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A Baltic University Programme Publication

Sustainable Water Management in the Baltic Sea Basin

Book II.

Water Use and ManagementEditor:

Lars-Christer LundinUppsala University

Department of Earth Sciences, HydrologyVillavägen 16, SE-752 36 Uppsala, Sweden

Tel +46-18-471 22 64, Fax +46-18-55 11 24, [email protected]

Project coordinator:Lars Rydén, Baltic University Programme, Uppsala University

Project management group:Nikolas Rolley, St Petersburg Technical University (1996)

Sivert Johansson, Baltic University Programme, Uppsala University (1997)Lars-Christer Lundin, Uppsala University (1998-99)

Bengt Hultman, Royal Institute of Technology, Stockholm (1996-99)

Layout: Magnus LehmanEnglish editor: Barbara Rosborg

Funds: Sida, SwedenProduction: The Baltic University Programme, Uppsala University

Printed by: Ditt Tryckeri i Uppsala ABSecond revised edition: 2000

ISBN: 91-973579-4-4

AUTHORS

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Lars Bergströmis an associate professor at the Department of Soil Sciences, Section of Water Quality Management at the SwedishUniversity of Agricultural Sciences. His special field is the leakage of nitrogen and pesticides into [email protected]

Göran Carlssonis a senior research manager at the Swedish Institute for Agricultural Engineering, JTI, with responsibility for engineer-ing in the Baltic Agricultural Run-off Action Program (BAAP). [email protected]

Lars-Göran Danielssonis a professor at the Department of Analytical Chemistry at the Royal Institute of Technology in Stockholm, [email protected]

Erik Erikssonis professor emeritus of hydrology at Uppsala University. His main specialisation is in theoretical hydrology andgroundwater chemistry. He has published extensively in a very broad field of research including meteorology, hydrol-ogy and soil science. He has contributed significantly to the development of the science of hydrology in [email protected]

Arne Gustafsonis a professor at the Department of Soil Sciences, Section of Water Quality Management at the Swedish University ofAgricultural Sciences, studying nutrient leakage and hydrological transport mechanisms of runoff from farm [email protected]

Bengt Hultmanis an associate professor at the Department of Civil and Environmental Engineering at the Royal Institute of Technologyin Stockholm. His speciality is wastewater treatment technologies, working on a broad co-operative basis with treat-ment plants in Sweden, Poland and the three Baltic states.

Folke Ingmanis professor emeritus at the Department of Analytical Chemistry at the Royal Institute of Technology in Stockholm,specialising in process analytical chemistry. He also works with the Union of Pure and Applied [email protected]

Christine Jakobssonis an expert on legislation concerning the environment and agriculture at the Swedish Board of Agriculture and at theSwedish Institute of Agricultural Engineering. She has recently been appointed director of the Baltic 21 secretariat inStockholm, working with implementing the agreement on Agenda 21 for the Baltic region signed by the Council ofBaltic Sea States in June 1998. christine.jakobsson @baltinfo.org

Lena Johanssonis a Ph.D. and researcher at the Department of Civil and Environmental Engineering at the Royal Institute of Technol-ogy in Stockholm. [email protected]

Sivert Johanssonwas a researcher in hydrology at the Department of Earth Sciences at Uppsala University, with considerable fieldexperiences from all over the world. Regrettably, he died during 1999.

Jenny Kreugeris a researcher at the Department of Soil Sciences, Section of Water Quality Management at the Swedish University ofAgricultural Sciences, where she monitors pesticides in agricultural catchments. [email protected]

Katarina Kyllmaris a research assistant at the Department of Soil Sciences, Section of Water Quality Management at the Swedish Univer-sity of Agricultural Sciences, where she monitors nutrients in agricultural catchments. [email protected]

Erik Levlinis a Ph.D. and researcher at the Department of Civil and Environmental Engineering at the Royal Institute of Technol-ogy in Stockholm. [email protected]

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Puhua Liis a researcher at the Department of Civil and Environmental Engineering at the Royal Institute of Technology inStockholm. [email protected]

Harry Linnéris a professor who heads the Department of Soil Sciences, Section of Agricultural Hydrotechniques, at the SwedishUniversity of Agricultural Sciences in Uppsala, Sweden. His special field is the irrigation and drainage of agriculturalsoils. [email protected]

Lars-Christer Lundinis an associate professor of hydrology and director of studies at the Department of Earth Sciences at Uppsala University.His main research interest is in climate processes and winter hydrology, to which he has contributed to the understand-ing of soil physics, especially freezing and thawing phenomena. [email protected]

Jozef Mosiejis a Ph.D. working as researcher and teacher in rural environmental engineering at the Department of EnvironmentalDevelopment and Land Improvement, Warsaw Agricultural University. His main interest is in water management inagriculture and water protection in rural areas, specialising in sustainable development. [email protected]

Rein Munteris a professor at the Department of Chemical Engineering at Tallinn Technical University in Tallinn, Estonia. Hisspeciality is wastewater treatment processes, to which he has contributed extensively to develop ozonation methods forwater treatment. [email protected]

Nasik Al-Najjaris connected with the Department of Civil and Environmental Engineering at the Royal Institute of Technology inStockholm as a researcher and is employed at Tekniska Verken i Linköping AB, Linköping, Sweden.

Hannes PalangM.Sc., is a researcher at the Institute of Geography at Tartu University. His research is focused on landscape change,landscape management and landscape perception issues. [email protected]

Elzbieta P∏azais a Ph.D. and researcher at the Department of Civil and Environmental Engineering at the Royal Institute of Technol-ogy in Stockholm. She is also active at the University of Technology in Krakow, Poland. [email protected]

Lars Rydénis a professor and director of the Baltic University Programme at Uppsala University. Since the early 1990s his maininterest has been the sustainable development of the Baltic Sea basin and sustainable use of its natural resources, now amain concern for the Baltic University Programme. Lars Rydén has a PhD in biochemistry. [email protected]

Staffan Steineckis a senior research manager at the Department of Soil Sciences at the Swedish University of Agricultural Sciences,studying nutrient recirculation in agriculture. He is presently in charge of the Baltic Agricultural Run-off Action Pro-gram (BAAP) at the Swedish Institute of Agricultural Engineering, with projects in the three Baltic states, Poland andNW Russia. [email protected]

Barbro Ulénis an associate professor at the Department of Soil Sciences, Section of Water Quality Management at the SwedishUniversity of Agricultural Sciences. Her main research field is leakage and runoff of phosphorus from agricultural [email protected]

FOREWORD

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Water and water management have a very special place in the efforts of countries in the Baltic Searegion and universities participating in the Baltic University network. A concern for our commonwater, the Baltic Sea, was almost the only unifying point of departure when we met for the firsttime in 1991 during the break up of the old system. It will remain an important dimension of ourwork as illustrated by declarations from prime ministers in the region and intensification of activi-ties e.g. within the Helcom co-operation. When work to improve the environmental situation startedon a larger scale a few years later, water was by far the most important point on the agenda. In 1995,for example, as much as 95 % of the Latvian investments in the environmental field were directedtowards water issues, especially wastewater treatment. Reducing emission into the air, soilremediation and natural protection were all secondary to water. The situation was similar in othercountries in the newly independent states in Central and Eastern Europe. On the western side of theregion investments to improve water quality have been substantial for several decades, which hap-pily have yielded some good results.

This is not difficult to understand. Like all lifeforms, we depend on water for our daily life andwell-being. We drink it, we wash ourselves in it, we enjoy seeing it flowing by, enjoy living in thebeautiful “waterscape” of our Baltic region. To have good and clean water is a first priority, as italways was.

The Baltic University Programme has selected water management for the first master levelcourse on issues on sustainable development. In this context water has a special role. It is a renew-able resource, and the access to this resource is quite well defined, not only globally or regionally,but also locally, based on the drainage area concept. It will also be the first resource to be managedon the basis of this concept, since European Union directives recommend drainage- area basedwater administration. Sustainable water management is a first goal in our development towards asustainable society.

The course material for Sustainable Water Management is, as with all Baltic University coursematerial, interdisciplinary in its approach. We strive to present the problems of water managementfrom a more holistic point of view. This transdisciplinary approach is intended to give students,regardless of background – natural scientists, engineers, social scientists etc. – a platform for work-ing with water issues in their professional career. It treats the system rather than its components sonaturally all specialists will be disappointed with the treatment of “their” specialities. The objectiveis to connect the specialities rather than to teach them.

The three books are the result of the combined effort of more than 50 researchers/teachers insome ten countries. They could not have been written by any single person, university or evencountry. They are a true result of the network and hopefully they will be used and studied in theentire Baltic region.

Uppsala January, 1999

Lars RydénDirector, the Baltic University Programme

PREFACE

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The textbook series

The current volume is the second in a series of three textbooks on sustainable water management.The prime purpose of the textbook series is to serve as reading material in the courses on SustainableWater Management given at a number of universities in the Baltic region. The series builds on theinput from teachers and students after the first course in 1998, which was a co-operative effortbetween Uppsala University, Tallinn Technical University, St. Petersburg Technical University andthe Royal Institute of Technology in Stockholm. However, it should be pointed out that the textbooksare of a general nature and can therefore be useful in other courses on water management or as self-study material.

The finite size of the book precludes a complete presentation of all water management aspectsand all possible problems found in the Baltic region. Instead, authors were selected from a numberof places in the Baltic region and invited to present their expertise views of the problems andprocesses involved. It is thus up to the local teacher responsible for each course to include othertexts that describe local conditions and local problems. Furthermore, it is up to the students to formtheir own opinions and develop their own understanding based on the varieties of presentations andviewpoints presented. Discussions with teachers and fellow students will be central in this process.The video and Internet conferences accompanying the course lectures are natural fora for thisdiscussion.

The volume on Water Use and Management

The second volume presents the principles behind sustainable management of water use. The Balticbasin is the reference point and target, but most issues are equally valid in other parts of the world.Practical problems of water use in different sectors of society are presented and discussed. Part Idiscusses water availability and shows water resources in a systems perspective. It then goes on todefine sustainable development as a basis for water management principles, also addressing theimplementation and financing of management.

In Part II, the focus is on agricultural water use and management. The issues of water loggingand draught are treated, leading on to drainage and irrigation. One improvement often made inplant productivity is to add nutrients to fields. Sustainable management of the use of nitrogen andphosphorus regards these nutrients as resources and aims to keep them in the soil solution, minimisingleakage to surface water and groundwater. In the chapters, both the farm level and the urban-ruralmanagement perspective are presented. The environmental impact of leakage from nutrients andpesticides is discussed, as well as the long-standing relation between wetlands and agriculture.

Part III is devoted to the management of urban water use. The handling of stormwater andsewage water, of course, is central here. Another important issue is how to handle, and preferablyuse as a resource, the sludge produced in wastewater treatment plants. The basic rules of trying toavoid the creation of sewage and of separating stormwater, sewage water and heavily pollutedindustrial water are emphasised.

Parallel to the above problems run the processes and principles of management of industrialwater use. These are the subject of Part IV of the book. Important processes in industrial watertreatment are presented and discussed. Once again, the golden rule that if you don’t create problems,you don’t have to solve them, is applied and closed-system production is discussed and exemplified.

L-C LundinEditor

CONTENTS

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AUTHORS ............................................................................................................................................................................ 2FOREWORD ........................................................................................................................................................................ 5PREFACE ............................................................................................................................................................................. 6CONTENTS .......................................................................................................................................................................... 7

Part ISustainability and Water Management

1. WATER RESOURCES AND WATER SUPPLYGreen and blue water .......................................................................................................................................................... 17Water as a natural resource .................................................................................................................................................. 18Water use for food production ............................................................................................................................................. 19Water resources in a systems perspective ........................................................................................................................... 20Concepts of water quality .................................................................................................................................................... 22The functions of water management ................................................................................................................................... 24

2. SUSTAINABILITY CONCEPTSIntroduction ......................................................................................................................................................................... 25Defining sustainable development ...................................................................................................................................... 25Conditions and goals ........................................................................................................................................................... 26

3. PRINCIPLES OF SUSTAINABLE WATER MANAGEMENTFunctions of urban water management ............................................................................................................................... 29Role of population growth .................................................................................................................................................. 29Energy and material flows ................................................................................................................................................... 30Scale and time aspects ......................................................................................................................................................... 34Guiding principles ............................................................................................................................................................... 35Natural resources and the environment ............................................................................................................................... 35Integrated management ....................................................................................................................................................... 37Emergency planning and risk assessment ........................................................................................................................... 39

4. IMPLEMENTING SUSTAINABLE WATER SYSTEMSThe water management system ........................................................................................................................................... 43Overview of instruments ..................................................................................................................................................... 43Technical instruments - Avoidance technologies ................................................................................................................ 44Monitoring, control and remediation .................................................................................................................................. 45Regulatory and economic instruments ................................................................................................................................ 47

5. FINANCING WATER SUPPLY AND SANITATIONFinancing principles ............................................................................................................................................................ 49The global situation ............................................................................................................................................................. 49Willingness to pay ............................................................................................................................................................... 51Financing and affordability ................................................................................................................................................. 53Application of low-cost handling methods ......................................................................................................................... 54Food consumption and import ............................................................................................................................................ 55Global water resource needs ............................................................................................................................................... 57Public participation ............................................................................................................................................................. 59

6. ENVIRONMENTAL IMPACT ASSESSMENTEnvironmental impact assessments ..................................................................................................................................... 61Stages and methods ............................................................................................................................................................. 62Procedures for writing an EIS ............................................................................................................................................. 62Impacts on hydrological systems ........................................................................................................................................ 63Impact comparison methods ............................................................................................................................................... 63Environmental Management Systems (EMS) ..................................................................................................................... 63Standardisation of EMS ...................................................................................................................................................... 64The history of life cycle assessments (LCA) ...................................................................................................................... 65LCA Objectives ................................................................................................................................................................... 66LCA of wastewater treatment .............................................................................................................................................. 68Developments in LCA ......................................................................................................................................................... 70

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Part IIAgricultural Water Use and Management

7. SOIL WATER MANAGEMENT IN AGRICULTURELand drainage ...................................................................................................................................................................... 75Why agricultural land drainage? ......................................................................................................................................... 75Design of a land drainage system ........................................................................................................................................ 78Ditches ................................................................................................................................................................................. 78Subsurface drainage ............................................................................................................................................................ 79Pumped drainage ................................................................................................................................................................. 80Drainage for salinity control ............................................................................................................................................... 81Drainage and environment .................................................................................................................................................. 81Irrigation .............................................................................................................................................................................. 81Irrigated crops ..................................................................................................................................................................... 82Water for irrigation .............................................................................................................................................................. 82Irrigation techniques ............................................................................................................................................................ 83Irrigation and nitrate leaching ............................................................................................................................................. 85

8. AGRICULTURAL NUTRIENT MANAGEMENTBackground ......................................................................................................................................................................... 87Measures to reduce the nutrient losses from agriculture ..................................................................................................... 87Livestock density ................................................................................................................................................................ 87Nutrient reduction areas ...................................................................................................................................................... 90Advisory service .................................................................................................................................................................. 90Plant nutrient balances on the farm level ............................................................................................................................ 91Strategies for manure spreading .......................................................................................................................................... 96Nutrient balance on the watershed level ............................................................................................................................. 96

9. URBAN-RURAL NUTRIENT FLOWSBackground ....................................................................................................................................................................... 101Definition and goals of sustainable agriculture ................................................................................................................. 101Legislation on sewage sludge ............................................................................................................................................ 101EU Sewage Sludge Directive (86/278/EEG) .................................................................................................................... 102Swedish legislation concerning the utilisation of sewage sludge ..................................................................................... 102Nutrient leakage - Nutrient balance .................................................................................................................................. 103Nutrient balances on a national level ................................................................................................................................ 103Regional balance of production and consumption of food ............................................................................................... 104Nutrient balance on town level ......................................................................................................................................... 105Nutrient balances on village and small-municipality levels ............................................................................................. 106Weak points in the situation today .................................................................................................................................... 107Actions to be taken ............................................................................................................................................................ 108

10. LEAKAGE OF NITROGEN AND PHOSPHORUSLeakage of nitrogen to water from agricultural areas ........................................................................................................ 111Requirement and water quality goals for nitrogen ............................................................................................................. 111The complexity of nitrogen losses to water and air ........................................................................................................... 112Denitrification .................................................................................................................................................................... 113Ammonia volatilisation ...................................................................................................................................................... 114How nitrate moves in the soil ............................................................................................................................................. 114Sources of leachable nitrogen ............................................................................................................................................ 115The role of soil organic material ........................................................................................................................................ 115Climate-related factors ....................................................................................................................................................... 115Overdoses of fertiliser ........................................................................................................................................................ 117Catch crops ......................................................................................................................................................................... 117Nitrogen leaching and soil type .......................................................................................................................................... 118Leakage of phosphorus from agricultural land .................................................................................................................. 119Requirement and water quality goals for phosphorus ....................................................................................................... 120The complexity of phosphorus losses from agricultural soil ............................................................................................ 120How to address the problem of phosphorus leakage ......................................................................................................... 121The occurrence of pesticides in water ............................................................................................................................... 125

11. PESTICIDE TRACES IN WATEREffects of pesticide traces in water .................................................................................................................................... 125Requirement and goals for handling of pesticides ............................................................................................................ 126Studying pesticide losses to water and air ......................................................................................................................... 126Pesticides in surface waters ............................................................................................................................................... 126

12.WETLANDS AND AGRICULTURAL RUNOFFWetlands – a key biotope .................................................................................................................................................. 129

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Functions of wetlands ....................................................................................................................................................... 129Restoring and creating wetlands ....................................................................................................................................... 130The Halmstad project ........................................................................................................................................................ 132Nitrogen reduction in wetlands ......................................................................................................................................... 132The Polish experience ....................................................................................................................................................... 132Irrigating agricultural land with wastewater ..................................................................................................................... 133Wetlands for ecosystems management .............................................................................................................................. 134The Ner-Warta catchments ................................................................................................................................................ 136Irrigation system and productive wastewater treatment .................................................................................................... 137Influence of wastewater irrigation on soil properties and yields of hay ........................................................................... 138The Ner River Valley during a transition period and in the future .................................................................................... 139

Part IIIUrban Water Use and Management

13. MUNICIPALITIES AND WATER USEHistorical aspects and changes in priorities ...................................................................................................................... 143Water supplied by municipalities ...................................................................................................................................... 145Local water supply and treatment ..................................................................................................................................... 146Water transport in central systems .................................................................................................................................... 148

14. WASTEWATER TREATMENT TECHNOLOGIESSurface and groundwater composition .............................................................................................................................. 151Wastewater composition ................................................................................................................................................... 152Stormwater composition ................................................................................................................................................... 152Health aspects on pollutants .............................................................................................................................................. 152Microbiological aspects of water quality and health ......................................................................................................... 153Chemical aspects of water quality and health ................................................................................................................... 154Labour safety ..................................................................................................................................................................... 155Biological treatment of wastewater ................................................................................................................................... 155Bacterial growth ................................................................................................................................................................ 156Chemical treatment of wastewater .................................................................................................................................... 157Separation methods ........................................................................................................................................................... 159Characteristics of ecotechnology ...................................................................................................................................... 160Artificial infiltration .......................................................................................................................................................... 161Onsite infiltration technologies ......................................................................................................................................... 161Aquatic and wetland systems ............................................................................................................................................ 161

15. WASTEWATER TREATMENT SYSTEMSWastewater treatment in local systems .............................................................................................................................. 165Sewer and stormwater net ................................................................................................................................................. 166Stormwater handling ......................................................................................................................................................... 167

16. NUTRIENT REMOVAL AND SLUDGE HANDLINGPhosphorus removal .......................................................................................................................................................... 171Nitrogen removal .............................................................................................................................................................. 172Combined phosphorus and nitrogen removal ................................................................................................................... 172Sludge handling goals ....................................................................................................................................................... 173Biological sludge stabilisation .......................................................................................................................................... 174Sludge volume reduction methods .................................................................................................................................... 174Final destination of sludge ................................................................................................................................................ 176System design of sludge handling ..................................................................................................................................... 177

Part IVIndustrial Water Use and Management

17. INDUSTRY AND WATER USEWater value and quality ..................................................................................................................................................... 181Water consumption ............................................................................................................................................................ 181Industrial water supply ...................................................................................................................................................... 182Use of water in the chemical industry ............................................................................................................................... 183Industrial municipal wastes ............................................................................................................................................... 184Physical characteristics ..................................................................................................................................................... 185

18. INDUSTRIAL WASTEWATER CHARACTERISTICSChemical characteristics .................................................................................................................................................... 186

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Heavy metals and inorganic species .................................................................................................................................. 186Thermal pollution .............................................................................................................................................................. 189Radioactivity and radioactive pollution ............................................................................................................................ 190Pollution load and concentration ....................................................................................................................................... 191

19. INDUSTRIAL WASTEWATER TREATMENTPathways of industrial effluents treatment ........................................................................................................................ 195Levels of treatment ............................................................................................................................................................ 196Unit operations .................................................................................................................................................................. 196Ion exchange ..................................................................................................................................................................... 199Membrane processes ......................................................................................................................................................... 201Electrodialysis ................................................................................................................................................................... 204Ozonation of wastewater compounds ............................................................................................................................... 204Applications of advanced oxidation processes ................................................................................................................. 207Thermal disposal of effluents ............................................................................................................................................ 213Exploitation of waste heat ................................................................................................................................................. 213

20. INDUSTRIAL COOLING WATERCooling tower water treatment .......................................................................................................................................... 213Wastewater reclamation and reuse .................................................................................................................................... 217Integrating needs and supply ............................................................................................................................................. 217

21. WATER MANAGEMENT APPROACHESZero aqueous discharge ..................................................................................................................................................... 217Water management ............................................................................................................................................................ 218The steps ............................................................................................................................................................................ 218The processes .................................................................................................................................................................... 219Examples of wastewater reuse and recycling .................................................................................................................... 219Water and wastewater minimisation ................................................................................................................................. 221Example ............................................................................................................................................................................. 222

22. INTEGRATED WATER MANAGEMENT IN THE PULP AND PAPER INDUSTRYIntroduction ....................................................................................................................................................................... 225Closing the system of the Kraft pulp mill ......................................................................................................................... 225The Kraft process .............................................................................................................................................................. 226Process Analytical Chemistry ........................................................................................................................................... 227What is PAC and what can it do? ...................................................................................................................................... 228Process analytical chemistry in the pulp and paper industry ............................................................................................ 228

REFERENCES .................................................................................................................................................................. 229INDEX .............................................................................................................................................................................. 235

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Photo by Inga-May Lehman Nådin

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ife originated in water and most of life on Earth still lives in the water itself. Life formson land have developed various means to carry water with them – humans consist to

some 70 % of water – and to secure a constant supply of water. Indeed, water is crucial.We humans, to take an example, can go for weeks without food, but only for a very shorttime without water. Our daily intake of water is about 2 litres. Some life forms have developedingenious ways to produce their own water. The camel, for instance, uses metabolic waterwhen consuming the fat in its hump.

Most of this water is needed to transport waste products, mainly nitrogen and phosphorus,out of the body, which happens when we urinate. In this perspective, the use of water fordrinking and for flushing the toilet is not so disparate. Only birds are able to evade thisrequirement, by producing solid nitrogen waste, uric acid.

The life forms that constitute our food also require a constant supply of water. Countedper person this is in fact a much larger volume. A plant need many litres of water to grow,which in most cases it receives naturally from groundwater or surface water. In irrigationabout 500 litres of water is used per kg of produced bread, while for vegetables it is closerto 50. Water is taken up by the roots, transported as nutrient to the growing plant andevaporating from the leaves. A growing head of cattle drinks about 50 litres of water foreach litre of meat it produces, in addition to the water it receives with the food.

The two litres of water we drink ourselves, however, is by no means enough. In ourhouseholds we use water for cooking, washing, cleaning, flushing toilets and so on. Evenin areas where water is scarce there is still a need for some 30 litres a day to cover allthese activities. In our region, where such scarcity is not even known, we frequently use200 litres a day in an average household. To provide a city of thousands of householdswith water is thus a major technical undertaking, as is the removal of the wastewater.

But we have not yet mentioned the major consumer of water, which, in a modern society,is industry. Industries consume water for various chemical processes, such as cooling,and many other processes. However this enormous water consumption is now on thedecrease. Minimisation technologies have been introduced to safeguard water. Industry islearning from biology to manage water more skilfully and efficiently. In the modern pulpand paper factory hardly any more water is needed than that which is introduced with thewood. Process water is recirculated, passing a system that may be compared to our kidneys,and used again. It is this more biological way of looking at water, water provision andwater safety that paves the way to sustainable water use.

Lars RydénUppsala University

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Part ISustainability

and Water Management

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WATER RESOURCES ON EARTH

Water in Hydrosphere1 386 000 000 km3

100 %

Fresh Water Salt Water35 000 000 km3 1 351 000 000 km3

2.5 % 97.5 %

Groundwater Lakes Soil Rivers Athmosphere Biological10 500 000 km3 102 000 km3 17 000 km3 2 000 km3 12 000 km3 1 000 km3

98.7 % 0.96 % 0.16 % 0.02 % 0.12 % 0.01 %

Permafrost, ice, etc Liquid24 300 000 km3 10 700 000 km3

69.4 % 30.6 %

Figure 1.1. Water resources on Earth (·106 km3) (Saiejs & van Berkel, 1995).

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1.WATER RESOURCES AND WATER SUPPLY

Lars-Christer Lundin, Harry Linnér, Bengt Hultman, Erik Levlin, Erik Eriksson1 &

Sivert Johansson1

Figure 1.2. Global water budget estimates in 103 mm/year (after Saiejs & van Berkel, 1995).

1 Responsible for Concepts of Water quality

Green and blue water

The Earth is abundantly supplied with water. How-ever 97.5 % of it consists of saltwater in the oceansand only 2.5 % of the water supply on Earth is fresh-water. This water is contained in the ground or inrivers and lakes and in the permafrost of the polarcaps or in glaciers high in the mountains. Of the freshwater 69.4 % exists in the form of ice, snow or per-mafrost and is not directly available for use. Almost99 % of the remainder is groundwater. The amountof fresh water in lakes is not more than 1 % of theliquid water available on Earth (Saiejs & van Berkel,1995; see Figure 1.1).

A global water balance is shown in Figure 1.2.The average annual rainfall over the continentsamounts to 110 000 km3 (Saiejs & van Berkel, 1995).Of this, 63�000�km3 returns to the atmosphere in theform of evaporation and transpiration from forests,grasslands, farm crops and other plant communities.

This portion of the water, utilised by natural vegeta-tion and rain-fed agricultural crops, is sometimescalled green water.

The difference between annual rainfall andevapotranspiration, referred to as the effective run-off, is approximately 47 000 km3. This is the sus-tainable, annually renewable, freshwater in lakes,reservoirs, streams and aquifers. In theory this so-called blue water is available for human use. Asustainability rule is thus: The water demandshould be met from effective runoff only (Pearce,1994). Water however is unevenly distributed overspace and time. A large part of the runoff is flood-water that is hard to contain. Reliable annual flowthat is realistically accessible for human use is esti-mated to be at least 9 000 km3. To this some 3�500�km3

of runoff regulated by existing reservoirs is added.Thus the total runoff accessible for annual humanuse is 12 500 km3. However, some of the availablesurface water must be left in streams and rivers to

Continental athmosphereMaritime athmosphere

Ocean Continents

accumulation

precipitation

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Figure 1.3. Mean annual specific runoff. (l/s km2). Balle-rina database at URL: http://www.baltic-region.net/

5 6

8

8

77

7

68

9

99

10

1014

13

1312

11

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safeguard conservation of the aquatic ecosystems andensure effluent dilution, which in practise furtherreduces the amount of available water.

The remaining 34 500 km3 of blue water is diffi-cult and costly to utilise because of topography, longdistances from population centres and social and en-vironmental consequences.

More than half of the easily accessible freshwa-ter resources are already utilised and in many regionsof the world water supply is a critical issue. An in-creasing number of countries suffer from freshwatershortages and competition between different users ison the rise. More than 25 countries are already clas-sified as water deficient and the number of countriesfacing severe water shortages during next decade islikely to increase dramatically.

In the Baltic drainage basin the annual volume offreshwater runoff is about 450 km3. Due to relativelyhigh precipitation and low evapotranspiration thewater resources are much greater in the northern andwestern part of the region (Figure 1.3) than in thesouthern part, where water is a limiting factor in ag-ricultural production.

In general, the Baltic region has good water re-sources compared to most regions of the world, al-though they are much more limited in the south thanin the north. The region’s agriculture is seldom sub-ject to severe droughts or floods, natural rainfall nor-mally gives good yields, rainfall intensity does notcause severe soil erosion, and salinity is not a prob-lem. Likewise, a safe supply of water to urban cen-tres is not, especially in the northern part of the region,a great problem, nor is industrial water supply a limit-ing factor. Norway’s share of hydropower is one of thelargest of all the national energy budgets of the world,and hydropower is important in Sweden and Finlandas well. Instead, the water problems of the Baltic re-gion are foremost connected to water quality.

Water as a natural resource

Water resources have probably influenced humansmore than any other natural resource and are still oneof the most important prerequisites for civilisation.Since human beings first settled, easy access to drink-ing water and water as a transport medium has beennecessary to stable and lasting settlements. A quickglance at a map still shows a concentration of vil-lages and cities to coastlines and rivers. In areas wherefreshwater is scarce the inhabitants spend a consid-erable amount of time every day collecting water,and development of such societies has been slow.

In the developing countries, at least one fifth ofthe people living in cities and three quarters of therural population lack access to reasonably safe sup-

plies of water, while many of the industrialised coun-tries are experiencing serious problems regardingwater pollution, scarcity and wasteful use.

The availability of freshwater in terms of locationand quantity is essential to all societies and consequentlythere are few natural resources of which our knowl-edge is more advanced (Table 1.1). Despite this exten-sive knowledge, the exploitation of water resources isdone on such scales, ranging from individual house-holds to cities of several million inhabitants, that evenmore detailed knowledge, especially concerning inter-action between the different users, is called for.

A further complication is the variability of wateravailability, not only spatially but also temporally.In many areas of the world freshwater is scarce, whichcreates a problem if the population demand is not inharmony with the available resources, even if theseareas normally have spots of high water availability,e.g. oases. Availability is also an issue in areas wherewater is plentiful, but where the quality is low be-cause of pollution, or where the demand is extremelyhigh. To a certain extent engineering solutions canbe applied, but this is often at a considerable cost.The temporal variation consists of a seasonal varia-tion, which is often quite predictable, and a variationbetween years that is more problematic. Most hu-man activities have been adapted to, or made inde-pendent of, the seasonal variation, farming perhapsbeing the best example. However, if, e.g. the expected

http://www.baltic-region.net/

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Category Per capita internal AnnualCountry renewable withdrawals

water resources, per capita,m3/yr (2001) m3/yr (year)

Very low: 1 000 or lessEgypt 26 1 055 (1996)Israel 119 287 (1997)Jordan 131 255 (1993)The Netherlands 688 519 (1991)

Low: 1 000 - 5 000South Africa 1 014 366 (1990)Denmark 1 123 233 (1990)India 1 211 592 (1990)Germany 1 305 579 (1991)Poland 1 391 321 (1991)China 2 173 439 (1993)United Kingdom 2 431 204 (1991)Japan 3 372 735 (1992)

Medium: 5 000 - 10 000Switzerland 5 637 172 (1991)United States 6 932 1 834 (1991)

High: 10 000 and moreSweden 19 391 340 (1991)Finland 20 645 439 (1991)Norway 84 787 489 (1985)Canada 91 147 1 607 (1991)Iceland 671 940 622 (1991)

Table 1.1. The availability of fresh water. Internal renewablewater resources are domestically generated runoff. Notethat all countries in the very-low category are dependenton withdrawing runoff generated in neighbouring countries(World Resources Institute, 2003)

Continent Agriculture Domestic Industrial Total(%) (%) (%) (km3/yr)

Africa1 85 9 6 128Asia1 84 6 10 1 444Former USSR1 62 10 28 270Europe2 30 14 62 551N&C America3 43 11 46 686Oceania&Australia3 51 11 38 30South America3 62 17 21 167World1 71 9 20 3 253

1 FAO, 2004 (data from 1988)2 Krinner et al., 1999 (data from 1997)3 Shiklomanov, 1999 (data from 1995)

summer precipitation does not occur at all or is con-siderably less than expected, a draught situation isimmediately at hand. If this is repeated several yearsin a row, extremely severe situations with starvation,desertification and population migration may ensue.Note the use of the word ‘expected,’ because some-times we expect more than the normal or mean value.

Sustainable water management must thus be along-term undertaking, remembering that the vari-ability of the water resources is such that what seemssustainable over a few years may not be sustainableover a ten- or thirty-year period. We should also bearthis in mind in our humid part of the world when weexpand our populated areas too close to rivers. Evenif we experience it as a surprise that a river suddenlyrises to a level that is much higher than anyone canremember, this is probably a situation that normallyoccurs every 30 years or so.

It should be noted that even in the humid condi-tions of the Baltic region, it is normal to experiencea certain draught, or rather a water deficit, in earlysummer. At that time, the vegetation normally de-mands more water than there is at hand during thisperiod. However, adaptation of the vegetation and,

if the crop is valuable, irrigation keep the problem ata reasonable level.

Water use for food production

Water is used for all life, including the farming thatsupplies us all with food. The basis is production ofgrain and other crops. Here water supply is the mainlimiting factor, along with e.g. temperature and soilconditions. The total world area of arable land is about1 500 million hectares which means approximately0.25�hectare per person. It is estimated that rain-fedfarm crops and grasslands transpire about 18�000 km3

of green water annually.About 250 million hectares, or 17 % of all farm-

land, are irrigated. Global estimates indicate that ir-rigated farmlands produce nearly 40 % of the foodon 17 % of the land. Half of the expansion of foodproduction in the last thirty years has come from theexpansion of irrigated farming. Half or even twothirds of future gains in crop production are expectedto come from irrigated land.

The amount of water needed to produce the annualfood requirement for one person is about 2�000 m3 fora balanced diet with meat. This explains why agricul-ture is the major user of water globally. Almost 70 % ofthe water withdrawn from rivers, lakes and aquifersgoes to the agricultural sector and mainly for irrigationpurposes (Table 1.2). Domestic and industrial users ac-count for the remaining 30 %. There are significant dif-ferences between different parts of the world. In de-veloping countries in arid zones farming often claimsmore than 90 % of the water. In humid temperate in-dustrial countries the figure is often less than 30 %.Most of the data in the table are from the 1980s. Thetotal water use today is almost 50 % higher.

In the Baltic drainage basin the total land area isabout 175 million hectares. About 20�% of the total land,or 35 million hectares, is arable. Some 10 million hec-tares are land for pasture. If we assume that the aver-

Table 1.2. Water use by continent (See below).

20

Country Population1 Annual renewable Annual with- Sectorial water withdrawals2004 water resources2 drawals Agric. Domestic Industry

(millions) (km3) (km3) (%) (%) (%)

Belarus 10.3 37 2.7 1990 35 22 43Czech Republic 10.2 13 2.7 1991 2 41 57Denmark 5.4 6 1.2 1990 43 30 27Estonia 1.4 13 0.2 1995 5 56 39Finland 5.2 110 3 1991 3 12 85Germany 82.4 107 46.3 1991 20 11 69Latvia 2.3 17 0.3 1994 13 55 32Lithuania 3.6 16 0.3 1995 3 81 16Poland 38.6 54 12.3 1991 11 13 76Russia 144 4 313 77.1 1994 20 19 62Slovakia 5.4 13 1.8 1991 0 - -Sweden 8.9 171 2.9 1991 9 36 55Ukraine 47.7 53 26 1992 30 18 52

1 PopulationData.net, 20042 Mean of 1977-2001

Table 1.3. Water resources and water use in the Baltic drainage basin (Source World Resources, 1994)

age annual evapotranspiration from farm crops andgrassland is 400 mm (= 4�000 m3/ha) the total use ofgreen water in agriculture approaches a magnitudeof 180 km3.

Only 3-4 % of the arable land in the region isunder irrigation. A rough estimate shows that the to-tal water use for agriculture is approximately 3 km3.The sectorial water use for the different countries inthe Baltic region is shown in Table 1.3.

The agricultural sector contributes significantly tothe pollution of the Baltic Sea. The total input of nutri-ents has been estimated at 1 600 000 tonnes of nitrogenand 60�000�tonnes of phosphorus per year. The majorsource of the nitrogen and phosphorus load is agricul-tural runoff, which accounts for about half. About 10% of the phosphorus comes from agriculture itself.

The most important sources of nutrients relatedto agriculture in the Baltic Sea region are:• leaching of nitrogen and phosphorus from arable

land;• leaching of nitrogen and phosphorus caused by

inappropriate storage of manure from animalproduction;

• atmospheric emissions of ammonia from animalproduction and field application of manure; and

• inadequate treatment of wastewater in rural areas.

Water resources in a systems perspective

The healthy development of human domiciles, soci-eties and human affairs is critically dependent onwater supplies. Safe water provision is needed inhouseholds, agriculture and industries. As a rule ofthumb we use 200 l/capita and day in households,and twice as much in industries in the Baltic region.In addition some agricultural productions depend not

only on the natural water supply but also on irriga-tion. This book deals with many aspects of water usein these sectors. The overall intention is to describehow we can manage this resource so that society hasa safe supply of water for all its various needs.

In this introductory chapter we will point out threeperspectives on water use in society:

The systems perspective, whereby the individualcomponents are all part of the same system, or areeven using the same water.

The recirculation perspective, how the water weuse is part of one or several hydrological cycles.

The ‘downstreamer perspective’, whereby thewater that leaves one user is the water provided forthe next.

Water is considered to be a renewable resource.This is of cause true in a regional sense but in a glo-bal perspective water resources are confined to aclosed system. On a global scale there are no waterincomes, except possibly the chemically bound wa-ter in meteorites, and there are no water expenses,either, except for the occasional water molecule en-tering free space.

There is a danger in viewing water resources froma narrow regional perspective. Since water is circu-lated globally in the hydrological cycle, all the waterwe use has a history and a past. If we pollute thewater regionally, for example, the effects may showup in a totally different region with unforeseeable en-vironmental effects. Pesticides used intentionally infarming in one region may cause the death of birds else-where, e.g. in the Baltic Sea. Another example is whensulphuric smoke pollution and the humidity in the airin coal-burning industrial regions kill the coniferoustrees in forest regions. These causes and effects are wellknown today but were either not foreseen or wereignored at the time when the practise was initiated.

21

The systems approach can also be taken whenstudying the main users of water resources: agricul-ture, industry, and urban areas.

In agriculture, the incomes are precipitation andirrigation. The expenses are evapotranspiration,drainage and groundwater formation. The strategyof water management is twofold: to deliver an ap-propriate amount of water to the growing plants andto distribute nutrients to the plant’s roots using wateras the transport medium. If there is a problem of watershortage, irrigation is applied using groundwater ora nearby river, while if there is too much water thefield is drained. The principal action in both theserespects is to divert the natural flow paths of the water.The second objective, increasing the nutrient statusof the field, adds another dimension to water man-agement, i.e. water quality. High nutrient contentmeans high quality for plants but low quality forhumans and animals. The ‘good life’ of the aquaticplants also causes lake eutrophication. Further issuesare erosion and salinisation but these problems areminor in the Baltic region. The environmental issuesin this system can thus be defined as i) minimisingthe harmful effects of the diversion of the naturalflow paths and ii) keeping the nutrient-rich waterinside the system, where it constitutes a resource.

In industry, water incomes and expenses are de-fined by the system of pipes entering and leaving theplant. The objective means using water either as a part,e.g. transport or cooling medium, or as an ingredient inthe industrial process. The main problem is the addi-tion of dissolved substances to the water, caused by theprocess. Another issue is the increased water tempera-ture caused by some industrial processes, such as en-ergy plants. If the water is exported to the same body ofwater from which it was imported, no significant di-version of the pathways has been made. However, usedgroundwater or surface water is normally redistributed

via the municipal sewage treatment plant into a sur-face water body, often a different one that the onewhere the water originated. The main environmen-tal issue is thus to i) minimise the impact of the in-dustrial processes on the water and ii) minimise thewater volumes handled. The optimal solution is ofcourse to close the system totally, avoiding strain onwater resources and export of polluted water.

Urbanised areas, i.e. cities and towns, have proper-ties that constitute a mixture of agricultural and indus-trial systems. The water incomes are precipitation, dis-charge and water from local or municipal wells or wa-terworks. Expenses are evapotranspiration, sewageand stormflow from sewage treatment plants or in-dividual houses, water lost in the distribution sys-tem, locally infiltrated precipitation and losses ofgroundwater. Note that the system can be defined indifferent ways, depending on the problem studied. Ifthe problem is the damage to buildings caused bythe lowered groundwater level, then locally infiltratedstormwater constitutes a systems income and a po-tential solution to the specific problem.

Several objectives can be identified. To deliver highquality drinking water and to treat sewage water arethe main objectives, but to get stormwater off the streets,to avoid inundation by regulating surface water levelsand in most cities preserving the groundwater level arealso important objectives. Urban water planning andmanagement is complex, involving the administrationof both waterworks and sewage treatment plants as wellas city and road planning. This area is of special impor-tance since it interfaces directly with citizens and theirneed of household water for everyday activities. Theenvironmental issues involved are those of supplyingdomestic water of sufficient quality and quantity, sani-tation and the proper treatment of sewage water, han-dling of storm flows and prevention of inundation andlowering of the groundwater table.

An individual person needsonly one cubic metre of water peryear for drinking, approximately100 cubic metres for his or herhousehold needs and roughly 1�000cubic metres per year to producethe food he or she needs to eat. Inaddition an average of about 50cubic metres are needed for mu-nicipal water used for general pur-poses and 200 cubic metres on av-erage for industrial water (see Fig-ure 1.4). These figures are indica-tive for semi-arid conditions andvary considerably in different re-gions. For an individual use of1�300 cubic metres per year anda population of 6 billion, the to-

Figure 1.4. Demand for water (indicative for semi-arid circumstances) in cubicmetres per capita per year (Allan, 1995b).

22

tal water need in the world is about7.8�cubic kilometres or about 17 % ofthe sustainably available water. Manycountries have a much smaller supply ofsustainable water per capita than 1�300 cu-bic metres (see Table 1.1) and the situationwill become worse in the future, especiallyin developing countries with their highpopulation growth rates.

An important feature of water pro-vision is the reuse of water inherent tothe nature of the hydrological cycle. E.g.villages throughout a river stretch usewater from the same stream, or watertranspired by the plants is released as precipitationuseful to plants in neighbouring fields. The runoffwater into a river in a farm area might be used laterfor preparing drinking water for the city downstream.Groundwater used for domestic purposes is releasedto a river and reused downstream or is infiltrated tothe benefit of the vegetation.

What this implies is that, with a systems view ofwater resources, the outflow in the system always con-stitutes someone else’s inflow. Among the creative ideasstemming from this implication is the suggestion thatindustrial water intake should be put downstream ofthe industry’s outlet, creating a self-regulating systemin which the industry would be highly motivated to keepwater quality high. The rational realisation of the ideais, of course, to create closed-system processes.

Another perspective is illustrated by the ‘urban’ or‘societal’ water cycle which points out that water usedfor one purpose may soon be reused for another (Fig-ure 1.5). After treatment, freshwater is normally trans-ported into urban areas via water pipes in order to se-cure a high water quality. Treated wastewater is typi-cally discharged into large receiving waters in orderto avoid severe local pollution problems. However,in some regions, the wastewater quantity should in-stead be regarded as a possible resource for increas-ing the groundwater level, for irrigation use or otherpurposes. Obviously, this requires even more effi-cient wastewater treatment (Ødegaard et al., 1996).If water is scarce the water might have to be ‘re-used,’ which means going through several rounds inan ever narrowing water cycle requiring more and morerefined methods of treatment. In urban water manage-ment this might be quite expensive. In industry it istaken to the extreme in the closed factory, where thesame water is used indefinitely.

Concepts of water quality

The quality of the water is related to the specific pur-pose of the water use, while the value and usefulness

of a water source is dependent on this particularuse. Water quality is thus a consumer term. Waterquality depends on the chemistry, physical appear-ance (colour, taste and smell) and biological prop-erties of the water. There are numerous ways ofutilising water – as drinking water, for washing andbathing, as a carrier of domestic waste, for irriga-tion, in various industrial processes and as an objectof recreation.

It is thus obvious that there is no universal, oreven general, requirement on water quality. Each userequires its own set of standards. These standardsare usually formulated as critical values of specificproperties, which should not be exceeded. Water thatis considered harmful as, e.g. drinking water, maybe excellent for irrigation or even swimming. Ex-amples of categories of use, some of which have beendiscussed above, are• domestic use• use in irrigation• use in industry• use in recreationIn all of these categories there is always the possibilityof treating the water to make it acceptable for its par-ticular use. This is well in line with the concept of sus-tainable use of water. Naturally, it should not be carriedto the extreme that water must be saved, because it is anatural resource. Water is, after all, a renewable resourceand it is the rate of natural renewal that sets the upperlimit for its rate of use.

The need for adjusting water to its use has nowbeen practised for decades within the category la-belled recreational use. Surface water is allowed tocarry a certain load of waste as long as this does notdepreciate its recreational value. Monitoring is setup to make sure that all functions are as they shouldbe. Recreational use is mainly a surface water con-cern. But surface water is not independent ofgroundwater, often being the source of the surfacewater.

The discussion in this introduction will be lim-ited to water quality standards for domestic and irri-

Figure 1.5. The hydrological cycle in society.

23

Table 1.4. Water quality standards for domestic water

gation water. Further treatment of industrial wateruse issues will be presented in later chapters.

Table 1.4 illustrates the work done in the past tocreate standards of guidance to society. It also showssome of the difficulties encountered in the effort todraw up an internationally unified set of standardsfor domestic use.

The table lists three categories of concern: toxic ef-fects, human health and general use. A number of ex-isting standards are also listed, first the one developedby the international WHO (World Health Organisation),then the one set by the European Community and lastlystandards adopted by the U. S., Sweden, France, andTanzania.

For toxic effects from various elements that nor-mally occur in low concentrations, the differences be-

tween the different standards are small. As regards hu-man health only fluoride and nitrate are listed. Highfluoride concentrations occur in parts of the MountKilimanjaro complex due to old lava flows, which arevery rich in sodium and poor in calcium, which nor-mally counteracts the fluoride concentrations in water.It can be seen that Tanzania uses a concentration limitthat is about eight times higher than other countries,which can be easily explained. If a limit of 1 mg/l wereto be used, a large part of the population would simplyhave no drinking water.

The table has no standard values for biologicalvariables. These would probably be difficult to ap-ply in some of the countries.

High salinity in soil water restricts the growth ofcrops. Sensitivity to salt varies widely from crop to

Substance Unit WHO1 EU2 USA3 Sweden4 France5 Tanzania6

Toxic effectsLead µg/l 10 10 0 10 50 100Arsenic µg/l 10 10 0 10 50 50Selenium µg/l 10 10 50 10 10 50Chromium µg/l 50 50 100 50 50 100Cyanide µg/l 70 50 200 50 50 50Cadmium µg/l 3 5 5 5 5 30Barium µg/l 700 - 2 000 - 100 1 000Mercury µg/l 1 1 0 1 1 1Silver µg/l - - 100 - 10 50

Human healthFluoride mg/l 1.5 1.5 4 1.5 1.5 8Nitrate mg/l 50 50 10 50 50 50

General useColour mg Pt/l 50 - 15 30 15 -Turbidity 57 - 58 1.59 27 -pH - 6.5-9.5 6.5-8.5 6-8 6.5-9 6.5-8.5Total dissolved matter mg/l - - 500 - 1 500 2 000Total hardness mg_qv/l - 12 - - - -Calcium mg/l - 150 - - 100 -Magnesium mg/l - 80 - 20 50 -Sulphate mg/l 500 250 250 100 250 -Chloride mg/l - 250 250 100 200 200Iron mg/l - 0.2 0.3 0.2 0.2 110

Manganese mg/l 0.5 0.05 0.05 0.05 0.05 0.5Copper mg/l 2 2 1 2 1 3Zinc mg/l 3 5 5 - 5 0.2Phenolic substances as phenol_g/l 2 - 1 - 0.5 2

1 WHO (1998)2 EC (1998). These standards were also adopted by Bulgaria (that appeared in previous editions of this textbook) in 2001. A differ-ence is the value for cupper where the Bulgarian source (Ministry of Health et al, 2001) reads 2.0 “_g/l” instead of “mg/l”; mostlikely a printing mistake.3 EPA (2002)4 SLV (2001)5 Ministère de la solidarité, de la santé et de la protection sociale (1989; 1990)6 The United Republic of Tanzania (1981)7 JTU (Jackson turbidity units)8 NTU (Nephelometric turbidity units)9 FNU (Formazin nephelometric units)10 The source reads “110” but it should most like be 1.0

24

crop. Of greater concern is often the effect that thesalts can have on soil structure. A high fraction ofsodium in irrigation water may decrease the ex-changeable calcium, replacing it with sodium. Thiswill turn the soil into mud when wetted and starvethe plants due to oxygen deficiency. There is, how-ever, a rather simple way of predicting this if the so-dium/calcium ratio in irrigation water is known. Thesodium adsorption ratio (SAR) can be computed ac-cording to the following:

SAR = [Na+] ([Ca2+] + [Mg2+]) - 0.5

According to Bolt & Bruggenwert (1978) the fol-lowing SAR values are valid:

safe water EC < 25 mS/m and SAR < 7marginal EC < 75 mS/m and SAR < 13unsuitable EC < 225 mS/m and SAR < 20

where EC is electric conductivity and SAR is thesodium adsorption ratio.

The functions of water management

A system for safe water provision should:• provide water for a variety of uses, such as in

agriculture, households, factories, offices and schools• remove wastewater from users in order to prevent

unhygienic conditions and treat this to removeenvironmentally harmful substances

• remove excess water from fields and other non-builtareas, and storm water from urban areas to avoiddamage from flooding

The essential function is thus to secure sufficientwater of adequate quality to the various users with-out harming the environment. Further requirementsmay be related to other, very special demands, suchas delivery security for hospitals, high flow rates infire fighting etc.

In urban areas water use in buildings is the keyissue. The choice of water-consuming devices (toi-lets, showers, washing machines and dishwash-ers) has great impact on water and sewage handling.Other technical factors, which could be influentialin domestic use, include separation of grey waterfrom black water and the use of garbage disposers.In addition, consumer behaviour has a major impacton domestic water and wastewater handling.

As a rule, industries in the Western world use ef-ficient methods of water saving and recycling. How-ever outdated technologies that require massive vol-umes of water are still in use in many places.

The challenge to managers of water systems isto find the best way to satisfy the demands of thewater users and of those expressed in the politicalarena. Earlier, the choice of water, wastewater andrunoff water handling was mainly determined byfunction efficiency and acceptability of cost. Thischoice was affected by factors such as climatic andtopographical conditions, population density andconvenience. Today, the choice of system mustalso take the long-term environmental impact andconservation of resources into consideration.

25

Bengt Hultman & Erik Levlin

2.SUSTAINABILITY CONCEPTS

Introduction

After the publication of the Brundtland Commission’sreport Our Common Future in 1987, the concept ofsustainable development was rapidly accepted. Theconcept had great impact on the thinking of thosewho work professionally with water and has also in-fluenced the aims of research, education and design,operation and management of water systems.

The purpose of this chapter is to introducesustainability concepts, describe the principles ofsustainable water management and discuss howsustainability can be implemented. Special evalu-ation methods such as environmental impact as-sessment (EIA), life cycle analysis (LCA) andstandardisation of environmental managementsystems using ISO 14 000 or EMAS are described.These methods are important tools in the assess-ment and implementation of sustainability in wa-ter management.

A special emphasis is given the increasing prob-lems of water scarcity and factors influencingwater use, water saving, water reuse, etc. and therole of food production on water use. Differentways to meet future water scarcity and sanitationproblems are discussed.

Defining sustainable development

The ideas behind sustainable development have along history and can be found in many religionsand philosophical systems (Harremoës, 1996). Gil-bert White, who died in 1793, is regarded as thefather of ecology and his book The Natural His-tory of Selbourne forms the basis for the modernecological movement.

Books such as Rachel Carson’s Silent Spring,Edward Goldsmith’s Blueprint for Survival andPaul Ehrlich’s The Population Bomb awakened theattention of the present generation to environmen-tal problems. They argued strongly that, unlesstoday’s society dramatically altered its approachto the consumption of resources and the pollutionof the environment, the world faced disaster(Clarke, 1994). A similar view was given in the fa-

mous MIT report to the Club of Rome, entitled Lim-its to Growth and issued in 1972. The report waswritten by a group of 30 individuals from ten coun-tries whose key conclusion was:

“If the present growth trends in world popula-tion, industrialization, pollution, food production,and resources depletion continue unchanged, the lim-its to growth on this planet will be reached sometimewithin the next one hundred years. The most prob-able result will be a rather sudden and uncontrolleddecline in both population and industrial capacity.”

Against this background the concept of sustain-able development was born and the definition ofsustainability in the Brundtland report is:

“…development that meets the needs of thepresent without compromising the ability of futuregenerations to meet their own needs”.

Harremoës (1996) gives the following interpre-tation of sustainability using a resource componentand a pollution component:

“Society should use its resources such that thesociety can continue its mode of operation withoutexhausting its resources.”

The thermodynamic principle of entropy illus-trates our present mode of operation. When mineralresources are mined and used, the final result is aconversion of the mineral from a concentrated to adispersed state. It requires energy to reconcentratethe matter, which makes renewable energy basicallythe ultimate measure of sustainability. The practicalsolution is to approach the ideal, which makes sensein societies that have violated the principle ofsustainability due to lack of concern in the past.

Society should protect the environment againstirreversible damage, including protection of uniquespecies and habitats.

The conflict is that the very basis for the suc-cess of human beings in modern society is our abil-ity to change the environment to sustain largerpopulations. Humans have now pursued this de-velopment to the extent where the changes are athreat to their very being.

The sustainability definition also involves socialand political aspects and the definition in theBrundtland report contains three key concepts(Clarke, 1994):

AGENDA 21 AND WATER

26

“Urban land-use planning and promoting the integrated provision of environmental infrastructure – water,sanitation, drainage and solid-waste management – in all human settlements is essential for environmen-tal protection, increased productivity, better health and poverty alleviation. Developing countries shouldensure that all municipal departments co-ordinate their efforts, such as capacity-building, monitoring,applied research, and using appropriate technology and technical expertise. In addition, developing coun-tries should adopt an integrated approach to the provision of water supply, sanitation, drainage and solidswaste management in all urban areas, including informal settlements, where standards and regulationsare best adapted to the living conditions and resources of the poor.”

“Early in the next century, more than half of the world’s population will live in urban areas. By the year2025, that portion will have risen to 60 per cent, comprising some 5 billion people. Rapid urban populationgrowth and industrialisation are putting severe strengths for human consumption and industrial use. Spe-cial attention needs to be given to the growing effects of urbanisation on water demands and usage andto the critical role played by local and municipal authorities in managing the supply, use and overalltreatment of water, particularly in developing countries for which special support is necessary.”

“The overall strategy for water and sustainable urban development should identify and implementstrategies and actions to ensure the continued supply of affordable water for present and future needs,and to reverse current trends of resource degradation and depletion. In particular, activities should aim toensure that, by the year 2000, all urban residents have access to at least 40 litres per head per day of safewater, that 75 per cent of the urban population are provided with on-site or community facilities for sanita-tion, and that the solid waste generated in urban areas is collected and recycled or disposed of in anenvironmentally safe way.”

“City development planning should be consistent with the sustainable management of water resourcesand satisfy the basic water needs of the urban population. This may involve the introduction of watertariffs, where affordable, to reflect the marginal and opportunity cost of water, especially in production.Throughout these programmes, the skills and potential of non-governmental organisations, the privatesector and local people should be utilised, taking into account public and strategic interests in waterresources. The public should also be made aware to the social and economic value of water, and encour-aged to use it rationally and protect its quality. Governments should develop legislation and policies topromote investment in urban water supplies and solid waste and sewerage management by encouragingthe autonomy and financial viability of utilities and providing training for professional personnel.”

Find the complete text of Agenda 21 on the Internet: gopher://gopher.undp.org/00/unconfs/UNCED/English/. From there you can download Chapter 18 on protecting freshwater resources (gopher://gopher.un.org/00/conf/unced/English/a21_18.txt).

Citations from A Guide to Agenda 21: Post-Rio Edition (UN, 1993)

1. the concept of “needs”, in particular the essentialneeds of the world’s poor,

2. the implied concern for social equity between gene-rations a concern that must logically be extended toequity within this generation; and

3. the truism that there are limitations imposed by thecapabilities of technology and social organisation onthe environment’s ability to meet present and futureneeds.

Political participation is an essential element ofsustainable development. Greater equality means ba-sic changes in patterns of consumption, the allocationof resources and, consequently, li

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