What is groundwater flow velocity?
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.
How is the flow velocity of groundwater determined?
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.” This value can be established by measuring water levels.
What factors affect the rate of 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.
How does pollution move through groundwater?
Groundwater contamination occurs when man-made products such as gasoline, oil, road salts and chemicals get into the groundwater and cause it to become unsafe and unfit for human use. For example, pesticides and fertilizers can find their way into groundwater supplies over time.
Why is groundwater flow slow?
Because of earth movements in the past, many aquifers dip below younger strata of impermeable clay. The velocity of flow under confined conditions is much slower than that in unconfined aquifers.
What causes groundwater flow?
Water moves underground downward and sideways, in great quantities, due to gravity and pressure.
How do landfills and sewage system pollute our groundwater resources?
Landfill leachate Leachate from sanitary landfills can lead to groundwater pollution. Chemicals can reach into ground water through precipitation and runoff. New landfills are required to be lined with clay or another synthetic material, along with leachate to protect surrounding ground water.
What are five ways that the groundwater supply can be polluted?
There are five major ways groundwater can be contaminated by chemicals, bacteria or saltwater.
- Surface Contamination.
- Subsurface Contamination.
- Landfills and Waste Disposal.
- Atmospheric Contamination.
- Saltwater Contamination.
Why is pollution of groundwater a greater environmental hazard than pollution of surface water?
Why do many scientists consider groundwater pollution to be a greater problem than surface water? Groundwater is more difficult to manage because it contains less dissolved oxygen, microbes, minerals, and organic matter than surface water or soil water.
How do porosity and permeability affect the flow of groundwater?
Porosity is a description of how much space there could be to hold water under the ground, and permeability describes how those pores are shaped and interconnected. This determines how easy it is for water to flow from one pore to the next.
What are some environmental threats to groundwater supplies?
Stressors that affect ground water condition include application of pesticides and fertilizers to the land, waste from livestock and other animals, landfills, mining operations, and unintentional releases such as chemical spills or leaks from storage tanks.
What are the main source of groundwater pollution?
The significant sources of contamination in groundwater are farming chemicals, septic waste, landfills, uncontrolled hazardous waste, storage tanks, and atmospheric pollutants.
How do you calculate groundwater velocity?
An accurate estimate of groundwater velocity can be calculated using Darcy’s Law. Darcy’s law is an equation that describes groundwater movement in aquifers based on three variables: horizontal hydraulic conductivity, horizontal hydraulic gradient and effective porosity. The equation for calculating ground water velocity is: V= KI/n.
How to calculate groundwater velocity?
Velocity Equation of Hydraulics is defined as the product of cross-sectional area and groundwater velocity is calculated using quantity_of_water = Cross sectional area * Groundwater Velocity. To calculate Velocity Equation of Hydraulics, you need Cross sectional area (A) and Groundwater Velocity (v).
Does groundwater flow faster than surface water?
Like surface water, groundwater flow moves downward in whichever the direction the water table slopes. Its flow rate is much slower than that of surface water. River water generally flows thousands of times faster.
What is the rate of groundwater flow?
But, most commonly, groundwater occurs within the small pores between soil and sediment particles. Groundwater does flow, however. But, it moves at a very slow rate. Flow rates of ground water may range from 2 meters per day to 2 meters per year.