The History of Groundwater Management in the South East of South
Australia
Towards Achievable Sustainability?
Ludovic Schmidt
Department for Environment, Heritage and Aboriginal Affairs, South
Australia
ABSTRACT
Since European settlement began in the area in the middle of the 19th
Century, land use practices have had a considerable impact on the hydrological
cycle in the region and on the quality of the groundwater. The removal
of more than 90% of native vegetation and its replacement with shallow
rooted crops and plantation forestry have greatly altered recharge patterns.
Comprehensive surface drainage schemes have also been implemented over
most of the region. Point-source and diffuse-source contamination
of groundwater from the surface has occurred. Salinisation of groundwater
has resulted from the mobilisation of salts in the unsaturated zone and
from irrigation-induced concentration of salts.
Legislative controls on the use of groundwater were first introduced
in the late 1960s. Legislation has progressively moved from treating
groundwater as a commodity in isolation to recognising the groundwater
as part of the broader environment. There was little recognition and consideration
given initially to the role of groundwater in the broader environment.
Management has also moved from being reactive to being proactive, from
trying to fix up problems after they have occurred to trying to prevent
problems from developing.
Current legislation aims for ecologically sustainable development, but
pressures for economic development, vested interests and political reality
will make this difficult to achieve. New legislation allows for the
empowerment of local communities in management of the groundwater resource,
reducing the direct influence of political pressure and centralised government.
The major challenges faced are in defining sustainability and then developing
and implementing policies which achieve it in the face of numerous competing
pressures.
THE HISTORY OF USE OF THE GROUNDWATER
Aboriginal use:
-
Coastal and inland springs
-
Sinkholes, caves
European settlement:
-
Cave Gardens, Englebrecht Cave and Umpherstone Cave were the first water
supplies for Mount Gambier.
-
Blue Lake has been the main public water supply for the greater Mount Gambier
area since 1883.
-
Development of town water supplies across the region from groundwater bores,
in both the upper unconfined aquifer and the lower confined aquifer.
-
Gouldens Waterhole and Little Blue Lake, for example, were modified to
allow stock access for drinking water.
Development of irrigation
-
Early history; very limited irrigation due to the difficulty of extracting
the large volumes of groundwater required.
-
Rapid expansion from 1950s onwards due to the development of new technology
such as turbine pumps, travelling irrigators and centre-pivot irrigators.
The recent use of the groundwater resource
WATER USE
|
PRESENT
|
1984
|
|
Megalitres (Ml)
|
Megalitres (Ml)
|
Irrigation: |
|
|
Unconfined aquifer |
141 000
|
200 000
|
Confined aquifer |
32 000
|
37 000
|
Public water supply |
7 700
|
8 800
|
Stock supplies |
17 000
|
|
Available resource (estimated ‘sustainable’ yield):
Upper unconfined aquifer 863 000 Ml
Lower confined aquifer ~ 100 000 Ml
Economic value of the resource
Total farm gate value of irrigated products in 1997 was $100 million.
The value added per megalitre of water use varies by a factor of about
40 between different uses.
VALUE ADDED PER MEGALITRE ALLOCATED FOR IRRIGATION
Product
|
$/Ml
|
Meat from pasture |
150
|
Pasture seed production |
500
|
Dairying |
750
|
Potato growing |
800
|
White wine grapes |
3500
|
Red wine grapes |
5000
|
Paper and pulp mill |
6000
|
Meat from pasture Pasture seed production Dairying Potato growing White
wine grapes Red wine grapes Paper and pulp mill 150 500
750 800 3 500 5 000 6 000
DEVELOPING PROBLEMS WITH THE GROUNDWATER SYSTEM
-
Altered recharge patterns due to vegetation changes, increasing or decreasing
the recharge rates, which affect the hydrological equilibrium of the groundwater
systems.
-
The removal of native vegetation has also led to salinisation of the groundwater
in some areas due to the increased flushing of salts stored in the soil
profile resulting from the increased recharge rates.
-
Extensive surface drainage of the region has also altered the hydrological
equilibrium.
-
Irrigation resulting in changes in groundwater levels and increases in
salinity levels due to evapo-transpiration and flushing of salt from the
soil profile.
-
Changes in nutrient cycles from highly efficient natural ecosystems to
relatively inefficient farming systems
Recognition of developing problems
Subsurface drainage of pollutants;
-
Department of Mines reports in 1930s and 1940s
-
Mil Lel and other cheese factories, underground disposal of effluent
-
Sewage disposal in Mount Gambier, directly into sinkholes or bores, or
via septic tanks
-
Rubbish disposal into sinkholes and landfills
Engineering & Water Supply Department;
-
pollution reports in 1970s identifying some sources
-
closure of town water supply bores near Mount Gambier in 1970s due to nitrate
and bacterial contamination
-
nitrate in the Blue Lake, increased in the 1970s but has stabilised since
Salinisation of groundwater in the Padthaway and Tatiara areas was first
investigated in the 1970s and 1980s.
Diffuse source contamination of groundwater from land management practices
was first recognised in the late 1970s. This is the major source
(about 90 %) of nitrate contamination to the groundwater, especially in
the lower South East region.
HISTORICAL LEGISLATION
Underground Waters Preservation Act 1969
Mainly concerned with trying to bring in controls on water level changes
resulting from use of groundwater.
Water Resources Acts of 1976 and 1990
Use of water resources committees, with a majority of private members,
to advise the Minister via the South Australian Water Resources Council
on how the resource should be managed.
Objects of Water Resources Act 1990:
-
Recognition of water resources as one of the most important natural resources
and that it is a limited resource
-
Mentions sustainability, water in the environment and preservation of ecosystems
-
Covers both water quality and water quantity issues
There were, however, poorly defined mechanisms in the Act on how these
objects would be achieved.
CURRENT LEGISLATION
Groundwater (Border Agreement) Act 1985
Provides a mechanism for limited cross-border management of the groundwater
resource between Victoria and South Australia. Sets the Permissible
Annual Volumes (sustainable yield) for zones within 20 km of State border.
The committee and the technical working group set up under this legislation
has developed much of the technical basis of groundwater management in
the whole region. This has also been widely adopted as the basis
for groundwater management in other parts of South Australia and in Victoria.
Water Resources Act 1997
Object:
A clear statement of the fundamental elements of ecologically sustainable
development – the use and management of resources in such a way that those
who rely on those resources today will reap the best environmental, social
and economic gain from them, whilst not compromising the ability of future
generations to reap those same benefits.
Principles:
Council of Australian Governments (CoAG) agreement on the reform of
the water industry:
-
Institutional separation of water resource managers and water users
-
Water ‘pricing’ - user pays to recognise the economic value of the resource
-
Water allocations and entitlements recognised as tradeable property rights
separate from land titles
-
Water for the environment - allocations must be made for environmental
requirements.
Mechanisms:
-
Local management planning focussed on catchment-based areas and the knowledge
and experience of local communities
-
Strong strategic direction from central Government
Environment Protection Act 1993
Objects:
Based strongly on the principles of ecologically sustainable development.
Principles:
Based on the Intergovernmental Agreement on the Environment, and national
policies set by the National Environment Protection Council.
Mechanisms:
-
Authorisations – licences, exemptions, works approvals
-
Orders to prevent and clean up pollution
-
Policies – codes of practice, area management plans, guidelines
HISTORY OF GROUNDWATER MANAGEMENT
Until recently, management has been largely reactive, with regulation
and active management only brought in once serious problems have developed
with the resource, such as severe salinisation or over-extraction.
The proclamation of the Lacepede-Kongorong area in 1997 has been the first
attempt to bring in pro-active management, to manage the development of
the resource in order to prevent problems from developing in the first
place.
Area
|
Year proclaimed
|
Padthaway |
1975
|
Tatiara |
1984
|
Naracoorte Ranges |
1986
|
Comaum-Caroline |
1986
|
Lacepede-Kongorong |
1997
|
Tintinara-Coonalpyn |
1999 (put under restriction)
|
General policies:
-
Licence required to take water for all major uses
-
Permissible Annual Volume based on the long-term annual vertical recharge
to the upper, unconfined aquifer
-
An area-based, rather than volumetric, allocation system is used
-
Allocations granted to existing users at the time of proclamation
-
Water trading – permanent and temporary, limited to local management areas
and subject to a hydrogeological assessment
-
Hydrogeological assessment required of all applications for new allocations
and for transfers to determine the impacts on the resource and on other
users of the resource
-
Irrigation Development and Management Programs are required for all new
developments to ensure the water allocation is developed and used
THE FUTURE OF GROUNDWATER MANAGEMENT
Major issues:
-
Salinisation of groundwater from irrigation, and mobilisation of salts
stored in the soil profile due to increased recharge resulting from removal
of native vegetation
-
The major limiting factor on the future use of the groundwater, especially
for irrigation, will be increasing salinity and environmental water needs,
rather than the volume of water available
-
Diffuse-source groundwater contamination from the intensification of agriculture
and other land uses
-
Defining and meeting environmental requirements for groundwater
-
Defining sustainable limits on groundwater use and the trade-offs involved
-
Reducing the influence of politics and vested-interest groups, and increasing
the input of scientific knowledge in groundwater management decisions
-
The lag between the technical information available and the information
needed for good decision-making.
-
Integrating groundwater management with surface water management and broader
natural resource management – towards integrated natural resource management
-
Integration of natural resource management with economic management – internalising
the costs of environmental management. Can we really achieve user
pays? There is very strong resistance to this from those with vested
economic interests, probably because they are not able to pass this cost
on to the consumers of goods produced from the use of natural resources.
Mechanisms are needed so that the full costs of the use and management
of natural resources are reflected in the prices paid by the ultimate consumers
of the resource or products derived from it.
Conclusions
This quote from Dr John Williams, Deputy Chief of CSIRO Land and Water,
encapsulates the issues we face in management of land and water resources:
“Our rural production has been built by drastically changing the nature
and seasonal patterns in the water and nutrient cycles of the continent.
Our present systems are not sustainable because they leak water and nutrients.
We desperately need solutions to plug the leaks and capture both water
and nutrients for productive use”
Current legislation aims for ecologically sustainable development, but
pressures for economic development, vested interests and political reality
will make this difficult to achieve.
New legislation allows for the empowerment of local communities in management
of the groundwater resource, reducing the direct influence of political
pressure and centralised government. The major risk is that these
local community groups can be ‘hijacked’ by vested interest groups, especially
if the groups are political appointees.
Historically, groundwater management has moved from an engineering focus
to the current ‘economic rationalist’, economic-commodity-based focus.
Future management needs to fully recognise and adopt a broader, environmental-ecological
focus, with economic and engineering factors being considered within this
over-riding context.
The major challenges faced are in defining sustainability and then developing
and implementing policies that achieve it in the face of numerous competing
pressures. |