The Role of Science

Groundwater for Socio-Economic

Development

The Role of Science

This presentation has been prepared to give an appreciation of the

complex and challenging issue of groundwater resources management.

It describes the role of science and the information needed to provide the necessary understanding of groundwater systems in order that they can be better and sustainably managed.

It was first presented at the Groundwater Theme session of the 3rd World Water Forum, held in Osaka, Japan on 18 and 19 March 2003.

It was commissioned by UNESCO and prepared by the International Association of Hydrogeologists with the support of:

The Food and Agricultural Organization (FAO)

The International Atomic Energy Agency (IAEA)

The International Groundwater

Resources Assessment Centre (IGRAC)

Ken Howard,

University of Toronto

Christine Colvin, CSIR, South Africa

Co-Hosts

Contributors come from all over..

Ken Howard from the University of Toronto, Canada

Christine Colvin, of CSIR, South Africa

Willi Struckmeier from BGR, Germany

Jac van der Gun from IGRAC in the Netherlands

Peter Dillon from CSIRO in Australia

Pradeep Aggarwal from IAEA, Austria Alfonso Rivera from the Geological Survey of Canada

Jacob Burke from FAO in Rome, Italy

Jaroslav Vrba Chair of the IAH Commission on Groundwater

Protection from the Czech Republic, Shammy Puri Chair of the IAH

Commission on Transboundary Aquifers from UK, and

Luiz Amore Manager of the Guarani Aquifer Project from Brazil

They include:

The presentation was initially developed as a series of linked themes and is ideally followed from beginning to end. For convenience, however, links are provided below ( ) that provide a direct route to specific topics. At the end

of each topic, the user can choose either to continue with the presentation ( - the default) or return to this page ( ) to seek another link.

List of Contents

1. Groundwater – Blue Gold

...Start of Full Presentation 2. Hydrologic Cycle - Christine Colvin 3. Distribution of World Groundwater

Resources - Willi Struckmeier 4. Resource Volumes - Ken Howard 5. Recharge Management - Peter Dillon 6. Groundwater Flow Velocities /

Isotopes - Pradeep Aggarwal 7. Transboundary Aquifers -

Shammy Puri / Luis Amore

8. Over-exploitation in Mexico City - Alfonso Rivera

9. Rock-water Interaction / Arsenic - Ken Howard

10. Water Quality Protection - Jaroslav Vrba

11. Agriculture - Jacob Burke 12. Urban Issues - Ken Howard 13. Ecological Issues -

Christine Colvin 14. Education &

UNESCO - Ken Howard 15. IGRAC - Jac van der Gun 16. Conclusion

GROUNDWATER

“ Blue Gold ” from

below the Earth ʼ s surface

Since ancient times, groundwater has been the key to human

survival on this planet.

It has also been one of life’s mysteries.

“A Hidden Treasure”!

Freshwater springs

emerging from the ground were a critical source of fresh water for Aborigines in the Australian desert 50

thousand years ago.

In the Middle East and China, groundwater drawn from wells and springs over 5000 years

ago was the catalyst of modern civilization

and sustainable water management based on scientific knowledge

There is,

however,

a huge

difference

between

water use

Surface water found in lakes and rivers, has been studied, quantified and carefully

managed for thousands of years

Examples here from the

Nile Basin

Ancient examples of surface water

management

Roman aqueducts

http://www.dl.ket.org

remain all over Europe

The laws of groundwater flow date back only 150 years to Henry Darcy who carried out experiments in 1856 on a fountain in Dijon, France.

In contrast, groundwater management is very recent.

The science of groundwater is young!

Our knowledge and understanding of how

groundwater is stored – in aquifers – dates back to Meinzer in the 1920’s - just 80 years.

Darcyʼs work is

commemorated today by this modern fountain in Dijon.

Darcy, H. (1856). Les Fontaines Publiques de la Ville de Dijon. Dalmont, Paris.

We plan to share our

knowledge about groundwater - our successes, our failures

and the many serious

challenges that must be faced.

In this presentation, we’ll be undertaking a journey of scientific exploration and discovery below ground.

We are headed down here!

You will find that groundwater is a crucial water resource that behaves very differently from surface

water found in lakes and rivers.

Recognising and fully understanding the key differences is critical if we are to manage

groundwater effectively and responsibly.

It also important to recognise that urgent

action and major financial investment is required if we

are to sustain groundwater resources for

generations to come

Photo By K. Howard

•  World groundwater resources, volumes and aquifer recharge rates

•  Flow velocities, flow directions and implications of flow across political boundaries

•   Poor groundwater quality due to both natural and pollutant sources

•  Pending issues – urban population growth, agricultural demand and

groundwater-dependent ecosystems, and

•  Education

Our journey covers a lot of territory:

So let ʼ s begin……

Ground and surface water derive from the same atmospheric source.

RAIN …or…..….…… SNOW

But that ʼ s where the similarities end….

Ando Hiroshige (1857)

Whitworth Art Gallery Caspar David Friedrich (1811) National Gallery, London

They include:

1.  Water pathways and the regional distributions of the resource

2.  Volumes in storage 3.  Flow velocities, and 4.  Chemical behaviour

There are four major differences between ground and surface water

We shall be examining each of these in more detail, but firstly, what exactly is

“ groundwater ” and how does it get there?

Groundwater is just one

component of the hydrologic cycle

Ultimately, the key to sustainable resource management is understanding and quantifying

all the components of the hydrologic cycle

AQUIFER

Where are the world’s major aquifers?

and….

How much water is available for use?

We introduce Willi Struckmeier, Chief Hydrogeologist with BGR, Germany to tell us about the distribution of groundwater

and the world ʼ s aquifers...

But, before we can do this,

two key questions must be addressed:

The World-Wide

Hydrogeological Mapping and Assessment Programme

(WHYMAP)

Willi STRUCKMEIER

Distribution of

Groundwater Resources

around the World

Groundwater is an invisible resource, a naturally hidden treasure of high strategic value

It is found in

CAVES

in

CRACKS

and in PORE SPACES in

SAND & GRAVEL

This map shows the world ʼ s distribution of surface water resources

Surface water moves quickly across the earth’s surface via discrete channels

(i.e. as rivers and lakes)

In contrast, groundwater resources are widely distributed and

move very slowly.

They use aquifers as natural

distribution networks to deliver water to

within a well‘s length of users.

Groundwater environments

are highly variable.

They can include:

 large deep groundwater basins

major groundwater basins with highly productive aquifers

Groundwater environments

are highly variable.

They can include:

 large deep groundwater basins

 complex areas with important aquifers

area with complex structure

including some important aquifers

 low production, surficial aquifers

Groundwater environments

are highly variable.

They can include:

 large deep groundwater basins

 complex areas with important aquifers

area with generally poor aquifers,

locally overlain by river-bed aquifers

The surface of the Earth…

… tells us little about groundwater

Source: USGS

At the ground surface, groundwater can only be detected from

secondary information, e.g.

  The discharge of springs from rocks

  Wetland ecosystems fed by underlying

groundwater

  Vegetation with deep roots that draw on

groundwater for growth.

But hydrogeologists - scientists who study the flow behaviour and storage

characteristics of rocks deep below the surface - can reasonably predict:

  rates and directions of groundwater flow

  the presence or absence of groundwater resources

  the groundwater quality distribution

  the accessibility and usability of

groundwater for human supply, industry

and agriculture

For example, hydrogeologists have shown that much of the world‘s groundwater is stored in

sedimentary basins, hundreds or even thousands of metres below ground surface

Sometimes these basins occur beneath deserts.

The aquifers are no longer replenished

but were filled with fresh water thousands of years

ago under much wetter climatic

conditions.

Deep wells allow these “fossil”

groundwaters to be used widely.

Today, highly productive aquifers

containing valuable groundwater resources have been found on all continents, but in

the interests of meeting future demand ...

  they must be precisely located and mapped

  the aquifer conditions have to be defined

  the groundwater resources must be fully quantified to provide a reliable basis for predicting how they can be developed sustainably.

  the physical and chemical properties of the

groundwater have to be studied

Groundwater is a hidden treasure, the strategic drinking water

reserve for our future ...

naturally clean, well protected and mostly annually replenished.

It is our common interest to develop a sound, quantitative

knowledge of groundwater

resources worldwide .

We need to understand:

•   The total groundwater reserves and

•  The rate they are being replenished

Ken Howard describes the total groundwater reserves………

Quantifying the resource is

always a difficult problem

Imagine that this 150 litre container is

filled with all the water on the planet

150 LITRES

WE FIND THAT JUST 4 LITRES

ARE FRESH !!

The remaining 146 litres are SEAWATER

THE WORLD ʼ S

WATER RESOURCES

X X X

The problem is that 3 out of these 4 litres are frozen in the earth ʼ s ice caps…

…leaving one lonely litre

The question is……how much

of this one litre is groundwater?

Let ʼ s draw 10 mL from our litre

(1000 mL) bottle

This tiny 10 mL represents all the water contained in the fresh water lakes of the world……

……including the Great Lakes of the U.S. and Canada

There they go!

Let ʼ s take a much smaller syringe – 1 mL, instead of 10 mL, as before …

1 mL 10 mL

And draw just 0.1 mL of water

This tiny amount of water represents all the rivers in the world:

The Nile, the Mississippi, the Ganges, the

Amazon, the

Danube, and so on…

0.1 mL

What does this tell us?

It tells us that 99% of fresh, available

water on this planet is GROUNDWATER!

It is clearly essential that we protect and manage groundwater resources

effectively.

99% GROUNDWATER

Unfortunately, 99% of funds for research and development go to support SURFACE water.

In the interests of sustaining world water

resources it is critical that this serious imbalance

be corrected.

Of course, groundwater volumes may be extremely large, but annual rates of replenishment – “ aquifer recharge ” are highly variable and can be very low.

To explain more about this, we introduce Peter Dillon from

CSIRO in Australia, one of the pioneers in this work.………..

In the interests of groundwater sustainability,

we need to maximize recharge.

Managing aquifer recharge for sustainable groundwater use

Peter Dillon

Chair, IAH Commission on Management of Aquifer Recharge Leader, Water Reclamation Research Team,

CSIRO Land & Water, Australia

demand supply

Our depleting groundwater resource

•  There are only two choices- reduce demand and/or increase supply

•  Recharge enhancement used as part of integrated groundwater and water resources management strategies can contribute to both aspects

•  In many arid areas groundwater storage is large but natural recharge is small

•  When groundwater abstraction exceeds recharge, water

levels drop, pumping costs increase, wells run dry, production fails, and there is economic hardship and social disruption

•  .. and in some locations stream base flow stops, riparian vegetation dies, aquifers become saline and land subsides

Methods for recharge enhancement

Injection wells

(ASR = aquifer storage and recovery from the same well) induced infiltration, bank

filtration and river releases

pond infiltration, water spreading, percolation tanks,

soil aquifer treatment

Benefits of managing aquifer recharge

  creates the cheapest new water resources to alleviate poverty, help the environment and prepare for climate change

  prevents evaporation losses

  freshens brackish groundwater

  prevents saline intrusion

  harnesses otherwise wasted water, and makes use of natural treatment capacity of aquifers

  conjunctive use of surface and groundwater makes robust water supplies

  can assist in winning support for demand management

supply

What’s New?

•  Wider range of methods, source waters and scales

•  Clogging and biogeochemistry better understood

•  Aquifers now relied on for some pathogen removal

•  Limits to operations and sustainability are better defined

•  Many sites now with 25 years of reliable operation

•  Sufficient science base for good regulations

•  Research is reducing risk and costs for water suppliers

Management Issues

•  Costs – capital costs are small but there are investigation costs

•  Investigations - essential so that expectations are realistic

•  Monitoring –essential for sustainable quantity and quality

•  Training – for operators, regulators and communities

•  Regulations – need more work - ownership of source water and banked water, water quality management and pollution prevention practices

•  Planning – evaluate alongside all water

management options as this may be a useful adjunct, for drought or emergency

supplies

Intentional recharge as part of the groundwater management toolkit

•  Recharge enhancement (Management of Aquifer Recharge, MAR) is often pointless unless combined with groundwater demand management

•  Implementation of demand management alone is extremely difficult and rarely successful

•  Used together they have potential to solve major overdraft problems – but this is rarely done

MAR can make it easier for communities to invest in demand management, e.g. groundwater pricing, and in monitoring groundwater use, estimating natural

recharge, improving irrigation efficiency, learning about groundwater and forming groundwater usersʼ associations, because it enables the minimum

reduction in demand to reach a groundwater balance

demand demand demand

Conclusions

•  Recharge enhancement can be an effective strategy in managing groundwater in water scarce areas

•  To harness it effectively, communities will need access to good groundwater technical investigations skills and data

•  It can be a vehicle to assist in implementing economic and other policy instruments where demand needs to be reduced

•  It requires new regulatory issues to be addressed in a holistic way e.g. water ownership

•  Its use opens the way for more sustainable and economic conjunctive use of surface and groundwater resources

•  It is not a panacea for water shortage, and every situation

demands adaptation to suit local natural resources and needs

IAH is currently working with UNESCO under IHP-VI, to inform and educate on recharge enhancement

so that all new projects will be sustainable.

•  How fast does it move?

•  Which way does it move? And….

•  How much can we pump without damaging the resource?

Knowing how much groundwater we have and at what rate it is being replenished is a good

start………but it ʼ s only part of the puzzle when it comes to managing the world ʼ s most

important source of fresh water.

Other issues include:

Pradeep Aggarwal is from the IAEA in Vienna and explains how isotopes help determine groundwater flow velocities…………

We ʼ ll take these one at a time…

How fast does

groundwater move?

……and why should we care?

Pradeep Aggarwal

Head, Isotope Hydrology Section United Nations’

International Atomic Energy Agency

Vienna, Austria

Rivers – meters / second

Groundwater – meters/day or year!

River vs. groundwater flow – very different time scales

According to Darcy’s Law, the flow rate is controlled by the material properties and the difference in

groundwater levels

between recharge (Pr) and discharge (Pd) areas

Pr

Pd

Observations – long-term monitoring of water levels, material properties, etc.

How do we determine how fast groundwater moves?

Natural “fingerprints” – isotopes in

precipitation and groundwater provide

information on the “age” of water that

can be used to determine flow rates

Isotopic mapping of global precipitation

YEAR

1950 1960 1970 1980 1990 2000

TRITIUM CONCENTRATION (TU)

1 10 100 1000 10000

Ottawa, Canada

Kaitoke, New Zealand

Tritium peaks in the northern and southern hemispheres

Monthly variation in oxygen isotope ratios – data from the IAEA global

network

So why do we care about how fast groundwater moves?

•  Rivers – flow is

rapid and river water is normally renewed in a few weeks

•  Groundwater – moves very slowly and is months to

thousands of years

old

In desert regions, water is available for

use today that

recharged the aquifer thousands of years ago when the climate

was more humid!

Consequences of slow rate of

groundwater movement

Muted seasonal fluctuations of water levels lead to a more reliable resource

0 2 4 6 8 10 12 14 16

Apr-95 Oct-95 Apr-96 Oct-96 Apr-97 Oct-97

Date

Water Level elevation (m)

River

Well

Filtering of inorganic and organic contaminants during movement

 

Groundwater can be used directly in most instances without treatment

 

However, once polluted, difficult to clean

 

Also, natural contamination e.g. arsenic

(as we will see later) can be present!

Summary

Groundwater movement is very much slower than surface water. As a result, groundwater is

 

a more reliable and cleaner water resource, and

 

the only resource available in

desert areas where rainfall is

limited

Flow rates are important, but so are groundwater flow directions.

This is particularly true when flow takes place across political

boundaries...

To explain this serious issue, we introduce Shammy Puri, Chair of the IAH Commission

on Transboundary Aquifers and Luis Amore, Manager of the

Guarani Aquifer Project,

South America ...

Shammy Puri

IAH Commission on Transboundary Aquifers

Luis Amore Manager of the

Guarani Aquifer Project, South America

Transboundary Aquifers:

equal rights & shared benefits

Transboundary basins

• 

account for 60% of global river flows

• 

• 

related treaties, though there is passing

mention of groundwater in some basin treaties

• 

• 

From Basins to Aquifers

3D bulk flow

The enigma of groundwater in transboundary context

 

WATER ignores political / administrative boundaries

 

WATER evades institutional classification

•  How many municipal water supply agencies also manage agricultural / industrial demands?

 

WATER eludes legislative generalisations

•  International Water Law / International Court of Justice: limited record in resolving transboundary water issues

 

… but GROUNDWATER, is a hidden resource,

consists of 99% of all accessible freshwater, and in a

transboundary context poses multi dimensional facets

for analysis

Aquifers in international treaties

•  Of the 400 world wide treaties, only 62 refer to aquifers

•  Most established after the 1950’s

•  Only 6 deal with

quality, 8 with quantity

•  Many concern border issues

•  Majority are bilateral

The inventory showed that of the 89 transboundary aquifers in Europe, many remain unrecognised by one

of the sharing countries

Transboundary aquifers in water scarce regions

Nubian Aquifer

Viewing point from

satellite

The Nubian shared aquifer

  Inhabitants in the GAS Region:

15 million

  Estimated freshwater reserves:

40,000 km³

  Annual recharge: 166 km³

  Depth of aquifer: surface - 1800 m

  Estimated mean thickness: 250 m

  Max. tube well

capacity: 1,000 m³/h

  Temperatures:

33° - 85°C

  Area: 1.2 million km²

The Guarani Aquifer System (GAS):

Location and Characteristics

The Guarani Aquifer System:

Transboundary Distribution

Issue / Countries

Argentina Brazil Paraguay Uruguay

SAG (km²) 225,500 839,800 71,700 45,000

National territory covered by SAG (%)

25

18

10 6

Geographic division of the SAG (%)

6.1 3.8

71

19.1

Why bring transboundary aquifers into the international policy arena?

•  Some contain drinking water needs for the

whole planet for tens of decades

•  Surface water is

tangible – aquifers are

‘out of sight, etc.…..’

•  Difficult for decision-

makers to conceptualise

•  Their significance may not be well understood:

provide buffer during droughts

•  Lack of awareness

might leave them at risk and potential conflict

Exploration water drilling to 1500m depth

The Message ?

•  Transboundary aquifers provide water for 40% of the world population

•  To ensure sustainability, we need to understand them

•  Translate equitable water rights to shared benefits of the water

Why do this…….?

Because aquifers only

obey hydraulic heads !

Selecting appropriate aquifer management policies (e.g. where and

how much we can

pump) is always difficult where there are

transboundary issues!

It is also a problem where aquifers

receive very little or no

natural recharge.

Some scientists believe that water has value “ only by virtue of use ” and that simply limiting pumping

to the often tiny amount that is renewed via recharge each year fails to utilize that value.

They advocate mining groundwater like oil or coal.

Certainly, resource mining can provide major

economic advantages, and there isn ʼ t a prosperous nation in the world that hasn ʼ t benefited at some

time from over-exploitation of groundwater.

There are, however, serious potential risks with over-exploitation, and an expert in this field is Alfonso Rivera of the Geological Survey of

Canada who tells us about Mexico City…...

Mexico City

Alfonso Rivera

Geological Survey of Canada

MEXICO

Water Administrative Regions

GROUNDWATER RESOURCES IN MEXICO

•  Water Management is divided between 13 Water Administrative Regions

•  About 66% of population relies on groundwater

•  Total annual groundwater extraction is ~ 28 km³ : 19 km³ - for irrigation

6 km³ - supply ~ 68 million inhabitants 2 km³ - to industry

•  Most over-exploited aquifers are in arid and semi-arid zones

•  Thanks to groundwater, arid and semi-arid zones have developed culturally and economically

Subsidence observed in Mexico City for the period of 1938 to 1977

Mexico City Subsidence

Mexico City

Groundwater Over-exploitation and Subsidence

•  Population = ~20 million

•  The City depends 67% on groundwater for:

drinking,

industry, and irrigation

•  The Cityʼs economy grew steadily by 6 to 7 % annually between 1935 and 1975 thanks to groundwater exploitation

•  However, over-exploitation of the resource led to serious land subsidence

•  Groundwater pumping was eventually reduced and other water sources were considered in the late

1980ʼs

Mexico City

(1500)

(1963)

(1900)

(1990)

Mexico City used to sit on a Lake!

The City ʼ s Perennial Water Problem:

Either too much in the

past or not enough today

Mexico City Satellite Photo in 1986

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 YEAR

1.0E+6 2.0E+6 3.0E+6 4.0E+6 5.0E+6 6.0E+6 7.0E+6 8.0E+6 9.0E+6 1.0E+7 1.1E+7 1.2E+7 1.3E+7 1.4E+7 1.5E+7 1.6E+7 1.7E+7 1.8E+7 1.9E+7 2.0E+7

Inhabitants [Millions]

Urban growth

0.0E+0 5.0E+5 1.0E+6 1.5E+6 2.0E+6 2.5E+6 3.0E+6 3.5E+6 4.0E+6 4.5E+6 5.0E+6

(m^3 / day)

Water consumption

Urban growth and water consumption in Mexico City

Mexico City’s

Perennial Water problem

Groundwater pumping in Mexico City for the period 1934 to 1986

Mexico City

Groundwater Overexploitation

San Joaquin Valley,

California USA Mexico City

1925

1955

1977

1922

1954 S=6.5 m S=9 m

Observed Land Subsidence

Simulations with a numerical model

Observed and simulated subsidence

CONCLUSIONS

•  From the 1950s to the 1980s, Mexico City developed at a pace of 7 to 8% per year

•  Without doubt, groundwater played a major role

•  Groundwater quality is good but sewage leaking from canals has caused nitrate contamination in some areas

•  Problems of over-pumping were evaluated and overcome

•  Socio-economic analysis led to the import of alternative water supplies from other sources

•  The city now manages water resources conjunctively.

•  Groundwater is still used but controlled. Surface water is imported from other basins

•  Subsidence has been largely controlled following scientific assessments using model predictions

And there are similar good news stories throughout the world.

In Tokyo, for example, over-exploitation of

groundwater led to subsidence and sea water intrusion but the

problems have been resolved through better

management.

The Message?

provided it is positively planned, realistically evaluated, and if close control over groundwater production is exercised.

There must also be a clear and feasible plan for alternative water supplies when groundwater resources are exhausted.

Photo from MORI Building Company Ltd.

Tokyo

Of course, pumping strategies that deliver large

volumes of water can be pointless, if the quality of the groundwater is impaired.

Groundwater quality can degrade in many ways, usually as a result of

•  natural rock-water interaction or

•  pollution by surface sources

Ken Howard explains the

effects of natural rock-

water interaction..….

Because groundwater and rock remain in close contact for hundreds, perhaps, thousands of years, there is ample opportunity for the water to

become mineralised

Rock-Water Interaction

ROCK + WATER DISSOLVED

MINERALS Normally, the level of

mineralisation is low, and the dissolved “ ions ” e.g. calcium, magnesium,

iron etc.

are harmless or

even beneficial.

Sometimes, mineralisation becomes so high that the water is too saline to drink.

The water is not necessarily unhealthy – it simply tastes bad!

In such cases, animals can tolerate much higher salt levels

than humans

The real concern is when

the dissolved minerals are

harmful ……. even deadly!

For example, fluoride in drinking water strengthens teeth and bones at low concentrations

of about 1 mg/L but can lead to a serious health condition - fluorosis at higher levels.

Some governments are not fully aware of the fluoride problem;

others are not convinced of its adverse impacts

on their populations.

A more recent concern is the presence of ARSENIC, a highly toxic and carcinogenic metal that has been

found in groundwater throughout the world.

In the U.S. 8% of wells have arsenic levels above 0.01 mg/L

(the WHO and U.S. guideline value);

1% exceed 0.05 mg/L.

The fluorosis problem has been

recognised and understood for many decades.

Recent studies suggest, however, that a far more serious problem exists in Bangladesh where 27% of

shallow wells produce water with arsenic levels above 0.05 mg/L

(the Bangladesh standard for

arsenic in drinking water).

This is a tragedy for a country that relies so heavily on

groundwater.

It is estimated that Bangladesh has between 6 and 11 million

shallow wells, and that

Thousands of people have already been diagnosed with poisoning symptoms; most of the

population has not yet been assessed for arsenic-related

health problems.

35 million people may have been exposed to arsenic levels

above 0.05 mg/L

The problem in Bangladesh is a tragic reminder that despite considerable scientific progress,

much remains to be done.

It is essential that adequate funding be made available for:

Basic scientific research into subsurface chemical processes, Water treatment technologies and The arsenic is natural in origin,

but the mechanisms by which the arsenic is released from the rock are poorly understood

scientifically.

Urgent funding is also required for water quality monitoring And adequate in-house

analytical facilities

Degradation of groundwater quality due to natural

processes is a serious concern, but it is also very difficult to avoid.

To tell us how this should be done we have Jaroslav Vrba from the Czech Republic.

Jaroslav is Chair of the IAH Commission on Groundwater Protection………...

*

In contrast, groundwater pollution by surface

contaminant sources can be

prevented!

Groundwater

Protection Policy and Management

Prevention is better than cure

Jaroslav Vrba Chairman of the IAH

Commission on

Groundwater Protection

Groundwater, a Vulnerable Resource

  Groundwater, a renewable and finite natural resource, is vulnerable to natural and human impacts

  Historically, little attention was given to the protection of

groundwater quality, mainly because people were unaware of the threats to this hidden resource

  The idea that the geological environment protected

groundwater from the impact of surface pollution prevailed for a very long time and many people still believe that

groundwater remains pristine, isolated from pollution

  This approach has had serious, long-term consequences on groundwater quality in many countries

Groundwater pollution

 

Anthropogenic groundwater pollution is a

process whereby water gradually or suddenly changes its natural physical, chemical or

biological composition and ceases to meet the criteria and standards set for drinking water, irrigation and other purposes

 

Various criteria have been used to classify groundwater pollution. The commonly used

classification systems are based on the extent of

pollution, the source of pollution and the kind of

pollutants

Groundwater Pollution Problems

Industry, mining, waste disposal sites domestic and livestock effluents, silage

Urban areas, rural settlements military areas

Agriculture – crop farming, irrigation

Horticulture

Roads, railways, oil pipelines, sewerage systems, streams

Acid deposition, salinisation

Extent of pollution Source of pollution Kind of pollutants

Physical

Chemical

Biological

Radiological

Point

Multipoint

Diffuse Line

Regional

Pollutants can enter aquifers due to

diverse human activities

Movements of contaminants in the groundwater system

 

Subsurface migration of contaminants and

mechanism of groundwater pollution depend on the nature of groundwater system as well as on the quantities and properties of the contaminants discharged

 

Movement and transformation of contaminants is controlled by a number of processes. Density

and viscosity are particularly significant when

light or dense nonaqueous liquids are the source

of aquifer pollution

Movement of LNAPLs and DNAPLs into the Groundwater System

Dense Nonaqueous Liquids (DNAPLs) Light Nonaqueous

Liquids (LNAPLs)

Gaseous phase

Water miscible phase

Water immiscible phase

Impact of Agriculture on Groundwater Quality

  The only non-point pollutants that are widely reported for groundwater are nitrates (due to excessive amounts of fertilizer) and pesticides applied to arable land.

  Where shallow aquifers underlie agricultural soils in Europe model computations indicate that:

85% show nitrate concentrations in excess of the EU target value (25 mg/L), 20% show nitrate concentrations in excess of the drinking water standard

(50 mg/L).

25% show pesticide concentrations in excess of the pesticide drinking water standard by a factor of 10 or more.

  In the US over 10% of community water supply wells revealed detectable residues of one or more pesticides. Groundwater nitrate – nitrogen concentrations exceeding the 10 mg/L

maximum contaminant level (MCL) can be found in many agricultural regions in the U.S.

To reduce agricultural threats on groundwater quality, Pollution Prevention Programmes must focus on:

  Improvements and/or modifications in agricultural

management practices to reduce groundwater pollution risks

  Increased efficiency in the use of fertilizers and pesticides

  Introduction of alternative, environmentally-friendly agricultural practices

  Environmental impact assessment and groundwater pollution risk assessment of agricultural activities

  Farmer education

  Cost-benefit analysis of the consequences of water quality degradation due to agricultural activities

  Soil and groundwater quality monitoring for conservation purposes

  Regulation and control of agricultural activities in vulnerable and recharge areas of aquifers and in zones of protection for groundwater supply.

Groundwater vulnerability

assessment and mapping, and Groundwater quality monitoring

should be integral parts of

groundwater protection policy and

management.

Groundwater Vulnerability

 

Vulnerability is an intrinsic property of a groundwater system that reveals the sensitivity of that system to human (specific vulnerability) and natural (intrinsic vulnerability) impacts.

 

Principal groundwater vulnerability attributes are:

  recharge rate

  topography

  soil properties

  unsaturated zone composition and thickness

  depth to the water table, and

  the characteristics of the aquifer

 

Specific vulnerability is assessed in terms of the risk of exposing the aquifer to contaminant loading. Key

parameters include the attenuation capacity of the soil, and the properties of the unsaturated zone and the

aquifer.

The concept of “Groundwater Vulnerability”

is based on the assumptions that

 

All groundwater is vulnerable (except deep fossil waters)

 

Vulnerability assessment mostly concerns the uppermost (shallowest) aquifers

 

The physical environment controls the degree of groundwater vulnerability

 

The reliability of the vulnerability assessment

depends on the amount, quality and consistency of the available data

 

Groundwater vulnerability is a relative, non-

measurable, dimensionless property

Groundwater Quality Monitoring Programmes

 

Generate data that allow evaluation of the current

status and future the current status and future trends in groundwater quality and quantity and help to clarify and analyze the extent of natural processes and

human impacts on groundwater in space and time

 

Operate at international and national levels

(background monitoring) and regional and local levels (specific monitoring). National groundwater quality

monitoring programmes operate in a few countries only

 

The objectives of the monitoring programme govern the extent of the monitoring networks, the design of monitoring wells, the methods and frequency of

sampling and the number of variables to be analyzed

Early Warning Groundwater Quality Monitoring

 

Early warning groundwater quality monitoring is an activity or sequence of activities that makes it possible to identify and to foresee the outcome of a process leading to groundwater pollution

 

The objective of early warning groundwater

quality monitoring is to observe early stages of

human impacts on groundwater system when

they are still controllable and manageable

Categories of Groundwater Monitoring Station used in Groundwater Quality

Monitoring Programmes

Category and importance of monitoring station

Monitoring programme

Baseline Trend Impact

Station

density Sampling

frequency Variables

analysed Monitoring stations characteristics

International D C LS VL L B +

O -

Baseline station: natural background groundwater quality

National D C LS L L B +

O -

Regional C D LS M M B +

O +

Trend station: trends in groundwater quality due to natural processes and human impacts

Local LS LS D H H O + Impact station: changes of groundwater quality

due to various human impacts

Station’s significance: D Dominant, C Complementary, LS Low significance

Station density: Station per km²: H High – m² to 10, M Medium – 10 to 100, L Low – 100 to 1 000, VL Very low – 1 000 and more Sampling frequency: H High – more than 12 times a year, M Medium – 2 to 12 times a year, L Low – 1 to 4 times a year

List of variables analysed: B Basic – physical, chemical and biological variables included into the drinking water standards

O Optional – heavy metals, organochlorine compounds, oil hydrocarbons and other variables depending on monitoring program objectives

+ Regular analysis - Occasional analysis

Groundwater quality monitoring programme

Groundwater

quality Critical point Definition of requested output information monitoring

system

Delimitation of monitoring area

Determination of groundwater Identification and inventory system geometry and parameters, of potential and existing evaluation of relevant data of pollution sources groundwater quality

Design and establishment of monitoring network and

Data acquisition

Sample collection Laboratory analysis

Data handling

Transmission Processing Storage Database management system

Feedback

Groundwater

quality Critical point information

system

Groundwater Information utilization

quality

management Legislative and institutional

system implementation of protective measures

Strategy Objective

designation of monitoring methods

Information communication Information products

Data analysis

Groundwater Protection Policy

GROUNDWATER PROTECTION POLICY GOVERNMENTAL

AUTHORITIES

PUBLIC INVOLVEMENT LEGAL

FRAMEWORK

HUMAN RESOURCES

INSTITUTIONAL CAPACITIES TECHNICAL CAPACITIES

GROUNDWATER SYSTEM ANALYSIS

RESEARCH PROGRAMMES

ADDRESSING POLLUTION PROBLEMS

GROUNDWATER MONITORING INSPECTION AND

CONTROL MECHANISM

Groundwater Protection and Pollution Prevention

  Prevention, not rehabilitation, is the key to effective

groundwater protection, water quality conservation and

sustainable management. “Prevention is far better than the cure”

  This is particularly the case when considering time constraints and available experience regarding the cost-effectiveness of groundwater quality restoration programmes

  In the long-term, “prevention” is also the most economic means for assuring the supply of unpolluted groundwater and finding a balance between environmentally sound groundwater

protection, sustainable economic development and potential social and health implications

Policy for Groundwater Protection,

Quality Conservation and Management should be:

  Based on institutional and technical capacity building

  Holistic, inextricably linked with the protection of surface water and other dependent ecosystems

  Coordinated with land use planning and economic development

  Linked to social policy in regard to the health hazards associated with the pollution of drinking water supplies

  Based on the value of groundwater with respect to both drinking water and ecological requirements

  Attentive to cultural and historical traditions of the society, and

  Ethical with regard to human basic water needs

Important scientific progress has been made during the past 150 years…but are these

advances sufficient to deal with the challenges we face?

Jacob Burke from the Food and Agricultural Organization of the United Nations in Rome

examines the role of groundwater in agricultural production……..

Some of the most serious challenges concern global population growth which has created an unprecedented

demand for water.

In many ways, this represents the ultimate challenge since sustainable development can never be achieved

without sustainable water resources!

Trends and Prospects for Groundwater Use and

Management in Agriculture

Jacob Burke

Senior Water Policy Officer,

Agriculture Department

Trends

•  FAO projects that agricultural water use will increase by 14% in 93 developing countries by 2030.

•  At global level, groundwater estimated to make up 30% of

agricultural water demand (but strict partition between surface and groundwater not possible - schemes are mixed).

•  Depletion and degradation of strategic aquifers continues largely unchecked

- much groundwater used by agriculture is of high quality.

•  But data limitations preclude a definitive estimate of the global risk to food security.

•  Nonetheless, our groundwater ʻcreditʼ is not in good shape.

•  Groundwater levels, not volumes, are important if equitable access is to be maintained.

Agriculture’s Response

•  Lack of focus on changing food security targets – should agriculture policy aim at intensification or extensification? – groundwater can be in instrumental in both.

•  Policy schizophrenia – is irrigation part of water or agriculture?

•  Institutional rigidity, policy response lagged.

•  Government agencies slow to understand demand factors and comparative advantage – but groundwater irrigators

usually ‘up to speed’

on market opportunities.

•  Suits agriculture to keep groundwater regulation a ‘grey’

area.

The Farmer Perspective

•  Wants an on-demand, just-in-time water service (hence groundwater uptake).

•  Wants to be de-coupled from hydrological variability.

•  Groundwater always the fall-back – buffers progressively being used up.

•  Farmer incentives to manage demand for groundwater are weak.

•  Opportunities to transition out of agriculture seized, but only if the

groundwater economy is ‘deep’ enough.

The Limits to Management

•  Millions of highly dispersed users making low intensity private investments. Customary practice & informal markets predominate.

•  Access to groundwater ultra-convenient for agriculture but perceived as intensely private.

•  Surface irrigation performance desultory but conjunctive use within surface commands growing.

•  Technical regulation, particularly volumetric allocation, rarely possible.

•  Economic incentives to

manage groundwater unclear

•  Participatory approaches involve sacrifice and

require time to become effective.

Prospects: Adaptation

•  Access to groundwater allows farmers to be much

more adaptive and responsive to market opportunities in high value crops.

•  Groundwater management adapted to the systemic character of aquifer systems and user groups will be more effective than ʻintegratedʼ approaches.

•  Opportunities to manage conjunctive use of surface and

groundwater sources under-realised - but can be opposed by rigid command and control

management styles in surface irrigation

commands.

Question:

•  Can groundwater regulators ʻ_lock-onʼ to millions of users before it is too late ?