Please enable JavaScript.

Coggle requires JavaScript to display documents.

WATER CYCLE (Water Flows (Issues of Changing Flows (Decreased snow cover…

- - - - Permeability
      - Precip. intensity + duration
      - Base flow
      - Soil characteristics (clays absorb less water at slower rate)
      - Soil saturation
      - Land cover - vegetation slows runoff (more infil. time), impervious surfaces = fast lanes into storm drains + streams
      - Slope (steep = less infil. time)
      - Evapotranspiration-
  - - - Rock density
        
        Denser layers (granite, clay) found deeper in bedrock
        
        So water instead flows horizontally across aquifer to an exposed body
      - No. of void spaces where groundwater accumulates
      - Bedrock may dissolve in water = large cavities that fill with water
      - Porosity - rate of flow
      - Permeability
        
        Granite NO
        
        Pumice, sandstone chalk YES
  - - - Temperature
        
        Energy breaks the bonds that hold the molecules together = gas
      - Humidity
      - Air movement
      - Length of insolation period
      - Saturation
        
        Air saturated with other substances = insufficient space for liquid to evaporate quickly
      - Air pressure
        
        High air pressure on surface of a body = difficult for evaporation as pressure on molecules means they can't escape
  - - - These collide with aerosols and stick together when air is cooled
        
        Large water droplets will form around aerosol particles that stick together = clouds
    - - Amount of water in air has increased
      - Air is cooled to its dew point
    - - Temperature
      - Humidity
      - Contrast in hot + cold air
        
        Greater contrast = greater rate of condensation
    - - High level
        
        Cirrus
        
        Cirrosumulus
        
        Cirrostratus
      - Mid level
        
        Altocumulus
        
        Altostratus
      - Low level
        
        Stratocumulus
        
        Cumulonimbus
        
        Stratus
      - Cumulus clouds form when sun heats ground, heating air around it + causing it to rise in columns
      - Layered clouds form via topography - air cools as it rises over mts/hills
  - - - Wind
      - Temperature- warmer =more evap.
  - - - Common in warmer conditions
      - Produced from convection cloud formed in vertical motions due to instability of atmosphere, which is caused by heating
        
        ground warms
        
        Moisture in ground evaporates
        
        Hot ground also heats air around it
        
        Causes bubbles of rising air
      - = small areas of rain with clear spells between
    - - Clouds form from topography
      - High ground:
        
        Moist air forced upwards = clouds + precip.
      - Common in NW UK
        
        Warm moist air from Atlantic cools as it's forced upwards over high altitudes
    - - Occurs when 2 air masses meet
      - warm and cold air have different densities
      - less dense warn air is pushed up over cold air = front
      - warm air cools and water vapour condenses = precipitation
  - - - Saturated
      - Froxen
      - Precip. is too intense for infiltration
    - - Rainfall intensity exceeds infil. rate
      - Can occur immediately
      - Common in deserts/urban areas - impervious surface due to:
        
        Lack of vegetation
        
        Compaction
        
        Urbanisation
    - - Due to saturation of soil
      - Rainstorms = increasing level of sat. higher up slope and decreasing infil. rate
      - Process takes time
      - Water table rising bc of percolation and thruflow
      - Rainfall intensity does not need to exceed infil. rates
      - Works well in vegetated areas e.g. tropics
  - - - Nature of soil - amount of impermeable components
      - Type of soil e.g. clay/loam
      - Saturation
      - Precipitation - intensity, duration
      - Base flow
      - Land cover
      - Slope
      - Evapotransp. -some infil. remains near plant surfaces where they put down their roots
  - - - Leaves and branches of trees may be covered in acid pollutants
        
        pH of rainfall may decrease between interception and groundfall
      - Location of plants - more pollution in urban areas
  - - - Leaf shape
      - Plant type, no. of branches/leves
      - Leaf size
  - - - Leaf shape
      - Presence/absence of waxy cuticle
      - Surface of leaf - hairy leaves retain more water
  - - - Density
      - Nature of vegetation - woodland intercepts more than grassland
  - - - Temperature
      - Humidity
      - Length of insolation period
      - Wind
  - - - 80% of water created in tropical rainforests created by trees
    - - s.l. rise
      - river erosion
- - - - Water stays for different lengths of time in different reservoirs
  - - - Largest ocean
      - Covers 1/3 surface
      - Deepest water body
    - - Circulation patterns and runoff from land = conds. for demersal species e.g. Pacific hake
    - - Has largest array of algae and animal species
      - Deepwater mineral deposits from
        
        Sea water
        
        Alluvial deposits
        
        Continental shelf
      - Fisheries
        
        Biological richness
        
        Large pop. on its border e.g. Japan
        
        Over-fishing e.g. herring
        
        Tuna is popular for SIS
    - - Inc. pop. = pressure on resources
      - Economic + ind. development of coastal regions = overfishing + affected habitats
      - Minerals extracted from sea water itself
  - - - 2nd longest river
      - 1/6 of fresh water that goes into ocean passes thru it
    - - Environmental
        
        Affected by seasonal change
        
        Width inc./dec. by 4-5km
      - Human
        
        Waterways used by means of construction to inner Brazil
        
        Roads, airstrips built in basin
    - - Provides range of habitats for different types of wildlife
        
        Swamps
        
        Marshes
        
        Streams
      - Subject to major annual flood cycles
        
        Affect ecology + landscape
      - Acts as drainage system for Amazon basin - imp. for basin ecology
  - - - Oldest lake (25m years)
      - Deepest lake (17k m)
      - Contains 20% of unfrozen freshwater supply
      - 300 rivers flow in; 1 flows out
    - - Over 2000 species (2/3 indigenous)
      - UNESCO World Heritage Site
    - - Industrial pollution
      - Fertiliser runoff
      - Mining
      - Potential oil + gas exploration
      - Poaching
      - Poaching + pollution dec. nos. of Baikal seal - one of only freshwater sea species
  - - - Normally found in porous + permeable rocks
        
        Have large pore spaces for water storage e.g. chalk + sandstone
      - Unevenly distributed
- - - - Drainage basin of River Cam
      - Greenland ice sheet
      - Antarctica
    - - Is a series of flows between stores
      - All storage is temporary
      - Water vapour condenses into liquid in clouds- becomes precipitation
      - Surface runoff moves over land
      - Infiltration and percolation move water into the coil and bedrock respectively
      - Transpiration (evaporation of water from plant surfaces) - moves soil water back into atmosphere
  - - - Hotter the air = more water that can be stored
  - - - Oceans, many lakes and seas
    - - Fresh water from evaporation and condensation of saline water
      - Accumulates on surface in rivers and freshwater lakes
      - Small amounts of water are erupted from magmas that contain water (HYDROUS MAGMA MELTS)
      - Water trapped in sediments
        
        At SDZ wet sediments are buried as one plate is subducted
  - - - Precip. over oceans
      - Precip. over land
    - - Evaporation
      - Transpiration
    - - Runoff
      - Infiltration
      - Percolation
      - Groundwater Flow
  - - - Northern hemis. covered in single ice sheet 12,000 m/a
        
        Iceland provides evidence for this
      - Ice expanding
        
        Drought in ME for centuries
        
        Response to lack of water was farming = first civilisation
        
        People needed a reliable water source for farming - rivers
- - - - overland flow = discharge rises
      - Always steeper than recession limb
      - Inc. in discharge is coz of quickflow processes
    - - Occurs as inputs to channel decrease
      - Slowflow processes e.g. thuflow
    - - Level maintained in dry periods due to groundwater flow
    - - time between rainfall max. + discharge peak
    - - Area under graph above base flow level
        
        Increase in discharge due to surface runoff + thruflow
  - - - steep slope = shorter lag time
    - - HIgh relief = shallow soil = fast transmission + high overland flow
    - - Affects surface stream network + water transmission
    - - Dampen the storm hydrograph - alke absorbs less water
    - - fertilisers + eqip. alter soil texture and infil. ability
    - - Accelerates runoff + erosion
      - Increases flood frequency
    - - Slows runoff + controls erosion
      - Evens out stream discharge + flattens hydrogrpah
    - - highest on impermeable rocks
      - Short lag times
    - - Short lag times
    - - Draining impermeable soils reduces the peak of the storm hydrograph
    - - Affected by abstraction + pumping
    - - causes higher channel velocity
      - reduces overbank storage
      - increases risk of flooding
  - - - Topography
      - Base flow
      - Saturation
      - Size of drainage basin
- - - - Overuse of groundwater supplies for urban areas
      - Building huge dams e.g. Three Gorges Dam in China
    - - Global Warming
        
        Changes in evaporation and precipitation
      - Deforestation
        
        Reduction in transpiration rates = fewer clouds and less rainfall
        
        Changes in runoff, infiltration and percolation rates
  - - - Desalinisation plants are an expensive but sustainable alternative
  - - - 85% of pop rely mostly on GW
      - Agriculture
      - Found in tiny pore spaces between sand + gravel
      - C's water storage capacity is 10% that of all our surface reservoirs
      - 30% of C's annual water supply is GW - and is used with surface water
      - usage doubled during drought (2013-now)
      - Land owner's can now take GW as they please
      - Removing GW is a simple process
      - Natural recharge used to balance the water that was pumped out
      - Areas w powerful electric pumps (Central Valley) take double the amount of GW that nature returns
      - Global/General
        
        Over 70% of earth is gorundwater
        
        1% is available for human use, from rivers + lakes
        
        99% is stored in GW
        
        Largest GW is to irrigate crops
        
        Aquifers
        
        Made of gravel, sandstone + fractured rock
        
        Have large connected spaces = permeable
        
        Rate that GF flows depends on size of spaces + how well they're connected
        
        GW tables can increase/decrease; rains = inc.; pumping = dec.
        
        Supplies area recharged by rain + snow melt
        
        Water in aquifers is brought to surface anturally via a spring/discharged in lakes + streams
        
        GW is extracted when a well is drilled into aquifer
        
        Can be polluted by:
        
        Landfills
        
        Septic tanks
        
        Leaky underground gas tanks
        
        Fertiliser overuse
    - - Pop has *2 to 3.8m since 80s
      - Pop expected to inc. to 6m by 2020
      - Greatest growth in state for water resources competition
    - - Drought for last few years coz of:
        
        Reduced precip.
        
        Increase in demand from urbanisation
        
        Increase in demand from agriculture - esp. almond trees that need year-round irrigation
        
        Rainfall is not captured and runsoff into Pacific
        
        Surface stores were 2/3 empty by 2015
        
        Little snow coverage in Sierra Nevada mts. - would normally feed rivers + streams
      - Prolonged drought = pumping of aquifers + sudden drop in GW levels
      - Primary concern is to channel torrents of water off hillsides to prevent mudslides
      - So there is little focus on capturing coastal runoff, but there are also problems of capturing coastal runoff
    - - Preparation
        
        Cliffs + sea walls reinforced
        
        Beaches bulldozed into defensive berms
        
        Drainage gullies cleared of rocks
        
        Concrete rails installed to channel flash floods on hillsides
        
        Water authorities have made an effort to capture Nino's precip. as protection against likliehood of continued drought
      - Causes
        
        Occur periodically across Pacific due to surface temperature changes
        
        Large body of warm water
        
        Disrupts the jet stream
        
        Affects weather patterns globally - allowing storms to travel as far N as California
      - Effects
        
        Unlikely to save C's drought entirely
        
        Raised pool levels in LA by 3 inches
        
        Main concern in C is to channel water off hillsides to prevent landslides - but should also be concerned with:
        
        Capturing coastal runoff from thunderstorms
        
        Curtailing mudslides + flooding
        
        But there are issues w the above:
        
        Cost
        
        Disruption of nimbyism
        
        Layering underground pipelines thru residential neighbourhoods
        
        Chanelling downpour to municipal water-treatment plants
    - - El Nino unlikely to save C's drought entirely
      - Extreme conds. of recent years likely to worsen w climate change
      - Droughts likely to become recurring feature
      - Growing awareness that depth + water content of Sierra Nevada mts. do not alone define the severity of drought nor likelihood of recovery
      - Snowpack feeds the rivers + reservoirs when it melts
      - Snowpack provides 1/3 of water consumed
      - Is deeper than it has been in psat 5 years coz of El Nino
      - 1400 surface reservoirs
      - Farmers use *4 the water than all urban consumers
      - By 2015 lakes + reservoirs were 2/3 empty
      - 51 groundwater basins
      - GW basins hold *3 the amount of usable water as all the surface storage combined
      - Normally aquifers supply 40% of state's water consumption - mostly for irrgation
      - With drought, GW provides 60% of farmers' needs
      - Farming
        
        Prev. farmers could let fields stand fallow when water was in short supply
        
        Crops are now orchards and vineyards - makes the farming trend permanent = no fallowing
        
        Almond trees are one of C's most profitable crops - needs year-round water supply
        
        Agricultural 'overdrafting' is a direct consequence
        
        Overdrafting is excessive pumping
        
        Surface water use is strictly managed; GW use is mroe lenient
        
        Prev. farmesr had been allowed to pump what they wanted so long as they had land ownership rights
        
        Effects
        
        Sucking aquifers dry =
        
        Land subsidence
        
        infrastructure damage
        
        Sucks water from nearby rivers + streams = reduces flow
        
        Basins close to coast are being replenished by sea water - salinity affects crops
        
        Deeper wells - greater their contamination from chemical fertilisers, manure + ind. waste
        
        Many rural settlements use GW for drinking
        
        Expensive to treat it to remove contamiannts
        
        May become necessary to bring daily supplies of bottled water - v. expensive
    - - Permeable pavements + rain gardens to capture storm water
      - Resurrectin flood meadows
      - Moving earthern leveees back from the river bank
      - The above capture runoff that would have escaped into the sea and store it in aquifers
      - Long Term
        
        Need to meet demands of households and agricultural industry
        
        Recharge is cheaper than otherr water supply options and surface storage
        
        Natural recharge - rain + streamflow infiltrate into aquifer
        
        Recharge ponds - most common artificial method
        
        Constructed as surface basins that let water infiltrate the aquifer
        
        Other options:
        
        Recycled water
        
        Treated water
        
        Storm water
        
        Agricultural runoff
        
        GW Management Act 2014
        
        GW users must manage the aquifers they use - extraction does not exceed replenishment
        
        Local agencies can monitor amount of GW withdrawn and charge pumping fees
        
        Reservoirs
        
        $2.7 billion bond approved - based on need to additional reservoirs to capture more runoff from winter storms
        
        5 surface reservoirs proposed = $9 bn
        
        Problems:
        
        C has all the water storage in needs (in underground basins)
        
        Reservoirs should instead by surfaced, to recharge aquifers + water farms + cities CONJUNCTIVE USE
        
        Conjunctive uses = additional runoff is captured and stored underground for use in dry periods, whilst creating space in reservoirs for more stormwater and snowmelt
        
        Desalinisation
        
        A plant is underway in San Diego
        
        $1 bn
        
        Serve 3.1m locals
        
        Recycling
        
        C discharges lots of water into ocean - could be recycled for residential + commercial use
        
        Purified waste water - could meet needs of over 8m Californians
        
        Cost $5/1,000 gallons