Victoria Slide Revision for Office Mix

AS Geography Fluvial Geomorphology

Geography
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Victoria Slide Revision for Office Mix

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AS Geography Fluvial Geomorphology
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  1. HYDROLOGY & FLUVIAL

    Slide 1 - HYDROLOGY & FLUVIAL

    • GEOLOGHY
  2. Global System Of Water Exchange

    Slide 2 - Global System Of Water Exchange

  3. Name A Input

    Slide 3 - Name A Input

    • Precipitation
    • Water in all its states i.e. rain, snow, hail, sleet.
  4. Name The Flows

    Slide 4 - Name The Flows

    • Interception
    • Through fall
    • Stem flow
    • Infiltration
    • Overland flow
    • Percolation
    • Through flow
  5.  Name  A Store

    Slide 6 - Name A Store

    • Water Tables
    • Recharge
    • Ground Water
  6. Name The Outputs

    Slide 7 - Name The Outputs

    • Evaporation
    • Transpiration
  7. Slide 8

    • Area of earths surface drain a river and its tributaries.
    • Important unit of study due to the fact that everybody lives in one.
    • DRAINAGE BASINS
  8. Water Cycle

    Slide 9 - Water Cycle

    • (hydro cycle)
    • Closed nothing new enters it.
    • The water we have is all we have got.
    • Only way to get more is for meteor to pass through our atmosphere.
    • Only 0.7% of the earths water is readily available to us.
    • Increase in population and pollution puts pressure on the water cycle.
  9.    WHY IS IT A CLOSED SYSTEM

    Slide 10 - WHY IS IT A CLOSED SYSTEM

  10. WHAT ARE THE 4 MAIN PROCESSES

    Slide 11 - WHAT ARE THE 4 MAIN PROCESSES

  11.  PRECIPITATION

    Slide 12 - PRECIPITATION

    • Where and how much
    • (location and magnitude)
    • Highest inputs are at the equatorial region
    • Lowest inputs are at the poles due to cold air and its limit to hold water.
    • Also low in sub-tropic areas where dry air creates deserts
    • When and how often
    • (seasonality and frequency)
    • When it is reflected in a rivers regime. In other words, a rivers flow level throughout the year ( different seasons)
    • In some dry environments there maybe no seasonality at all apart from the occasional and irregular storm/ flash flooding
  12. How heavy

    Slide 13 - How heavy

    • (intensity)
    • Rainfall is measure in mm/hr
    • Steady drizzle= 0.5mm/hr moderate =3mm/hr
    • Tropical storm=1mm/1minute!!!
    • What type
    • (form)
    • Water can enter drainage basin as snow, rain, sleet and hail. Water stored as a solid will have a delayed delivery to channel flow. Melting impacts risk of seasonal flooding
  13. Interception

    Slide 14 - Interception

    • Amount of precipitation interrupted by vegetation as it falls
    • Rate of interception is called “interception loss”
    • leaf structure contributes to interception
    • (refer to pg 14)
    • interception
  14. Duration of rain fall: more is intercepted at the start of a shower due to dry leaves.

    Slide 15 - Duration of rain fall: more is intercepted at the start of a shower due to dry leaves.

    • Type of precipitation: most snow falls straight through to the ground not much is intercepted
    • Type of vegetation: spruce needled
    • Water clings to needle
    • Open spaces
    • Evaporate
    • Beech leaves
    • -Allow water to merge over large area
    • -less evaporation
    • -Less air circulation
    • Vegetation structure: forest has layers (canopy, shrub, ground) act as 2nd interception. Allows water to slowly make its way down.
  15. THROUGH FALL

    Slide 16 - THROUGH FALL

    • Contents
    • Stem flow
    • Evaporation
    • Transpiration
    • Factors affecting evapotranspiration
    • - temperature
    • - humidity
    • - wind
    • - albedo
    • - soil texture
    • Some water falls through spaces in the vegetation directly to the ground or drips off the leaves and twigs to the ground .
    • Most snow reaches the ground as through flow
  16. STEM FLOW

    Slide 17 - STEM FLOW

    • Water which trickles along twigs, branches and down the tree trunk to the ground.
  17. Evaporation

    Slide 18 - Evaporation

    • Some precipitation does not find its way to the river
    • Instead it leaves the system as evaporation, returned to the global hydro cycle.
    • Evaporation occurs from:
    • -vegetation surfaces
    • -bare soil
    • -artificial surfaces eg. Roads
    • -water surfaces such as lakes and rivers.
  18. Transpiration

    Slide 19 - Transpiration

    • Process in which water is drawn through living plants and evaporated through the stoma.
    • Does not continue through drainage basin as it is taken up by plants
    • For transpiration to occur soil must be moist
    • Vegetation+evaporation+transpiration= evapotranspiration
  19. Factors that effect Evapotranspiration

    Slide 20 - Factors that effect Evapotranspiration

    • Temperature=varies over earths surface. High temps allow more evapotrans. Temp varies over year and day
    • Humidity= humidities above 705 cant absorb much water so little evapotrans occurs.
    • Wind= evaporation is greater in windy turbulent conditions
    • Albedo= dark surfaces such as soil absorb heat for evapotrans
    • Evaporation from porous soils is greater than that of silt or clay
  20. Infiltration

    Slide 21 - Infiltration

    • Process in which water enters the surface
    • Can be measured and called
    • infiltration rate (mm/hr)
    • Infiltration Capacity
    • Amount of water particular soil can absorb
    • Key process as percolation does not infiltrate it will run off quickly into streams and rivers as “overland flow”
    • The speed at which a store will fill up depends on the intensity of the rain.
  21. Through flow

    Slide 22 - Through flow

    • Water that does not infiltrate swings downslope due to the effect of gravity.
    • The rate of infiltration decreases with depth. Due to soils becoming more compact with less spaces and cracks.
    • Downslope movement via percolines= through flow
    • Slow process approx. 1mm/ 1minute
  22. SOIL PORES AND PERCOLINES

    Slide 23 - SOIL PORES AND PERCOLINES

    • Soil in which water passes around due to whether it is permeable or not
    • An underground network of water seepage zones. Old root channels and soil cracks. Percolines are important in the development of through flow.
  23. OVERLAND FLOW

    Slide 24 - OVERLAND FLOW

    • Two types Hortonian and saturated
    • Hortonian: water that does not infiltrate, collects on ground in hollows as surface storage. When hollows fill up water will overflow and trickle off into riverlets as sheets of overland flow.
    • In hard banked and urban environments this process is called Hortonian flow
  24. SATURATED OVERLAND FLOW

    Slide 25 - SATURATED OVERLAND FLOW

    • Soils at foot of slope become saturated as water arrives by through flow.
    • As soil stores fill up further infiltration is prevented=SATURATED OVERLAND FLOW
    • This flow delivers water quickly to streams and channels
    • ANTECEDENT MOISTURE
    • -already been high rainfall
    • -soils stores full
    • -no more water can be stored
    • -overland flow happens more quickly as rain arrives
  25. Percolation

    Slide 26 - Percolation

    • Some water will continue to move vertically downwards through soil horizons under the influence of gravity towards water table by percolation
  26. Surface storage

    Slide 27 - Surface storage

    • The part of precipitation retained temporarily at the ground surface as interception or depression storage so that it does not appear as infiltration or surface runoff either during the rainfall period or shortly thereafter. Also known as initial detention; surface retention
  27. Ground water Storage

    Slide 28 - Ground water Storage

    • The water table is a level of water capable of moving up and down depending on how much water there is in soils storage.
    • The Vadose Zone above the water table is unsaturated meaning there is room for more water unlike the phreatic zone below water table which is saturated meaning there is no more room for more water
    • Water stored below ground
  28. Water table

    Slide 29 - Water table

    • also called Groundwater Table, upper level of an underground surface in which the soil or rocks are permanently saturated with water. The water table separates the groundwater zone
  29. CAPILLERY FRINGE

    Slide 30 - CAPILLERY FRINGE

    • The capillary fringe is the subsurface layer in which groundwater seeps up from a water table by capillary action to fill pores.
    • Pores at the base of the capillary fringe are filled with water due to tension saturation.
  30. VADOSE ZONE

    Slide 31 - VADOSE ZONE

    • The Vadose zone, also termed the unsaturated zone
    • Is the portion of Earth between the land surface and the top of the phreatic zone i.e. the position at which the groundwater (the water in the soil's pores) is at atmospheric pressure.
  31. PHREATIC ZONE

    Slide 32 - PHREATIC ZONE

    • The phreatic zone, or zone of saturation, is the area in an aquifer, below the water table, in which relatively all pores and fractures are saturated with water. The phreatic zone may fluctuate with changes of season and during wet and dry periods
  32. AQUIFERS

    Slide 33 - AQUIFERS

    • An aquifer is a wet underground layer of water-bearing permeable rock or gravel, sand, or silt from which groundwater can be usefully extracted using a water well.
    • The study of water flow in aquifers and the characterization of aquifers is called hydrogeology.
    • Related terms include aquitard, which is a bed of low permeability along an aquifer.
  33. Hydrology & Fluvial Test

    Slide 34 - Hydrology & Fluvial Test

    • 1. The system whereby water is circulated throughout earth and the earths atmosphere.__________________
    • 2. The system consists of 4 components what are they?
    • ______________________
    • 3. What is a drainage basin?
    • ____________________________
    • Water Cycle
    • Inputs, Flows, Stores and Outputs
    • An area of the earths surface that is drained of water.
  34. 4. Two factors that might affect discharge in a drainage basin?_____________________

    Slide 35 - 4. Two factors that might affect discharge in a drainage basin?_____________________

    • 5. What is Infiltration?_____________________________
    • 6. Type of graph used to plot rainfall?________________
    • 7. Worlds largest dam?______________
    • 8. Type of graph used to show percentage of land use in a drainage basin?____________________________
    • Rain fall, slope and vegetation
    • Movement of water from surface into soil layer
    • Hydro graph
    • 3 Gorges Dam
    • Pie Graph