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Aquifers :droplet:: - Coggle Diagram
Aquifers
:droplet::
Advantages
:heavy_check_mark:
Pollution is less likely as theyre naturally filtered by rock
Heavy metals
Plastic cant get through pores
Toxic ions
Low turbidity
Less rapid fow fluctuations
No evaporation
Treatment not needed
Screens
Sedimentation
Disadvantages
:heavy_multiplication_x:
Expensive to drill borehole/pump
Slower recharge than reservoir
Slow recovery after overexploitation
Subsidence
Increased hardness
Salt water incursion
Needs porous, permeable rock
Sandstone
Limestone
Over exploitation
:forbidden:
Changes in surface hydrology
:mount_fuji:
Rivers, lakes, marshes are fed by groundwater
Groundwater is overexploited
Water table is lowered
Reducing/stopping the outflow of water into the wetland
Ecological impacts
:cow2:
Water table lowered :fountain:
Plants with higher water requirement will die
Or less abundant
Fail to compete with plants with lower requirements
Aquatic or semi aquatic animals: :tropical_fish:
die if wetlands dry out
Other species :lion_face:
Affected even if they dont need it
depended on food from other species that needed the water
Salt water incursion
:shell:
Coastal areas
Water table may be slightly higher than sea level
Rainwater perlocates down the aquifer
water flows sideways and out into the sea
seawards flow of water prevents seawater from flowing into the aquifer
Overexploited
seawater flows sideways into aquifer
Salt makes the aquifer unsuitable for irrigation
Kills crops by osmotic dehydration
Subsidence
:derelict_house_building:
Water is no longer present in interstitial spaces
Cannot provide support for the rock particles
Will be compacted by the weight of the material above
Subsidence is caused at the surface
Causing serious damage to buildings/pipelines
Reduced supplies
:sparkles:
extraction rate exceeds recharge rate
Volume available is reduced
Unsustainable use may have happened for years before consequences are seen
Human activities may have to sudden stop
Nearly half of the world's population live in countries over exploiting their aquifers
Ogollala
High Plains aquifer
USA - Mid west states
Over 450,000km^2
One of the most important agricultural regions
Food production relies on irrigation
Largely paleowater - fossil water
Recharged the aquifer in the last ice age (or before)
Long term abstraction rates for agriculture are greater than recharge rate
Monitoring depletion
:desktop_computer:
Monitored by checking the level of water table
In wells
In boreholes
Very slow
Difficult to coordinate on a large scale
NASA operates two GRACE satellites
Gravity Recovery And Climate Experiment
Orbit is affected by the orce of gravity
Influenced by the mass of water in aquifers
Below their flight paths
Entire earth is surveyed every 30 days