1. Groundwater What is it and why is it important?
Click on any number for an explanation
Adapted from: “Groundwater Interactive”
The Kesab Watercare Club

2. 1. What is Groundwater? Water that runs below the earth’s surface
Water found in most water bodies such as lakes, rivers, streams and wetlands is known as surface water

3. 2. Aquifer
If it weren’t for aquifers we’d be wading in water up to our waists
Water runs off into streams, lakes, ponds and aquifers
Aquifers are underground reservoirs
Water that enters aquifers
Usually is much cleaner than surface water
Contains almost no bacteria
Many pollutants are filtered out
Two types of Aquifers: confined and unconfined

4. 3. Confined Aquifer
An aquifer below the surface that is saturated with water
Contains layers of impermeable material both above and below
These layers cause the water to be under pressure
If penetrated by a well the water will rise above the top of the aquifer

5. 4. Unconfined Aquifer
Allows water to enter freely from above and below
Closer (generally) to the surface than confined aquifers
Impacted by drought conditions sooner than confined aquifers

6. 5. Porosity & Permeability (1)
The amount of water that can be stored in an aquifer depends on two factors:
Porosity: refers to the amount of pore spaces or fractures in an aquifer
Porous aquifers consist mainly of loose gravel, sands and silts
Water fills any space between the gravel, sand and silt

7. 6. Porosity & Permeability (2)
Refers to the rate of infiltration
Sandy soils allow quick infiltration of rainfall
Clay soils quickly saturate and surface flow removes most of the rainfall
Only all small portion reaches groundwater
Impermeable rock would not allow water to enter

8. 7. Groundwater Wells
Groundwater is obtained by drilling a well into an aquifer
A casing or pipe is placed inside the well to stop the wall from falling inward
The space between the casing and rough wall is filled with concrete to prevent leaking
Well screen at the bottom is used to filter out sand and gravel

9. 7. Groundwater Wells (cont’d)
Once this is done a pump is inserted into the well
A well can become contaminated if not properly constructed
Two types of wells
Artesian: Comes from a confined aquifer
Unconfined : comes from an unconfined aquifer

10. 8. The Water Cycle

11. 9. Groundwater Use Groundwater
Industry uses: beer, soft drinks, spring water, pulp and paper. Etc
May be used as the sole water supply for stock and domestic purposes
Requires minimal treatment

12. 10. Threats to Groundwater
Groundwater is usually of excellent quality
Since it is naturally filterer it is usually clear colorless, and free from microbial contamination
A threat to groundwater is now posed by a number of soluble chemicals from urban, industrial and agricultural activities
These chemicals can not be completely removed by the natural filtration process

13. 11. Groundwater Contamination
Many of the pollutants of surface water also contaminate groundwater
Surface pollutants can move through the soil and find their way into aquifers
Examples are:
Pesticides
Fertilizers
Motor oil
Gasoline
Untreated waste

14. 12. Groundwater Salinity
The most common cause is the replacement of perennial, deep-rooted native plants with crops and grasses

15. 13. Saltwater Intrusion
The key to controlling this problem is to maintain the proper balance between water being pumped from the aquifer and the amount of water recharging it.

16. 14. Threats to Quantity
Overdraft occurs when groundwater is removed faster than recharge can replace it. This can result in;
A permanent loss of some of its storage capacity.
Contamination of clean water with low quality water.
Drawdown A temporarily lowered water table generally caused by pumping.
The water table only recovers when the supply is replenished.
Subsidence
Is one of the dramatic results of over pumping.
As the water table declines, water pressure is reduced.
This causes the fine particles that hold water to become compacted.
In addition to permanently reducing storage capacity, the land above the aquifer can dramatically be effected causing it to sink.
This can damage property and fields.

17. 15. Wetlands
Nature’s filter