Victoria Slide Revision for Office Mix
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Slide 1 - HYDROLOGY & FLUVIAL
Slide 2 - Global System Of Water Exchange
Slide 3 - Name A Input
- Water in all its states i.e. rain, snow, hail, sleet.
Slide 4 - Name The Flows
- Through fall
- Stem flow
- Overland flow
- Through flow
Slide 6 - Name A Store
- Water Tables
- Ground Water
Slide 7 - Name The Outputs
- 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
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.
Slide 10 - WHY IS IT A CLOSED SYSTEM
Slide 11 - WHAT ARE THE 4 MAIN PROCESSES
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
Slide 13 - How heavy
- Rainfall is measure in mm/hr
- Steady drizzle= 0.5mm/hr moderate =3mm/hr
- Tropical storm=1mm/1minute!!!
- What type
- 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
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)
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
- 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.
Slide 16 - THROUGH FALL
- Stem flow
- 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
Slide 17 - STEM FLOW
- Water which trickles along twigs, branches and down the tree trunk to the ground.
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.
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
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
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.
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
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.
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
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
Slide 26 - Percolation
- Some water will continue to move vertically downwards through soil horizons under the influence of gravity towards water table by percolation
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
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
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
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.
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.
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
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.
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.
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