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Water Cycle (Water Flows (Evaporation (Factors (Temp. - energy is used to…

- - - - Permeability of soil
      - Precip intensity + duration
      - Baseflow - the sustained flow in streams from groundwater
      - Soil characteristics - clays absorb less water than loam soils
      - Soil saturation
      - Lnad cover
      - Slope
  - - - Dense layers are deep in the rock = water can't percolate further + flows in a horizontal dir. across the aquifer to an exposed body
      - Varying amounts of void spaces where groundwater accumulates
      - Can dissolve in water = large cavities that fill with water
      - Water moves more wuickly in porous rocks
    - - Rock type - vol. of pores
      - Permeability - granite is not; sandstone + chalk are
  - - - Temp. - energy is used to break the bonds that hold molecules together, allowing them to escape as a gas
      - Humidity
      - Air movement
      - Saturation - when air is saturated with other substances, there is not enough space for liquid to evaporate quickly
      - Air pressure - high air pressure on the surface of a body of water = evap. is difficult as pressure on molecules means they can't escape
  - - - The amount of water in air has increased
      - Air is cooled to its dew point
    - - Temperature
      - Humidity
      - Larger the contrast between hot + cold air, the greater the rate of condensation
  - - - Convective clouds formed in vertical motions due to instability of E's atmosphere
      - Atmosphere may become unstable due to heating
        
        Ground warms
        
        Moisture in ground evaporates
        
        The hot ground also heats the air around it
        
        = bubbles of rising air - updraughts
      - = Small areas of rain with celar spells between
    - - Produced form clouds formed by topography
      - High ground
        
        Moist air forced upwards
        
        Forms clouds + then precipitates
    - - When 2 air masses meeet
      - Warm + cold air have diff. densities
      - Less dense warm air is pushed up over the cold air = a front
      - Warm air cools + water vapour condenses = precip.
  - - - Wind + Temp. - more of either = more evap.
  - - - Rainfall intensity exceeds infil. rate
      - Occurs all over slope, simultaenously
    - - Overland flow bc of soil saturation
      - Level of sat. will increase higher up the slope, and infil. rate will decrease correspondingly
      - Water table rises bc of percolation + throughflow
      - Rainfall intensity does not have to exceed infil. rate
  - - - Nature of oil - amount of impermeable components
      - Soil type - clay/loam
      - Saturation
      - Precip. - intensity + duration
      - Base flow
      - Land cover
      - Slope
  - - - Location of plants
      - Pollution - acid pollutant - pH
  - - - Shape of leaf
      - Type of plant
      - Size of lead
  - - - Shape of leaf
      - Presnse of waxy cuticle
      - Surface - hairy leaves retain more water
  - - - Nature of veg.
      - Density
    - - When intercepted water evaporates
      - Factors
        
        Length of insolation period
        
        Temp.
        
        Humidity
        
        Air movement
  - - - Precipitation
      - Evaporation
      - Transpiration
      - Run-off
      - Infiltration
      - Percolation
      - Throughflow
    - - Water and ice that falls from clouds towards ground
      - Forms
        
        Rain, snow, hail, sleet, drizzle
      - Formation
        
        Water vapour cools to its dew point and condenses into tiny water droplets/ice particles = clouds
        
        Droplets/ice particles aggregate, reach a critical size + leave cloud as precipitation
      - Varies in terms of character - imp. on drainage basin scale
        
        High latitudes + mountainous catchments = precipitation falls as snow - remains on ground for months = considerable lag time between snowfall + runoff
        
        High intensity precip (10-15 mm/hour) moves rapidly overland into streams + rivers
        
        Duration - Prolonged events (depressions + frontal systems) = large amount of rainfall = river flooding
        
        Rainy seasons = high river discharge + flooding; dry seasons = rivers dry up
      - Cloud Formation
        
        Form when water vapour cools to its dew point
        
        Dew point = critical temp. when air becomes saturated (100% relative humidity)
        
        = condensation, as excess water changes state = liquid water droplets
        
        Aggregated, these droplets = clouds
        
        Rain develops thru droplets coalescing or ice crystals growing within clouds
    - - Diffusion of water vapour to atmosphere from stomata
      - = 10% of moisture in atmosphere
      - Factors
        
        Temperature
        
        Wind speed
        
        Water availability
        
        Deciduous trees shed leaves in dry/cold seasons to reduce moisture loos via transp.
    - - Change of vapour to liquid water
      - Occurs when air is cooled to its dew point = air saturation with vapour = condensation
      - Cumuliform clouds
        
        Flat bases + considerable vertical development
        
        Formation
        
        Air is heated locally thru contact with E's surface
        
        = heated air particles rise thru atmosphere - convection
        
        Particles expand due to fall in pressure with altitude + cool
        
        Cooling reaches dew point = condensation = clouds
      - Stratiform/layer clouds
        
        Advection
        
        When an air mass moves horizontally across a cooler surface (e.g. ocean)
        
        Turbulence + mixing
      - Cirrus clouds
        
        Form at high altitude
        
        Consist of tiny ice crystals
        
        Do not produce precip. = little influence on water cycle
      - Condensation at/near ground = dew + fog
        
        Deposit large amounts of moisture on veg. + other surfaces
    - - Clouds = visible aggregates of ice and/or water
      - Form when water is cooled to its dew point
      - Cooling occurs when:
        
        Air warmed by contact with E rises = pressure falls = cooling via expansion - adiabatic expansion
        
        Air masses move horizontally across a relatively cooler surface - advection
        
        Air masses rise as they cross a mountain barrier or turbulence forces their ascent
        
        A relatively warm air mass mixes with a cooler one
      - Lapse Rates
        
        Vertical distribution of temperature in lower atmosphere
        
        Temperature changes within an air parcel as it rises vertically away from the ground
        
        ELR
        
        Environmental lapse rate
        
        Vertical temp. profile of lower atmosphere
        
        Temp. falls by 6.5 degrees for ever km of height gained
        
        DALR
        
        Dry adiabatic lapse rate
        
        Rate at which a parcel of dry air (under 100% humidity = no condensation) cools
        
        Rate of cooling is 10 degrees/km
        
        SALR
        
        Saturated adiabatic lapse rate
        
        Rate at which a saturated parcel of air cools as it rises thru the atmosphere
        
        Condensation releases latent heat, cooling is lower - 7 degrees/km
- - - - Permeability of soil
        
        Determined by nature + arrangement of soil peds
        
        Decomposed leaf litter = organic matter = improved structure + permeability = more efficient infiltration
      - Loam/clay
  - - - Rock type - vol. of pores
      - Granite is not permeable
      - Pumice, sandstone + chalk are permeable
  - - - Wind - more wind = more evap.
      - Temperature - higher temp. = more evap.
      - Veg. type - transp. loss is greater from trees than crops
        
        Humid air adjacent to the leaves is more rapidly removed by air currents = steeper diffusion gradient between stomata + atmosphere
  - - - Nature of soil - amount of impermeable components
      - Type - clay/oam
      - Saturation
  - - - Leaves + branches could be covered in acid pollutants = pH decreases between interception + when it reaches the ground
      - Location - urban areas are more polluted
      - Type of plant - is greatest on trees with smooth bark + steeply-angled branches
  - - - Shape of leaves
      - Type of plant e.g. no. of branches
      - Size of leaves
  - - - Shape of lead
      - Presence/absence of waxy cuticle
      - Surface - hairy leaves retain more water
  - - - Nature of veg. - woodland intercepts more than grassland
      - Density
    - - When intercepted water evaporates
      - Factors
        
        Temperature
        
        Humidity
        
        Length of insolation period
        
        Air movement
  - - - Rainfall intensity
      - Rainfall duration
- - - - In porous + permeable rocks - they store water as they have large pore spaces
- - - - Oceans, Surfaces, Atmosphere
    - - Saline - oceans, lakes + many seas
      - Meteoric - evaporation + condensation of water + accumulates on the surface in rivers + freshwater lakes
      - Other
        
        Small amounts are erupted from magmas that contain water - hydours magma melts
        
        Trapped in seds. e.g. at SDZ where wet seds. are buried as one plate is subducted
    - - Inputs - precipitation over oceans + land
      - Outputs - evaporation + transpiration
      - Throughputs - runoff, infiltration, percolation, groundwater flow
  - - - Rivers, Lakes, Ice caps, Oceans
    - - Evaporation - amount of water, temperature
      - Condensation - contrast in temps
      - Precipitation - sunlight + heat - hotter the air, the more water than can be stored
  - - - Direct
        
        Overuse of groundwater supplied for urban areas
        
        Building dams
      - Indirect
        
        Global warming - changes in evap. + precipitation patters
        
        Deforestation
        
        Reduction in transp. rates = fewer clouds + less precip.
        
        Changes in runoff, infiltration + percolation rates
    - - Drought
      - Water movement
      - Changing climate
      - Overuse of groundwater - finite resource
- - - - Compares drainage basins + how they respond to rainfall events
      - Work out speed + scale of rise in discharge - assess the rate of flooding in drainage basin
      - Monitors changes in management of a catchment
    - - Flashy
      - Non-flashy
  - - - Max. discharge recorded after a rainfall event
    - - When the discharge begins to rise due to overland flow
      - Almost always steeper than recession limb
        
        Bc the increase in discharge is due to quickflow processes e.g. runoff + overland flow
    - - Occurs as the inputs to channel decrease
      - Slowflow processes e.g. throughflow + groundwater flow, dominate at this stage of the hydrograph
    - - Level that the stream maintains in dry spells, due to groundwater flow
    - - Time between the rainfall max. + discharge peak
    - - Max. rainfall value
    - - Area under the graph above the base flow level
      - Comprises throughflow in cracks + pipes in the soil, channel precip. + overland flow if the soil is saturated
  - - - Steep slopes = shorter lag times + high peak discharge
      - No necessarily high velocity
    - - High relief = shallow soil = fast transmission + high overland flows
    - - Rock structure
      - Folding + faulting + tilting
      - Affects surface stream network + therefore transmission of water
      - Impermeable rocks have more surface stream
    - - Duration + intensity
      - Type - snow may be stored in high relief areas of river basin
    - - Dampen the storm hydrograph
        
        Water entering the lakes loses velocity + lakes absorb water vol.
    - - Fertiliseres + equipment alter soil texture + infil. ability
      - Water may move differently thru the soil horizons
    - - Accelerates erosion + runoff
      - Increases flood freq.
    - - Slows runoff + controls erosion
      - Evens out stream discharge + flattens the hydrograph
    - - Usually highest on impermeable rocks
      - Short lag times
    - - Shortens lag times
    - - Draining impermeable soils reduces peak of the hydrograph
    - - Affected by abstraction + pumping
  - - - Cross-sectional Area = Width * Mean Depth
  - - - Topography
      - Base flow (amount of water stored underground)
        
        High base flow = slow response
        
        Low base flow = fast response
      - Saturation
      - Size of drainage basin
        
        Small basin = water reaches gauging station quickly
        
        Most basins are large
- - - - Energy is absorbed as latent heat + released in condensation
  - - - Interception storage capacity
        
        Before rainfall, veg. surfaces are dry = ability to retain water is at its max.
        
        Most rainfall is initially intercepted
        
        As veg. becomes saturated, stemflow + thrufall increases
        
        = interception depends on duration + intensity of event
      - Wind speed
        
        Increased w/s = increased evap.
        
        Increased w/s = increased turbulence = additional thrufall
      - Veg. type
        
        Grasses = greater interception loss than crops
        
        Trees have greater interception loss than grasses
        
        Surface area + aerodynamic roughness
      - Tree species
        
        Interception losses are greater from evergreen conifers than deciduous trees
        
        Conifers
        
        Leaves year-round
        
        Water adheres to spaces between needs = increased evap.
  - - - Infiltration into soil + lateral movement of throughflow to stream + river channels
        
        Rainfall, regardless of intensity always inffiltrates the soil
      - Overland flow across ground surface either as a sheet or trickles to stream + river channels
        
        Soil's infiltration capacity
        
        Occurs when soil is saturated and water table rises to surface - saturated overland flow
  - - - Melting
      - Evaporation
      - Sublimiation
- - - - Is bc of the rapid flux of water in + out of it
      - The average residence time of a water molecule in the atmosphere is 9 days
  - - - = water vapour evaporated fro oceans, soils, lakes + rivers
      - Vapour transpired form plant leaves
      - Together these processes are known as evapotransp.
    - - Most rivers flow to the ocean; some drain into basins
    - - This groundwater eventually reaches the surface as springs/seepages + contributes to runoff
- - - - 85% of C's pop. rely on groundwater
      - Its water storage capacity is 10% that of all our surface reservoirs
      - 30% of its water supply is from GW
      - During drought (2013-now) GW usage has doubled
      - Land owners can take GW as they want as there are now regulations so long as they own the land
        
        Removing GW is a simple process also
      - Central Valley
        
        Has powerful electric pumps + is taking twice the amount of GW that nature is returning
        
        Since 1980 its pop has doubled to 3.8 million
        
        Pop. expected to increase to 6 million by 2020
    - - Over 70% of E is groundwater
      - 1% is available for human use, from rivers + lakes
      - Largest use is irrigation
      - Aquifers
        
        Made of gravel, sandstone + fractured rock e.g. limestone
        
        Permeable as they have large interconnected spaces
        
        Rate of flow of GW depends on size of spaces + how well they're connected
      - Groundwater tables may increase/decrease
        
        Heavy rain = increase; heavy pumping = decrease
      - Supplies are recharged by rain + snow melt
      - Water is aquifers is brought to surface naturally via a spring/discharged in lakes
      - Polluted by
        
        Landfils
        
        Septic tanks
        
        Leaky underground gast anks
        
        Fertiliser over use
  - - - Overpumping harms nearby waterfalls, fish + wildlife, plants + trees
      - Overdraft forces people to deepen their wells - $500,000
      - Excessive pumping
      - Use of surface water is strictly managed but GW is less so
      - Until recently, farmers had been free to pump as long as they had land ownership rights
      - = land subsidence
    - - Need year-round water supply
      - Take a generation before fruiting
    - - nad subsidence
      - Infrastructure damange
      - Dried nearby rivesr + stream
        
        Reduces their flow + harms sea life
      - Basins close to the coast are being replensihed by sea water
      - Deeper wells = greater their contamination from chemical fertilisers, manure + ind. waste
        
        Many rural settlements use GW for drinking
        
        Expensive to treat it to remove the contaminants
        
        May become necessary to bring in daily supplies of bottled water - expensive
  - - - GW users must find ways to manage their aquifers, so extraction does not exceed replenishment
      - Local agencies will have authority to monitor the amount of GW withdrawn and to charge users pumping fees
    - - Based on the assumption that additional reservoirs were needed to capture more runoff from El Nino storms
      - 5 surface reservoirs - $9 billion
      - Additional storage capacity - but only 1% of annual farm + city use
      - Problems
        
        California has all the water storage capacity it needs - in underground basins
        
        The reservoirs should instead be surfaced, to recharge aquifers during the wet winter months, as well as water farms + cities - conjunctive use
        
        Conjunctive use - runoff captured + stored underground for use in dry periods + creates space in reservoirs for more stormwater + snowmelt
    - - Resurrecting flood meadows
      - Moving earthern leveees back from the river bank
      - Some experiment with permeable pavements + rain gardens to capture storm water
    - - SD plans in order to manage GW basins thruout California
      - Gov. have the control to step in where necessary
    - - Need to meet demands of households + agriculture ind.
      - Cost of recharge is cheaper than other supply options + surface storage
      - Natural recharge - rain + streamflow sock thru the ground into the aquifer
      - Recharge ponds - most common artifical method
        
        Constructed ass surface basins that let water infiltrate the aquifer
    - - A plant underway in San Diego
        
        Serve 3.1 million locals
        
        Cost $1 billion
        
        Portable water produced there will cost $7/100 gallons - twice the cost of typical treated runoff
    - - C discharges lots of water into ocean or inland waterways
        
        Could instead be recycled for residential + commercial use
      - Purified waste water could yield over 1 billion gallons/day of portable water
        
        Would meet demands of over 8 million people
      - Cost $5/1,000 gallons