Introduction
Groundwater in the Keith area in the state's South East is part
of the aquifer system that is present throughout the South East.
This groundwater is an important source of water for agriculture.
>> More
There are two separate aquifers in the area - an upper unconfined
aquifer and a lower confined aquifer. The EPA monitors water quality
in the unconfined aquifer. This aquifer is at most risk of being
affected by pollution because the water table is within 5 metres
of the surface. The unconfined aquifer is susceptible to contamination
from past and present agricultural and industrial sources.
Water quality assessment
Water quality is assessed as being in good, moderate or poor
condition by interpreting water chemistry data in the context
of protecting environmental values. >>
More
Groundwater samples are collected annually from seven bores in
the Keith area. The indicators that are measured are nutrients
(nitrogen and phosphorus), heavy metals, arsenic and salinity.
The environmental values that need to be protected are freshwater
ecosystems, irrigation use and livestock use.
Water quality classification for 2005
|
Indicator
|
Ecosystem
|
Drinking Water
|
Irrigation
|
Livestock
|
|
|
NA
|
Good
|
NA
|
NA
|
|
|
NA
|
Good
|
NA
|
NA
|
|
|
Poor
|
NA
|
NA
|
NA
|
|
|
Poor
|
NA
|
Good
|
NA
|
|
|
Good
|
NA
|
Good
|
NA
|
|
|
Good
|
Moderate
|
Good
|
Good
|
| Salinity |
NA
|
Poor
|
NA
|
Poor
|
Notes NA = not applicable
Overall, the groundwater quality in the Keith area is considered
poor for irrigation and livestock water due to its high salinity,
which is largely due to excess irrigation water leaching salts
through the soil. For freshwater ecosystems, the groundwater is
poor because of its high nitrogen concentration, which is most
likely to be due to inappropriate agricultural practices. Total
nitrogen is considered moderate for irrigation because it may
lead to clogging irrigation pipes.
Pesticides in groundwater
Groundwater samples are collected annually and analysed for a
variety of pesticides that may leach into the unconfined aquifer
as a result of past or present agricultural practices. Pesticides
analysed in groundwater samples include several herbicides, fungicides
and insecticides. >> More
If pesticides are detected in an aquifer, the environmental values
of the aquifer are compromised. Therefore, the detection of any
pesticides in groundwater is considered significant and warrants
further assessment and or management response.
The results of groundwater pesticide monitoring in the Keith
area
|
Year
|
1998
|
1999
|
2000
|
2001
|
2002
|
2003
|
2004
|
2005
|
|
Have pesticides been detected?
|
No
|
No
|
No
|
No
|
No
|
NS
|
NS
|
No
|
Notes NS = not sampled
>> Archived results
Download graphs
Download raw water quality data
What is being done to improve groundwater
quality in the South East
The EPA is responding to the groundwater issues in South Australia
in several ways. These include running extensive monitoring programs,
administering the Environment Protection Act through licensing
activities which could affect groundwater, and developing codes
of practice that encourage effective management and protection
of groundwater systems. >> More
The EPA has a regional office in the South East. One of the roles
of this office is to manage and regulate pollution of the aquifers.
Key EPA strategies for managing the pollution stresses include:
- groundwater monitoring programs as core licence conditions
for licensees who could pollute groundwater
- a risk assessment of groundwater contamination associated
with historical and current copper-chrome-arsenate timber treatment
plants
- a risk assessment of pollution threats to Blue Lake is currently
being undertaken as a joint government and CSIRO research project.
This project is intended to link aquifer hydraulics with surface
water pollution threats to provide planning and management tools.
The risk assessment will provide the basis for future groundwater
monitoring in the Mount Gambier region
- presence on regional management boards, engaging the community
and industry and providing guidance
- development of a code of practice for regional stormwater
disposal
- development of a concept model of Blue Lake identifying information
gaps
- monitoring programs targeting key aquifer units and Blue Lake
- commissioning work to investigate long-term trends in nitrate.
This page was last modified 31-10-2006
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