What is specific yield of an aquifer?
Specific yield is defined as the volume of water released from storage by an unconfined aquifer per unit surface area of aquifer per unit decline of the water table. Thus, specific yield, which is sometimes called effective porosity, is less than the total porosity of an unconfined aquifer (Bear 1979).
What is zone of aeration in groundwater?
Groundwater is all the water that has penetrated the earth’s surface and is found in one of two soil layers. The one nearest the surface is the “zone of aeration”, where gaps between soil are filled with both air and water. Below this layer is the “zone of saturation”, where the gaps are filled with water.
What is the connection between aquifers and the zone of aeration?
ZONE OF AERATION: The area of an unconfined aquifer above the water table where the pore spaces among soil particles and rock formations are filled with air. CONE OF DEPRESSION: Pumping from a well in a water table aquifer lowers the water table near the well.
What is aeration zone?
Quick Reference. The subsurface zone between the ground surface and the water table, where the pores in soil and rock contain both air and water. Also known as unsaturated zone, vadose zone, or zone of aeration.
How do you find the specific yield of an aquifer?
The specific yield is the volume of water pumped during the test divided by the gross volume of dewatered material within the cone of depression.
How do you calculate the specific yield of an aquifer?
Specific yield is the water removed from unit volume of aquifer by pumping or drainage and is expressed as percentage volume of aquifer. Specific yield depends upon grain size, shape and distribution of pores and compaction of the formation.
Which zones are together called as zone of aeration?
The soil water and intermediate zones are sometimes collectively referred to as the zone of aeration.
What is Zone of aeration what are its various sub zones?
They are vadose water present in the zone of aeration and groundwater present in the zone of saturation. The vadose water is further subdivided into three zones, i.e., soil water zone, intermediate zone and capillary zone.
Which zones are together called zone of aeration?
What is the zone of aeration useful for?
The zone of aeration is commonly referred to as the root zone. It is within this critical area where soil aeration (respiration) takes place. Aeration, water and nutrient management within this zone is absolutely critical to ensure healthy plant growth.
How do you calculate specific yield?
What are the zones in a water table aquifer?
The lowermost zone is characterized by semicontinuous capillary saturation while the uppermost zone is characterized by discontinuous capillary saturation. In both of the latter zones, the materials will yield no water to wells.
How is the ground saturated with water called an aquifer?
Below a certain depth, the ground, if it is permeable enough to hold water, is saturated with water. The upper surface of this zone of saturation is called the water table. The saturated zone beneath the water table is called an aquifer, and aquifers are huge storehouses of water.
How is the specific yield of an aquifer determined?
Thus, the specific yield is equal to the total volume of pore space in the rock, expressed as a percentage of the total volume of the rock, minus the specific retention — the amount of water held or retained by molecular attraction to the rock particles. In most unconfined aquifers, the specific yield ranges from 10 percent to 30 percent.
Which is better coarse grained or fine grained aquifers?
A coarse-grained aquifer will have a higher specific yield than a fine-grained one. Specific yield is not to be confused with maximum yield, which is affected by the size of the aquifer.