Groundwater

Groundwater is found underground in the spaces and cracks in the soil, sand, and rock and it moves slowly through geologic formations called aquifers.

Groundwater levels can be recharged from surface water, and eventually it flows back to the surface at springs (for example Wanaka Spring, below), seeps or wetlands.

In Otago, some groundwater is extracted for town drinking supplies and agriculture via wells and bores. 

  

Groundwater issues in Otago

A decline of groundwater quantity or quality can be due to natural, hydrological processes, and/or anthropogenic impacts. Natural causes for groundwater quantity or level changes include a period of dry years in an aquifer that is mainly recharged from rainfall.

An example of human impact would be taking an amount of water that causes groundwater levels to decline. A natural hydrological process that can alter groundwater quality or the concentrations of minerals in groundwater is rock-water interaction.

Some ions, such as iron and manganese, can exceed drinking water standards, or guidelines in some parts of the Otago Region without any human intervention.

Anthropogenic impacts refer mainly to land use associated activities such as replacing native vegetation, the use of fertilisers, urbanisation and on-site waste disposal that affect the quality groundwater resource.

 

What is ORC doing to monitor groundwater?

ORC monitors groundwater to ensure a continuing supply for groundwater dependent ecosystems and human use; and to avoid the undesired depletion of aquifers and a decline in the quality of groundwater.

Groundwater levels in Otago are monitored either continuously using automated sites or manually. Groundwater quality is monitored to determine the suitability of groundwater for drinking and other uses. Several key indicators are monitored which are normally grouped to physical, chemical, bacterial, and organic (pesticide). 

Click here to read more about how to protect your groundwater bore head.

For reports and publications about specific Otago aquifers please click here.

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