Ground Water Flashcards
(26 cards)
What is groundwater?
Water stored beneath the Earth’s surface in soil, rock, and aquifers
Groundwater is a vital component of the global water cycle and supports human life, agriculture, and ecosystems.
What are aquifers?
Water bearing rock found underground, consisting of permeable rock, soil, or sand that stores and transmits large amounts of water
Aquifers act as natural reservoirs, supplying freshwater to wells, springs, and rivers.
What is the process of aquifer formation?
Involves deposition, compaction, cementation, uplift, and erosion
Each step contributes to creating a permeable layer that can store water.
What are the types of aquifers?
Confined Aquifer and Unconfined Aquifer
Confined aquifers are sandwiched between impermeable layers, while unconfined aquifers allow direct recharge from the surface.
Define a confined aquifer.
An aquifer sandwiched between layers of impermeable rock or clay, filled with pressurized water
These aquifers recharge slowly, usually from a distant source.
Define an unconfined aquifer.
An aquifer where water seeps directly from the ground surface into the aquifer
They are more exposed to pollution due to direct recharge from rainfall and surface water.
What is one importance of aquifers?
They supply drinking water to many communities
Aquifers are crucial for sustaining human life.
List three roles of aquifers in ecosystems.
- Support irrigation for agriculture
- Maintain healthy ecosystems
- Supply water to rivers, lakes, and wetlands
What challenge do aquifers face related to over-extraction?
Can lead to land subsidence and decreased water quality
Excessive pumping depletes aquifers.
What is a major cause of aquifer contamination?
Pollutants such as agricultural runoff or industrial waste
Contamination can severely impact water quality.
True or False: Aquifers can be affected by climate change.
True
Changes in precipitation patterns and increased evaporation can impact aquifer recharge and water levels.
Fill in the blank: Aquifers are a vital resource that requires careful _______ to ensure sustainability.
management
What is a drawdown in relation to aquifers?
A long-term, cone-shaped depression in the groundwater level due to pumping large amounts of water
Drawdowns can affect water levels in wells, streams, and wetlands.
What can large drawdowns cause in drinking water?
Increased levels of arsenic, radium, and salinity
This can lead to health risks for communities relying on aquifers.
What are shallow wells?
Hand dug wells constructed in the uppermost layer of the earth’s surface
From which aquifers do shallow wells obtain water?
Unconfined water table aquifers
How is groundwater recovered from shallow wells?
By hand or low rate suction pump
What are some other names for shallow wells?
- Draw wells
- Gravity wells
- Open wells
- Dug wells
- Perforated wells
What is a limitation of water quantity in shallow wells?
Water is limited as it is drawn from the uppermost part of the earth
In which season can shallow wells dry up?
Summers
What is the recommended depth for shallow wells to avoid drying up?
About 6 to 8 meters below the water table
What is the typical yield of water from shallow wells?
About 5 litres per second
Are shallow wells suitable for public water supply for large communities?
No, they are not suitable
How does the water quality of shallow wells compare to river water?
Better than river water but not reliable and needs purification
