How is storativity calculated?
To estimate a storativity for an aquifer of known lithology and thickness, select appropriate value of specific storage from the table and multiply it by the aquifer thickness.
What is storativity in aquifer?
Storativity (S) is a dimensionless measure of the volume of water that will be discharged from an aquifer per unit area of the aquifer and per unit reduction in hydraulic head. For a confined aquifer, storativity results only from the rock and fluid compressibilities and is typically very small (~10−4–10−5).
How do you calculate aquifer compressibility?
Use compressibility data to estimate the storativity of a 35-ft thick confined sand aquifer (assume ρ = 1000 kg/m3 and n = 0.3). How much does the expansion of water contribute to the total storativity in this example?…Representative Values.
| Material | Compressibility, α (m2/N or Pa-1) |
|---|---|
| Sound rock | 10-11 to 10-9 |
What is confined and unconfined 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.
What is transmissivity in hydrogeology?
Transmissivity describes the ability of the aquifer to transmit groundwater throughout its entire saturated thickness (Figure 7). Transmissivity is measured as the rate at which groundwater can flow through an aquifer section of unit width under a unit hydraulic gradient.
How do I calculate specific yield?
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 is Storativity different in a confined and an unconfined aquifer?
Storativity (S) is the volume of water removed from a unit area of an aquifer for a unit drop in hydraulic head; in confined aquifers, it is equal to the specific storage times the thickness of the aquifer, in unconfined aquifers, it is equal to the specific storage times the thickness of the aquifer plus the specific …
What is the pressure of upper surface of unconfined aquifer?
What is the pressure of upper surface of unconfined aquifer? 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.
How is hydraulic conductivity of aquifer calculated?
The hydraulic conductivity K can be calculated through the analytical solution of equation (9): A = −C′Q2/4π2K2H02, where H0 is the hydraulic head in the pumping well (equal to 1.96); C′ is the slope factor of the linear relationship between self-potential and drawdown data in Figure 12 (until 0.4 m) and represents the …
What is unconfined aquifer?
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.