The rate of groundwater flow depends on the permeability (the size of the spaces in the soil or rocks and how well the spaces are connected) and the hydraulic head (water pressure).
What is groundwater discharge proportional to?
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.
How do you calculate groundwater flow rate?
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.”
What increases groundwater flow?
The hydraulic gradient has both a magnitude and direction. 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.
What determines groundwater flow?
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.
What is a groundwater flow system?
Regional groundwater flow systems are characterised by laterally extensive aquifers, which may be thicker than 300 metres, and recharge and discharge areas separated by distances of fifty or more kilometres. They occur in areas of low relief such as alluvial plains.
What is Dh in Darcy law?
Q = -KA dh/dl
Q = rate of water flow (volume per time) K = hydraulic conductivity. A = column cross sectional area. dh/dl = hydraulic gradient, that is, the change in head over the length of interest.
How do you calculate groundwater flow gradient?
The hydraulic gradient is the change in total head divided the distance over which the change occurs. 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.
How does Darcy’s law relate to groundwater flow?
Darcy’s Law gives the relationship among the flow rate of the groundwater, the cross-sectional area of the aquifer perpendicular to the flow, the hydraulic gradient, and the hydraulic conductivity of the aquifer.
Can groundwater flow from lower to higher elevation?
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.
