consequences of aquifer oversue
- Created by: Luke Mitchell
- Created on: 16-01-13 19:27
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- Consequences of aquifer overuse
- Reduced supplies
- if the extraction rate exceeds recharge rate = volume of water available reduced for future use
- unsustainable use of aqifer carried on for many years before problems became obvious, so human activities that relied on it may have to stop
- Subsidence
- water that is no longer present in interstitial spaces in rock cannot support rock particles so compacted by weight above
- casues subsidence at surface causing serious damage to buildings and pipelines
- Changes in surface hydrology
- many rivers, lakes and marshes fed by groundwater flowing out of aquifer springs
- if groundwater is overexploited then the water table will be lowered and flow from the springs will decline
- because of flow of water into wetlands has declined they may dry up
- Ecological impacts
- if water table is lowered then plants that have higher water requirments will die/become less abundant as fail to compete with plants which have lower requirments for water
- other species may be affected even though dont rely on water directly but depend on species that need water e.g. for food
- Saltwater incursion
- 1). in coastal areas water table higher than sea level
- 2). as rainwater percolates down to aquifer water flows sideways and out into sea
- 3). seawards flow of freshwater prevents sea water from flowing into aquifer
- 4). if aquifer overexploited then seawater flows sideways into aquifer replacing freshwater
- 5). salt makes aquifer water unsuitable for irrigation as it could kill crops by osmotic dehydration
- Seawater
- Desalination of seawater is very energy intensive + expensive so only used in countries where seawater is available bu lack of freshwater supplies
- Reduced supplies
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