The equation for calculating ground water velocity is: V= KI/n. In this formula V stands for “groundwater velocity,” K equals the “horizontal hydraulic conductivity,” I is the “horizontal hydraulic gradient,” and n is the “effective porosity.”
Ground water may flow through an aquifer at a rate of 50 feet per year or 50 inches per century, depending on the permeability. But no matter how fast or slow, water will eventually discharge or leave an aquifer and must be replaced by new water to replenish or recharge the aquifer.
The velocity of groundwater flow is proportional to the magnitude of the hydraulic gradient and the hydraulic conductivity of the aquifer (see Chapter 12). Groundwater flows faster where the hydraulic gradient and/or hydraulic conductivity are larger.
Q = Discharge (L3/T) v = water velocity (L/T) A = Cross sectional area (L2)
average pore water velocity v = -K/n(∆h/∆L) The average velocity of the water is the Darcy equation divided by the porosity of the sediment. The aquifer covers approximately 200 km2 and serves as a water supply for approximately 110,000 people in BC and WA.
Darcy’s law says that the discharge rate q is proportional to the gradient in hydrauolic head and the hydraulic conductivity (q = Q/A = -K*dh/dl). Definitions of aquifers, aquitards, and aquicludes and how hydraulic conductivity relates to geology.
the actual flow velocity v may be calculated with the following formula: v=Q/(A*f)=q/n, n is the porosity, and q the specific discharge. if the porosity n is 30%, the flow velocity in the example above is 10.5 m/y.
|Fluid||Typical Pipe Velocity (m/s)|
|Water||0.9 – 2.4|
The higher the gradient level the faster the river will flow. How quickly would groundwater flow through rock with high porosity and high permeability? … It would flow faster because there is more space for the water to move. An area’s rate of groundwater recharge exceeds its rate of groundwater discharge.
How does the rate of groundwater flow compare with that of ocean currents or river currents? The rate of groundwater flow is slower than that of surface-water currents.
The porosity and permeability of the soil controls the rate of movement of groundwater.
Topography and geology are the dominant factors controlling groundwater flow. Storativity describes the property of an aquifer to store water. Hydraulic conductivity is measured by performing a pumping test, i.e. by pumping one well and observing the changes in hydraulic head in neighboring wells.
The rate at which groundwater moves through the saturated zone depends on the permeability of the rock and the hydraulic head. The hydraulic head is defined as the difference in elevation between two points on the water table.
The best sources of ground water, called aquifers, have high porosity and also high permeability. Sand, gravel, and fractured rock make the best aquifers. Ground water flow is much slower than flow in streams and rivers.
Rainwater infiltrates downwards through the unsaturated zone. This infiltrating water is known as soil water when it is still shallow enough to be used by plants. … High water tables are often above the level of basement floors or crawlspaces. This almost always causes flooding in these areas.
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.
In theoretical terms, hydraulic conductivity is a measure of how easily water can pass through soil or rock: high values indicate permeable material through which water can pass easily; low values indicate that the material is less permeable.
Some of the common methods for calculating Hydraulic Conductivity are described below: Hydraulic conductivity is the coefficient k in the Darcy’s law v = ki, where v is the velocity and i the hydraulic gradient. Hydraulic conductivity values can be determined in the laboratory using disturbed soil samples.
Seepage velocity is the velocity of groundwater calculated from Darcy’s law. Seepage velocity is not the actual velocity of the water in the pores, but the apparent velocity through the bulk of the porous medium.
What does Darcy’s law tell us about how the hydraulic gradient and permeability affect discharge? Darcy’s law/equation reveals that steeper slopes deliver more water (or have a higher discharge), and more permeable materials deliver more water (or have a higher discharge).
The Brinkman equation is a combination of linear momentum and mass conservation for the fluid in large pores and flow channels, and Darcy’s equation for regions with unresolved pores.
Darcy’s law is valid for laminar flow through sediments. In fine-grained sediments, the dimensions of interstices are small and thus flow is laminar. Coarse-grained sediments also behave similarly but in very coarse-grained sediments the flow may be turbulent. Hence Darcy’s law is not always valid in such sediments.
“Hydraulic Conductivity” (K), in hydrogeology and hydrology, represents the capacity of a porous medium (such as soil) to transmit water, as per Darcy’s Law.
Darcy’s law is critical when it comes to determining the possibility of flow from a hydraulically fractured to a freshwater zone because it creates a condition where the fluid flow from one zone to the other determines whether hydraulic fluids can reach freshwater zone or not.
direction of groundwater flow is determined by
groundwater flow direction
the rate of groundwater flow quizlet
what is groundwater
groundwater flow examples
how to check ground water level
groundwater flow equation
groundwater flow direction map