Search results
Results from the WOW.Com Content Network
Schematic of an aquifer showing confined zones, groundwater travel times, a spring and a well. An aquifer is an underground layer of water-bearing material, consisting of permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics.
For a confined aquifer or aquitard, storativity is the vertically integrated specific storage value. Specific storage is the volume of water released from one unit volume of the aquifer under one unit decline in head. This is related to both the compressibility of the aquifer and the compressibility of the water itself.
In a confined aquifer, the upper surface of water is overlain by a layer of impervious rock, so the groundwater is stored under pressure. [2] Aquifers receive water through two ways, one from precipitation that flows through the unsaturated zone of the soil profile, and two from lakes and rivers. [2]
The above figures simulate possible coastal aquifers. In reality, it is complex. Due to complex geology - non-uniform rock layers and weathering, both confined and unconfined aquifers can be found within a coast. It is possible to have multiple confined aquifers at the bottom and an unconfined aquifers at the top of a coast.
Aquifers of the United States Withdrawal rates from the Ogallala Aquifer.. This is a list of some aquifers in the United States.. Map of major US aquifers by rock type. An aquifer is a geologic formation, a group of formations, or a part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to groundwater wells and springs.
An aquifer may be artificially recharged, such as by pumping reclaimed water from wastewater management projects directly into the aquifer. An example of is the Orange County Water District in California. [6] This organization takes wastewater, treats it to a proper level, and then systematically pumps it back into the aquifers for artificial ...
The majority of deep aquifers are classified as artesian because the hydraulic head in a confined well is higher than the level of the top of the aquifer. If the hydraulic head in a confined well is higher than the land surface it is a "flowing" artesian well (named after Artois in France). [citation needed]
(confined), where S=S s b is the aquifer storativity and = +. (unconfined), where S y is the specific yield of the aquifer. Note that the partial differential equation in the unconfined case is non-linear, whereas it is linear in the confined case. For unconfined steady-state flow, this non-linearity may be removed by expressing the PDE in ...