Hydrosphere Flashcards
Hydrosphere -The hydrological cycle
Challenge; draw a diagram to show the hydrological cycle
I must include; Clear arrows showing the circulation of water Key words;evaporation condensation precipitation transpiration/evapotranspiration infiltration storage (ice/snow/lochs) interception store infiltration overland flow percolation groundwater store & flow
DESCRIBE (say what you see) the hydrological cycle
The hydrological cycle is the circulation of water on Earth. It is powered by the sun’s energy.
Moisture is evaporated from the sea and the water vapour gas rises into the atmophere where it cools, condenses and is stored as clouds.
The clouds rise over the land and the moisture falls as precipitation.
Some of this may be stored as snow and ice on mountains or in lochs and rivers.
Some of the precipitation may land on vegetation and be intercepted before either being evaporated back into the air or dripped onto the ground surface.
Some moisture will be stored in plants and then released back into the air by the process of evapotranspiration.
Precipitation falling onto the ground may infiltrate the soil or move over the surface as surface runoff.
Precipitation in the soil may percolate deeper and be stored as groundwater in the rocks.
Ground water flow and surface runoff will return the water to rivers and the sea under the force of gravity.
The water is then available to be recycled again through the process of evaporation.
Check your understanding of key words Soil water Groundwater storage Precipitation Evaporation Condensation Transpiration Interception store Evapotranspiration Surface run-off or overland flow Infiltration Percolation
Soil water - water stored in the soli. A deep soil will hold more than a thin soil.
Groundwater storage - water stored in porous rocks underground. This level will change depending on the amount of water and is known as the water table which will rise and fall.
Precipitation - any form of moisture which falls from the sky (rain, hail, sleet, snow).
Evaporation -when water turns from a liquid to a gas
Condensation - when water turns from a gas to a liquid
Transpiration - the evaporation of moisture from plants, This process helps to lift needed water from the roots to the tops of plants, then back to the atmosphere.
Interception store - storage of water in plants or on the surface of vegetation
Evapotranspiration - includes the transpiration that occurs in plants. The term is more inclusive as it also includes evaporation of lakes, streams and oceans.
Surface runoff -water which runs ove rthe surface of the ground, usually because the soil is already waterlogged and cannot allow any more moisture to infiltrate.
Infiltration - the process by which water soaks into the ground. water is stored in the spaces between soil particles. A thin soil or soil that has been compacted or baked hard by drought will increase surface runoff.
Percolation - water seeps down into the rock beneath the soil by the force of gravity.
Storm Hydrographs -what information do they show?
A storm or flood hydrograph shows the changes in the flow rate of a river on a specific date. It is shown as a line graph.
The total rainfall amount on the same date is shown as a bar graph.
How do I describe a storm hydrograph?
What terms must I use?
Say what you see! Add as much detail as you can. Be specific and accurate about times and amounts.
DESCRIBE THE LINE GRAPH!
Start with stating the BASE FLOW in cumecs and give the time.
State the time that the base flow CHANGES and give the AMOUNT in cumecs and the TIME the changes occurred at.
You must identify the;
BASE FLOW - the normal level of the river (in cumecs)
RISING LIMB (there may be more than 1) - give times and amounts
PEAK FLOW - identify time and amount
LAG TIME - difference between peak of rainfall on bar graph and peak flow on line graph -give answer in hours/mins
RECESSIONAL LIMB - indicates the time it takes the river discharge to drop after peak flow.
How do I EXPLAIN changes on a storm Hydrograph?
You must offer reasons/explanations for the changes.
These should include;
Linking PEAK RAINFALL in bar graph(s) to PEAK FLOW in line graph (there will be a lag time between the 2 types of graph).
Delay between RAINFALL EVENT and CHANGE IN DISCHARGE is due to;
Rainfall takes time to reach the river due to water landing on vegetation which intercepts it and slows the rate of rain reaching the ground surface.
Water infiltrating the soil and being stored.
Water percolating into the rocks below the soil and being stored.
Evaporation of a small amount of rainfall (if graph is in summer months due to warm weather).
STEEP RISING LIMB is due to;
Soil storage is full so this increases overland flow.
Impermeable surfaces like tarmac in urban areas accelerate overland flow into river/ drains.
Steep gradient in drainage basin so water returns rapidly to river due to gravity.
Drainage systems (drains, sewers) in urban areas increase the speed of water returning to river.
Small drainage basin so water reaches main river quickly via tributaries.
Removal of vegetation (deforestation, crops harvested) so less interception store. Urban areas have less vegetation than rural areas.
Thin soil has little storage space so increased overland flow.
Impermeable rocks are unable to let water percolate so increases overland flow.
Ground may be baked hard after period of hot & dry weather so this increases overland flow (check date on the graph).
