Teacher Earth Science Education Programme PARTNERS
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Transcript of Teacher Earth Science Education Programme PARTNERS
Teacher Earth Science Education Programme
Teacher Earth Science Education ProgrammePARTNERS
PRINCIPAL
PLATINUM
GOLD
Teacher Earth Science Education Programme
Teacher Earth Science Education ProgrammePARTNERS
Teacher Earth Science Education ProgrammePARTNERS
BRONZE Anglo Coal Australian Nuclear Science and Technology
Organisation CS Energy Department of Sustainability and Environment, Vic Essential Petroleum Flinders University Gordon Wakelin King Great Artesian Basin Coordinating Committee Hot Dry Rocks Macquarie University Sandy Menpes Monash Energy Museum Victoria Our Water Our Future, Vic Petroleum Geo-Services Primary Industries and Resources SA Stanwell Corporation Velseis ZeroGen
SILVER• The Australian National University
• Department of Primary Industries, Vic
• Earth Science Western Australia
• Pitney Bowes Business Insight
• PowerWorks
• Queensland Resources Council
• Rob Kirk Consultants
• The University of Sydney
• The University of Tasmania
Teacher Earth Science Education Programme
Teacher Earth Science Education Programme
Wet Rocks – Learning about Groundwater
PresenterAffiliation
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Wet Rocks
• Overview of groundwater• Basics of groundwater• Management of groundwater resources• Management as an integrated resource with
surface water • Management of groundwater as a hazard
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Overview of the Groundwater Resource
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World Groundwater Resources
Source: http://www.whymap.org
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Importance of Groundwater to Australia
10%
11%
72%
35%
63%
37%
4%
7%
Groundwater as a % of total water use (2000)
21% of total Australian use Source: Google MapsNational Land and Water Resources Audit (2000)
Irrigation(52%)
Urban / Industrial (29%)
Rural (18%) Other (1%)
Groundwater Use by Type
Groundwater Use 4986 GLSurface Water Use 19109 GLTotal Volume 24095 GL
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Groundwater Dynamics
Flow time: Hours to years
Flow time: Years to millennia
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How does groundwater flow?• Are there “underground rivers”?
• How does water flow through rock and soil?
• Does groundwater flow “downhill”?
• How long does it take for groundwater to flow?
• How do you get it out?
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Porosity and PermeabilityPorosity = the gaps between the soil and rock particles
Permeability = how well the gaps are connected to allow water to move between them
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Flowing water underground
1m
2m
3m
3m
2m
1m
“Map” View“Block” View
“Gradient” of the groundwater surface
“Contours” of the groundwater surface
“Head” elevation
Groundwater flows from the higher “head” to the lower “head” – the hydraulic head of the system.
Bores measure the head elevation at specific points
3m
2.5m
1.5m
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Aquifers and Aquitards
Aquifer: A layer of soil or rock that has relatively higher porosity and permeability than the surrounding layers, enabling usable quantities of water to be extracted.
Aquitard: A layer of soil or rock that has relatively lower porosity and/or permeability than the surrounding layers, limiting the movement of groundwater through it and the capacity to extract useable quantities of water.
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Confined and Unconfined Aquifers
Unconfined: Surface of the groundwater (the watertable) is at the same pressure as the atmosphere.
Confined: The “surface” of the groundwater is constrained by an aquitard. It is under pressure. If the aquifer is tapped, the water level will rise up in response to the pressure. The distribution of pressure is called the potentiometric surface.
Confined zone
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Multi-Aquifer Systems
Source: Groundwater Notes, Department of Sustainability and Environment, Victoria http://www.ourwater.vic.gov.au
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Scale of groundwater systems
• Local systems – recharge and discharge areas within 5km of each other• Intermediate system – recharge and discharge areas within 50km of each
other• Regional system - recharge and discharge areas grater than 50km of
each other
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Groundwater Dynamics – Unconfined Aquifers
Water entering the soilWater used from the soil
Change in saturated zone storage
Aquifer through-flow
Groundwater Pumping
Soil storage (unsaturated zone)Recharge
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Groundwater System Dynamics – Unconfined Aquifer
Out-flow
• waterways• flooding• water
supply• irrigation
• land-use
Recharge
Rainfall Infiltration
Plant use Soil
Evaporation
Pumping
In-flow
Discharge to the
Environment
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Rainfall variabilityCumulative rainfall residual
Risingtrend
Fallingtrend
Fallingtrend
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Ability to predict what is climate change
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Landuse impacts on recharge
Recharge for six soils and Landuses
-0.2
0
0.2
0.4
0.6
0.8
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1.2
1.4
1.6
1.8
AnnualPasture Crop PerennialPasture NativeForest Plantation Woodland
Landuse
Tota
l rec
harg
e (M
l/ha/
yr) 1
23456
1 Sandy Loam, Light Clay over Fractured Rock; Basalt, Rhyolite, Rhyodacite, Ignimbrite
2 Loam over Fractured Rock
3 Sandy Loam, Light Clay over Sedimentary; Silt, Alluvium
4 Loamy Sand, Medium Clay over Sedimentary; Silt, Alluvium
5 Loamy Sand, Medium Clay over Sedimentary; Sand
6 Sandy Loam, Light Clay over Sedimentary; Clay, Aeolian / Evaporates, Mudstone/Marl/ Laterite
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Unsaturated Zone Storage
Depth
Soil Moisture
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Significance of climate variability on recharge
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
ML/
yr
Recharge10% of rainfall
Recharge 5%of rainfall
Recharge, 5%/ 20%
Recharge,0%, 20%
Recharge, 5%/ 20%, last 10
years
0
5
10
15
20
25
30
35
40
45
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100-200mm 200-300mm 300-400mm 400-500mm 500-600mm 600-700mm >700mm
Freq
uenc
y
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500
1000
1500
2000
2500
Rech
arge
(mm
)
5% of Rainfall5% of Rainfall
10% Rainfall10% Rainfall
5% of Rainfall, with 20% of high rainfall
5% of Rainfall, with 20% of high rainfall
20% of high rainfall
20% of high rainfall
1998 to 2008
comparison
1998 to 2008
comparison
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Groundwater Dynamics – Unconfined Aquifers
Water entering the soilWater used from the soil
Change in saturated zone storage
Aquifer through-flow
Groundwater Pumping
Soil storage (unsaturated zone)Recharge
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Groundwater Pumping
Takes water from storage by reducing level or pressure.Changes flow patternsChanges recharge / discharge relationships
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Environment as a water user
Out-flow
• waterways• flooding• water
supply• irrigation
• land-use
Recharge
Rainfall Infiltration
Plant use Soil
Evaporation
Pumping
In-flow
Discharge to the
Environment
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Groundwater Dependent Ecosystems
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Groundwater and Waterways
Source: http://www.connectedwater.gov.au/processes
Connected losing stream (loss varies with difference in level between river and groundwater)
Disconnected stream (rate of loss more or less constant)
Gaining during low flow, losing during high flow.Gaining stream
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Groundwater use affects surface water and environment
Source: http://www.connectedwater.gov.au/processes
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Groundwater/surface water“connectivity”
Source: CSIRO Sustainable Yields Projecthttp://www.csiro.au/files/files/pkgb.pdf
“Losing streams” – surface water recharging groundwater
“Gaining streams” – groundwater base flow to surface water
Seasonally variableNot connected
Example: Goulburn Broken catchment
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Groundwater / surface water interaction
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Groundwater Management Basics
Water entering the soilWater used from the soil
Change in saturated zone storage (groundwater levels)Aquifer through-flow
Groundwater Pumping
Soil storage (unsaturated zone)Recharge
Rainfall
Land use (forest, agriculture, urban)
Discharge (waterways, ocean, land)
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Managing groundwater – as a resource
• Sustainable yield is inherently intergenerational because it implies resource use in ways that are compatible with maintaining them for future generations.
• Proposed National definition (2002):
”The groundwater extraction regime, measured over a specified planning timeframe, that allows acceptable levels of stress and protects the higher value uses that have a dependency on the water.”
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• Sustainability and SY are dynamic concepts that will continue to be refined
• The challenge is to turn the principles of sustainability and groundwater sustainable yield into achievable policies and then practice.
• Science alone cannot choose the correct interpretations for society but any interpretation must be based on sound hydrologic analysis and understanding, and community involvement.
Sustainable Yield – a dynamic concept
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Sustainable yield for an aquifer
A
B
BA
Hydraulic Properties
Recharge
What are the elements of defining SY?• Annual aggregate abstraction volume• provision for groundwater dependent
ecosystems• time element• social/economic aspects
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Sustainable yield (cont)
BA
Discharge Volume
Well hydraulics
Leakage impacts on water quality
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Wetland / Waterway Protection
A
B
BA
Hydraulic Properties
Recharge
Management zone
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Dryland salinity management(a) Prior to development(b) With clearing and development
Note: Historical “salt” refers to concentrated solute
Impact: • 2.5MHa of cultivated land (5%)
affected by salinity
• 5.7MHa has immediate potential to be affected by salinity
a
b
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Salinity in a catchment
A
B
BA Hydraulic
Properties
Recharge
Trade off in land-use can affect viability of the land and adjacent areas
Requires LARGE SCALE CONTROLS eg dewatering and interceptor networks, evaporation basins, stream regulation
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Managing groundwater for construction
Mine or Building Basement / Foundation
Dewatering bores
Watertable reduced for stability and to
provide safe operating conditions
In-pit pump
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Saline intrusion into fresh aquifers
Saline lake or the sea Sea / lake
level
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Key management principles…
• Regardless of the key issue for management, the same key elements of the water cycle apply – it is how you use them to achieve your objective that differs.
• Groundwater systems are complex natural systems – the response to your management action is not always what you may expect. Always think of the range of potential outcomes.
• Scale matters – there is a much greater likelihood of interacting with local systems in observable timeframes than with a regional system.
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Threats of pollution on groundwater
The many sources of contamination to groundwater
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Point Source and Diffuse Sources• Point source (localised) eg.
• Leaking tanks• Spills• Landfills• Tar pits
• Diffuse source• Agricultural chemical application (fertilizers / pesticides)• Large scale mining
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Point source
Type Source Contaminants
Industry Manufacturing sites, refining sites, gasworks
Organic compounds, heavy metals
Waste disposal LandfillsSeptic tanks
Heavy metals, organic compounds, BOD1, COD2, nutrients
Commercial Petrol stationsDry cleaners
Petroleum hydrocarbons, chlorinated hydrocarbons
1: BOD - biological oxygen demand2: COD – chemical oxygen demand
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Diffuse sources
Type Source Contaminants
Agriculture Intensive agriculture, irrigation
Pesticides, nutrients (fertilizers)
Large scale facilities Defence sites, firing ranges, water treatment plants
Organic compounds, heavy metals, dioxins
Large scale mining Tailings Heavy metals
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A complex picture...
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Advective processes, concentrations – single point sourceSingle point source
t1
C0
C
0
1
0
1
0
1
t2 t3
t1
t2
t3
C0
C
C0
C
Distance (x)
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Concentrations – continuous point sourceContinuous point source
0
1
Distance (x)Distance (x)
At t2
t1 t2 t3
C0
C
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Mechanical Dispersion
Dispersivity is a function of the porous media
Long
itudi
nal
Transverse
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Dispersion of the soluteContinuous point source
Distance (x)
At t2 Results in spreading of the front
Longitudinal (l) Tran
sver
se (t
)
0
1
C0
C
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t1 t2 t3
Dispersion effectInstantaneous point source
Distance (x)
C0
C
0
1
0
1
0
1
t1
t2
t3
C0
C
C0
C
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Reactions in solute transport
• Initial assumption for advection – dispersion equation is that the porous media and the solute are non-reactive
• However, in reality, the solute often interacts with the porous media, other components of the pore water and / or undergoes decay
• Main processes are decay / degradation and retardation
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Degradation and daughter products
Cp Cd
Time or Distance
Assumes a first order kinetic reaction, in that the solute is lost to the pore water through the decay or degradation (ie only deals with the loss term)
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Biodegradation
• Where biological processes aid the breakdown of contaminants
• Rate specific to:• Bacterial population• Nutrient / substrate availability• Solution chemistry (redox, pH)• Co-metabolites / toxins• Temperature
• Laboratory determined
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Retardation
Taken from “In-situ” presentation on “Groundwater Contamination and remediation
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Effects in the field....
From Fetter, 1999, Contaminant Hydrogeology
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Perchloroethene
Carbon Tetrachloride
Chloride
Effects in the field (cont.)
From Fetter, 1999, Contaminant Hydrogeology
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Contamination Summary
• Generally a legacy issue.• Can be from localised “point sources” or
distributed over large areas (“diffuse source”).• Once in the ground, interact with the material they
are passing through.• Main processes affecting the concentration in the
groundwater are advection, dispersion, degradation / decay and retardation.
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Contributions
• Prepared by Chris McAuley, Principal Hydrogeologist, Department of Sustainability and Environment, Victoria.
• Support figures sourced from:• Lectures given by Chris McAuley• TESEP teaching package developed by Louse Goldie
Divko (Department of Primary Industries, Victoria), Megan Bourke (independent education consultant) and Philomena Manifold (independent consultant)
• Referenced sources
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Geoscience Pathways
TESEP uses this fabulous website to distribute materialswww.geosciencepathways.org.au
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Please partner!• TESEP will only succeed in the long term if
we continue to grow our partnerships• Contact either
– Executive Officer, Greg McNamara• [email protected]
– Chairperson, Jill Stevens• [email protected]
to discuss the options
Teacher Earth Science Education Programme
TESEP wishes to thank the following partners
Partners
PRINCIPAL
PLATINUM
GOLD
Teacher Earth Science Education Programme
Partners
BRONZE Anglo Coal Australian Nuclear Science and Technology
Organisation CS Energy Department of Sustainability and Environment, Vic Essential Petroleum Flinders University Gordon Wakelin King Great Artesian Basin Coordinating Committee Hot Dry Rocks Macquarie University Sandy Menpes Monash Energy Museum Victoria Our Water Our Future, Vic Petroleum Geo-Services Primary Industries and Resources SA Stanwell Corporation Velseis ZeroGen
SILVER• The Australian National University
• Department of Primary Industries, Vic
• Earth Science Western Australia
• Pitney Bowes Business Insight
• PowerWorks
• Queensland Resources Council
• Rob Kirk Consultants
• The University of Sydney
• University of Tasmania
Teacher Earth Science Education Programme
TESEPAlso wishes to thank: Australian Geoscience Council Australasian Institute of Mining and Metallurgy Geoscience Australia Minerals Council Australia
Teacher Earth Science Education Programme
Thank you