FOREWORD

The XXIX Biennial Congress of the International Association of Hydraulic Engineering and Research (IAHR) was held at the Beijing International Convention Center (BICC) in Beijing, September 16-21, 2001. The central theme of the Congress is:

21^st Century: The New Era for Hydraulic Research and

Its Applications

The central theme was divided into five sub-themes, covering broad aspects of hydraulics, such as water resources, ecology and environmental hydraulics, forecasting and mitigation of water-related disasters, hydraulics of river, water works and machinery, and hydraulics for maritime engineering. More than 600 papers were presented and posted during the five days of the Congress. All papers that have been selected for presentations and posters on the XXIX IAHR Congress are included in 7 volumes (the John F. Kennedy student competition papers also included).

During the IAHR Congress some prominent and outstanding speakers invited by the Local Organizing Committee delivered 2 General Reports and 4 Keynote Lectures and other reports. As these excellent lectures dealing with many actual problems of hydraulic engineering and research could not be included in the Congress Proceedings. The LOC of XXIX IAHR Congress decided to publish a Post Congress Volume, which included mainly the contributions mentioned above. The authors of these contributions are: Prof. Forrest Holly, USA; Prof. Suo Lisheng, China; Dr. Torkil Tonch-clusen, Denmark; Mr. Zhu Erming, China; Dr. Wolfgang Kinzelbach, Switzerland; Mr. Oda Hideak, Japan; Dr. Zhaoyin Wang and Prof. Bingnan Lin, China; Dr. S. T. Su, USA; Prof. E. Plate and Prof. Rodi, Germany and so on. Besides, a few late papers are also included in this volume.

On behalf of the Local Organizing Committee the editor would like to deeply thank all delegates of the XXIX IAHR Congress for their attendance. We would also like to thank all the IAHR Council members for their confidence and help to the host of the XXIX IAHR Congress, 2001. The LOC would like to dedicate the Post Congress Volume to all the scientists and engineers and hope it may be reminiscence for those who have to take responsibility on the water related themes for mankind in future.

Guifen LI

Editor

Beijing, September 2001

CHIna_Times

Forest Holly

Professor, President of IAHR

Welcome

w Welcome to 29^th Congress of International Association of Hydraulic Engineering and Research

w Hosted by Chinese Hydraulic Engineering Society

w Organized by China Inst of Water Resources and Hydropower Research, and Tsinghua University

Recent events in US make this a difficult period for the world

w Many of you here today wondered if it was right to travel and engage in “normal” activity in this period of grieving for civilized discourse

w Some have asked if the Congress would be cancelled, as many international events have been

w Many of our colleagues who had expected to join us are not even able to do so

w Please join me in a few moments of silence for civilian victims of terrorism and strife not only last week in the US, but throughout the world

What can we do to help heal the situation?

w As water engineers and scientists, we are builders of civilization, not destroyers

w In our own relations with colleagues and peers, and especially with those we might not agree with, we must practice the qualities of civilized discourse and respect that we wish to see expressed in global relations among citizens of the world

Closing of welcome

w In this 29th IAHR Congress, even as we grieve for victims and our society, let us strive to combat a belief in the power of terrorism by affirming what is good and positive and constructive among civilized peoples throughout the world

w I wish you a technically productive and socially enjoyable week here in Beijing, and I declare the 29^th IAHR Congress to be open.

29th IAHR Congress

w Demographics: China 337; Japan 98; USA 40; Italy 37; Germany 26; UK 24; Netherlands 23; Iran 20; Korea 17; Canada 14;Switzerland 13; Austria 12; Russia, Portugal, Spain 11;

w Two invited general addresses

w Five technical themes, each with keynote speaker

w JFK Student paper competition

w Poster sessions

w Technical workshops

w Memorial Symposium: Pioneers of Modern Hydraulic Engineering in Asia (Thursday)

w LOC organized UNESCO support to enable attendance of 40 participants

Third World Water Forum

w World Water Council hosted First and Second World Water Forums, Marrakech and the Hague

w Gathering of global water interests

w Third forum to be held in Kyoto, Japan, March 2003, 8500 expected

w IAHR a strong supporter of this initiative

w Hideaki Oda, Sec General of WWF3, a Congress keynote speaker, Thursday

w Please visit WWF3 stand for more information

Busy two years for IAHR

IAHR Secretariat Relocation

w CM Delft Hydraulics generously hosted IAHR since its founding in 1935

w In 1996 CM CEDEX offered to host IAHR as we move into the new century

w Relocation achieved last month

w Appreciate patience of all during period of relocation and training of new staff

w Thanks to WL Delft and CEDEX

w Thanks to staff in Delft, especially Marjorie Keuning and Cheryl van der Zee with whom many of you have had direct contact

w Please sign commemorative books for each at IAHR stand

JHR Editor

w Prof. Marcelo Garcia, UIUC, begins term as new JHR Editor in October

w Thanks to Rodney White, who is retiring from HR Wallingford for his dedicated five-year term of service; JHR a top quality journal under his leadership

w Prof. Garcia unable to fly to Beijing; also Ippen Awardee

w Ippen lecture slot on Friday to be used for IAHR Member Forum

w Includes presentation of Prof. Garcia’s plans for changes in Journal editorial management

New IAHR Council Election Procedure

w No need to fear you’ll be named to nominating committee during Congress!

w After Graz, Council developed new election procedure for trial

w More democratic, less burdensome to Congress participants, still respects our constitutional boundary conditions

w My predecessor President Helmut Kobus appointed to chair NC in Iowa City July 2000

w NC worked very hard during past year

w Nominees published in Newsletter

w Large number of ballots already received

w Final ballot deadline Wednesday end of day

w If you’ve not voted, pick up ballot at IAHR stand or Secretariat

w Submit ballot in SIGNED envelope to Secretariat

w In this first trial, we learned of a few things needing adjustment

w Overall a positive change that is less complicated than it looks

w Friday’s GMA will include announcement of election results, and formal adoption of the consequent constitutional changes to Council composition.

w New Council takes office in October

Corporate Member Task Force

w Council working to actualize addition of “engineering” to our name

w IAHR historically and presently primarily an Association of researchers – this identity will not change – but we must offer value to members whose activity is primarily in applications

w Council member Gaele Rodenhuis organized Corporate Member Task Force, and Symposium on Managing Change in Research Institutes

w Invited Symposium, held in parallel with 29th Congress

w Council looking forward to facilitating further activities bringing together practitioners and researchers

Student Chapters

w Rapidly developing new area of IAHR affiliate membership, idea began in Graz

w U. Stuttgart; U. Illinois; U. Naples; U. Idaho; U. Iowa; Cal State U.; U. North Carolina; U. Minnesota

w 100 members at Stuttgart!

w Friday’s IAHR Member Forum will include presentation on activities of U. Stuttgart student chapter. Please attend

Affiliations with Other Water Organizations

w Council seeking ways to enlarge the connections, influence, impact of member activities

w Closer links with other organizations offers promising opportunities to do this

w EWRI agreement in effect, joint instrumentation sections conference in Colorado, ‘02, Journal info exchange

w COPRI agreement imminent, joint conferences on waves, tsunamis

w IWRA Investigative Task Force launched

w IAHS may offer opportunities for combined efforts

Is Hydraulic Engineering a Dinosaur?

w It’s been said that the 21st Century is the Century of Water

w Developed countries: water quality, allocation of water for irrigation, flood control, river restoration, wetlands restoration, fish passage, etc

w Developing countries: water supply, flood control, land reclamation, wetlands restoration, hydropower development, navigation, etc.

w Council met Friday with Mr. Wang Sucheng, Minister of Water Resources, China

w His excellency gave us a marvelous overview of water resource development in China

w The classic view is that it is the uneven distribution, not quantity, of water that is the challenge

w In China, it is the distribution AND the quantity that pose enormous challenges

w China is tackling this head on, and hydraulic engineers are leading the charge.

Why IAHR?

w IAHR is NOT a research institution

w IAHR is NOT a source of research funding

w IAHR has ONE professional employee

w But IAHR has 2500 volunteer members who benefit from exchanges and contacts with colleagues from around the world, facing a broad array of water challenges and opportunities

w “Them” is “Us”

w We can all learn from each other

w Task of IAHR Secretariat and Council is to facilitate and empower the efforts of volunteers sharing a common love of water science and engineering

w If you are not already a member of the family, please consider joining - applications at the IAHR stand

Closing of Address

w Thanks to LOC for what looks to be a highly rewarding and well-organized Congress

w Thanks to IAHR members for their patience during relocation of Secretariat and support of this fine association in a period of rapid change and opportunities

welcome speech at the Opening Ceremony of the 29^th IAHR Congress

Suo Lisheng

Professor, Vice-Minister of Ministry of Water Resources

Distinguished President Holly,

Distinguished Guests, Ladies and Gentlemen,

The opening of the 29^th IAHR Congress in Beijing, China at the beginning of the new century is a very significant event, for this congress has attracted so many world famous experts and scholars and will discuss and exchange ideas about subjects of rational utilization of water resources, water environment, water–related disasters, hydraulics of water works, and river mouths and coasts, summarize successful experiences and deficiencies and look forward to the challenging future, and will play an important role for the development of hydraulic research both in China and the world. On behalf of the Ministry of Water Resources, P. R. China, I wish to extend a warm welcome to all the more than 800 participants from more than 50 countries and regions all over the world! And also I wish to extend admiration and thanks to the efforts made by all of you in the field of hydraulic engineering and research and its applications.

Water is the source of life and lifeblood for the survival and development of human beings and without water there would be no human beings. Water is limited and is a natural resource that has no substitute. With the continuous development and progress of the human beings’ society, water has become an increasingly precious resource of strategic significance, and water resources issues and problems are concerned with the survival and development of human beings.

As everyone knows, China is situated in the Asian monsoon climate zone with uneven distribution of precipitation in time and space, frequent occurrence of flood, waterlogging and drought disasters and scarcity of water resources. The per capita volume of water resources in China is only 1/4 of the world average. For thousands of years, the Chinese nation has made indomitable struggles against water related disasters. Since the founding of the P. R. China, particularly, the Chinese Government has led the whole nation to construct a large number of water projects for flood control, farmland irrigation and drainage, water environment, hydropower generation and river transportation, and made brilliant achievements attracting worldwide attention. We not only have built more than 80000 reservoirs, but also are constructing the well-known Three Gorges and Xiaolangdi projects, have preliminarily established a flood control and disaster reduction system covering the whole country; the area of irrigated farmlands has increased to 54.7 million ha, thus providing a guarantee for the stable economic and social development. But, with the sustained and rapid economic development in recent years, the problems of water shortage, frequently flooding and deteriorating water environment have become more and more serious, and hence a stern challenge to us in the new century. Those problems have caused widespread concerns in all the social circles.

After decade’s years of practice of water harnessing, Chinese government has recognized that, in order to solve water issues and problems, we must change the traditional thinking for water harnessing, shift from the project oriented towards the resource management oriented and from the traditional towards the modern water resources undertakings, ensure sustainable economic and social development with sustainable utilization of water resources, and realize the safeties of water use, flood control, grain supply and eco-environment.

In the China Agenda 21, the Chinese Government puts the sustainable economic and social development among important strategic goals. The sustainable utilization of water resources put forward by the Chinese Government is a strategic issue for the economic and social development in China. In the Outline of the 10^th Five-year Plan for the Economic and Social Development in the P. R. China, it is pointed out that water conservation technologies and measures of various kinds should be extended comprehensively, with the enhancement of water use efficiency at the core, to develop a water saving agriculture and establish a water saving society; the bearing capacity of water resources should be fully considered in the construction of cities and layout of industry and agriculture, and agricultural and urban water saving should be intensified; planning and management should be strengthened, rational allocation of water resources for the whole river basin should be well conducted and water uses for domestic, production and ecological purposes should be coordinated; artificial precipitation enhancement, wastewater treatment and reuse and sea water desalinization should be actively conducted; groundwater resources should be rationally used and overdraft should be put under strict control; the reform of water management system should be strengthened to establish a rational managerial system and rational mechanism of water pricing.

The change of thinking for water harnessing and the huge challenges facing water resources undertakings provide a vast arena for the hydraulic professionals from China and even from all over the world to give play to their wisdom, and also open a new horizon for international hydraulic professionals to make cooperative studies in China. With China’s entry to WTO as a developing country, more international experts will surely be invited to take part in the water resources undertakings in China, and more Chinese hydraulic professionals will also take part in the undertakings of water resources and hydropower in the world. We welcome and encourage hydraulic professionals of other countries to come to China to carry out cooperative hydraulic studies, introduce more advanced technologies and experiences to China and make joint efforts with the Chinese people to solve water issues and problems.

The International Association of Hydraulic Engineering and Research is a very influential organization in the research and application of hydraulics. Since its founding in 1935, 28 congresses with seminars have been held, fruitful research achievements and examples of application were presented at each congress and the participants also included many scientists with initiative, important achievements, who made outstanding contribution to hydraulic research and set good examples for us. The Chinese hydraulic professionals have taken part in many activities of IAHR, not only making many friends but also learning many advanced international experiences through exchange.

I wish to take this opportunity to thank President Holly and other members of the IAHR Council for their help and support to the Chinese Hydraulic Engineering Society, and hope that close cooperation will continue between China and IAHR in the fields of sustainable utilization of water resources and so on.

I hope that this congress will provide a good chance for the participants to make extensive technical exchange, carry out academic discussions and look into the future, so as to further strengthen the friendship and cooperation among all the hydraulic professionals from different countries, promote hydraulic research in the world and the application of research achievements in different countries, thus making greater contribution to solve water issues and problems!

I wish the congress a great success and all guests’ good health and a pleasant stay in China.

Thank you!

Research Challenges arising from the World Water Vision

Dr. Torkil Jonch-Clausen

Chairman, Technical Committee, Global Water Partnership

Director, DHI Water & Environment

Danish Hydraulic Institute

Summary

Eighteen months after the presentation of the World Water Vision in The Hague a number of activities have been launched that will lead to achievement of the Vision for 2025. The third World Water Forum in Kyoto will focus on reporting on these activities. To achieve the Vision, a major contribution was expected through research and development efforts of the science and technology communities. The author reviews the research program of IAHR with comments on elements that could be given a different or greater emphasis based on his experience in the Vision exercise. Among these are:

Hydroinformatics

Indicators

Probabilistic methods

Data acquisition

Urban water management

Water resources management

Ecohydraulics and

Maintenance and development of research capabilities

The author concludes by asking whether it may not be time to resurrect the proposal of the World Water Commission to create a Research and Innovation Fund.

The World Water Vision: Where Do We Stand?

About eighteen months ago I had the pleasure of being with thousands of participants at the Second World Water Forum in The Hague. To-day I would like to report on the impact of that happening, of the World Water Vision exercise that led to it and on some of the many activities underway around the world to follow up on commitments made in The Hague. I will then turn my attention to reflecting on some of the implications that I see for the research agenda of IAHR that arise from the rapidly evolving approach to managing water.

Within weeks of the Forum, Kofi Annan issued his Report to the Millennial Summit of the United Nations. In it he referred to “a set of realistically achievable targets on water and sanitation” recommended by the Ministerial Conference of the World Water Forum. He urged the Summit to adopt the target of reducing by half, between now and 2015, the proportion of people who lack sustainable access to adequate sources of affordable and safe water. And they adopted this target!

Obviously also drawing on the Vision and Forum discussions, he stated that to arrest the unsustainable exploitation of water resources, we require water management strategies at national level and local levels. He said these should include pricing structures that promote both equity and efficiency. “We need a “Blue Revolution” in agriculture”, he said. “that focuses on increasing productivity per unit of water — “more crop per drop” — together with far better watershed and flood plain management”.

Just a month after the Forum, then USA Secretary of State Madeleine Albright referred to the Forum in her Earth day address. She said she intended to mobilise; to heighten public awareness; and issue a call for action; because the world has the capacity, and increasingly the will, to create water security for all. These are two examples of rather immediate impact of the Vision exercise and the Forum.

The World Water Vision

Those who participated in the Vision exercise wanted a world in 2025 in which almost every woman and man, girl and boy in the world’s cities, towns, and villages will enjoy safe and adequate water and sanitation and have enough food to meet their nutritional requirements. Their Vision could be achieved in a sustainable manner with a 10% increase in water withdrawals and consumption. Nevertheless, food production must increase 40%. This will only be possible within a sustainable water budget if people recognise that water is not only the blue water in rivers and aquifers, but also the green water—in soil. Recognition of its crucial role in the hydrological cycle will help make rain-fed agriculture more productive while conserving aquatic and terrestrial ecosystems. The percentage of water delivered to the domestic and industrial uses consumed by evaporation can be reduced, with most being returned after proper treatment to the ecosystems from which it is drawn. Domestic and industrial water reuse should become common, and new methods of ecosanitation not dependent on water as a carrier could be applied in many areas to reduce pollution and make full use of human waste as agricultural fertiliser. Natural and artificial wetlands can be used to improve polluted waters and treat domestic effluents. Countries that face water scarcities early in the century may invest in desalination plants—or reduce the amount of water used in agriculture, transferring it to the other uses, and importing more food.

Commitments

Many commitments were made at the Second World Water Forum to take actions that will help to achieve our Vision. The Netherlands Government has prepared a database of all such commitments that was released in Kyoto in June. They will be writing shortly to those who made commitments, thanking them for their participation in the Forum and asking them to share their progress with us, as inspiration to others to take similar action. This information will be used by the Water Action Unit of the World Water Council to track progress on these commitments along with other actions begun since. For we have passed from the stage of talking about what must be done, to one of action!

The Secretariat of the Second World Water Forum has worked closely with the World Water Council and the Secretariat for the Kyoto Forum. It has transferred all of the information in its data bases and the management of its web site so that these may serve the next event. The third Forum will be focussing on the actions that are being taken around the world as a means of raising awareness that solutions are available and actions are being taken by many. This will lead to greater commitment to action coming from the third Forum.

Focus Themes

There are some issues that will benefit from co-ordinated action. Three of these are:

Agriculture and environment security

Climate variability, climate change and water, and

Valuing water and financing infrastructure

It is useful to say a word about each of these.

One of the key challenges we face is to ensure food security for the increasing global population. Best estimates by many are that with more efficient irrigation, we can produce the 40% more food that will be needed with 15-20% more water consumed. Some feel that these estimates are too low. Others point out that in some regions, water withdrawals for agriculture and poor agricultural practices have already caused serious harm to the environment. Most recognise that this subject was inadequately addressed at The Hague. Follow-up began almost immediately in a meeting of stakeholders in Stockholm last summer. This led to a workshop on Food and Environmental Security sponsored by eight international organisations and hosted by IWMI in Colombo in December. Once again, all agreed that we have had enough talk, and that solutions will be found only by cross-disciplinary, multi-stakeholder actions taken at the country and basin level. A possible dispute between agriculturists and environmentalists is being replaced by a common effort to respond to the justifiable concerns of each community. It was agreed in Colombo that we have failed to recognise that resolution of this issue (and many other water-related issues) is not just a technical matter, but will be done by politicians. There therefore will be a special exercise to begin to address this factor. The stakeholders present in Colombo have agreed a “loosely co-ordinated” plan of action. Representatives of farmers and the private sector have agreed to join them. A step in their work plan will be to report on success achieved to date at the third Forum. This program of action was launched during the Stockholm Water Symposium in August.

The time horizon selected for the Vision exercise was 2025. While this helped us to focus on near-term problems and their solution, we ended up neglecting one of the biggest long-term drivers with respect to water resources management - climate change. The latest reports from the Intergovernmental Panel on Climate Change confirm that the process of climate change caused by human activities is well underway. They further tell that us that changes may be more severe than previously thought and that there are known serious consequences for the management of all natural resources, including water. A preliminary discussion of interested parties at an ad hoc workshop in Colombo noted that present water management approaches needed to better deal with climate variability. New water management strategies may offer solutions to some of the longer-term problems, and if widely adopted, create more resilience in our water management systems.

The United Nations University in Tokyo, together with the Secretariat of the third World Water Forum and the World Water Council hosted a more comprehensive workshop early last month. Its objective was to determine whether we might manage water resources better given the increasing predictability of climate variability and climate change and to develop commitment for action by all. There was unanimous agreement that we can manage water better using climate science, and that a program should be developed to this end. A workshop during Water Week in Stockholm this year has provided the framework and support for developing a Dialogue on Water and Climate.

A third challenge we face is that we simply are not seeing enough investment in water – neither in infrastructure, nor for that matter in urgently needed research into innovative solutions. The World Commission on Water rightfully was very concerned with this issue. It remains unresolved. It is also very complex, as investment requires returns. This links investment to the questions of valuing and pricing water, to the roles of the public and private sectors and of political stability and transparent governance. Many conferences have been held on the subject. Many books have been written on elements of the subject. Yet total investment levels at best remain stagnant while estimates are that they need to be at least doubled. The World Water Council and the Global Water Partnership have agreed to launch an initiative to create a partnership that will determine the scope of the problem on a national and regional basis and suggest optional approaches to specific local situations. Progress is being made on this front thanks to the co-operation of concerned international financiers. I am confident that we will be able to report concrete suggestions during the Forum in Kyoto.

World-Wide Movement

Thus there is a world-wide movement underway to act to resolve the water management issues displayed in The Hague. It involves cross-disciplinary partnerships and closer collaboration among international organisations. But most importantly, it is based on learning by doing at the local level, so that those so badly hurt by problems of lack of access to water, food and healthy environments may benefit from ACTION.

The Research Agenda

IAHR

When I was invited to speak at this conference, I did a little research about IAHR and its research agenda. I learned that scientific exchange is the main activity of IAHR. You develop technology transfer in several ways. Education is, of course, the classical way. You also encourage lifelong learning through exchange between individuals, national and regional groups using workshops, publication of books and manuals. You encourage management of the research program through exchanges among directors of hydraulic research laboratories. Corporate and national members are essential to your organisation. The transfer of new R & D results into engineering practice is accomplished through involvement of consulting and engineering organisations. Finally, you assure the participation of colleagues from developing countries through a Third World membership fund paid by IAHR members. This impressed me.

I was even more impressed when I read through the IAHR 1999 Research agenda by its comprehensiveness and the innovative approaches being taken in several sectors. Every area of concern being researched by you will increase the chances of achieving the World Water Vision. Nevertheless, I was motivated by your program to make some comments on areas I think of particular significance.

Hydroinformatics

I was delighted to find the emphasis placed in your research agenda on the concept of Informatics as opposed to Information and Communications Technologies (ICT) only.

This reflects the growing understanding of water professionals that our role is to inform and support water stakeholders before and after the decision-making process that is their responsibility.

In fact the evolution has been rapid. Without what might be regarded as simple ICT, it would have been impossible to develop the World Water Vision. The use of electronic mail and posting of documents on the Vision website to facilitate sharing of information and opinions that led to the creation of the Vision would not have been possible even two years earlier, especially in Africa and many parts of Asia.

Your agenda states that the rationale and purpose of hydroinformatics is to develop a new relationship between the stakeholders and users and suppliers of the systems. It offers the systems that supply useable results, the validity of which cannot be put in any reasonable doubt by any of the stakeholders involved. If the hydroinformation system is objective, the stakeholders may criticise a hypothesis of cultural practice (policies) leading to undesirable results, but not the system or tool. Thus the tool creates a possibility of negotiation and trade-offs based on merit and not on irrational sentiments. It was this type of hydroinformation system or tool that led to the agreement on water resources management that was part of the original Middle East peace agreement.

Hydroinformation correspondingly always works in a team, and may indeed create the sociotechnical means through which the team functions. The users become part of the system.

An example of this is the system through which the third World Water Forum is being created. The World Water Council’s second World Water Forum in The Hague was organised to be a participatory exercise. The Japanese hosts of the third World Water Forum proposed to the Council that the Forum should be created through participation. The main tool or system being used in the process is the Virtual Water Forum. Each group that proposes to hold a session in Kyoto in March 2003 is requested to open a page in the Virtual Water Forum. Through participation in discussions in a virtual session, interested individuals can shape the discussion that will eventually take place in the “real” Forum in 2003, even though they may not be able to be physically present themselves at that time. In addition, the degree of interest expressed in the virtual forum becomes a measure by which the Forum organisers may decide the importance (time and space) that should be given to the real session.

Usefulness of Indicators in Hydroinformatics

One of the principal concerns that is noted in your research agenda is how to make it possible for non-specialist stakeholders to have access to and to interpret the knowledge generated by specialists. A question that is often asked, for example by members of the boards of catchment management associations, is “how do I know whether we are making any progress in the management of our waters?” Or, “are we doing as well as or better than others, and why?”

Some “knowledge bases” have already been established. Others are being established, for example in the context of the Dialogue on Water for Food and Environment referred to earlier and in the Dialogue on Water and Climate. However it is unlikely that these will provide the kind of comprehensive and readily understandable information required by the non-specialist decision-maker. Similarly, those who cannot see “common-sense” relationships between various elements of water management and the environment will view sophisticated models with suspicion. Some indicator or indicators such as those provided in UNDP’s World Development Report might be developed to inform clearly and avoid suspicion.

Efforts are underway to develop such indicators for the environment in general and for water resources in particular. Most are familiar with the excellent work that was done by the World Resources Institute together with the World Bank, UNEP and UNDP in developing indicators for global ecosystems. They classified ecosystems under five main categories for agricultural, coastal, forest, freshwater and grasslands. At the same time they noted three other possible categories: mountains, polar and urban. Case studies illustrated the relationship between people and ecosystems. Their work led to and will be followed by the Millennium Ecosystem Assessment.

Another approach to developing a Pilot Environmental Sustainability Index was produced at the Davos Conference in 2000 by the Global Leaders for To-morrow Environment Task Force. The components in the system of indicators they developed were:

Environmental Systems

Environmental Stresses and Risks

Human Vulnerability to Environmental Impacts

Social and Institutional Capacity, and

Global Stewardship

This system was developed with the idea that, when refined, it could be used to measure environmental sustainability and even compare environmental sustainability practices of nations – an indicator similar to the UNDP’s development indicators.

The World Water Assessment Program is in the process of developing indicators for the state of the world’s water. This is not an easy task, as it must deal with the issues of scale and of boundaries that do not match the world’s administrative and national boundaries. A methodology is being developed that will attempt to develop indicators that will link water availability with water uses needs and demands while taking account of the ability to cope with water-related stress. Preliminary results of this work will be published at the third World Water Forum.

As has been stated by the National Research Council (USA): “Indicators used to report on a transition toward sustainability are likely to be biased, incorrect, inadequate, and indispensable. Getting the indicators right is likely to be impossible in the short term. But not trying to get the indicators right will surely compound the difficulty of enabling people to navigate through the transition to sustainability.” The task of developing these indicators will not be an easy one. Beyond a doubt it should clearly be on the research agenda of IAHR.

As your research agenda has noted, the presentation of comprehensive and understandable “encapsulated” information placed a great responsibility on those who prepare and provide it. Guidance on the ethics of this process will require the participation of philosophers as well as scientists.

Given the extent of work required in the field of hydroinformatics, I am inclined to take exception to the statement in your research agenda that “Hydroinformatics is a technology – not a science”. Like other sciences, it will evolve, but the basics will remain the same. We must develop means to inform all stakeholders of the issues concerning water resources management so that they may take informed decisions; not only decisions directly concerning water management but also those social and economic decisions that impact water resources and environmental sustainability.

Probabilistic Methods

Probabilistic approaches provide basic analytic tools to systematically integrate involved uncertainties, to quantify performance reliability of a hydraulic system, and to incorporate uncertainty and reliability information in decision-making for a more comprehensive project design and evaluation. What has been missing until now in conceptualising water management projects (as well as other infrastructure projects) is recognition of the number of associated risks. A recent research project that examined 60 infrastructure projects found that the complex relationship described in Figure 1 below. Systematic unbundling of these factors makes it possible to understand their importance and variation during the life cycle of a project.

As this research covered infrastructure projects in general, researchers associated with IAHR might usefully extend the analysis to examine risks related specifically to water infrastructure projects. This might provide information on risk reduction that we lead to increasing investments in the sector.

Data acquisition

The current research agenda refers mostly to technology issues related to the installation of data acquisition equipment in the field. Yet there is a world-wide decline in water monitoring. The number of monitoring stations for water flow and quantity in Africa, for example, declined 90% between 1990 and 2000 (Johnson et al, 2000). Fully understanding the complex interrelationships between man’s actions and global and local systems depends on better knowledge about such issues as minimum in-stream flows for maintaining biodiversity and groundwater recharge, maximum thresholds for common pollutants, and the relation of land use to hydrologic functions.

Rain and stream gauges around the world are disappearing, victims of loss of funding for monitoring programs. Better basic hydrological information about river discharge, flood frequency, dry season flows, condition of wetlands, and location of dams would help planners meet the growing human demand for water.

Increased funding for data gathering is essential. However given modern satellite and other technological systems, more research is needed to determine the appropriate density and type of monitoring stations necessary to-day to ensure the least-cost approach to obtaining the data required on weather, runoff, water quality and other parameters for integrated water management at different geographic scales. This too should be a challenge for IAHR member institutions.

Urban Water Management

I was pleased to read under your research agenda that urban drainage systems should be designed to convey storm water runoff and sewage flows of magnitudes varying from dry-weather flows to floods, control fluxes of pollutants resulting from human activities, and contribute to the general well-being of the human population. This is to be achieved within the framework of integrated management of urban waters, with minimal impacts on receiving waters in a cost-effective way, and under conditions of increasing populations of large cities. I presume that a further condition would be to have minimal impact on the upstream sources of water required for urban agglomerations. The objective of IAHR/IHA is to promote an ecosystem approach to the planning, design and operation of urban storm drainage. I could not agree more with this enlightened concept. However, I wonder if it goes far enough?

One of the concerns that I had while working on the World Water Vision exercise was the tendency to automatically link issues of sanitation to water. Thus we tend to say that there are over 1.2 billion people without access to safe drinking water, and in the next breath, that nearly half the world population lacks access to sanitation. In our minds when we say this, sanitation is water-borne sewerage. I think this is a serious mistake.

The developing world is falling further and further behind in the provision of means to dispose of its wastes. As communities develop water supplies, generally without provision for sewerage, the volume of waste grows. To the nearly three billion people that do not have access to sanitation must be added the billions of equivalent population from industrial and agricultural wastes. Where waste is collected, much of it is discharged without treatment. This situation impacts on health and on the environment. One of the effects is the pollution of surface and groundwater, sometimes rendering them unsuitable for domestic purposes even through treatment. The cost of correcting this situation through conventional collection and treatment processes will be thousands of billions of dollars. The less developed economies cannot afford these solutions or they have higher priorities for economic development. Inhabitants of rural and marginalized urban areas in particular are not able to pay, even if they were willing.

In the industrialised world, much of the urban infrastructure, particularly the sewage collection systems, will need to be replaced over the coming decades. In the constrained budget environment faced by all countries, it is not at all clear how these replacements will be financed, as the burden on taxpayers has often reached its limit. To improve the efficiency of sewage treatment and reduce the volume of residual pollutants reaching the environment, responsible authorities are having recourse to increasingly expensive treatment processes (e.g. chemical treatment) with increased operating costs. Many of the older sewer systems carry both sewage and storm water. Most of what is said above may appear to apply only to sanitary sewerage (the collection and disposal of human excrement). However there are clear linkages with the disposal of industrial and toxic liquid and even solid wastes.

The basic processes for the collection and treatment of wastes have been in use for two thousand years. Modern engineering and science have focused on methods to make them more effective and efficient, rather than on finding alternatives. Processes to treat or eliminate wastes at the source, rather than at the outlet from a transportation system, could drastically reduce the costs of sanitation. Indirectly this would reduce the costs of surface drainage. Such processes would likely ensure better protection of the environment.

While there is a wide range of sanitation issues that would benefit from shared research, the basic concept which needs challenging is that of water-borne sewerage. An alternative to this would open the field for innovative thinking with regard to the disposal of other wastes. Benefits that would result from finding such an alternative would include:

Elimination or reduction of the costs of construction, maintenance and operation of collection (sewer) systems, treatment works and final disposal;

Reduced water consumption;

Reduced costs of storm water drainage systems;

Elimination of residual pollutants currently discharged by treatment works; and as a consequence,

Protection of ground and surface waters, and their environment.

I invite researchers in this field to consider whether the approach to management of human waste that we began to use thousands of years ago is still appropriate and economical in this age of modern technology and natural resource constraints.

Water Resources Management

The IAHR Section for water resources Management has adopted, as a primary long-range goal, to promote the use of advanced technologies to address problems of environmentally sound water resources management, and has committed itself to encourage interdisciplinary approaches in hydraulic engineering with special regard to ecological concerns. Moreover, the Section wants to promote the adoption of appropriate methodologies for developing countries by education and training.

Most of those involved in the management of water now accept the principle of integrated water resource management (IWRM). I will not expound on those here. However, no matter how well-founded this principle is – and it is well-founded – what we often fail to recognise is that we have arrived at this principle and this approach in the countries of the North through a gradual process over the past 150 years. The economic development of the industrialised world took place in the first hundred years of this period driven by the “enlightened” belief that using science and under capitalism system nature could be controlled. It was in response to the Green movement in the North that this paradigm has shifted in the North.

As Tony Allan has pointed out, the underdeveloped countries of the South are now faced with improving their quality of life while at the same time being expected to shift from the water management paradigm under which developed countries evolved to that which the industrialised countries now espouse. This poses a moral dilemma for the North. But it also poses a research challenge for us – to develop cost-effective ways to provide for economic development under the principle of IWRM that calls for a sustainable environment.

One aspect of IWRM that proponents nearly always fail to recognise is that IWRM requires not only a demanding holistic professional and scientific approach but also an unprecedented level of political co-operation. We must recognise that water users and policy makers operate in political systems that determine whether or not the new paradigms can be assimilated that useful debate can take place. Political systems make sense to most of the players who live in them. Such systems have a political rationale. Decision-makers and water users will assimilate IWRM only if the innovation of integration is appreciated as a political process and not just as a technical, investment or information sharing process. Water policy will be transformed if it is politically feasible. Such innovation will be achieved by taking an inclusive approach and emphasising the institutional dimension of the inescapably political the integrated water resource management process. In brief, we must learn how to assess and influence political feasibility. Research into these processes will be sensitive, but is essential.

Ecohydraulics

The environment, especially in terms of water quality, pollution and protection of ecosystems is one of the major concerns of modern civilisation. Research in this field has significantly increased in recent years. However a lot of work remains to be done to improve our knowledge and capacity to understand phenomena, predict the effects of human works on natural ecosystems, and find solutions for maintaining acceptable water quality and biodiversity in our marine and continental environment. During the Vision exercise I often represented this dilemma by asking the question “How much water does a river need?”

All these reasons have led IAHR to create a new section on Eco-hydraulics to encourage collaboration between hydraulicians, biologists and chemists and others. I can only applaud this effort, and note a strong linkage to the issue of research in adapting to shifting paradigms of which I have just spoken.

Maintenance and Development of Research Capabilities

With a better understanding of the economic value of water and more public-private-partnerships, there will undoubtedly be more privately funded research. However many of the issues described in your research program will not be attractive to the private sector. One of the conclusions of the Vision exercise was that there should be an increase in public funding for research and development in the public interest.

The World Water commission saw that given the potential of the new technologies and the innate abilities of people, enormous gains could be made as new innovations occur in either institutional arrangements or technology application. The latter may be by the rediscovery and deployment of traditional technologies or the emergence of new technologies. A key to get the maximum benefit globally of these new developments would be how quickly they will be adequately evaluated, disseminated and adopted throughout the world.

Innovation also requires some assistance in incubation. The Commission recommended the establishment of an Innovation Fund that would help promote environmentally and socially desirable technical and institutional innovations. Some of the institutional innovations that could be considered for support included:

national “water stamps for the poor” programs;

time-bound subsidies for transition arrangements;

providing medium-term “bridging loans” in countries where long-term capital markets are not developed;

political risk guarantees for private operators entering risky markets;

new forms of mobilising NGOs and communities to improve services and protect the environment, and

exploring new approaches to negotiation of international water treaties.

In terms of technology the Commission also saw innumerable opportunities, which include innovations in particular “orphan” areas such as biotechnology for the food crops of the poor in water deprived areas. Finally, they saw geographic areas with problems that cry out for new approaches. For example, the Indo-Gangetic Plains have very large numbers of poor people and hunger, yet so much water badly distributed in space and time. It is a very big challenge to work out a water management paradigm for this area that is environmentally sound, socially responsible and economically productive.

Perhaps the time has come to lobby again for the creation of a Research and Innovation Fund with support from both the private and public sectors?

References

ALAN, ANTHONY. 2000. Millennial water management paradigms: making IWRM work. (SOAS- unpublished)

COSGROVE, WILLIAM J. AND FRANK R. RIJSBERMAN for the World Water Council. 2000. World Water Vision: Making Water Everybody’s Business. Earthscan.

MILLER, ROGER AND DONALD R. LESSARD. 2000. The Strategic Management of Large Engineering Projects – Shaping Institutions, Risks and Governance. MIT Press.

NATIONAL RESEARCH COUNCIL (NRC). 1999. Our Common Journey - A Transition toward Sustainability. Washington. National Academy Press.

UNDP, UNEP, WORLD BANK, and WORLD RESOURCES INSTITUTE (2000): World Resources 2000-2001- People and Ecosystems – the Fraying web of Life. World Resources I

THE MAIN PROGRESS IN THE HYDRAULIC RESEARCH

IN CHINA

Zhu Erming

Chairperson of the Executive Board, Chinese Hydraulic Engineering Society

Abstract

This paper summarizes the natural conditions, achievements of water resources undertakings and major existing water problems in China, emphatically expatiates upon the major progress in hydraulic research and, in consideration of the requirement of economic and social development for water resources, presents prospects for the development of water resources undertakings in the early 21^st century (2030).

NATURAL CONDITIONS AND ACHIEVEMENTS IN WATER RESOURCES UNDERTAKINGS

Natural Conditions

China has a vast territory ranging over 62° of longitude or 5200 km from east to west, and 52° of latitude or 5500 km from north to south, covering the tropical zone, sub-tropical zone, warm humid zone, temperate zone and cold temperate zone. The topography is complicated and presents three obvious steps from the “World Roof” at the western end to the eastern coastal plains. China has a large number of rivers, in which more than 1500 each have a drainage area of more than 1000 km² and have a total length of 430000 km. Most of the large rivers flow from the west towards the east with divides in between in the same direction, thus natural hydraulic links are lacking in the south-north direction. The climate is affected by monsoon and the precipitation varies greatly in time and space. The southwestern regions are rich in hydropower potential, and the northwestern regions are poor in rainfall and suffer frequently from droughts. The total volume of water resources in the country is 2800 billion m³ and the per capita volume is 2170 m³. As affected by the natural and climatic conditions, China suffers frequently from flood, waterlogging and drought disasters, the soil erosion is serious, and the eco-environment is fragile. The natural environment determines the position and role of water resources undertakings in the economic and social development and the eco-environmental protection in China.

Achievements of Water Resources Undertakings

The Chinese nation has a long history of water harnessing. The Dujiang Weir Complex in Sichuan Province, the Zhengguo Canal in Shaanxi Province, the Ling Canal in Guangxi Autonomous Region and the Beijing-Hangzhou Grand Canal were all built Anno Domini and water resources projects of various kinds such the Yellow River embankments were built in later periods. Since entering the 20^th century, particularly after the founding of the P. R. China, the water resources undertakings have seen a period of great development. In the last 50 years, a lot of water resources infrastructure has been built. By the end of year 2000, the total length of consolidated and newly-built embankments had amounted to 270000 km; more than 85000 reservoirs had been built with a total storage capacity of 518.3 billion m³, and 98 flood detentions zones had been established with a total detention and storage capacity of 97 billion m³, thus preliminarily creating a flood control engineering system for large rivers and lakes which can control normal floods, protect 40 million ha of farmland, 460 million population, more than 600 cities and major communication lines, industries and mines; the total annual capacity of water supply had amounted to 580 billion m³; the area of irrigated farmland to 55 million ha; the installed capacity of hydropower generation to 76.8 GW; the mileage of river transportation to 110000 km; and the soil erosion area that has been put under preliminary control to 800000 km², thus reducing annual sediment discharged into rivers by about 1.5 billion t. The water resources undertakings in China have played an important role in flood control, urban and rural water supply, hydropower generation, river transportation, water and soil conservation, ecological improvement, harbor, aqua-culture, recreation, etc, thus providing great supports for the sustainable, rapid and healthy economic development, social stability, promotion of the people’s living standard, smooth progress of reform and opening-up and the national economic safety and, at the same time, also providing extensive horizons for hydraulic research.

The Main Water Problems

Low capacity against flood and long term treats of flood and waterlogging disasters

At present there are 70% of the cities and 50% of the major embankments are not up to the national standards for flood control, the situation of flood control is still stern and the tasks of flood control are very arduous.

Uneven distribution of water resources in time and space and a big gap between water supply and demand

As affected by the monsoon climate, China’s precipitation varies greatly in time and space. The southern China is rich in water resources but poor in farmland, and the northern China is poor in water resources but rich in farmland. It is very pressing to implement rational allocation of water resources in order to solve the water shortage in the Huang-Huai-Hai region

Severe soil erosion and fragile eco-environment

According to the second national soil erosion remote-sensing survey, the water erosion area in the country is 1.65 million km² and the wind erosion area 1.90 million km². Therefore, the soil erosion is still very severe and the tasks to harness soil erosion are very arduous.

Serious water pollution and deteriorating water environment

By now about 38% of the river reaches of the seven major rivers in the country have been polluted to a varying degree, about 30% of industrial wastewater and 80% of domestic sewage are directly discharged into rivers, lakes and reservoirs without any treatment. To facilitate the harnessing of water pollution sources will be put on the important agenda of infrastructure construction in China.

MAiN PROGRESS IN HYDRAULIC RESEARCH

In the last tens of years, China has stick to the thoughts that sciences and technologies are the first productivity, economic development must rely on sciences and technologies and scientific and technologic work must be oriented to economic development, and the large-scale construction of water resources engineering has promoted hydraulic research.

Water Resources Research

The natural precipitation in China is distributed unevenly in time and space with great inter- and intra-year variations, and both consecutive wet and dry years often occur, which is the basic reason for the imbalance between land and water resources and the frequent occurrence of drought, flood and waterlogging disasters. In the last tens of years, China has achieved great progress in water resources assessment, allocation of water resources, water environmental protection, water legislation and water management. Structural and non-structural measures are applied to coordinate the relationship between water and the society, economy, ecology and environment and implement unified planning and management of development, utilization and protection of water resources. The multiple levels, multiple objectives and group decision large system analysis method was applied to the formulation of national mid to long term water plan, national groundwater plan, national water conservation plan, etc so as to promote the foresight for sustainable utilization of water resources. At the same time, the research projects of Macroeconomic Based Water Resources Planning and Management in North China and the Rational Allocation and Ecological Protection in Northwest China were implemented for the areas of serious water scarcity. In order to alleviate the water shortage in some areas, a number of inter-basin and inter-regional water transfer projects have been implemented, such as Datong River-Qinwangchuan and Yellow-Shanxi transfer projects. At present the South to North Transfer Project is being studied, which would cover the four major river basins of Yangtze, Huaihe, Yellow and Haihe.

At present coordinated planning is being made for the three large systems of water cycle, socio-economy and eco-environment of river basin with the dissipation theory, fuzzy mathematics and artificial intelligence in order to provide comprehensive guarantee of water resources for the regional economic development and eco-environmental protection.

Environmental Hydraulic Research

Water is an important element of the environment and water resources undertakings exert multiple impacts on the environment, in which the positive ones include: control of flood and waterlogging disasters, development of irrigation, improvement of navigation, hydropower development, water and soil conservation, water supply for human beings’ life and production, ecology and environment, and the negative ones include: inundation of large areas of land by reservoir construction, resettlement of large numbers of residents, layered distribution of water temperature in large-sized reservoir affecting water ecology, river barriers stopping fish migration, release of low temperature water from reservoir affecting water ecology; excessive upstream water use causing water shortage and river’s drying-up downstream, discharge of untreated wastewater upstream causing pollution of river channel downstream, and excessive overdraft of groundwater causing ground subsidence. Therefore, to strengthen water demand and use management, promote water use efficiency, protect and improve the eco-environment is an important task of water resources undertakings.

Water eco-environmental protection

w Conduct scientific zoning of water functions and formulate protection plans accordingly.

w Carry out targeted water quantity and quality evaluation and make forecast regularly.

w Strengthen the monitoring and information collection on water eco-environment and establish a data base system for water quantity and quality.

w Protect water eco-system and biological resources.

w Strengthen research and water pollution control, and accelerate the progress of water and soil conservation.

w Strengthen legislation for water ecological protection and protect water eco-environment by law.

Hydraulic works environmental protection

The impacts of hydraulic works on the environment are a complicated system of multiple variables, multiple structures and multiple levels, and are generally evaluated in a comprehensive way according to the varieties, components, elements and measures of environment, covering reservoir inundation, land occupation, induced changes in water and sediment regimes, river regime, storage and release, water table, etc, and impacts of construction. The Law on Environmental Protection of P. R. China was issued in 1979, the Regulations on the Management of Environmental Protection for Capital Construction Project in 1981, and the Regulations on the Environmental Impact Evaluation of Hydraulic Works in 1982, thus establishing a system of EIA for hydraulic works.

w The planning and design of hydraulic works should follow the policy of putting prevention first, combining prevention with remedy and implementing comprehensive harnessing so as to reduce as far as possible adverse impacts on the eco-environment. Reliable protection measures must be adopted for unavoidable impacts.

w In the planning and design, impacts on the eco-environment should be fully studied as an important element for the rational selection of design schemes, resident relocation plans and operation rules.

w Construction must not start before the EIA report for the project is approved.

w The system should be fully implemented that the environmental protection measures are designed, constructed and put into operation at the same time as the main works. The acceptance of environmental protection measures should be taken as a component of project completion acceptance.

w The monitoring and management of eco-environment during operation should be taken as a component of project management.

w In the formulation of the EIA report for hydraulic works, representatives from related areas and sectors, experts and the public must be invited to participate and an effective supervision mechanism should be established.

Major progress in water environmental research

w Observation has been made of pollutant diffusion and transportation for the main reaches of large rivers and studies have been carried out on the range and concentration distribution of offshore pollution belt and mutual impacts among multiple waste outlets.

w Studies have been made on the impact of regular waves on re-oxygenation coefficient for each system of the river dissolved oxygen model and the model for oxygen production of algae photosynthesis and methods for the determination of parameters have been determined.

w Studies of basic theories have been made on the pattern and rate coefficient of adsorption and resolution of suspended substances to metals in water of heavy metal quality.

w Long term, systematic studies have been made on thermal pollution mainly with physical models for cooling water of thermal power plants to put forward the measures to overlap intakes and outlets of cooling water. Studies have also been made with multiple hydraulic and thermal models for cooling water of nuclear power plants.

w Studies have been made on groundwater pollution and purification measures, offshore pollution, self-purification of pollutants, and analysis and simulation techniques for diffusion.

Studies of River Channel Evolution and Sediment Movement

Soil erosion is severe in many river basins in China. The rivers carry huge quantities of sediment and river sediment movement directly affects river configuration. Therefore, long term observation, studies and harnessing have been made for river sediment movement. The Chinese scholars have achieved a number of theoretical, semi-theoretical, semi-empirical and empirical results, and have made breakthrough progress in the studies of cohesive sediment running-up, high sediment content flow movement, density flow and mud-rock flow by combining the mechanical theories with statistics and physical chemistry.

In the aspect of river channel evolution, the theories of sediment movement and geomorphology have been applied to study the laws of scouring and sedimentation of natural rivers. The alluvial rivers are divided into five types: straight, curved, serpentine, braided and wandering, and harnessing measures have been adopted according to the evolution laws to achieve good results. The sediment movement at river mouth is affected by river flow, tidal flow and waves. The studies of river mouth are focused on the development of river mouth delta and the formation and variation of sand barriers and bars. Long term observation has been made to provide a scientific basis for the harnessing of river mouth.

In the aspect of engineering sediment, the focus has been put on the studies of reservoir sediment, water complex sediment, river channel and lake sediment, sedimentation at tidal gates and sediment induced abrasion of water turbine. A series of theories and experiences have been produced for sediment treatment, such as the theories of “storing the clear water and discharging the muddy to regulate water and sediment” for reservoir operation, “forward diversion and lateral sediment discharge” to separate water from sediment for the layout of water complex, “diverting flood for warping irrigation to improve soils, warping on the front and back to consolidate embankment” to utilize sediment resources, “carrying out transportation in static water and scouring sand regularly” to solve sedimentation of navigation routes.

While solving the sediment problems for river channel and hydraulic works, theoretical studies and technical development of mathematical simulation, physical model and prototype model observation have been promoted in the fields of river basin sediment generation, river channel modeling, laws of sediment movement at river mouth and coast, experiment on high sediment content water flow, and the results have been extended and applied effectively.

Studies of High Water Head Ship Lock Hydraulics

China has many large rivers, a large number of lakes, reservoirs and coastal lines connected to river mouths. Those waters provide favorable conditions for the development of river shipping and river-sea joint shipping. The total length of the rivers open to navigation is about 110000 km. The water resources in China vary greatly in time and space and the river sediment problem is serious, therefore, in order to develop river shipping, studies must be made on many scientific and technological issues. During the construction of ship locks of the Gezhouba Project, a lot of studies and experiments were carried out to solve the issues and problems, such as sedimentation affecting navigation, the harnessing of the Nanjinguan navigation channel and hydraulics of high water head ship locks. The Nanjing Hydraulic Research Institute established an experimental tank for non-steady flow and made 1:10 model experiments for extra-large valve in combination with mathematical models to optimize gate shape; at the same time, studies were made on the shape of valve intake, water inflow and ventilation of internal shaft in combination with prototype observation of the Gezhouba lock, etc to solve the problems of current vibration and cavitation erosion.

Studies of High Speed Flow Energy Dissipation

There are many high water head flood relief structures in China. Table 2-1 shows the existing high water head and large discharge relief structures and Table 2-2 shows those under construction and to be constructed. Because of the high dam, large discharge, high flow velocity and narrow channel, energy dissipation and scouring prevention are the most outstanding issues for high water head flood relief structures. Many types of energy dissipation structures have been developed through model experiments, theoretical analysis, prototype observation, etc. with consideration of practical conditions of engineering structures.

Table 2-1 Existing high water head, large discharge flood relief structures in China

Basic data					Relief structures
No	Dam	Dam type	Dam height (m)	Discharge (m3/s)	Openings on dam			Spillway No.–width´ height	Tunnel No.–width´ height
					Surface Opening No.–width´ height	Middle Opening No.–width´ height	Deep Opening No.–width´ height
1	Shuikou	PG	101	51800	12-22´15		2-5´8
2	Panjiakou	PG	107.5	42600	18-15´15		4-4´6
3	Shuifeng	PG	106	40000	26-12´6.5			10-9´10	D8.6
4	Ankang	PG	128	37000	5-15´17	5-11´12	4-5´8
5	Yantan	PG	111	33400	7-15´21		1-5´8
6	Yunfeng	PG	113.75	24230	21-11.0´7.5		4-4.25´4.25
7	Ertan	VA	240	23900	7-11´11.5	6-6´5	4-3´5		2-13´13.5
8	Geheyan	GV	151	23458	7-12 ´18.2	6-6´5	4-4.5´6.5
9	Fengtan	GV	112.5	23300	13-14´12		1-6´7
10	Tianshengqiao I	ER	178	21750				5-13´20	1-6.4´7.5
11	Wujiangdu	PG	165	21350	4-13´18.5		2-4´4.4	2-13´18.5	2-9´10.44
12	Manwan	PG	126	20910	5-13´20		2-5´8		1-12´12
13	Baozhusi	PG	132	16060	2-15´17.3	2-13´15	4-4´8
14	Sanmenxia	PG	106	15100		12-3´8	8-3´8		2-8´8
15	Guxian	PG	125	13894	5-13´16.5	1-6´9	2-3.5´4.23
16	Huanglongtan	PG	107.5	13300	6-12´10		1-5´6	Emergency 10´12
17	Xin’anjiang	PG	105	13200	9-13´10.5
18	Dongfeng	VA	173	12580	3-11´7	2-5´6 1-3.5´4.5		Left 1-15´20	1-12´17.5
19	Baishan	GV	149.5	11000	4-12´12		3-6´7
20	Bikou	TE	101.8	9550				1-15´16	Left 1-9´8 Right 1-8´10
21	Liujiaxia	PG	147	9220			2-3´8	3-10´8.5	1-8´9.5

Table 2-2 High water head, large discharge flood relief structures under construction or to be constructed in China

Basic data					Relief structures
No	Dam	Dam type	Dam height (m)	Discharge (m^3/s)	Openings on dam			Spillway No.–width´ height	Tunnel No.–width´ height
					Surface opening No.–width´ height	Middle opening No.–width´ height	Deep opening No.–width´ height
1	Three Gorges	PG	183	102500	22-8´17	2-18´11 raft floating	23-7´9
2	Dachaoshan	PG	115	23800	5-14´17.8		3-7.5´10
3	Xiaolangdi	TE	154	17063				3-11.5´17	3-D14.5 3-D6.5 1-10´11.5 1-10.5´13
4	Xiluodu	VA	273	50311	8-12.5´18		7-5´6
5	Xiangjiaba	PG	161	48680	5-19´26	7-7´11
6	Longtan	PG	216	35500	7-15´20		2-5´8
7	Nuozadu	ER	258	35300				10-15´20	2-5´8.5
8	Goupitan	VA	225	26950	6-16´15	7-6´7	2-6´7
9	Xiaowan	VA	292	20683	5-11´15	6-6´5			2-10´12
10	Shuibuya	ER	232	15243			2-4´5	5-14´21.5
11	Pubugou	ER	186	9780				3-12´16	1-9´9 1-12´7.5 (transformed from diversion tunnel)

w Bottom flow (jump) energy dissipater. It dissipates energy through hydraulic jump to make upstream flow connect downstream flow steadily. This type of energy dissipaters is used in the Yanguoxia and Puxi projects constructed in the 1960s and the flood and sediment relief gates of the Gezhouba Project. Flaring pier-cushion pool joint energy dissipater is used for the high water head flood relief structures of the Ankang and Wuqiangxi projects constructed after the 1980s. Aerated pier-cushion pool and T-shaped pier-cushion pool joint energy dissipaters are also applied, which can reduce the length of cushion pool and promote the efficiency of energy dissipation.

w Submerged bucket dissipater. With this kind of dissipaters energy is dissipated through the rapid diffusion as induced by the spiral mixing function of bottom spiral flow and surface flow of overflow dam. Practices of years show that surface flow dissipates a small amount of energy and has a large speed, thus causing bank scouring over a long distance. Therefore, better dissipation effects can only be achieved with supporting dissipaters, in which flaring pier is one of the most effective ones.

w Ski-jump energy dissipater. With this kind of dissipaters, a trajectory bucket at the end of overflow dam is used to make the jets discharge in air to collide and diffuse and, after dissipating a part of dynamic energy, fall into a downstream cushion pool to dissipate energy through diffusion, turbulence and rolling. There are many types of trajectory bucket, and the common ones are continuous type, differential type, diffusion type, oblique deflecting type, torsional type, high-low sill type, etc. Multiple types of ski-jump dissipaters have been used for about 100 high dams, such as Xinfengjiang, Zhexi, Liuxihe, Wujiangdu, Baishan and Longyangxia projects, and have greatly reduced downstream scouring.

w Contracting energy dissipater. It is formed by sudden contracting side walls or blocks to create diffusion in both the longitudinal and verticdal directions, thus achieving significant energy dissipation. A flaring pier contracting dissipater is used in the Ankang Project to make the length of the cushion pool reduced by more than one third. For the overflowing dam of the Wuqiangxi Project, flaring piers are used to create longitudinal diffusion and traverse contraction of jet and bottom release openings are provided in the water free area of dam surface to increase release capacity and promote energy dissipation. In this way the length of cushion pool is reduced by 60%. Slit-type buckets of different contracting ratios and deflecting angles are used in the Dongjiang, Dongfeng, Longyangxia, Nanyi and Xiongdu projects to achieve satisfactory energy dissipation effects.

w Stepped joint energy dissipater. With this kind of dissipaters, water flow becomes aerated, slowed down, mixed and turbulent along the steps on dam slope or spillway surface to dissipate energy, and good effects are achieved in combination with energy dissipation from longitudinal diffusion created by flaring piers on dam crest. This kind of dissipaters is used in the Shuidong and Dachaoshan projects, etc and is being considered for some dams under design. The steps themselves cannot dissipate energy significantly, but can promote aeration to reduce cavitation and can achieve good results jointly with flaring piers.

w Dissipater in flood relief tunnel. It includes many types such as orifice plate type, vertical shaft type and vortex flow type. In the Xiaolangdi Project three orifice plates are used in the flood relief tunnels and energy is dissipated step by step by using the orifice plates to create contraction, then diffusion, and further contraction and diffusion repeatedly. In the Shapai Project, vertical shaft vortex flow energy dissipation in flood relief tunnels is applied, that is, reservoir water flows into a vortex chamber at the inlet of vertical shaft to create vortex flow entering the vertical shaft. Within the shaft frictional force of free vortex flow against the side wall and internal shearing and resistance forces of the flow dissipate a large amount of energy. After entering the horizontal free flow section, the vortex flow continues to dissipate energy significantly.

w Dam crest water fall-cushion pool energy dissipater. Cushion pool is applied to both the Liuxihe and Ertan arch dams, with which a spillway on dam crest throws the jet downstream far from the dam site. The jet dissipates a part of dynamic energy in air and most of dynamic energy is dissipated in the downstream cushion pool.

Studies of Technologies of High-velocity Flow Aeration for Cavitation Erosion Reduction

Because there are irregularities on the surface of spillway left from construction, cavitation erosion often occurs to high-velocity relief structures. Since the 1970s studies have been carried out on technologies of aeration for cavitation erosion reduction, applying the shapes of spillway surface and aeration measures recommended by model experiments to real projects and making prototype observation. Observation results further show that the designed hydraulic indexes are rational and the effects of aeration to reduce cavitation erosion are significant. In the last tens of years, research, design, construction and management agencies have made joint efforts to carry out experiments, prototype observation and theoretical analysis, thus achieving development and improvement in the studies, design and application of technologies of aeration for cavitation erosion reduction. Since the 1980s aeration cavitation reduction measures have been applied to almost all high water head relief structures in China. The Codes for the Design of Spillway issued in 1990 stipulates that aeration cavitation reduction measures shall be applied to water relief structures with a flow velocity of more than 35m/s. During the same period, in-depth studies have also been carried out on pulse pressure and current vibration of high-velocity flow with measures to reduce erosion adopted accordingly.

PROSPECTS FOR THE DEVELOPMENT OF WATER RESOURCES UNDERTAKINGS IN CHINA

Water resources engineering is important infrastructure for the national economic and social development and is thus of overall and strategic significance. With the economic and social development new requirements are being put forward and the water resources undertakings will enter a new era.

Requirements

w Provide safety against flood for the economic and social development.

w Provide water supply for food safety, urban and rural domestic use and production.

w Provide a good water environment and water ecology.

w Provide clean hydropower for the adjustment of energy structure and implement “West to East Power Transfer”.

w Harness the rivers for water transportation.

w Realize development of water resources undertaking coordinated with economy, society, ecology and environment.

Basic Thinking

The water resources undertakings in the new era should seriously implement the strategies of sustainable development and prospering the country by relying on sciences and education, correctly deal with the relationships between water resources undertakings with economic and social development, ecological improvement and environmental protection. The principles of comprehensive planning, taking all factors into consideration, and looking into the root causes while solving a problem should be implemented, and comprehensive measures of river and lake harnessing, hydropower generation, water and soil conservation, rational development, optimized allocation, high efficiency utilization, effective protection and strengthened management of water resources should be adopted to provide powerful support and an important guarantee for the coordinated economic, social and eco-environmental development and ensure a sustainable, stable and healthy development of the socialist modernization of China.

Goals and Objectives

The goals and objectives for water resources undertaking in the early 21^st century (2030) are:

w Establish a sound comprehensive flood control system. Through the establishment of flood control engineering system and non-structural measures, the standards of flood control and capacity against flood and waterlogging will be promoted step by step, and the standards of main protection areas against flood will reach a level consistent with the level of economic and social development.

w Establish a safe, reliable water supply system. The national capacity of water supply will reach 750 billion m³, water saving will be intensified, the area of irrigated farmland will be increased by 8 million ha, the grain yield per m³ of applied irrigation water will reach about 1.5 kg, and the water consumption per 10000 yuan of industrial output value will be reduced to about 10 m³.

w Establish an effective system for water and soil conservation and water resources protection. 50-60% of the water erosion area in the country will be put under primary control and soil erosion will be effectively reduced. Effective protection of water resources will be carried out based on the water functional zoning, the control of water pollution will be strengthened, and the water eco-environment of rivers, lakes and reservoirs will be improved step by step.

w Rationally develop hydropower resources in the western regions. A sound mechanism for the development of hydropower resources will be established, that is, conducting rolling development on the basis of river basin by implementing cascade and multi-purpose development. By 2030 the total installed generating capacity of hydropower in the country will reach 130-140 GW and the rate of hydropower potential exploitation will reach 34-37%.

w Establish a sound system for water resources management, a comprehensive legal system for water resources and the development, management and utilization of water resources by law will be achieved, unified management of water resources will be realized so as to ensure sustainable economic and social development with sustainable utilization of water resources.

In the 21^st century, the water resources undertakings in China will further develop vigorously and large-scale construction of water projects will open a great horizon for hydraulic research. We hope that the hydraulic professionals in the world will join us in the construction of hydraulic works and hydraulic research and make contribution to the solution of global water issues and problems.

Flood disaster management

Erich Plate1¹ and Zhao-Yin Wang²

¹ em.Prof. Universität Karlsruhe

² Tsinghua University, Beijing, China

Introduction

The concept of „sustainable development“ has been introduced as guiding principle for future development during the Rio Conference on Environment and Development in 1992. The concept requires an economic and social development of humanity which satisfies the need of the present generation without compromising the need of future generations to satisfy their own needs. It is generally understood to mean that the resources of the earth should be used sparingly, and that Some of the principles implied by this new paradigm of sustainable development have been summarized in the recommendations of IAHR that were initiated by Prof.E.Naudascher (IAHR,1997). Their application requires considerable effort and some rethinking from planners of hydraulic engineering works and hydraulic engineers.

When one looks at the interaction of humanity with natural rivers, the concept of sustainable development has been translated to mean that we should adhere to the ancient principle of „Living with rivers“ and to use this principle for our modern approach to river management. During the Second World Water Forum, in den Haag in March 2000, the members of the Japanese delegation organized a section on “Living with rivers”, which was based on a paper prepared by Dr. Rodney White for an IAHR task force (see also GWP, 2000).

A further prerequisite for sustainable development is that societies and nations are allowed to develop in peace and without destabilizing influences that divert the economic resources of a country into emergency handling and away from improving social structures and development of infrastructures. Among the destabilizing influences are natural disasters, and in particular floods. Therefore the paradigm of sustainable development implies that we learn to manage floods in a way which saves human lives and property while minimizing the impact of our measures for flood protection on the natural environment. As a subset of “Living with rivers” this implies a new way of looking at floods from the perspective of “living with floods”, which means that we should look at the problem of flood protection in an integrated way, involving experts from all fields of science and administrations touched by floods. A possible way of introducing this concept into the planning of flood protection measures was practiced after the den Haag forum, in a workshop in Maputo on the spring floods of the year 2000 in Mozambique. The meeting was organized by the Japanese Organizing Committee for the Third World Water Forum (to be held in Japan in 2003), in cooperation with IAHR. International experts of flood management interacted with regional experts and planners in identifying the most promising actions for improved flood management and presented their conclusions to the political leaders of the country in a high level ceremony. Prince William, the crown prince of Holland, also present at the meeting, called this approach the “Maputo spirit”. The Maputo Spirit requires to develop concepts on how to handle flood protection problems with due regard to satisfying all needs in a sustainable manner, i.e. so that environmental impacts of human actions are minimized.

Application of the principle of sustainable development as expressed in the concept of “living with floods” requires integrated planning of river measures, so that the benefits that can be derived from the river are optimized, with a minimization of the impact on the natural fluvial environment, and with due consideration of flood protection and flood management. This is the planning task of designing and constructing a flood protection system. Application of the Maputo spirit also requires to learn to live with the residual risk, which means that a disaster which occurs because the available protection fails – meaning that uncontrolled flooding occurs – is handled with minimum possible damage and losses of human lives. This is the task of operation of an existing system. Planning and operation are different sides of the same coin, but because they involve different actors and different concepts they need to be treated separately. This is an important statement, because in many discussions of flood protection systems the two tasks are treated as if they were the same.

Flood risk management for an existing system

Flood risk management in a narrow sense is the process of managing an existing flood risk situation. In a wider sense, it includes the planning of a system which will reduce the flood risk. These two aspects of flood risk management will be considered separately, starting with the management of an existing system, which consists of the processes indicated in Fig.1.

Fig.1: Stages of operational risk management (Plate, 2000)

Risk management for the operation of an existing flood protection system is the sum of actions for a rational approach to flood disaster mitigation. Its purpose is the control of flood disasters in the sense of being prepared for a flood and to minimize its impact. It includes the process of risk analysis, which provides the basis for long term management decisions for the existing flood protection system. Continuous improvement of the system requires a reassessment of the existing risks and an evaluation of the hazards depending on the newest information available: on new data, or on new theoretical developments, or on new boundary conditions, for example due to change of land use. The hazards are to be combined with the vulnerability into the risk. The vulnerability of the persons or objects (the “elements at risk”) in the area which is inundated if a flood of a certain magnitude occurs, is weighted with the frequency of occurrence of that flood. A good risk analysis process yields hazard or risk maps, which today are drawn by means of Geographical Information Systems (GIS) based on extensive surveys of vulnerability combined with topographic maps. Such maps serve to identify weak points of the flood defense system, or indicate a need for action, which may lead to a new project. Other weaknesses of the system become evident during extreme floods. For example, the Oder flood of 1997 has indicated (see for example Kowalczak, 1999) that weak points contributing to flooding of a city in a flood plain not only are failures of dikes, but also seepage through the dikes and penetration of flood waters through the drainage system, i. e. through backwater into the sewerage system or water courses inside the city.

Risk analysis forms the basis for decisions on maintaining and improving the system, which is the second part of the operation of an existing system. It is a truism that a system requires continuous maintenance to be always functioning as planned, and new concepts of protection may require local improvements of the existing system. A third part of the management process is the preparedness stage, whose purpose is to provide the necessary decision support system for the case that the existing flood protection system has failed. It is evident that no technical solution to flooding is absolutely safe. Even if the system always does what it is supposed to do, it is hardly ever possible to offer protection against any conceivable flood. There is always a residual risk, due to failure of technical systems, or due to the rare flood which exceeds the design flood.

It is the purpose of preparedness to reduce the residual risk, through early warning systems and measures which can be taken to mitigate the effect of a flood disaster. An important step in improving an existing flood protection system is the provision of better warning systems. Obviously, the basis for a warning system has to be an effective forecasting system, which permits the early identification and quantification of an imminent flood to which a population is exposed. If this is not accurately forecasted or at least estimated early enough, a warning system for effective mitigating activities cannot be constructed. Therefore, it is an important aspect that systems managers remain continuously alerted to new developments in flood forecasting technology, and to be prepared to use this technology to the fullest extent.

The final part of operational risk management is disaster relief : i.e. the set of actions to be taken when disaster has struck. It is the process of organizing humanitarian aid to the victims, and later reconstruction of damaged buildings and lifelines.

Flood protection as a dynamic process

Historically, flood protection underwent a number of development steps, depending on the type of flood: a flash flood obviously required different responses than a flood which inundates the lower part of an alluvial river. Flash floods have high velocities and tremendous erosive forces, and only extremely solid structures can withstand their destructive force. The only way for escaping a flash flood used to be to get out of harms way by moving houses and other immobile belongings to grounds which are so high that no floods can reach them. Later on, banks were strengthened with riprap or concrete linings against erosion. The damage potential of flash floods is confined to the direct neighborhood of the river, the total damaged area usually is not very extensive – although due to the high velocities the individual damage to structures or persons caught in such floods are very high. In recent times, flash flood caused large losses of life only of people unfamiliar with the potential hazard, such as tourists, which camp in the mountain canyons. Flash floods can be avoided by flood control reservoirs. However, this is usually an option only if can be combined with other purposes, such as hydropower generation, because the cost of the reservoir have to be compared with the potential benefits.

Floods in alluvial plains of large rivers are controlled by dikes and polders. Velocities are comparatively low, and the main danger to life is from the wide lateral extent of inundated areas, as has been experienced for example during the floods in Mozambique in February, 2000, in which a large part of Central Mozambique south of the Zambezi river was flooded. In the earliest days, people responded to such floods by moving the location of their cities and villages out of reach of the highest flood which they experienced, or of which they had clear indications, such as deposits on old river banks along the flood plain. Typical is the situation in the upper Rhine valley between Basel and Mannheim, where one finds the old villages and cities always on high ground or on the high bank of the old river flood plain. And if an extremely rare flood was experienced, which reached even higher, then people had no choice but to live with the flood damage. In other areas, people learned to live with frequent floods: for example, in Cologne the low lying parts of the city near the Rhine used to experience regular floods and they were prepared for it. Their method of protection is called today object protection: protection through local measures, such as building houses on high ground, perhaps on artificially generated hills, such as the farmers on the North Sea, by temporarily closing openings with sandbags or brick walls, or just by moving one´s belongings to a higher level of the house.

Population pressure and lack of other farmland made people to move into the flood plain, and to protect themselves by means of dikes: already the ancient Chinese started to build dikes along their large rivers to protect farmland and villages. The Herculean tasks of diking the Yangtse and the Yellow river, against floods of unimaginable magnitude, united the Chinese people into a nation in which no longer the individual was responsible for his own safety, but where flood protection became a national task. However, the protection by means of dikes cannot be perfect, as dikes can fail, and floods can occur which are larger than design floods. In recent times, the failure of the dikes caused some of the largest flood disasters in the world. The Oder river flood of 1998 (Bronstert et al. 1999, Grünewald, 1998) comes to mind, but even more striking are the floods of China, with the floods on the Yangtse a very illustrative example. Table 1 (from Wang & Plate, 2001) gives a summary of historical floods on the Yangtse river, which in 1998 experienced one of the largest floods of the twentieth century. Through a superhuman effort, the Chinese people were able to protect the vast area of the lower Yangtse flood plain from being flooded, and managed to reduce the number of casualties to the smallest number of any comparable floods in the twentieth century – in spite of a dramatic increase in population in the affected area.

Year	Discharge at Yichang Station (m³/sec)	Return period (years)	Inundated area (km²)	Grand levee breaches (No)	Death toll (persons)
1788	86,000	140	70 counties		10,000
1870	105,000	>200			30,000
1931	64,600	10	40,000	300	145,000
1935	56,900				142,000
1954	66,800	10	31,700	60	33,000
1998	63,300	8*	3,210	1	2292

Table 1: Major floods on the Yangtse river, with the highest ever observed flood in 1870. Modern hydrologic measurements started in 1877. The recurrence interval of the 1998 event in terms of maximum discharge is about 8. The Yangtse river experienced about 7 floods of approximately the same magnitude between 1896 and 1998, of which the last four in Table 1 are examples (adapted from Wang, 2000)

But the data of Table 1 also reveal one of the most fundamental features of rivers: in flood plains they are not stationary, but tend to shift their beds continuously. When the large rivers of the world leave their mountain confinement, they carry large amounts of sediment into the flood plain, and due to their lower velocity deposit the sediment on the plain. Without interference by man, the rivers build up alluvial fans: moving across a fan shaped area over which they spread their sediments – a rather complex process which only recently has found some theoretical discussion (Parker, 1997). This is in conflict with the demands of settlers, who want to have the state of nature to remain unchanged, so that property boundaries are maintained forever. In fact, a study by the University of Bern (Hofer & Messerli et al., 1998) of the effects of river floods in the delta of the Brahmaputra and Ganges rivers in Bangladesh showed that people were less concerned with the appearances of river floods, which they had learned to live with, but with the shifting of the river banks during floods, which destroyed land on one side of the river and built up land without owner on the other.

The effort of keeping the large rivers of China within the boundaries set by the dikes is an extreme case of man fighting the rivers, rather than to live with them. For by confining the river between dikes, one also confined the area on which sediment could be deposited, and a gradual increase of the river bed between the dikes is unavoidable. This is illustrated by the fact that the Yangtse flood of 1998 was a flood with a recurrence interval of only 8 years. Yet in terms of stages in the middle reach between the cities of Yichang and Wuhan it was higher than the stage observed in 1954, and in many places the highest stage ever recorded. Tulla in his works on the upper Rhine knew the sedimentation problem of the alluvial Rhine, and he found an at least temporary solution by straightening the river: this increased the erosive capacity, and in essence moved the sediment problem downriver: since the sediment was not deposited in the upper Rhine, it had to be deposited further downstream. Fortunately, the Rhine is a small stream by comparison with the large rivers of Asia, and the sediment problem proved to be manageable. The situation in China is different: against the floods of the large rivers, in particular the Yellow river, the Chinese won many battles, but they had to suffer many setbacks when the rivers breached their dikes and in extreme cases found a new bed by destroying all settlements in its new course.

The case of the Yangtse river is not only the story of a fight against nature of epic proportions, it also is an illustration of the development of the technology of defenses against floods. Protection of the vast fertile lands of East Central China against earliest floods was sought through dikes, and when these proved ineffective, the dike system was supplemented by polders, into which water was to be stored when the flood stage exceeded critical levels. But the relentless growth of the population forced people to move into the polders: today, the polders are inhabited by many thousands of people, and during the 1998 flood, the largest flood diversion basin – the Jingjiang Polder with a surface area of 920 km² and storage capacity of 6 billion m³, which had been the main reason for the reduced number of losses in 1954 as compared to earlier floods of similar magnitude - was not flooded because of the opposition of the people living in the polder.

The different examples of adjustment to floods serve very well to illustrate that modern options for flood management are not absolute, but depend on three variable factors: the available technology, the availability of financial resources, and the perception of the urgency of the protection, which is embedded into the value system of a society. As these factors change with time, the options which one has to consider also change, and new paradigms of thinking may require new solutions to old problems. When one looks at the time development of a protection system – not only against floods, but also against all kinds of other hazards – it is evident that this is a circular process, as indicated schematically in Fig.2. A state of a system may be considered satisfactory at a certain time, meeting both the demands on the river as a resource and for protection against floods. But new developments take place, leading to new demands on the river. Side effects occur, which impair the function of the system and which have not been anticipated. After some time, the system is considered inadequate, and people demand action to change the existing conditions.

In this circular process, the determining factor of technology is self evident. When J.G.Tulla planned his momentous correction of the Rhine river between Basel and Mannheim, he was planning a task for at least two generations, with people who would be ordered to work on the river with shovels and wheelbarrows to create the long lines of dikes along the river. In modern times, such a task would be finished in a few years, with only a few professionals, such as drivers of caterpillars and other large earth moving equipment, with modern geotechnical engineering skills guaranteeing long lasting earth dikes. Furthermore, the scientific basis for planning changes with the advance in scientific knowledge and the translation from science into engineering. Remedial measures have to be planned according to the new state of the art. Hydrologic inputs have changed, or better methods of calculation require a new evaluation of the flood potential (or the hazards).

Fig.2: The cycle of responses to changing value systems and changing environmental conditions for water management.

When we look for further technological development in flood control, many new possibilities have become available through modern communication technology. Of great significance is the development of modern forecasting and early warning systems. The possibilities of remote sensing are just being recognized, and the technology for converting forecasts from mathematical models of meteorological weather situations into warning systems is being explored at many locations. Indeed, great strides have been made in forecasting and warning for large rivers, with fairly long lead times between forecast and actual occurrence (see i.e. Wilke, 1997), and hydrodynamic models are available which can rapidly convert meteorological precipitation forecasts into flood forecasts (Moore & Jones, 1997, Goeppert et al. 1998), whereas for forecasting flash floods, which requires to localize usually randomly occurring convective storms, the success has not yet been high (see i.e. Quiby and Schubiger ,1998, for an example of forecasting in the Alps). However, forecasting and warning is only one aspect of the possibilities of communication technology – it also permit the dynsamic operation of flood control systems. A reservoir for flood control can be controlled on the basis of forecasting results to provide maximum protection by chopping off the peak of the flood wave, or a series of barrages, such as on the Rhine river, can be operated through remote control to provide maximum storage in the system of barrages.

There also is the human influence on the system. The catchment may have changed: a rural area which was heavily wooded some years back is now cleared for agriculture, a patch of land used for agricultural purposes is converted into urban parking lots, agricultural heavy machinery compacts the soil and changes the runoff characteristic of a rural area. Today as always, a further important criterion is the availability of funds, i.e. the financial resources which can be allocated to flood protection; resources which usually have to come from public funds and are in competition with other needs of society.

But finances are not the only issue. Decisions for flood protection also depend on the changing value system of the society, starting with the solidarity of the non – flood endangered citizens of a country with those endangered by floods. For example, in the not so distant past the infringement on the natural environment by engineered river works usually has been accepted as the price to pay for the safety from floods. However, in recent times flood protection by technical means faces serious opposition, not so much because of concern about the long range geomorphic adjustment of the river (which is bound to occur sooner or later), but generated more directly from the fact that dikes and land development cut off the natural interaction of river and riparian border. The reduction of wetlands and the impairment of riparian border fauna and flora in many – particular in the developed – countries causes great concern of environmentalists and has led to a backlash against flood protection by dikes and reservoirs. For example in some parts of Germany people are actually talking about removing some of the existing flood protection works, and moving the dikes further away from the river is a technical approach favored by many. In other countries, complete removal of existing dams has been talked about as a means of giving back to nature what used to be hers, (but also because some people find the failure risk of a dam unacceptable). Pristine nature is assumed to have a right of its own that needs enforcement, in order to reduce the steady decline of rare species, and recreate habitats for wild life, which in the past were given up in favor of human development.

The recognition that the adjustment process is open ended - is a transient only in the stream of development - is part of the principle of sustainable development: while revising or constructing a flood protection system to meet our needs, this principle requires us to remember, that future generations may have other needs and other knowledge, and that we should not cast our solutions into immutable solidity, such as producing irremovable gigantic concrete structures, or permanently degraded soils. For a discussion of issues involving sustainable water resources management on the basis of the original Brundtland report (WCED 1987) see Jordaan et al.(1993) and Loucks et al. (1998)

Planning a flood protection system

Development of a flood protection system traditionally is a sectoral task, and in many countries of the world flood management is still seen as a task which has to be solved in a regional or a sectoral context. Regional: Agricultural areas are protected or not protected according to agricultural needs, flood control of a city is done without regard to the surrounding country side. Sectoral: highway planning takes little cognizance of the needs for flood protection. Roads can have a significant effect on floods. In rural areas of Germany, the tendency is to pave the roads used by farm vehicles, without due regard to the fact that the roads act as channels for rainwater. Or the roads can act in the opposite way by inhibiting runoff. For example, in the Mekong delta highways have been built on dams to keep them operational when one of the frequent floods occurs. However, the design has not given sufficient regard to the need of draining the water off after the flood, and the dams act like retention structures.

When we look at flood protection from the point of view of a modern decision maker, developing a new project starts with a set of guide lines which are based on the value system of the present society. In this setting, and in countries like Switzerland or Germany, environmental protection and flood management are tasks of similar importance, and the optimum flood control system is a compromise between these two conflicting objectives. To illustrate this process, the case of integrated planning for flood safety and a healthy environment as part of a sustainable project is shown schematically in Fig.3 (adapted from A.Götz, Swiss Institute for Water Resources. Personal communication).

Fig.3: Integrated project planning for considering flood safety and ecology as complementary objectives (adapted from A.Götz, oral communication, 1999)

The societal goal of sustainable development is converted into a set of objectives: objectives for the safety, and objectives for the preservation of natural functions. If an analysis of the existing situation is showing that the existing conditions meet the objectives, then the only action required is to keep it that way, i.e. to maintain the conditions and to prevent intrusion of external demands that could alter the situation to the negative. For example, to prevent settlement of a flood plain, it might be necessary to set up legal barriers. If the existing situation does not meet the objective, a process has to be initiated for improving the situation.

The next stage is the decision process for finding the best alternate which meets the objectives of the design. There are many cases when it is impossible to meet all requirements, in particular when constraints are set, which might be financial, social, or political. Then it is necessary to change the objectives, to make them to conform more to reality. In this manner, many well meaning nature preservation objectives had to be overruled, or protection objectives had to be set aside. Finally, the alternative selected is implemented, and the project is completed.

The response to the reassessment of the flood danger is the phase of project planning for an improved flood disaster mitigation system. Experts involved in risk management have to ensure that the best existing methods are used to mitigate the damages from floods: starting with a clear understanding of the causes of a potential disaster, which includes both the natural hazard of a flood, and the vulnerability of the elements at risk, which are people and their properties. The project planning aspect of risk management is summarized in Fig.4., which basically consists of the two parts: risk assessment, which yields the basis for decisions on which solution to use, and the implementation phase, which involves a great deal of activity ranging from the fundamental decision to go ahead to the complex of detailed design and construction. When this is accomplished, the flood management process reverts to the operation mode described in the first part of the paper.

Fig.4: Project planning as part of risk management

Hazard maps, as used for operational risk management are also the foundation on which decisions for disaster mitigation are to be made. Risk assessment does, however, not stop at evaluating the existing risk, i.e. with the analysis of the risk. The risk analysis process has to be repeated for each of the structural or non-structural alternatives for mitigating flood damage. Good technical solutions integrate protection of rural and urban areas, through coordinated urban storm drainage projects, stream regulation in rural and municipal areas with bridges and culverts designed to pass more than the design flood. Structures including reservoirs and dikes are usual technical options, but other possibilities adapted to the local situation also exist, such as bypass canals and polders on rivers. Risk assessment, for example, also includes to investigate the option to do nothing technical but to be prepared for the flood if it strikes: i.e. to live with the situation as is and be prepared for the floods.

It is obvious that the process of evaluating the risk depends on the technical or non-technical solution contemplated, and therefor, the risk mitigation step is not an independent third step in series with the second, but it interacts and the two are interdependent: the technical or non-technical solution is evaluated, the new hazards determined and the decision basis is enlarged by this analysis.

The decision for which of the possible alternatives to use depends on a number of factors, among which the optimum solution in the sense of operations research is one important factor. The classical approach for optimizing a cost function can easily be extended, at least formally (Plate, 2000) to the case of flood protection systems. But there might be other compelling reasons for deciding on a particular alternative, even if it is not cost effective for flood protection. One of these reasons might be the expected loss of human lives. Without question, the foremost purpose for flood protection must be the saving of lives, and cost effectiveness can only be of secondary concern.

Conclusions

A framework was given for classifying the different processes of flood management. It was found useful to distinguish three levels within flood risk management: the project operation level, the project design level, and the level of engineering decision making involving estimating the risk in the setting of a cost benefit analysis. The risk management process for the operation has been described extensively in previous papers – for example in Plate, (1997). Details therefore have been omitted – as have details of the structures design level, on which the writer has published a number of comprehensive papers. It was an interesting exercise to identify the different processes which contribute to the three different levels, and it was particular important to identify the changing conditions under which flood protection has been approached during different times. It was concluded that the natural environment is always changing, due to natural processes such as geomorphological modifications of a flood plain, or due to human interference, such as using the flood plain for agricultural purposes and cutting the flood plain into different regions by building dikes. Under such conditions, sustainable development is difficult to achieve, and the efforts which the Chinese population is making for preventing the large rivers of China to behave like natural rivers are cited as examples of non-sustainable development, which implies that the fight against the huge floods of the Yangtse and Yellow River will never be completely won, and also the less dramatic changes of smaller rivers like the Rhine need to be constantly observed and solutions for flood control adjusted to the changing conditions.

Acknowledgement

The paper is a modified version of a paper presented by the first author for theEuropean Conference on Advances in Flood Research, Potsdam, November 1 – 3,2000.

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SUSTAINABLE GROUNDWATER MANAGEMENT

Wolfgang Kinzelbach

Institute for Hydromechanics and Water Resources Management, ETH,

Zürich, Switzerland

Contents

w Global ground water situation

w What does sustainable mean in terms of groundwater?

w Tools for recharge determination

w Models and uncertainty

w Interfacing to economics

w Conclusions

Global water availability

w Accessible runoff 13000 km³/a

w Human withdrawals 4000 km³/a

w Human in stream use 3000 km³/a

w Groundwater available 2500 km³/a

w Groundwater used 800 km³/a

w Depletion of groundwater reservoirs 100 km³/a

Averaging is misleading

Stored Volume vs. Renewal Rate of fresh water resources

Surface water (lakes and rivers):

w Volume 104,000 km³

w Renewal rate 30,000 km³/a

Groundwater:

w Volume 10,000,000 km³

w Renewal rate 3,000 km³/a

Structure of Water Use

w Agriculture 69% (90% consumptive)

w Industry 23% (20% consumptive)

w Domestic 8% (20% consumptive)

Groundwater is special…

w Groundwater use is much smaller than surface water use, but

w Groundwater is a strategic resource for drinking water in the arid and semi-arid world

w Groundwater is practically the only resource available year round

w Sustainability problems are most severe in groundwater both in the context of quantity and quality

w The feasibility of increasing the resource is low

SUSTAINABILITY CONSTRAINTS

w Abstraction < Recharge

w Limitation of drawdowns (vegetation, subsidence, collapse of fractures)

w Prevention of saltwater intrusion/upconing

w Prevention of soil salinization, salt backflow

w Guarantee of minimum downstream flow (wetlands, vegetation, users)

w Prevention of groundwater pollution

GENERAL PRINCIPLE

w Withdrawal (Consumptive use) < Recharge (from precipitation and surface water infiltration)

w Considering the downstream: Withdrawal < Recharge–Minimum downstream requirements

Main Cause for Water Table Decline:

Large Scale Irrigation with Groundwater, Examples:

w Ogallalla Aquifer, USA

w North China Plain

w Karoo Aquifers, South Africa

w Aquifers of the Arab Penninsula

w Chad Basin aquifer

w Northern Sahara Aquifer System (SASS)

Typical decline rates 1 to 3 m/a

SALTWATER UP CONING

SALINIZATION DUE TO HIGH GROUNDWATER TABLE