to get recharged
why does the river rescheme for the Colorado river have a rapid increase
- a rapid increase due to snowmelt
what are 6 factors affecting river reschemes
- the amount and type of vegetation cover
-the size of the river
-the geology and overlying soils (think permeability)
-the amount, pattern and intensity of precipitation
-the temps experienced ( greater evaporation when temp is higher)
-human activities such as dam building which can regulate flow
in tropical climates, there can be seen to have two peak discharges for the river regime , what does this indicate
two wet seasons are present
talk abt the Amazon river
its in a humid tropical climate
-its peak discharge is in April-may and lowest discharge in September which is linked to wet and dry seasons and snowmelt in the Andes.
-affected by wet and dry seasons-
talk abt the Yukon river
its in a tundra climate and flows through a mountain range. its peak discharge is may to June with a dramatic increase due to melting of snow and ice. its low from December to may due to low precipitation and frozen condition
-affected by snow and ice-
talk abt the River Nile
has been significantly changed by the construction of the Aswan Dam in 1970. the flow below the dam was reduced by 65% and became regulated between seasons so that the flood peaks in September were reduced
-has been affected by human interference-
whats the rising limb
the part of the storm hydrograph in which the discharge starts to rise
whats peak discharge
the time when the river reaches its highest flow
whats lag time
the time interval between peak rainfall and peak discharge
whats the falling/ recessional limb
the part of the storm hydrograph where the water in the river starts to decrease
whats the base flow
the normal day to day discharge of the river
whats the peak rainfall
the time when the rainfall reaches its highest
whats a storm hydrograph
a graph showing changes in the discharge of a river over a short period of time . it shows the rate of flow ( discharges versus the time past a specific point in a river)
bullet point the themes of a short lag time
-small basin
- impermeable rock
-urban
-saturated ground
-deforested area
-steep slopes
-increase in surface runoff
bullet point the themes of a long lag time
-permeable rock
- large basin
-forested area (would created interception, stem flow)
-sandy soil= allows infiltration
-high evaporation
