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Catchment Water Management Plan – VOLUME 3
Water Allocation Plan
Northern Adelaide PlainsPrescribed Wells Area
This report has been prepared with the assistance of the Northern Adelaide
Plains Catchment Committee for the Northern Adelaide and Barossa Catchment
Water Management Board.
December 2000
I Mark Brindal, Minister for Water Resources, hereby adopt this
Water Allocation Plan pursuant to section 104 of the Water
Resources Act 1997.
Hon Mark Brindal MP
Minister for Water Resources
Date: 22.12.2000
For further information contact:
Northern Adelaide and Barossa Catchment Water Management Board
1st Floor, 59 Commercial Road, Salisbury SA 5108
Telephone: (08) 8285 2033
Facsimile: (08) 8285 2133
Email: nab.office@cwmb.sa.gov.au
Web: www.catchments.net/nab
Northern Adelaide and Barossa Catchment Water Management Plan – Volume 3
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Contents
1. Northern Adelaide Plains Prescribed Wells Area 1
1.1 Underground Water Resources of the Northern Adelaide Plains Prescribed Wells Area 1
1.2 Natural Recharge Mechanisms 3
2. Assessment of Needs of Dependent Ecosystems 4
2.1 The Gawler River 4
2.2 Little Para River 4
2.3 Buckland Park 5
3. Assessment of Effect on Other Water Resources 6
4. Assessment of Capacity of Resources to Meet Demands 7
4.1 Demands 7
4.2 Current Status of the Tertiary Aquifer Systems 7
4.3 Capacity of Resource to Meet Demands 8
5. Water Allocation Criteria 10
5A. Water Allocation Criteria for Recharged Water 12
6. Transfer Criteria 14
7. Permits 16
7.1 Water Affecting Activities 16
7.2 Drilling, Plugging, Backfilling or Sealing of a Well 16
7.3 Repairing a Well 17
7.4 Draining or Discharging Water into a Well 17
7.5 Importation of Water 18
7.6 Use of Effluent 19
8. Monitoring 20
9. Miscellaneous 22
10. Glossary 23
Figures
1 Cross section of the Northern Adelaide Plains aquifers and confining layers
2 Northern Adelaide Plains Prescribed Wells Area
3 T1 Cone of Depression around Waterloo Corner and Penrice
4 T2 Cone of Depression around the Virginia/Angle Vale area
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1. Northern Adelaide Plains Prescribed WellsArea
The Northern Adelaide Plains Prescribed Wells Area covers approximately 800 km2 of an area
centred 30km to the North of Adelaide (Figure 2). The area was initially proclaimed under the Water
Resources Act 1976 by notice in the South Australian Government Gazette dated 13 May 1976 at
page 2459. Pursuant to clause 2(1) of the Water Resources Act 1997 (the Act), the proclamation in
1976 is in force as though it declared the wells in the Proclaimed Region to be prescribed wells under
the 1997 Act. The area is now known as the Northern Adelaide Plains Prescribed Wells Area. The
area contains relatively fertile soils underlain by a series of water bearing beds of sand, gravels and
limestone aquifers which are used as a source of irrigation water.
1.1 Underground Water Resources of the Northern Adelaide Plains PrescribedWells Area
The Northern Adelaide Plains are formed by Tertiary and Quaternary sediments up to 600 metres
thick which contain numerous aquifer systems. The sediments are of deltaic origin formed by the
accumulation of sediments from the surrounding hills. Figure 1 features a cross-section of the
resource showing the Tertiary and Quaternary aquifers and the flow of water in those aquifers.
1.1.1 Quaternary Aquifer Systems
The Quaternary sediments contain up to six thin aquifers comprising mainly of clay and silt with thin
layers of sand which form minor unconfined and semi confined systems. Measurements of
groundwater salinity recorded in the shallow upper aquifers (referred to as Q1 and Q2) are generally
high, ranging from 2000 mg/L to 15,000 mg/L towards the coast. Salinity in the deeper Quaternary
aquifers tends to decrease with depth and ranging from 1500 mg/L to 3000 mg/L in the (Q3)
Quaternary sediments. However, in some areas, the shallow sandy Quaternary aquifers (Q1 and Q2)
situated near the Gawler and Little Para Rivers generally exhibit low salinity ranging from 400 mg/L to
1500 mg/L. These salinities reflect the influence of winter recharge from the rivers. The Quaternary
aquifers are not generally used for commercial irrigation purposes because of low yields and salinity
problems.
1.1.2 Tertiary Aquifer Systems
The underlying Tertiary sediments contain several aquifer systems that exhibit significant variations in
thickness, lithology, salinity distribution and yield. There are two main deep aquifers that act as the
primary source of irrigation water in the region.
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• T1 Aquifer
The shallowest Tertiary aquifer, known as T1, is the main source of irrigation water in the area
south of Waterloo Corner. The top of the aquifer is approximately 60 metres below ground and is
composed of Dry Creek sands and Port Willunga limestone. It is wedge shaped with an average
thickness of 70 metres in the south, thinning out as it nears the Gawler River.
Underground water salinity ranges from 600 mg/L to 2000 mg/L with lower salinities recorded
near the Little Para River to the south. The aquifer is hydraulically connected to the overlying
Quaternary aquifer (Q4), which has a salinity ranging from 1820 to 4850 mg/L, and is separated
from the underlying aquifer by a layer of impervious clay to sandy, silty clay, which extends over
the entire region south of the Gawler River, although this is thin or intermittent in the vicinity of
Waterloo Corner.
• T2 Aquifer
The second underlying Tertiary aquifer known as T2 occurs throughout the entire region. It
consists of a large, water bearing layer of well-cemented lower Port Willunga formation limestone
which has a thickness between 80 and 120 metres. Salinity levels range from 600 mg/L in the
Gawler River area to greater than 3000 mg/L to the north and south. The T2 aquifer is generally
not used for crop irrigation purposes in areas south of Waterloo Corner due to high salinity levels
and the depth of the aquifer in that region.
• T3 and T4 Aquifers
Two other deeper water bearing aquifers (T3 and T4) have been identified in the area. However,
underground water salinity in these saturated sediments exceeds that in T1 and T2 and has been
as high as 80,000 mg/L, which is totally unsuitable for any form of crop irrigation use.
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Figure 1 - Cross section of the Northern Adelaide Plains aquifers and confining layers
1.2 Natural Recharge Mechanisms
The main source of recharge for the Tertiary aquifers of the Northern Adelaide Plains is from the
rainfall-fed fractured rock aquifers in the Mt Lofty Ranges to the east of the prescribed area. The
higher elevation of the Mt Lofty Ranges acts to pressurise water, which flows laterally in a westerly
direction through the fractured rock aquifers of the ranges into the Tertiary aquifers of the Plains
(Figure 1).
In the period prior to the major expansion of underground water irrigation in the region, the main
aquifers were sufficiently pressurised to ensure that most wells west of Port Wakefield Road were
free flowing (artesian) approximately 10 to 15 metres above ground level. However, levels began to
decline dramatically in the 1930s due to increasing irrigation activity. By the 1940s T1 and T2 were
no longer artesian and by the 1960s intensive pumping had resulted in the formation of a cone of
depression (the area around a pumping zone where the level of underground water is lowered by
pumping) around Virginia and the Little Para River.
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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2. Assessment of Needs of DependentEcosystems
Information on the extent of underground water dependent ecosystems in the Northern Adelaide
Plains Prescribed Wells Area is extremely limited. There are no known ecosystems that are
dependent on the deep Tertiary aquifers of the Northern Adelaide Plains Prescribed Wells Area. It is
likely that ecosystems associated with the Gawler River and Little Para River and the estuarine
wetland of Buckland Park have a level of dependence on the shallow sandy Quaternary (Q1)
underground aquifers of the region.
2.1 The Gawler River
The underground water dependent ecosystems associated with the Gawler River environment
include riparian communities dominated by river red gums (Eucalyptus camaldulensis) and a diversity
of in-stream vegetation including Cyperaceae sp, Juncus sp and Typha. Other ecosystems
dependent on underground water include fauna communities living in the shallow sandy Q1 aquifers
(known as hypogean fauna) and watercourse sediments (known as hyporheic fauna) of the region.
2.1.1 Environmental Requirements for Dependent Ecosystems of the Gawler River System
Recent studies suggest that the riparian communities of the Gawler River system depend upon the
maintenance of the natural discharge regime whereby approximately 5000ML of watercourse water is
lost as groundwater recharge to the shallow sandy Quaternary (Q1) aquifer of the Gawler River.
These recharge events occur on a seasonal basis over three to four months during the winter period
and serve as a means of reducing underground water salinity. The available information suggests
that the riparian ecosystems require the water quality of the shallow sandy Quaternary (Q1) aquifer to
be maintained at present levels. The salinity of the shallow aquifer should therefore remain at
relatively low level, ranging from 400mg/L to 3000 mg/L. The volume of water associated with the
current flow regime should also be maintained at current levels as the minimum requirement for
groundwater dependent ecosystems associated with the Gawler River system.
2.2 Little Para River
The underground water dependent ecosystems associated with the Little Para River environment
include riparian communities dominated by river red gums (Eucalyptus camaldulensis) Acacia sp and
a diversity of in-stream vegetation including Cyperaceae sp, Juncus sp and Typha and Phragmites
sp. Other ecosystems dependent on underground water include fauna communities living in the
shallow sandy Q1 aquifers (hypogean fauna) and watercourse sediments (hyporheic fauna) of the
region.
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2.2.1 Environmental Requirements for Dependent Ecosystems of the Little Para System
The structure and diversity of the riparian communities of the Little Para System are similar to those
found in the Gawler River system. The underground water dependent ecosystems of the Little Para
River require the maintenance of the natural discharge regime whereby approximately 1200 ML of
surfacewater flow is lost as groundwater recharge to the shallow sandy Quaternary (Q1) aquifer.
These recharge events usually occur over the winter period. The available information also suggests
that these riparian ecosystems of the Little Para system require the water quality of the shallow sandy
Quaternary (Q1) aquifer to be maintained at present levels. The salinity of the shallow aquifer should
average less than 2,000 mg/L. The volume of water associated with the current flow regime should
also be maintained at current levels as the minimum requirement for groundwater dependent
ecosystems associated with the Little Para River system.
2.3 Buckland Park
Buckland Park is an estuarine wetland, which was artificially created by damming the deltaic mouth of
the Gawler River system (Figure 2). There is considerable variation in the filling and drying regime of
the wetland from year to year. The wetland is often filled during the winter period with flood flows
from the Gawler River. These flows have the effect of reducing salinity levels in the wetland. The
decrease in salinity allows the growth and development of a range of freshwater invertebrates and
aquatic plants including Muehlenbeckia sp, Halosarcia sp and Typha sp. The wetland system also
hosts a diversity of migratory and resident waterbirds. The number of waterbirds using the wetland
fluctuates seasonally and is linked to changes in wetland water levels.
2.3.1 Environmental Requirements for Dependent Ecosystems of Buckland Park Wetland
There is no information available on the extent to which underground water contributes to inundation
of the Buckland Park system. However, the hidden lateral flows of underground water from the
Gawler River system may assist with maintaining water quality during periods of freshwater
inundation. These seasonal flows are associated with watercourse water flows that occur over the
winter period and are necessary to reduce wetland salinity. The available information suggests that
the quality of water and the volume of hidden lateral flow associated with the Gawler River system
should be maintained at present levels as the minimum requirement for the ecosystems of the
Buckland Park system.
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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3. Assessment of Effect on Other WaterResources
There is currently no evidence to suggest that the taking of underground water from the Tertiary
aquifers in the Northern Adelaide Plains Prescribed Wells Area has caused any detrimental impact to
surfacewater resources in the region. The bulk of underground water extractions in this area occur
during the summer period from the deeper, mostly confined, Tertiary aquifers (T1 and T2). There is
little, if any, hydraulic connection between the surfacewater resources and the main production
aquifers of the region. The underground water resources outside the Northern Adelaide Plains
Prescribed Wells Area experience pressure fluctuations as a result of heavy level of use within the
Northern Adelaide Plains Prescribed Wells Area over the summer period. There is no evidence to
suggest that these pressure variations are having a detrimental impact on the underground water
resources outside the prescribed area.
The best available information suggests that the present rate of underground water use from the
shallow Quaternary aquifers has no detrimental impact on surfacewater resources in the region.
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4. Assessment of Capacity of Resources toMeet Demands
4.1 Demands
4.1.1 Underground Water Extractions from the Aquifer Systems
Water users in the Northern Adelaide Plains Prescribed Wells Area rely heavily on the extraction of
underground water from the Tertiary aquifers for industrial use and crop irrigation purposes. The bulk
of the extractions occur from the T1 and T2 aquifers. The average use over the last 10 years is
18,000 ML per year which is pumped from over 1200 wells spread throughout the region.
The extraction rate has been fairly constant for the last decade. Most of the underground water
utilised in the Virginia/Angle Vale area is drawn from T2 aquifer. Total extractions from this aquifer
have been calculated at 13,500 ML per year on average. Most of the water (10,000 ML) is pumped
from the aquifer during the summer months.
Extractions from the T1 aquifer occur in several main pumping centres including the Waterloo Corner
region, where an average of 1500 ML to 2000 ML of underground water is used per year. T1 aquifer
is also used extensively for industrial purposes. A large industrial company located within the
Northern Adelaide Plains Prescribed Wells Area also draws approximately 1500 ML to 2000 ML per
year of low quality (saline) underground water for processing of its products.
An estimated 500 ML per year of underground water is extracted from the Quaternary aquifers (Q1-
Q4) within the prescribed area. The Quaternary aquifers are not normally used as a source of water
for commercial irrigation because of low yields. Most of the water extracted from the Quaternary
aquifers is used for stock and domestic purposes.
4.1.2 Demands of Ecosystems that Depend on the Resource
It has previously been stated that there are no known ecosystems that are dependent on the deep
Tertiary aquifers of the Northern Adelaide Plains Prescribed Wells Area. The quantity of water
required by ecosystems dependent on the Quaternary (Q1) aquifer is the quantity required to
maintain the present underground water levels of the aquifer.
4.2 Current Status of the Tertiary Aquifer Systems
The current total water allocation on water licences in the Northern Adelaide Plains Prescribed Wells
Area is 26,500 ML per year. The average use over the last 10 years has been 18,000 ML per year,
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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however, in dry years, use has exceeded 24,000 ML. It is a matter of general policy that no additional
underground water has been allocated since the early 1970s.
Recent hydrogeological investigations have continued to identify two major problems associated with
the current level of underground water use in the region. The problems concern water level decline
and increasing underground water salinity levels.
The water level recorded in T1 aquifer has declined by 10 to 30 metres in the area around Waterloo
Corner over the last 30 years where a steep cone of depression has developed, mostly as a result of
intensive irrigation (Figure 3). The decline is in response to a number of factors including the intensity
of pumping during summer. The water level does not recover completely during winter, partly as a
result of pumping during the winter period.
The major pumping regions drawing water from T2 aquifer are centred in Virginia, Angle Vale and the
area north of the Gawler River. The extraction rates of underground water from these areas have
been relatively constant over the last 15 years. However, monitoring has shown that the aquifer
water level has declined by approximately 70 to 75 metres in the centre of the irrigation area over the
last 40 to 50 years. The cone of depression that exists in the T2 aquifer is characterised by a drop of
several metres during the heavy irrigation periods of summer and a slower incomplete recovery over
winter, causing the cone to progressively expand and spread laterally over a large portion of the
irrigated area until it reaches a new equilibrium (Figure 4).
Over the last 30 years, the average salinity recorded in the Tertiary aquifers of the Northern Adelaide
Plains has increased by 200mg/L in some parts of the T2 aquifer and up to 800mg/L in the T1 aquifer
near Waterloo Corner. The increases in salinity are related to the current rate of underground water
use from the Tertiary aquifers.
4.3 Capacity of Resource to Meet Demands
The capacity of the resource is presently insufficient to meet the current demands for water use in the
Northern Adelaide Plains Prescribed Wells Area without causing detrimental impacts on the
underground water resources of the area. The current level of underground water use in the Northern
Adelaide Plains Prescribed Wells Area is therefore in excess of what is considered to be an
acceptable safe yield because of the problems associated with the potentiometric surface (the
theoretical water level in an underground aquifer as determined by the pressure within that aquifer)
and underground water salinity.
The hydrogeology of the Northern Adelaide Plains aquifer system is extremely complex. The ability
to quantify an acceptable safe yield of underground water from the aquifer system is dependent upon
regular monitoring of underground water levels, extraction rates, salinity trends and a range of other
variables which can vary over time. The recent investigations on recharge mechanisms in the
Northern Adelaide Plains suggests that a single numerical value reflecting an estimated rate of
recharge does not represent a realistic measure of the volume of water that can be extracted from the
aquifer system without inducing unacceptable impacts on that system. The unacceptable impacts
would include increases in underground water salinity, losses of elastic storage, reduction in pressure
and water level decline to an unconfined situation.
The acceptable safe yield for the Tertiary aquifers of the Northern Adelaide Plains Prescribed Wells
Area lies within a range of predetermined potentiometric surface levels. The range can vary over
different periods (summer and winter), and in accordance with external influences such as the use of
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imported water (Bolivar reclaimed water) in the region. The limits to that range will reflect a yield
which can be sustained over a specific timeframe without causing unacceptable impacts on the
aquifer system or on the users who rely on the availability of good quality underground water.
The underground water levels need only be a few metres above the confining layer of each
production aquifer (T1 and T2) during the high demand period over summer provided that they rise to
an acceptable level in the aquifer(s) during the low demand winter period. The underground water
levels would need to rise to a point that would allow sufficient pressure recovery in the relevant
aquifer in order to minimise potential leakage from high salinity aquifers in the region (Q1, Q2, T3,
T4).
Regular monitoring will provide data that can be used for numerical modelling to predict an
acceptable safe yield of underground water use in the Northern Adelaide Plains Prescribed Wells
Area. The results of modelling will determine the extent of draw-down that can be tolerated over
summer and the rate of water level recovery that will be necessary over the winter period to maintain
an acceptable level of underground water use in the region.
In the absence of such modelling it is not possible to give an estimate of the volume of water that
represents an acceptable level of water use at this stage. However, it is clear that current use is
significantly above what can be considered an acceptable safe yield. The evidence shows that
underground water levels are continuing to decline and salinity is increasing in some areas of the
aquifer system.
At this stage it is not possible to predict the effect that the use of reclaimed water from the Bolivar
Reclaimed Water Treatment Plant will have on the capacity of the underground water resource to
meet demand for water in the area.
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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5. Water Allocation Criteria
The following objectives and principles apply to the taking and use of water from the Northern
Adelaide Plains Prescribed Wells Area.
The Northern Adelaide and Barossa Catchment Water Management Board, in formulating these
objectives and principles, has considered:
• the present needs of the occupiers of land situated within the Northern Adelaide Plains
Prescribed Wells Area for water and their anticipated future needs
• the anticipated future capacity of land and the prescribed water resource within the Northern
Adelaide Plains Prescribed Wells Area for new uses
• the likely effect of the criteria for the allocation of the prescribed water resource on the value of
the land within the Prescribed Wells Area.
The present day uses of water by landholders in the Northern Adelaide Plains Prescribed Wells Area
largely include irrigation for horticultural production, commercial/industrial use, recreational water use
as well as stock and domestic use. The present needs for water by landholders is approximately
18,000 ML per year.
The use of water for stock and domestic purposes is expected to remain stable. Commercial
irrigation for horticulture will continue to place the greatest demands on the prescribed water
resources of the Northern Adelaide Plains.
The area of arable land within the Northern Adelaide Plains Prescribed Wells Area covers
approximately 16,000ha; however, at the present time only 4,500ha of land is used for horticultural
production. It can therefore be seen that the capacity of the land can sustain existing irrigation and
there is considerable potential for future irrigation development. The limiting factor to future irrigation
development will be access to water.
It is expected that the potential future demand for water can be met through the use of imported water
from the Bolivar reclaimed water scheme which can deliver approximately 22,000 megalitres of
reclaimed water for irrigation purposes to the region. Other options will include the use of water from
aquifer storage and recovery (recharged water) schemes in accordance with this plan.
The water allocation policies contained within this plan are unlikely to have a significant impact on the
value of land within the Northern Adelaide Plains Prescribed Wells Area in the foreseeable future.
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Objectives
1. Allocation and use of underground water in a sustainable manner.
2. Allocation expressed as a volume of water that may be taken and used.
3. Efficient use of water.
4. Maintenance of water quality.
5. Maintenance of underground water dependent ecosystems.
6. Maintenance of the integrity of the aquifers.
Principles
Basis of allocation
1. Water to be taken and used from the wells in the Northern Adelaide Plains Prescribed Wells Area
will be allocated:
(a) by the volume of water that may be taken and used
(b) for use for a specific purpose such as commercial/industrial, environmental, irrigation,
recreational, stock and domestic; and
(c) according to the aquifer from which the water allocation is to be extracted.
Water available for allocation
2. Water allocations from the Tertiary aquifers (T1 and T2) and the shallow Quaternary aquifers
(Q3, Q4) shall not exceed 26,500ML, being the total volume of water allocated at the
commencement of this plan.
3. The volume specified in principle 2 will vary in accordance with any variations to the water
allocations made under the Act.
4. Water shall not be allocated from the shallow Quaternary aquifers (Q1, Q2) if the taking and use
of that water is likely to have any adverse impact on:
(a) the integrity of the aquifer
(b) the quantity and quality of water in the aquifer and underground water dependent
ecosystems; and
(c) existing users of the resource.
5. Water shall only be allocated from the shallow Quaternary aquifers (Q1, Q2) if the underground
water has a salinity level greater than 3000 milligrams per litre (mg/L).
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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5A. Water Allocation Criteria for RechargedWater
The following objectives and principles apply to the allocation of water drained or discharged to a well
in accordance with a permit under section 9(3)(c) of the Water Resources Act (“recharged water”).
Objectives
1. No negative impacts on the underground water resource, or the productive capacity of land from
the taking and use of water.
2. Maintenance of water quality.
3. Maintenance of the integrity of the aquifers.
4. Allocation based on a percentage of water recharged.
5. Maintenance of underground water dependent ecosystems.
Principles
Basis of Allocation
1. The basis for allocating recharged water will be:
1.1 an entitlement to take during a water use year, a percentage (generally not exceeding 80%)
of the volume artificially recharged in the previous water use year pursuant to a permit
issued under section 18 of the Act; or
1.2 (a) an entitlement to take during a water use year, a percentage (generally not exceeding
80%) of the volume artificially recharged in the previous water use year pursuant to a
permit issued under section 18 of the Act; and
(b) where any entitlements calculated in accordance with paragraph (a) in respect of the
preceding period have not been used, an entitlement to use those unused
entitlements.
Discussion
A ‘water use year’ is the period from 1 July in a calendar year to 30 June the following calendar year.
The ‘preceding period’ means the period nominated on the licence, not exceeding four years,
immediately preceding the previous water use year.
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This basis for allocation allows some flexibility in the use of recharged water in that, if the licence
allows, unused entitlements can be carried over for up to five years.
2. The percentage of recharge available should not exceed 80% except in those circumstances
where there is hydrogeological evidence which demonstrates that the extraction of up to 100% of
recharge water would not have a detrimental impact on the resource or on other users of the
resource.
Criteria for Allocation
3. Recharged water shall only be allocated where the proposed location and manner of use of the
recharged water is not likely to:
(a) have a detrimental effect on the underground water resource, including, but not limited to,
an accelerated increase in salinity or pollution
(b) have a detrimental effect on the productive capacity of the land, including, but not limited to,
creating perched water tables close to the surface or waterlogging
(c) cause unacceptable interference with the water supply from existing wells; and
(d) have a detrimental effect on any ecosystems.
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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6. Transfer Criteria
The following objectives and principles apply to the transfer of licences and/or allocations in the
Northern Adelaide Plains Prescribed Wells Area.
Objectives
1. Minimal impacts on the underground water resource, or the productive capacity of land from the
taking and use of water.
2. Efficient use and management of water.
3. Sustainable use of the underground water resource.
4. Maintenance of water quality.
5. Maintenance of underground water dependent ecosystems.
6. Maintenance of the integrity of the aquifers.
Principles
1. Transfers of licences and/or allocations shall not be permitted where the taking and use of the
water transferred is likely to have any adverse impact on:
(a) the integrity of the aquifer
(b) the quantity and quality of water in the aquifer
(c) any underground water dependent ecosystems
(d) existing users of the resource; or
(e) the productive capacity of the land.
2. Transfers of licences and/or allocations shall not be permitted where the transferred water
allocation will be taken from a well in a different aquifer (T1,T2, Q3 or Q4), unless there is
hydrogeological evidence to demonstrate that there will be an overall benefit to the underground
water resource.
3. Transfers of licences and/or allocations shall not be permitted where the transferred water
allocation is from an area of high potentiometric surface to an area of low potentiometric surface,
unless there is hydrogeological evidence to demonstrate that any negative impact on the
underground water resource is negligible.
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Discussion
The potentiometric surface is the theoretical water level in an underground aquifer as determined by
the pressure within that aquifer. This principle provides that the transfer of a water allocation is not
generally permitted to move down gradient of a potentiometric surface.
4. Transfers of licences and/or allocations shall not be permitted where the proposed transfer or
variation will result in the taking of water from a well located in the shallow Quaternary aquifers
(Q1, Q2) where the salinity is less than 3000 milligrams per litre (mg/L).
5. Except where there is hydrogeological evidence to demonstrate that there is not likely to be any
adverse impact on the underground water resource, transfers of licences and/or allocations shall
not be permitted where:
(a) the proposed transfer or variation is from an area of low intensity pumping to an area of
high intensity pumping; or
(b) the proposed transfer or variation is from an area of high underground water salinity to an
area of low underground water salinity.
Water Allocation Plan – Northern Adelaide Plains Prescribed Wells Area
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7. Permits
Section 9 of the Water Resources Act 1997 provides that a permit is required for the various water
affecting activities listed in section 9(3) of the Act.
In addition, permits are required for:
(a) the activity listed in section 9(4)(i) of the Act where water use is at a rate which exceeds 1
kilolitre/year (see ‘importation of water’ below)
(b) the activity listed in section 9(4)(j) of the Act where water use is at a rate which exceeds 1
kilolitre/year (see ‘use of effluent’ below).
7.1 Water Affecting Activities
The following objectives and principles apply to all water affecting activities in the Northern Adelaide
Plains Prescribed Wells Area. They are additional to the objectives and principles applying to the
specific activities set out below.
Objectives
1. Protection of the quantity and quality of water resources and the maintenance of natural
hydrogeological systems.
2. Prevention of deterioration in the quality of underground water.
3. Protection and restoration of the natural character of underground water.
4. Protection of the ecological functions of water resources and dependent biological diversity.
7.2 Drilling, Plugging, Backfilling or Sealing of a Well
The following objectives and principles apply specifically to the activities of drilling, plugging,
backfilling or sealing of a well under section 9(3)(a) of the Act.
Objectives
1. The drilling, plugging, backfilling or sealing of a well in a manner which will protect the quality of
the underground water resource.
2. Protection of underground water resources from pollution, deterioration and undue depletion.
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Principles
1. The equipment, materials and method used in the drilling, plugging, backfilling or sealing of a well
should not adversely affect the quality of the underground water resource.
2. Aquifers should be protected during the drilling, plugging, backfilling or sealing of a well to
prevent adverse impacts on the integrity of the aquifer, including contamination of the
groundwater resource.
3. A well shall only be drilled where it will not cause, or will not be likely to cause, salt mobilisation or
a rising water table.
4. The headworks of a well for the draining or discharge of recharged water shall be constructed so
that recharge and draining or discharge operations can be metered without interference.
7.3 Repairing a Well
The following objectives and principles apply specifically to the activities of repairing, replacing or
altering the casing, lining or screen of a well under section 9(3)(b) of the Act.
Objectives
1. The repairing, replacing or altering the casing, lining or screen of a well in a manner which will
protect the quality of the underground water resource.
2. Protection of underground water resources from pollution, deterioration and undue depletion.
Principles
1. The equipment, materials and method used in the repair, replacement or alteration of the casing,
lining or screen of a well should not adversely affect the quality of the groundwater resource.
2. Aquifers should be protected during the repair, replacement or alteration of the casing, lining or
screen of a well to prevent adverse impacts on the integrity of the aquifer, including
contamination of the groundwater resource.
7.4 Draining or Discharging Water into a Well
The following objectives and principles apply specifically to the activities of draining or discharging
water directly or indirectly into a well (“artificial recharge”) under section 9(3)(c) of the Act.
Objectives
1. Draining or discharging water directly or indirectly into a well in a manner which does not
adversely affect the quality of underground water, the aquifer or any ecosystem that depends on
the underground water.
Principles
1. Subject to clause 3, water may be drained or discharged into a well for the purpose of aquifer
storage and recovery where the concentrations, levels or amounts of the substances, materials
or characteristics set out in clause 4 below, in the water to be drained or discharged, do not
exceed the concentrations, levels or amounts of those substances, materials or characteristics in
the native underground water.
2. For the purposes of clauses 1 and 3, the relevant concentrations, levels or amounts shall be
measured by sufficient representative samples of:
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(a) the water to be drained or discharged, collected either from an existing dam or directly from
the source; and
(b) native underground water collected from the proposed point of injection, or as near as
possible to the proposed point of injection, and from the same aquifer as that in which
storage is proposed.
where “sufficient representative samples” means suitable samples, collected with equipment
appropriate for the substance, material or characteristic to be measured and taken at suitable
locations and times to accurately represent the quality of the relevant water.
3. The draining or discharge of water directly or indirectly into a well may occur (despite clause 1)
where the concentrations, levels and amounts of the substances, materials or characteristics of
or in the water set out in clause 4 are not sufficient to degrade ecosystems dependent upon
underground water within the prescribed water resource or to reduce the suitability of the
underground water for other purposes for which it might reasonably be used.
4. For the purposes of clauses 1 and 3 above, the list of substances, materials and characteristics
comprises substances, materials and characteristics that may be reasonably expected to be
present in the water to be drained or discharged and have the potential to degrade the native
underground water and the ecosystems that depend upon the native underground water,
including where relevant (but not limited to):
(a) pH, TDS, turbidity, ammonia, nitrate, nitrite, total phosphorous, sodium, chloride, sulphate,
calcium, magnesium, bicarbonates, iron, total arsenic, total boron, total cadmium, total
chromium, total lead, total manganese, total zinc, total coliforms and faecal coliforms; and
(b) where the water to be drained or discharged comes from a source likely to contain
pesticides, Giardia, Cryptosporidium, volatile organic compounds and petroleum
hydrocarbons (including but not limited to water from land used for intensive agriculture or
industrial purposes) those substances, materials and characteristics
(c) trihalomethanes where the water to be drained or discharged has been treated by
chlorination.
5. The draining or discharging of water directly or indirectly to a well must not detrimentally affect
the ability of other persons to lawfully take from that underground water or damage any
ecosystem that depends on the underground water.
6. For the purposes of this plan the term “native underground water” means the underground water
in the relevant aquifer before any water has been drained or discharged to that aquifer by artificial
means.
7.5 Importation of Water
The following objectives and principles apply specifically to the activity of using water in the course of
carrying on a business in a catchment area at a rate that exceeds the rate prescribed by this plan
where the water has been brought into the catchment area by means of a pipe or other channel under
section 9(4)(i) of the Act (“use of imported water”). The prescribed rate is 1 kilolitre per year. The
relevant authority for this activity is the Minister responsible for the administration of the Water
Resources Act 1997.
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Objectives
1. Use of imported water in a manner that does not adversely affect water resources within the
catchment.
2. Ecologically sustainable use of imported water.
Principles
1. Use of imported water shall not cause a rise in the underground water level sufficient to
detrimentally affect a structure or ecosystem.
2. For the purposes of principle 1, structure includes, but is not limited to, a building, fence or wall.
3. Use of imported water shall not adversely affect the natural flow of water or the quality of
underground water.
4. Use of imported water shall not adversely affect the productive capacity of the land by causing
salinity, waterlogging or perched water tables or other such impacts.
5. Imported water shall not adversely affect water dependent ecosystems.
7.6 Use of Effluent
The following objectives and principles apply specifically to the activity of use of effluent in the course
of carrying on a business in a catchment area at a rate that exceeds the rate prescribed by this plan
under section 9(4)(j). The prescribed rate is 1 kilolitre per year. The relevant authority for this activity
is the Minister responsible for the administration of the Water Resources Act 1997.
Objectives
1. Use of effluent in a manner that avoids adverse impacts on the water resources within the
catchment, other natural resources and ecosystems that depend on water resources.
Principles
1. Use of effluent shall not cause a rise in underground water level sufficient to detrimentally affect a
structure or ecosystem.
2. For the purposes of principle 1, structure includes, but is not limited to, a building, fence or wall.
3. Use of effluent shall not adversely affect the natural flow of water or the quality of underground
water.
4. Dams used to store effluent should be constructed:
(a) to prevent leakage of the effluent downward through the soils
(b) to prevent overflows from the dam to the surface of the land surrounding the dam; and
(c) to prevent overflow from the dam into a watercourse.
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8. Monitoring
This section of the plan provides for the regular monitoring of the capacity of the prescribed water
resource to meet the demands for that water on a continuing basis.
It is proposed that monitoring of the resource will involve:
1. Monitoring of the underground water levels in the main production aquifers (T1 and T2) and in the
Quaternary aquifer system over the summer and winter period.
2. Monitoring of an observation well network of approximately 90 wells completed in the Quaternary
and Tertiary aquifer systems, comprising the following:
• 30 observation wells in the Quaternary aquifers, which are currently used to monitor
recharge from surface drainage and any hydraulic connections with the underlying Tertiary
aquifers
• 20 observation wells in the T1 Aquifer
• 35 observation wells in the T2 Aquifer
• five wells in the deeper highly saline T3 and T4 aquifers.
3. Monitoring a range of other variables including but not limited to:
• underground water levels
• underground water salinity
• volume of water extracted from aquifers.
4. The monitoring program will also incorporate information provided by all licensees and permit
holders through the provision of annual irrigation reports. These reports will include information
on:
• area under irrigation
• the type of crop irrigated
• volume of irrigation water applied to the land and time of irrigation
• source of irrigation water (T1,T2 Q1,Q2), imported water, recharge water
• the exact location of the well
• irrigation water salinity.
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Discussion
It is proposed that the full observation network will be monitored every three months. The data
collected from the network will, amongst other things, be used to develop potentiometric surface
maps, which will identify underground water levels within the aquifers. These levels will be mapped
at different times including the high use summer period and the low use winter period. The
information on potentiometric surface levels will be used in conjunction with information from the
Annual Irrigation Reports to assist in assessing the capacity of the resource to meet demands for
underground water use in the Northern Adelaide Plains Prescribed Wells Area. The information from
annual reports will be provided back to water users in the form of a report on trends in water use,
water quality and water quantity.
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9. Miscellaneous
In preparing this plan, the Northern Adelaide and Barossa Catchment Water Management Board has
had regard to the following:
1. The matters referred to in section 6(2) of the Water Resources Act 1997
2. The benefits of consistency with:
• relevant management plans under the Coast Protection Act 1972
• relevant Development Plans under the Development Act 1993; including
⇒ Development Plan Playford (City)
⇒ Development Plan Gawler (CT)
⇒ Development Plan Port Adelaide Enfield (City)
⇒ Development Plan Salisbury (City)
⇒ Development Plan Light (DC) (Metro)
• relevant environment protection policies under the Environment Protection Act 1993;
including “South Australian Reclaimed Water Guidelines: Treated Effluent”. EPA April 1999
• relevant plans of management under the National Parks and Wildlife Act 1972
• relevant district plans under the Soil Conservation and Land Care Act 1989
• guidelines relating to the management of native vegetation adopted by the Native Vegetation
Council under the Native Vegetation Act 1991.
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10. Glossary
Deltaic - Sediments formed by deposition at the 'delta', orthe portion of a river where it meets the sea.
Horticulture - The use of land for market gardening,viticulture, floriculture, orchids, wholesale plant nurseriesor commercial turf growing.
Mg/L - Milligrams per litre. In the case of groundwaterresources, it is a measure of salinity. The value ofdissolved salts in mg/L can also be referred to as 'partsper million'.
ML - Megalitre, or one million litres. An Olympic sizeswimming pool contains approximately one and a halfmegalitres.
Potentiometric Surface - A surface describing thepressure in a groundwater aquifer. The height at thesurface at a point represents the level the water wouldrise to in a well at that point.
Quaternary - Sediments that are between 1 and 2 millionyears old.
Tertiary - Sediments that are between 2 and 65 millionyears old.
Water Resources - The total amount of water that isavailable to supply the needs of all water users, includingwater-dependent ecosystems, irrigators and other humanconsumers. This includes water in watercourses, lakes,surfacewater (including stormwater), and effluent.
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Figures