The Leading Movie On Groundwater

Month: June 2021


Groundwater is found below the earth’s surface and includes water from bores, springs, wells and other sources. There are risks involved in using groundwater.

Groundwater may contain disease-causing microorganisms which can cause illness. Some groundwater supplies in Victoria have been found to contain high levels of chemical contaminants, such as arsenic, which can cause illness in people who drink the water. Groundwater containing high levels of salts such as sulfate and nitrate can also be harmful.

Other dissolved salts can make the water hard, which can result in scale build-up and corrosion in pipes. This can release harmful metals such as lead and copper into the water.

If mains water is available, use it instead of groundwate

Water in the Ground;

Using a groundwater supply

If you use groundwater as a water supply, contact your local water agency for information on local groundwater quality and suitability of use.

It is important that you understand:

  • the risks of using groundwater
  • the quality of your groundwater supply
  • what use(s) it is suitable for
  • what type of treatment is needed to make groundwater suitable for its intended use – be aware that different treatments are required for different uses. For example, a treatment to remove harmful microorganisms does not remove other types of contaminants that may be present
  • what it cannot be used for
  • how to maintain and monitor your groundwater supply to be sure that it continues to be safe to use.

Anyone with a private water supply should have a water supply management plan to ensure water is suitable for the intended end use and does not pose a human health risk.

Key Victorian water agency websites have information on bore licensing and maintenance, including:

Hazards to groundwater quality

Groundwater quality can be influenced by factors such as the time of year, the depth at which the water is stored, the catchment area (the area of land from which the water is collected and channelled into the groundwater storage) and land uses in that area.

Groundwater can be contaminated by a range of sources including:

  • sewage
  • animal waste
  • agriculture (pesticides and fertilisers)
  • industrial pollution
  • floodwater
  • seepage from rubbish tips
  • polluted stormwater
  • chemical spills
  • contaminated surface waters
  • high levels of naturally occurring chemicals and radioactive substances.

Groundwater Quality

Managing health risks from groundwater

Health risks from groundwater depend on the type and concentration of contaminants in the groundwater, and how often, for how long and in what ways people are exposed to the water (for example, drinking, inhalation, or skin contact).

Disease-causing microorganisms found in water supplies can cause diarrhoea, vomiting or other gastrointestinal illness. Some of these microorganisms can also lead to more serious illnesses, even death.

The people most at risk from unsafe water are the elderly, young children, pregnant women and people with weakened immune systems.

To reduce your risk of ill-health from using contaminated groundwater:

  • Where a mains water supply is available, always use it for drinking.
  • When mains water is not available, choose the next best source of water (see the risk hierarchy below). You may need to treat the alternative water supply to make it safe for drinking.

Image - showing the risk of hierarchy for water sources used in private drinking water supplies

Groundwater Issues in Construction

Considerations for Identification and Evaluation

10 November 2020

Groundwater is found beneath the Earth’s surface in soil pore spaces and rock formation fractures. The flow of groundwater below the surface is a fundamental property that controls the strength and compressibility of soil impacting soil’s ability to hold up on structural loads.

When soil is saturated, the soil media takes on very specific physical characteristics due to the relative incompressibility of water. These characteristics come into effect below the groundwater-surface or table.

Groundwater tables can fluctuate with time. Changes in groundwater surfaces can be slow as they can change seasons, or they can be relatively rapid such as in tidal basins or stormwater detention basins. Groundwater pressure heads can exceed elevation heads and, in those cases, result in water flowing out on the ground surface as artesian flows or springs or swampy wetlands.

Whenever construction must take place below the water table or soil is used to retain water, groundwater affects the project by impacting the function and design of the facility, and the cost of its construction. Groundwater is a frequent cause of disputes between owners and contractors in construction projects.

Common groundwater issues during construction:

  • Unstable subgrade
  • Unstable excavation and water seepage
  • Construction delays and cost overrun

Common groundwater problems after construction:

  • Water leaks, wet basements, and mold growth
  • Cracked and uneven floors
  • Cracked and uneven walls
  • Unstable slopes and retaining walls
  • Delayed movements of foundations

How is groundwater identified and evaluated during planning and construction?

Reconnaissance: Using imagery interpretation and site visits to identify an overview of water table conditions, but often requires subsurface investigations.

Subsurface Investigation: Test borings and/or test pits to depths below the anticipated excavation will be required to define the groundwater depth and conditions including static, perched, and artesian conditions. Groundwater conditions can typically be visually observed in cohesionless soils (sands, gravels, and silty sands) because water can flow more readily through these types of soils. Groundwater conditions in cohesive soils (clay and silty clay) cannot be visually observed for water flow and often need to be tested in the lab. Flow velocities in clays can be less than 1 foot/year.

Due to the slow rate of flow in cohesive soils and wells, piezometers and other subsurface instruments may take days to months to record groundwater changes and pressure. When these changes are paramount to a design process, groundwater reading may require a “zero” volume change device such as a diaphragm transducer to read changes in groundwater head in a real-time environment.

The engineering team responsible for all the phases of a project, from initial planning and budgeting through final construction, needs to be aware of the potential impact of groundwater during design, construction and after construction, so their decisions will be effective.

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