An aquifer is a geologic layer of porous and permeable material such as sand and gravel, limestone, or sandstone, through which water flows and is stored. An artesian aquifer is confined between impermeable rocks or clay which causes this positive pressure.

confined aquifer

A confined aquifer is an aquifer below the land surface that is saturated with water. A water-table–or unconfined–aquifer is an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall.

c) Equal to atmospheric pressure. d) Greater than atmospheric pressure. Explanation: In unconfined aquifer, the upper surface of water or the water-table is under atmospheric pressure which may be acting through the interstices in the overlying rocks.

A good example is the water of the Nubian Sandstone Aquifer System, which extends through several countries in an area that is now the Sahara. The water is being used extensively for water supply and irrigation purposes. Radioisotope dating techniques have shown that this water is many thousands of years old.

What is another word for aquifer?

There are two general types of aquifers: confined and unconfined. Confined aquifers have a layer of impenetrable rock or clay above them, while unconfined aquifers lie below a permeable layer of soil.

An aquifer is defined as a body of rock or unconsolidated sediment that has sufficient permeability to allow water to flow through it. Unconsolidated materials like gravel, sand, and even silt make relatively good aquifers, as do rocks like sandstone. Other rocks can be good aquifers if they are well fractured.

Sandstone: Fine-grained rocks such as sandstone make good aquifers. They can hold water like a sponge, and with their tiny pores, they are good at filtering surface pollutants.

In order for a well to be productive, it must be drilled into an aquifer. Rocks such as granite and schist are generally poor aquifers because they have a very low porosity. However, if these rocks are highly fractured, they make good aquifers. A well is a hole drilled into the ground to penetrate an aquifer.

Clay textured soils have small pore spaces that cause water to drain slowly through the soil. Clay soils are known to have low permeability, which results in low infiltration rates and poor drainage. As more water fills the pore space, the air is pushed out.

Silt 3

Why do you believe the rock you chose as the best aquifer is correct? The rock I choose was Sandstone for the best aquifer, because it has more porous and permeability. This are two important characteristics for a rock to have aquifer.

Both sand and clay deposits (and sandstone and mudstone) are quite porous (30% to 50% for sand and 40% to 70% for silt and clay), but while sand can be quite permeable, clay and mudstone are not. Unconsolidated materials like gravel, sand, and even silt make relatively good aquifers, as do rocks like sandstone.

Porosity is the ratio of pore volume to its total volume. Porosity is controlled by: rock type, pore distribution, cementation, diagenetic history and composition. Porosity is not controlled by grain size, as the volume of between-grain space is related only to the method of grain packing.

Gravel. Gravel makes a good aquifer because it is extremely permeable and porous. The large pieces of sediment create significant pore spaces that water can travel through. Often, gravel must be surrounded by a less permeable soil type, such as rich clay or impenetrable rock.

: a water-bearing stratum of permeable rock, sand, or gravel.

Gravel

When a water-bearing rock readily transmits water to wells and springs, it is called an aquifer. Wells can be drilled into the aquifers and water can be pumped out. Precipitation eventually adds water (recharge) into the porous rock of the aquifer.

Groundwater can be found in a range of different types of rock, but the most productive aquifers are found in porous, permeable rock such as sandstone, or the open cavities and caves of limestone aquifers.

An aquifer is an underground layer of rock that holds groundwater. Aquifers can be drained by man-made wells or they can flow out naturally in springs. aquifer. an underground layer of rock or earth which holds groundwater.

Aquifers are critically important Municipal, irrigation, and industrial water supplies are provided through large wells. Multiple wells for one water supply source are called wellfields. Using ground water from deep, confined aquifers provides more protection from surface water contamination.

Aquifers are bodies of saturated rock and sediment through which water can move, and they provide 99% of our groundwater. Humans rely on aquifers for most of our drinking water.

As already noted, groundwater does not flow in straight lines. It flows from areas of higher hydraulic head to areas of lower hydraulic head, and this means that it can flow “uphill” in many situations.