Surface water and groundwater interaction
Australian states and territories have traditionally managed surface water and groundwater resources as independent systems. This has led to overallocation of resources and adverse environmental impacts. NWI and other initiatives demonstrate the increasing recognition of the connectivity between surface water and groundwater systems and the need to plan and manage accordingly.
Springs are an obvious expression of surface-groundwater interaction
Because of the current structures of most state and territory departments, questions regarding connectivity are generally answered from a surface water perspective and then from a groundwater perspective, which reflects a lack of joint management.
Only a small number of surface water management plans consider groundwater as part of their resource management process. The majority do not take groundwater into consideration directly and rely on groundwater management plans to consider surface water allocations and environmental water requirements. There are some exceptions, with more recent area and regional management plans across the country taking a more inclusive approach to surface water and groundwater interactions.
For groundwater management plans, the most common approach is to rely on statewide policy to ensure that surface water is considered. Only recently written plans include more comprehensive and specific controls for groundwater and surface water interactions in the day-to-day licensing, management and operation of the resource.
NWI objective of recognising connectivity
The National Water Initiative (NWI) has set a specific objective of recognising the
connectivity between surface and groundwater resources' and the need to manage
these connected systems as a single resource. Objective X (10) of the National
Water Commission Act 2004 , and the Intergovernmental Agreement on a National
Water Initiative (NWI) specifically address the need for more integrated management
of surface water and groundwater resources.
Under the NWI, states and territories are required to identify systems that
have close interaction of surface water and groundwater and to establish integrated
annual accounts for these systems.
From a groundwater perspective, groundwater management plans generally include
allowances for surface water through streamflow interactions (river baseflow).
In many cases, this as far as the assessment goes. In a minority of groundwater
management units the management plans detail more specific groundwater surface
water interaction management actions and environmental water requirements,
such as in groundwater dependent ecosystems. In other cases, statewide licensing
regulations dictate that bore interference assessments on other users (including
surface waters) must be undertaken prior to the granting of new groundwater
extraction licenses.
Further information on the technical and policy aspects of groundwater surface
water interaction and conjunctive management can be found at the Department
of Agriculture, Fisheries and Forestry (DAFF)
and Natural Heritage
Trust websites.
The Connected
Water website has been developed by BRS to progress a coordinated approach
to managing surface and groundwater resources in Australia. It is intended to
provide an up-to-date resource for water managers, policy makers and catchment
management groups.
Summary assessment
Of the surface water management plans that take groundwater into account only
four (within the Australian Capital Territory, New South Wales and South
Australia) include groundwater as part of the environmental water requirements
with direct allowances given. All others include groundwater indirectly.
There are many water management areas in which surface water and groundwater are not managed as an integrated resource. This is primarily because the connection between the resources is either unknown and has not been assessed, or because there is minimal connection between the resources, or because there is no consideration of the interconnection within the plan. The Murray-Darling Basin Ministerial Council Cap is an example of where a surface water cap on diversions has been in place for a number of years, but where the integrity of the cap is compromised through there not being an equivalent cap on groundwater extractions across the basin.
The extent to which surface water and groundwater were planned and managed together in draft and final water management plans was identified as part of the Level 1 Assessment. It was found that 14 of 63 of these surface water management plans in 2004-05 considered groundwater in their development, while 78 of 120 of these groundwater management plans considered surface water. Eight surface water management areas had combined final surface water and groundwater plans in 2004-05. This suggested surface water planning and management less commonly considered groundwater, than groundwater management planning, and lack of knowledge of connectivity and separate management of systems across state borders can be a barrier to integrated management.
Barriers to integrated management
One of the barriers to managing the resource conjunctively has been that groundwater
unit boundaries sometimes cross traditional surface water catchments, so it
is difficult to define the actual area to be designated for management. In
other areas there is no connection because the groundwaters are deep (e.g.
most of the Great Artesian Basin , except the recharge areas at the eastern
and northern margins) or surface water is non-existent (e.g. Central Australia
).
The variation across the country has meant each jurisdiction has developed
its own policies and management practices to deal with groundwater and surface
water interactions. It has generally only been where the resource is highly
developed that impacts of extraction from groundwater on surface water( and vice
versa) have been noted, and management plans changed to take this into
account. Integrated management of groundwater and surface water also requires a detailed
understanding of the degree of connectivity between the two resources. Only
limited technical information on the degree of connectivity between groundwater
and surface water is available across Australia and more detailed on-ground
assessments of connectivity need to be completed to improve the level of integrated
management of groundwater and surface water resources nationally.
There are many surface water management areas and groundwater management
units in which surface water and groundwater are not managed as an integrated
resource. This is primarily because the connection between the resources is
either unknown and has not been assessed, or because there is minimal connection
between the resources, or because there is no consideration of the
interconnection within the plan. The Murray-Darling Basin Ministerial Council
Cap is an example of where a surface water cap on diversions has been in place
for a number of years, but where the integrity of the cap is compromised through
there not being an equivalent cap on groundwater extractions across the basin.
There are 17 groundwater management units where groundwater and surface water
resources are managed under combined plans. These are in New South Wales (seven),
Queensland (four), the Northern Territory (four) and South Australia (two).
Apart from these 17 units, the resource is managed separately in most of Australia
(including these states named above), except for some areas that have recently
had plans updated or are currently being reviewed.
Summary comments on surface water / groundwater interaction are provided for
all water management areas on the
Regional
water resources assessments page under the management tabs.
Below are summary comments for each state and territory:
Australian Capital Territory
All groundwater in the Australian Capital Territory is managed in conjunction
with surface water through the use of combined surface water and groundwater
management plans for short-term and long-term interaction.
New South Wales
In New South Wales , new water sharing plans that integrate surface water
and groundwater came into effect on July 2006. They are based on policy changes
for inland waters that were implemented in 2003.
Northern Territory
The Northern Territory manages four groundwater management units in a conjunctive
manner (with an additional one in progress). In all cases, this is accomplished
through using a combined surface water and groundwater management plan for
short-term and long-term impacts. In addition, there are two groundwater management
units (Mereenie Sandstone Alice Water Control District and Ti Tree) that
are assumed to have minimal connection. Elsewhere in the Northern Territory
, there is no conjunctive management because the connectivity is unknown.
Queensland
Queensland manages water resources conjunctively for those areas under finalised
water resource plans (covering 27 per cent of water resource plan areas).
South Australia
There are two groundwater management units (water management areas) in South
Australia where groundwater and surface water resources are managed under combined
plans (Barossa and Clare valleys). In the Eastern and Western Mount Lofty Ranges
, which are subject to notice of intentions to prescribe, all the water resources,
surface water and groundwater will be managed under combined water allocation
plans.
Tasmania
In Tasmania , the Water Management Act 1999 allows for integrated
management of surface water and groundwater resources. Groundwater management
provisions are included in surface water management plans as appropriate.
Victoria
The Victorian Government is undertaking a statewide project to better understand
the interaction between groundwater systems, surface water systems and groundwater
dependent ecosystems. Assessments of the connectivity of surface water and
groundwater have been undertaken for approximately 50 per cent (32 of 62) of
the groundwater management units across Victoria .
Western Australia
In Western Australia , the Collie Group and Collie Nakina aquifers in the
Collie groundwater management unit and the Carnarvon Superficial aquifer in
the Carnarvon groundwater management unit are managed in conjunction with surface
water. For the Collie Group aquifer, this is achieved using separate surface
water and groundwater management plans that allow for short-term and long-term
impacts. For the Collie Nakina aquifer this is done through implementation
of the strategy agreed in 1999 for water resources management in the Collie
basin. The Carnarvon groundwater management unit uses a combined surface water
and groundwater management plan that allows for short-term and long-term impacts.
Your location:
|