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- Introduction to groundwater resources management -
1
Introduction to groundwaterresources management
Jac A.M. van der Gun
, Previously employed with
Deltares/TNO Netherlands Geological Survey & International Groundwater Resources Assessment Centre
(IGRAC)
- Introduction to groundwater resources management -
2
Prologue:
Watershed and River Basin Management:How does groundwater fit?
Some distinguishing features of groundwater:1 Spatial units:
– aquifers rather than river basins
– other horizontal and vertical boundaries
2 Time scales of processes are different
3 Different storage/flux ratio
4 Less open to observation
5 Different interaction with people
- Introduction to groundwater resources management -
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Introduction to groundwaterresources management
1 Introduction
2 Basic concepts and supporting subjects (shortened)
3 Water resources plan development (shortened)
4 Groundwater resources management issues
5 Implementing groundwater resources management
6 Case studies
Jac A.M. van der Gun
- Introduction to groundwater resources management -
4
Chapter 1: Introduction
• Role of water in human society (and beyond)• Complicating factors regarding water resources• Water resources management
- Introduction to groundwater resources management -
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Water and Man– Domestic use– Irrigation– Production/cooling water– Navigation– Fishery– Source of energy– Recreation– Sewage/ wastewater disposal– Flooding/ water-logging– Environment and ecosystems
Water is …...a biological need, …..an economic commodity, ….and an environmental factor
- Introduction to groundwater resources management -
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Role of groundwater
- Introduction to groundwater resources management -
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Groundwater abstractionIntensity (mm/year)
Purpose of use
(shares of main water use sectors)
70% of global abstraction is by
ten countries only
- Introduction to groundwater resources management -
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Groundwater abstraction
Evolution 1950-2010(in km3/yr)
Strong declines of the groundwater levels
Ogalalla, USA
Jeffara,Libya
- Introduction to groundwater resources management -
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Competitive demands in a water scarcity environment
reservoir
town
projectedcomplex ofirrigated lands
projected reservoir
river system
- Introduction to groundwater resources management -
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Interdependency
Project 1 goal 1Project 2 goal 2
Project n goal n
Traditional perception
A more realistic perception
Project 1 outcome 1Project 2 outcome 2
Project n outcome n
- Introduction to groundwater resources management -
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Soil salinization in ancient Mesopatamia
• Prosperous irrigation areas• Steadily progressing soil salinization• Reactions:
- moving to new lands - fallow-land rotation - from wheat to barley
• Results:- general decline- diminishing crop yields- abandoned agricultural lands
- Introduction to groundwater resources management -
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Mechanism of soil salinationVolumes of water: R I ET
rainfall irrigation evapotransp.
Salt concentrations: cr ci ce
Control volume of soil: (undrained)
cc
capillary flow C
Soil salt quantity S
Mean annual soil water balance: R + I + C - ET = 0
Mean annual soil salt balance: Rcr + Ici +C cc - ETce = ΔS
Because ce < cr , ci,,, cc it follows: ΔS > 0
- Introduction to groundwater resources management -
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It took long before the hydrological cycle was correctly understood
Oceanus theory
Condensationtheory
Percolationtheory
HomerosThales of MiletePlinius the ElderLeonardo da VinciJohann Kepler
AristotleSenecaRené Descartes
Theories on the origin of groundwater and springs
VitruviusBernard PalissyPierre PerraultEdmund HalleyEdmé Mariotte
Athanasius Kircher, 1665
- Introduction to groundwater resources management -
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Global population growth1900 - 2000
0
1000
2000
3000
4000
5000
6000
7000
1900 1920 1940 1960 1980 2000
millio
ns
- Introduction to groundwater resources management -
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Changing water demands per capita
• Increasing wealth:- affordability of buying water- willingness to pay for water
• Motivators for more water per capita: - improvement of hygiene and health- improved & controlled food production
- steadily developing water using industry- comfort, recreation and leasure
• Enabling technological development:- knowledge on water resources- water development technology- water use technical infrastructure
- Introduction to groundwater resources management -
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Evolution in groundwater resources development technology
shaduf
Noria (saqiyah)
- Introduction to groundwater resources management -
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Climate change
Source:IPCC, 2001
- Introduction to groundwater resources management -
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Complicating factors regarding water resources
- Conflicts of interest - Interdependency of activities - Poor perception of reality / lack of data- Water is a common property resource- Water is a vulnerable resource- The world is continuously changing (local & global change)
Consequently……there is often a need for intervention
- Introduction to groundwater resources management -
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Water resources management: intervention objectives
Conserve and control water resources + related ecosystems and environment
Provide water and maintain water functions according to requirements
Maximize total benefits from the resource and allocate them optimally
Minimize costs involved in water sector
- Introduction to groundwater resources management -
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Typical evolution in water sector activities
Time
reconnaissance
water resources development
water resources management
increasing populationindustrialisationhigher consumption levelsawareness of interdependencies
- Introduction to groundwater resources management -
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Groundwater resources management (GWRM) defined:
“A planned and ongoing activity to optimize the exploitation and use of regional or national groundwater resources……...
……. taking into account the sustainability of the groundwater resources and the groundwater related environment and ecosystems.”
- Introduction to groundwater resources management -
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Groundwater resources management in a nutshell
Groundwater
Problems?Opportunities?
Planning
Plan approval and acceptance
Implementation
Monitoring
Other policy fields
- Introduction to groundwater resources management -
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Chapter 2: Basic concepts and supporting subjects
• Systems approach• Groundwater systems• Water demands• Economics
- Introduction to groundwater resources management -
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Systems approach
“real world”
water resourcessystem
“systems”and
interrelations
system 1
system n
- Introduction to groundwater resources management -
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System operation (1)
Natureof
system
Physical laws
Systemoperation
System
- Introduction to groundwater resources management -
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System operation (2)
Systemoperation
System
Input Output
- Introduction to groundwater resources management -
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System operation (3)
Natureof
system
Physical laws
Systemoperation
System
Input Output
System
- Introduction to groundwater resources management -
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The hydrological cycleas a system
land surface
atmosphere
surface water
oceans
soil
groundwater
deep lithosphere
vegetation
- Introduction to groundwater resources management -
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Systems approach to water resources management
Socio-economic system
Present state,functions,performance, etc.
Desired state,functions,performance, etc.
Physical water system
State at time t Systemoperation
State at timet + Δt
Decisionvariables
Uncontrollablevariables
- Introduction to groundwater resources management -
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Some aspectsof groundwater systems
• Invisible resource• Ratio storage/flux is large
(mean residence times between 10 and 1,000 yrs are common)
• Common pool & open access resource • Many functions• Schematization
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Functions of groundwater systems
More than a source of water only …..
• “sustained yield” reservoir• “mining” reservoir• reservoir for artificial recharge
• conduit for water transmission• energy absorber (pumping)• source of energy (geothermal energy)• reservoir for seasonal heat storage
• water quality modifyer• control of base flow and springs• water supply to
phreatophytes/wetlands• control of land subsidence
- Introduction to groundwater resources management -
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Groundwater in a “lumped system” schematization
Groundwater system(stored volume, water quality, average head, etc.)
Subsurfaceinflow
Direct recharge
Recharge fromstreams, lakes, etc.
Artificial recharge Abstraction
Spring flow & discharge to streams, lakes, etc.
Diffuse discharge
Subsurfaceoutflow
- Introduction to groundwater resources management -
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Distributed groundwater systems(1) hydraulic schematization
(2) flow systems schematization
aquifer
Aquitard/aquiclude
aquitard
- Introduction to groundwater resources management -
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Water demands
Quantity:• Domestic: total and per capita demands• Irrigation: irrigation requirements, leaching requirements• Industry: process water, cooling water demands• Environment /nature: desired/ minimum/ maximum groundwater level
Quality:• Standards for drinking water quality• Idem for irrigation, industry, environment, nature• Aspects: chemical, bacteriological, physical (incl. sediments)
It is important to know what impacts violating any of the requirements or standards will have
- Introduction to groundwater resources management -
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Role of economics in water resources management
• Comparing economic merits (scores) of alternatives or strategies
• Defining economic optima: Maxx Profit = (ΣR-ΣC)
• Understanding or predicting people’s behaviour
- Introduction to groundwater resources management -
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Conventional economic theory ignores market failures
• Missing markets• Poorly defined ownership or user rights• External benefits • External costs (disbenefits)• Unequitable allocation of benefits/costs • Lack of intergenerational equity• Environmental and sustainability problems
Market failures are triggers for government interventions
- Introduction to groundwater resources management -
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Natural resources
• Characterised by “stock” (reserves) and “flow” (quantities transfered per unit of time)
• Important distinction:
- perennial resources
- renewable resources
- exhaustible or mining resources
Examples:
solar energy
water, fish, forests, etc
oil and gas, mineral ores
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Optimal exploitation of natural resources
Dilemma:Exploit ‘stock’ - or exploit ‘flow’ - or both?
Different views, criteria and priorities:e.g.: • Presence/absence of substituting resources• Economic optimization• Sustainable development• Poverty alleviation• Protection of ecosystems• Self-supporting food production
- Introduction to groundwater resources management -
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Economically optimal exploitation of natural resources
Dilemma:Exploit ‘stock’ - or exploit ‘flow’ - or both?
Economic optimization:Given : S = stock of natural resource
b = input of natural resource a = input of other production factors G = growth function of natural resource V = value of discounted profits
π = profit function
Then the optimum follows from:
subject to:
dteb).π(a,=VMAX rt-T
o=t
b)(a, b-G(S)=
dt
dS
- Introduction to groundwater resources management -
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Set of equations for natural resources management
(1) “Maximum Principle”
(2) Portfolio balance equation
(3) Dynamic constraint
dteb).π(x,=VMAX rt-T
o=t
(x)
dteb).π(x,=VMAX rt-T
o=t
(b)
b-G(S)=dt
dS
Note:x is envisaged production output
Production output oriented
Resources use oriented
Continuity equation
- Introduction to groundwater resources management -
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Introduction to groundwaterresources management
1 Introduction
2 Basic concepts and supporting subjects
3 Water resources plan development
4 Groundwater resources management issues
5 Implementing groundwater resources management
6 Case studies
Jac A.M. van der Gun
- Introduction to groundwater resources management -
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Chapter 3: Water resources policy and plan development
• Basic aspects
• Outline and elements of water resources management planning
• Models used for groundwater resources management planning
• ‘Open’ or ‘interactive’ plan development
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Difference between policies and plans
• A policy encompasses in general terms the objectives, priorities and the line of actions opted for
• A plan translates this policy into action, it facilitates communication on it among stake-holders and it enables the results to be monitored
- Introduction to groundwater resources management -
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What is planning?
“Planning is the process that converts data and information into a decision”
O. Helweg, 1985
Planning is commonly a cyclic process: the plan
is intended to cover a limited period of time (planning period) and needs to be updated periodically
Before starting planning: consensus needed on jurisdiction, scope, stage (hierarchical level) and on the roles of partners in the planning process
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Hierarchical levels in water resources management
GENERAL POLICIES
AREA-SPECIFICSTRATEGICPLANNING
IMPLEMENTATION AND MONITORING
development scenariosobjectivesconstraintspreferences
area-specificWRM plan
generaldirectives
feed-back
feed-backfeed-back
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Potential main partners in planning
Target group
Decision makersTechnical specialists
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Framework for WRM planning
WATER RESOURCES ASSESSMENTWater resources, demands, scenario conditions, issues, etc.
STRATEGIC ANALYSISObjectives, options, strategies, measures, evaluation
VIABILITY ANALYSISFeasibility and expected acceptance
PLAN APPROVAL
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Water resources management objectives and criteria
(examples)
• Economic efficiency B-C, NPV
• Equity water allocation income from water
• Sustainability stock, water levels, water quality
• Safety no. of victims,damage
- Introduction to groundwater resources management -
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Decision space and feasibility
Technical feasibility
Economic feasibility
Financial feasibility
Political feasibility
Legal feasibility
Environmental feasibility
- Introduction to groundwater resources management -
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Main types of models in WRM planning
• Simulation models
• Optimization models
• Decision rules
• Evaluation models
- Introduction to groundwater resources management -
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Simulation models
• Differential equation• Model parameters• Initial conditions• Boundary conditions• Solution algoritm
- Introduction to groundwater resources management -
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Examples of differential equationsfor simulation models
t
hS=h)k( si
t
c=c)v(-c)D( ii
t
p=
z
p(p)c 2
2
v
Saturated groundwater flow
Solute transport
1-D consolidation
- Introduction to groundwater resources management -
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Optimization models
Given: decision variables x1 through xn (control variables)
Then an optimization model typically consist of:
(1) OBJECTIVE FUNCTION
Maximize F(x1, x2 , ……….. , xn )
2) CONSTRAINTS
gi(x1, x2 , ……….. , xn ) < 0 or = 0 (j=1, 2, ….., m)
If all equations are linear linear programming
- Introduction to groundwater resources management -
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Example: Set of equations for optimizing natural resources management
(1) “Maximum Principle”
(2) Portfolio balance equation
(3) Dynamic constraint
dteb).π(x,=VMAX rt-T
o=t
(x)
dteb).π(x,=VMAX rt-T
o=t
(b)
b-G(S)=dt
dS
Note:b = groundwater pumping ratex = envisaged production outputπ = profit functionG(S) = growth rate of resource
- Introduction to groundwater resources management -
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• Used to compare strategies or alternatives
• Economic models:
Present Value of Discounted Cash Flows,
Internal Rate of Return, etc.
• Multi-Criteria Decision Models (MDCM)
Evaluation models
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Principle of multi-objective evaluation
Evaluation
Alternative 1 Alternative 2 Alternative 3 Alternative 4
Objective 1:Maximize PV
Alt. 4Alt. 2Alt. 3Alt. 1
Objective 2:Wetland
conservation
Alt. 2Alt. 3Alt. 1Alt. 4
Ranking:
Best
Worst
Multi-criteria decision methods
are needed to underpin a decision
- Introduction to groundwater resources management -
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Dealing with uncertainty in planning
• Safety factors• Emergency provisions• Statistical analysis• Sensitivity analysis• Stochastic approaches• Risk analysis• Additional data collection
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‘Open’ or interactive plan development
• Top-down planning (technocratic or ‘closed’) often fails: no or limited acceptance/co-operation by stakeholders
• Common reasons: – lack of mutual understanding government-stakeholders – lack of trust between parties– lack of confidence in the quality of the plan– unsolved conflicts of interest– lack of commitment of essential partners
• Therefore trend towards interactive plan development, involving representation of all major stakeholders
• Degree of interactivity may vary
• Real communication is a must
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Arnstein’s sequence of interactivity
Informing
Inquiring
Consulting
Co-producing
Delegating
Selfruling
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Techniques in IP
• Brochures and leaflets• Press articles• Radio and TV programmes• Information meetings• Enquiries and interviews• Work shops• Public hearing meetings• Stakeholder comments and position statements• Working groups and task forces• Electronic meetings and discussion sessions• etc.
- Introduction to groundwater resources management -
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Introduction to groundwaterresources management
1 Introduction
2 Basic concepts and supporting subjects
3 Water resources plan development
4 Groundwater resources management issues
5 Implementing groundwater resources management
6 Case studies
Jac A.M. van der Gun
- Introduction to groundwater resources management -
62
Chapter 4: Groundwater resources management issues
• Groundwater management policy and plans have to address the issues relevant for the area concerned
• World-wide experience is useful to help identify issues and to benefit from ideas and solutions already developed elsewhere
• Diagnostic analysis on relevant issues should take place in an early stage of plan development
• Main approaches to identify relevant issues:– inference from water system characteristics– communication with stakeholders
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Main groundwater resources management issues
Rate of aquifer exploitation Encouraging or restricting groundwater pumping?Allocation of scarce groundwaterConjunctive management
Salinity controlPollution controlConservation of ecologically desired ‘water type’
Groundwater level controlControl of land subsidence
Water quantity management:
Water quality management:
Environmental management:
- Introduction to groundwater resources management -
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Groundwater development in the Sadah aquifer, Yemen
- Introduction to groundwater resources management -
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Rate of aquifer exploitation Sadah aquifer
Wajid Sandstone
Granitic gneisses Schists
2000 m
0
Rainfall: 100 - 200 mm/yearIn 1983: 1160 wellsEstimated recharge: 7 - 10 M m3/yearNet pumping: 51 M m3/year
- Introduction to groundwater resources management -
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Early diagnosis Sadah aquifer
• Water balance:
mean depletion of 42 M m3 / year
• Numerical model simulation:
in most likely scenario there will be continuous groundwater level decline of 4 - 5 m per year
• How to manage the aquifer?
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Rate of aquifer exploitation(groundwater storage management)
grw.storage
grw.level
time
(1) sustainable yield (2) mining, followed by sustainable yield (3) mining, followed by exhaustion
(1)
(2)
(3)
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Burt’s approximate decision rule
• Groundwater pumping (at rate Q) from isolated aquifer
• Short-term profits of over-exploitation are balanced against perpetual additional pumping cost (externality)
• Expanding abstraction beyond mean sustainable yield (MSY) is profitable until:
annual costsor revenues
MSY Qopt aggregate abstraction rate Q
revenues minus direct costs
adjusted profit
externality due tostorage depletion
S
S)NB(Q,
r
1=
Q
S)NB(Q,
slope = Q
NB
slope =S
Q
S
NB
r
1
pseudo optimum
- Introduction to groundwater resources management -
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Profit function in Burt’s rule
EB+EC-EN-
Sqr-dt
dqS+
dt
dSq+
bc-aw-xp=π
eee
e
eee
Check whether these simplifications are acceptablefor the case considered for application
Production profit
Portfolio profit
Externalities
- Introduction to groundwater resources management -
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100
grapes
MSYwheat
0 100 200 years
Optimal abstraction ratesSadah aquifer
according to Burt’s rule
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What happened actuallyin the Sadah area?
Gwl (m)
-30
-40
-50
-60
-70
-80 1983 1985 1987 1989 1991 1993 1995
• Abstraction doubled from 1983 to 1995• Many dry wells• Sharp increase of ground water cost• Loss of irrigation profitability• Small farmers gave up and migrated
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What about the following statement?
Groundwater storage depletion (ΔS) occurs only when groundwater abstraction (A) exceeds natural groundwater recharge (R)
….. and in that case it can be calculated as follows:
ΔS = A – R (all values expressed as volumes per unit of time)
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The previous statement is wrong:“The water budget myth” (Bredehoeft et al.)
• Groundwater balance should include changes in recharge (ΔR), natural discharge (Q) and changes in natural discharge (ΔQ): ΔS = Outflow – Inflow = A + (Q + ΔQ) – (R + ΔR)
• Typical components of ΔR: induced recharge, return flows and artificial recharge.
• Typical components of ΔQ: reduction in spring flows, evapo(transpi)ration and baseflows (then ΔQ is negative)
• Many hydrogeologists think according to the water budget myth, but their intuition is wrong
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Maximum sustainable yield
• Any new abstraction is intitially fed completely by storage depletion
• The storage depletion – in turn – may lead to reduction of natural groundwater outflow (ΔQ) and increase of recharge (ΔR)
• MSY depends on how the system will adapt at the long run: MSY = - ΔQmax,final + ΔRmax, final
• It follows for isolated aquifers without artificial recharge: MSY ≈ R
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Encouraging or restricting groundwater pumping?
• Water needs (quantity and water use category)• State of aquifer (over- or underexploitation)• Groundwater quality• Environmental effects of groundwater pumping• Presence/absence of alternative supplies• Profitability of water use• Renewable or non-renewable groundwater?
Depends on:
Partly conflicting aspects - thus: choice based upon preferences
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Renewable versus ‘non-renewable’ groundwater
Renewable groundwater:• Recharge is sufficient for realistic
sustainable development• Hence, the resource is exploited by
virtue of its renewal• Mean annual recharge typically
more than 0.1 % of storage• Abstraction leading to steady
reduction in groundwater storage is called ‘overexploitation’
• Part of abstraction exceeding maximum sustainable yield is called ‘overdraft’.
• Renewable grw is more common than non-renewable groundwater.
Non-renewable groundwater:• Recharge is insufficient for realistic
sustainable development • Hence, the resource is exploited by virtue
of significant storage • Mean annual recharge typically less than
0.1 % of storage• Abstraction leads to steady reduction in
groundwater storage and is called “mining”
• Non-renewable groundwater usually is fossil, but not all fossil groundwater is non-renewable
• Examples: N-African deep aquifers (NWSAS, Nubian Sandstones, etc.), Arabian Platform aquifers, Great Artesian basin.
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Environmental impacts of exploiting ‘non-renewable’ groundwater of the
NWSAS
Exploitable reserves: 1280 km3Current abstraction rate: 2.6 km3/a
Reversal of flow at current diffuse discharge zones (chotts) may cause aquifer salinization
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Great Artesian Basin: groundwater level declines and recovery
• Mean aquifer recharge: around 0.45 km3/year • Discharge by numerous artesian wells since 1887• Total discharge declines since 1917• Number of wells, however, kept increasing• Since 1997 well capping and piping programme• Aim: pressure recovery and preservation• Prognosis: around 0.211 km3/year saved by 2014
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Allocation of scarce groundwater
• Among potential users: – use a guiding principle (water rights, sector
priority, economic optimization, etc.)– zoning + assignment of functions– no or very limited control (e.g. water markets)
• In space:– negative impacts not independent of aquifer zone– use simulation model or simulation-optimization– uncontrolled
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Conjunctive management of groundwater and surface water
• Artificial recharge (Managed Aquifer Recharge - MAR)
• Watershed management (ponds, rainwater harvesting, surface water reservoirs)
• Baseflow replenishment
• Conjunctive use of groundwater and surface water
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Examples of artificial recharge
Sand dam in Kenya Huge recharge dam in Oman (5 km of crest length)
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Conjunctive use GRW - SW
Groundwater Demands Surface water basins sources
i = 1
i = 2
i = M
j = 1
j = 2
j = N
k = 1
k = 2
k = L
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Optimizing conjunctive use
t k
Q
i j i
tjij
tji
tjk
tjk
tik
tik
tkk
t
tk
SWRfSWfGWfdQQpr
z0
)()}()()({)1
1(max
Discount factor Profit from
water use Cost of groundwater Cost of
surface water Cost of
artificial recharge
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Salinity control First step to be made is assessing occurrence and origin
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Salinity control: control of upconing
• Upconing under a pumped well in response to decrease pressure in fresh domain
• Methods to prevent upconing:– skimming well (creating a stable mound)– scavenging well (dual pumping: saline and fresh water)
Fresh groundwater
Saline groundwater
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Salinity control: sea water intrusion
• Simultaneous outflow of fresh groundwater and intrusion of seawater
• Stronger fresh water flux reduces intrusion tongue• Note: Climate change/sea level rise may interfere
Coastal zone
Sea
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Irrigation-induced soil salination Volumes of water: R I ET
rainfall irrigation evapotransp.
Salt loads: Rcr Ici ETce
Control volume of soil: (undrained)
cc
capillary flow C
Soil salt quantity S
Mean annual soil water balance: R + I + C - ET = 0
Mean annual soil salt balance: Rcr + Ici +C cc - ETce = ΔS
Because ce < cr , ci,,, cc it follows: ΔS > 0
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Mechanism of soil salinity controlVolumes of water: R I ET
rainfall irrigation evapotransp.
Salt loads: Rcr Ici ETce
Control volume of soil: (drained)
Pcp
percolation flow P
Soil salt quantity S
Long-term soil salinity control (ΔS = 0 ) for Ici Pcp
Add “leaching requirement” to crop irrigation requirement and provide for drainage as needed
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Groundwater pollution: understanding water quality
• Observe current groundwater quality• Define the groundwater’s origin• Define water quality of recharge water• Define flow processes and patterns• Identify physical chemical and bacteriological
processes in the unsaturated zone• Identify presence, infiltration and/or injection of
contaminants• Identify modifications in the saturated zone (e.g.
solution, precipitation and other chemical reactions)
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Documented zones with excessive arsenic in groundwater (Smedley, 2008)
Groundwater quality constraints – either observed or probably present Risk of excessive fluoride in fresh
groundwater (IGRAC, 2005)
Natural groundwater quality variations are primarily related to geology
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Variations of water quality explained by flow systems
Polluted local flow systems
Unpolluted regional system of good water quality
Unpolluted but brackish regional system
Connate saline water
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Summary of the processesAtmosphere
Dissolution of gases and particles
Earth surfaceConcentration by pollution and by evapotranspiration
Saturated zone Dissolution and precipitation
Ion exchangeRedox reactions
AdsorptionGas generation and consumption
Interaction with other water bodies
Unsaturated zone Concentration by evapotranspiration
Dissolution and precipitationIon exchange
Redox reactionsAdsorption
Zone open to gasses
Influence of biosphere and soils
Presence of O2 and CO2
Zone closed to external gasses
Large residence times
At depth high T and p
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Contaminants
• Related to human activities, e.g.:– industry– traffic– agriculture (fertilisers, pesticides)– urban life– sanitary land fills
• Categories of sources: point-, line- and diffuse sources• Effects: toxicity and biodegradation• Migration of contaminants by underground transport
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Micro-pollutants: an emerging issue
• Two main categories:– Pharmaceuticals and personal care products (PPCPs)– Endocrine disruptive compounds (EDCs)
• Origin of EDCs: steroid-based food supplements, drugs, fungicides, herbicides + various household & industrial products
• Mode of dissemination: sewage, landfills, manure
• Concentration: nano- to pico-gram level (10-9 to 10-12 g/l)
• Effects: unknown yet, but potential capacity to interfere with hormones controlling human and animal growth and reproduction
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Contaminant transport
Pollutionsource
Pollution plume
Important processes:• Density flow• Convective transport• Dispersion
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Groundwater pollution control(preventive)
• Wellfield protection:
Zone IIIb
Zone IIIa II
I
• Aquifer protection:• control pollution at the source • avoid unnecessary risky activities above/in the aquifer • plan unavoidable risky activities where impacts are low• use vulnerability maps and monitor pollutants
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Dealing with pollution
Alternatives:– removing and disposing polluted soil/ water– in-situ remediation– technical isolation– hydrogeological isolation– treatment of polluted water– using polluted water where quality does not
matter
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Need for pollution control
Value of theresource
Aquifer vulnerability
Presence of
pollutants
Pollutionrisk
Needfor control
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Vulnerability: questions and factors
Topography
Soil properties
Unsaturated zone
Aquifer
Depth to phreatic level
Relation with surface water
Recharge
Do flows of water exist to
enable invasion of pollutants?
Do these waters infiltrate and migrate
easily ? Will pollutants decay?
(by adsorption, desintegration or
discharge)
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DRASTIC method for mapping vulnerability
Parameters:Depth to water tableRechargeAquifer typeSoil typeTopography (slope)Impact of unsaturated zoneHydraulic conductivity
Scores are calculated for each parameterfor each spatial unit
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DRASTIC vulnerability index
DRASTIC index =
5TD+ 4TR + 3TA + 2TS + TT + 5TI + 3Tc
Values between 26 and 220
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Groundwater level control
• Important in zones of shallow
groundwater tables:– phreatophytic agriculture– wetlands (“wet nature”)– build-up areas
• Control by surface water systems or by pumping
river
land
Drainage and subirrigation
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The Netherlands: Groundwater level control by manipulating surface water
• First stage: getting dry feet by drainage
• Second stage: drain during wet periods,
supply during dry spells (winter level, summer level)
• Third stage: establish ‘prefered groundwater
and surface water regimes’ (GGOR or PGSR)
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Defining GGOR or PGSR
OptimalRegime
Water system
Measures
Functions
Target satisfied ?
Regime accepted(GGOR)
Start analysis
Current regime
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Old and new approaches
Old approach:
• No limits to functions
• Evacuate surplus water as quickly as possible
• Provide allochtone water as needed
New approach:
• Adapt functions to conditions • Provide space to store surplus water (retention areas)
• Minimize supply of allochtone water
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Land subsidence
Groundwater abstraction
Decreasing pore pressure
Increasing effective pressure
Compression of porous layers
Land subsidence
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Introduction to groundwaterresources management
1 Introduction
2 Basic concepts and supporting subjects
3 Water resources plan development
4 Groundwater resources management issues
5 Implementing groundwater resources management
6 Case studies
Jac A.M. van der Gun
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Chapter 5: Implementing groundwater resources
management
• Institutional and regulatory requirements• Instruments and measures• Effects: prediction and monitoring
• How to play the game: ‘top-down’ law enforcement or a participatory approach?
• Crossing borders: transboundary aquifers
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Institutional and regulatory requirements
• Implementing agency (with a mandate)• Legislation and regulations• Groundwater management policy and plan• Monitoring systems• Financing mechanisms• Definition of communicacion/cooperation
with stakeholders (‘rules of the game’)
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Level PhysicalPlanning
WRM Environm.Management
NatureManagement
National BillPh.Pl.
BillWRM
EM Plan NM Plan
Provinces(12)
Regionplans
WRMplan
GWRMplan
EM PlanSoilManPlanGW ProtPlan
Waste dis-posal plan
NM plan
Water boards(58) WMPlan
Municipalities(504)
Functionplan
EM Plan
Planning effort in The Netherlands( strategic and operational )
Above these levels there are International Agreements and EU Directives
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Instruments and measures
• Categories of measures:– structural works (wells, dams, artificial recharge
works, etc.)– government funding/operation of facilities– law/ plan enforcement (including sanctions,
taxes, licenses, EIA, etc.) – incentives and encouragement of good practice
(incl. subsidies, water markets, privatization,etc.)
• Supply and demand management approaches for water quantity management
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Measures for groundwater storage management
• Due to external costs of groundwater pumping:
Q opt, private > Q opt, social
• Corrective measures to establish “social optimum”:
- restrict access (licenses)- increase private cost (taxes)
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Groundwater licensing
• Obligatory request for granting grw. user rights• To be submitted to GWRM agency• Basis for decision: GWRM plan• Different possibilities:
– decision depends on known parameters (area, purpose, quantity, etc.) immediate “yes” or “no”
– decision depends on predicted effects: then carry out study and compare predicted effects with maximum permissible decision
• After granting license: monitoring
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Obligations regarding groundwater
in the province of Gelderland Pump Abstraction
capacity rate
(m3/hr) (m3/ 3months)
• Declaring: > 1
• Registering: > 35
• Licensing: > 25 000
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Groundwater tariff
• Tariff breakdown:– Annual external cost per m3
• interference between pumpers• salination• pollution• land subsidence• wetland conservation & other
environmental impacts• user cost (scarcety premium)
– Annual GWRM cost per m3• studies & planning• licensing• collecting taxes• monitoring, etc.
• Tool for demand management and for recovery of external costs and management costs
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Measures for pollution control
• Pollution risk mapping• Land use planning and functional zoning• Prohibition of certain chemicals• Regulations for handling harzardous
substances and waste disposal• Obligatory treatment provisions• Proper sanitary waste disposal practices• Monitoring• Quick action in case of accidental pollution
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Who implements the plan?
• Should be decided upon in a pragmatic way, but consistent with local mandates and practices
• One extreme: centralised government action (‘top-down’)
• Other extreme: self-management by stakeholders’ WRM organisation
• Involvement of stakeholders usually increases succes rate
Informing
Inquiring
Consulting
Co-producing
Delegating
Selfruling
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Monitoring and adjustments
• Monitoring “effects” and “compliance” to be preferred over “monitoring the efforts spent”
• Corrective action and sanctions for violators of regulations
• Feed-back for plan adjustment, after comparing observed effects with predicted ones
• Water resources management follows planning cycles
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Crossing borders: transboundary aquifer resources management
• Aquifers: main reservoirs for subsurface storage of water and ‘highways’ for groundwater flow
• Many aquifers are crossed by political boundaries
• Potential cross-boundary interferences: changes in groundwater flows, levels, pressures, volumes and dissolved substances
• Invisible groundwater• Very slow flow• Why should we bother?
1. Eliminating potential sources of conflict2. Improving the overall benefit from
groundwater
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Important international initiatives on TARM
Emerging awareness on transboundary aquifer
issues
TARM/ISARM Programme – since 1997 (IAH & UNESCO-IHP)
Regional Inventories:Europe, Balkans, The Americas, Southern Africa, Caucasus/Central Asia, etc.
Mapping Transboundary Aquiferse.g. WHYMAP’s World Map (2006) and IGRAC’s TBA World Map (2009)
Regulatory & institutional efforts (e.g. ILC Draft Articles on the Law on TBAand EU Water Framework Directive)
Pilot projects (e.g. Guarani, North-Western Sahara, Iullemeden)
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318 inventoried transboundary aquifer systems
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Law of Transboundary Aquifers
• Souvereignity of aquifer States
• Equitable and reasonable utilization
• Obligation not to cause significant harm
• General obligation to cooperate
• Bilateral and regional agreements and arrangements
Main principles:
Present status:• Draft articles approved by UN General Assembly (Resolution
A/RES/63/124, December 2008)
• States are encouraged to consider them for water management
• Upgrade to legally binding framework convention desirable
good neighbour-
ship
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Global priorities and favoured approaches
• Millenium Development Goals
• Sustainable Development
• Transition to a Greener Economy
• Addressing Climate Change
Global policy priorities:
Favoured or emerging approaches:• IWRM
• Adaptive management
• Groundwater governance
• Integrated subsurface management
• Linking water management with other types of spatially defined management (‘getting out of the water box’ )
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Groundwater resources management in a nutshell
Groundwater
Problems?Opportunities?
Planning
Plan approval and acceptance
Implementation
Monitoring
Other policy fields
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Suggested Reading
http://www.unesco.org/new/fileadmin/MULTIMEDIA/HQ/SC/pdf/Groundwater%20and%20Global%20Change.pdf
Systematic description of the world’s ground- water systems, their resources, use and management, around 300 pages + maps and pictures (expected to appear by the end of 2012)
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... More suggested reading
Recommended