Systems (The Water Cycle) Flashcards
Describe the Global Distribution of Water?
Hydrosphere- the discontinuous layer of water at or near the Earth’s surfaces.
Only 2.5% of water on Earth is freshwater.
Cryosphere= 69%
Groundwater= 30%
Liquid= 0.3% (rivers, lakes on the surface of the earth)
What do hydrographs show?
Hydrographs show the changes in river discharge (cumecs per second) over a period of time at a particular point in a river.
Rising limb= discharge is rising.
Falling limb= discharge is falling.
What factors affect storm hydrographs?
- Rock and soil type- If permeable eg: limestone, ppt can infiltrate= increased lag time, reduced peak discharge. If impermeable eg: clay= no infiltration.
- Relief and vegetation= steeper catchment of basin= decreased lag time and greater vegetation= infiltration and increased lag time.
- Shape, Size and Drainage basin density- larger means higher peak discharge, circular means shorter lag time, denser networks transport water better= increased peak discharge. “FLASHY”
Define Drainage Basin?
The area of land drained by a river and it’s tributaries.
OPEN SYSTEM.
Define cascading system?
A systems outputs and the inputs to another system.
Water Budget Equation?
Precipitation= total discharge +evapotranspiration+ change in Soil storage P = Q + E + (change in) S
Human factors affecting lag time?
- LAND USE- land that remains forested will allow reductions in peak discharge. Ploughing of agricultural land decreases surface run-off and affects it.
- URBANISATION- increase in impermeable surfaces, decrease in infiltration.
- WATER MANAGEMENT- dams and reservoirs can be used to regulate the flow of a river. Extraction of aquifers and ground water increases percolation and infiltration.
CASE STUDY: The River Eden Drainage Basin
Source- Kirby Stephen, Mouth- Solway firth which meets the Scottish border.
Flows between Lake District and Pennines + CARLISLE.
Carlisle is vulnerable to flooding: urban area, low lying, input from river Petrol and Caldew.
Lake District- wettest part of England. Over the average rainfall (80 inches) annually.
CASE STUDY: Describe the River Eden Drainage Basin
Long and narrow sides, steep gradient. Impermeable CLAYS to the west of the basin. Soils have become compacted due to agriculture - forms 40% of economy. Only 8.6% woodland.
CASE STUDY: Storm Desmond (Cumbria 2015)
North- West of England, county in the UK.
High density of tributaries and steep gradient, not ideal relief of land.
Local rock type within Cumbria is impermeable= runoff and no infiltration. EXAM= INPUTS, FLOWS, STORES.
Above average rainfall= antecedent rainfall, saturation.
Carlisle= significant urbanisation. Only 8.6% forestry, but 72% grassland.
CASE STUDY: Social Impacts of Storm Desmond.
43,000 homes without power in Cumbria.
5,200 homes affected by flooding.
40 schools closed in Cumbria.
2 lives taken in Cumbria and the Republic of Ireland #RIP dawgs
CASE STUDY: Economic Impacts of Storm Desmond.
Criticism of government due to 7 million pound defences built in 2005 being ineffective.
700 million point spent on flood defences in 2015
250 million spent on insurance claims.
CASE STUDY: Environmental Impacts of Storm Desmond.
Record amounts of rainfall in Cumbria: 341mm fell into HONISTER WITHIN 24HRS
More than 15 severe flood warnings.
Hundreds of litres of sewage overflow.
Give an example of a POISTIVE feedback loop in the water cycle?
Temperatures increase, causing snow ice to melt.
Sea ice cover shrinks, leading to a reduction in surface albedo effect.
More sunlight is absorbed by the sea due to no highly reflective sea ice.
Temperatures increase, causing snow and ice to melt.
Give an example of a NEGATIVE feedback loop in the water cycle.
An increase in water vapour creates more cloud cover.
This reflects more solar radiation back into space.
Smaller amounts of solar radiation are absorbed by oceans, land, atmosphere.
Average global temperatures fall.
