Wells can extract water from the ground by digging or drilling. Water is brought until ground level by pumps or by drawing it out from well through buckets or large utensils.
Dug Well vs Drilled Well
The difference between Dug well and Drilled well is that the Dug well is a traditional way to obtain water where a shallow hole is dug down into the water table. The water obtained by dug well can get contaminated as it is extracted from the topmost layer of soil. Whereas in Drilled well, a hole is drilled deep in the soil for the extraction of groundwater from the groundwater table.
A dug well is generally hand-dug in rural areas or a shovel is used hence it is shallow. It obtains water from less permeable and top layers of soil like sand, silt, and clay.
A drilled well is drilled deep into the ground by a rotatory drilling machine. The drilling machine is cased within a protective covering to prevent the collapse of the driller when it strikes hard rocks.
Comparison Table
Parameters of Comparison | Dug Well | Drilled Well |
---|---|---|
Construction | It is either hand-dug or dug by shovel. | It is drilled using a rotary drilling machine. |
Depth | It has a shallow hole and extracts water from the topmost layers. | It can go up to 300-400 meters or 1000 feet deep into the ground. |
Water quality | The water extracted is high in minerals and hence needs to be treated well. | The water extracted is muddy until it passes through a semipermeable membrane that filters out the impurities. |
Water extraction | It can be drawn out using handpumps, electric pumps or can be hand-drawn. | Water is pulled out using suction or electric pumps. |
Used for | It is used in rural areas for everyday use at homes. | It is used in urban areas at home or in factories as groundwater level is low in cities. |
What is Dug Well?
A dug well is generally seen in rural areas or in some localities of the urban areas that have been built years ago. A dug well is shallow and the water that is retained is highly contaminated by either pollutants or minerals.
There are high chances of water getting exhausted during the dry season as dug wells draw water from topmost layers of groundwater table like sand, silt, and clay.
After digging the well, it is protected by building bricks or concrete materials so that it does not collapse due to seepage of water.
The dug wells need low technology means and are inexpensive. It generally needs manual labor to access groundwater. The lifespan of dug wells depends upon the climate and nature of rains as they are responsible for filling up the groundwater table.
What is Drilled Well?
A drilled well is drilled by table rotary, or cable tool drilling machines which creates a cutting action in-ground or on hard rocks. The depth of these wells might range from 300 to 900 meters.
The drilled wells use PVC or metal pipes that pull out water from the bore but water can be muddy since it is extracted from deep strata of ground so a semipermeable screen or casing is used to protect and filter the water.
To avoid contamination through pathogens, the surface seal is used that provides an impermeable barrier between the outside environment and well.
The water is pulled out from the ground using electric pumps as much energy is needed to pull out water from such a depth. Most drilled wells last up to 30-50 years.
Main Differences Between Dug Well and Drilled Well
- Water from dug wells can be drawn out using handpumps, electric pumps or can be hand-drawn. Water from drilled wells is pulled out using suction or electric pumps.
- Dug wells are used in rural areas for everyday use at homes. Drilled wells are used in urban areas at home or in factories as groundwater level is low in cities.
References
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