Two volumes, Publs 280 & 281, resulted from the International Symposium on: Water Resources Systems—Global Change, Risk Assessment and Water Management held during IUGG 2003 (Sapporo, Japan). The provision of adequate water supply is of fundamental importance to social and economic security worldwide. In many regions, the awareness of the wider community of the importance of water resources management has increased dramatically over the past few years. It has become clear that, in order to sustainably balance supply and demand of natural resources, the integration of a range of disciplines from a comprehensive systems perspective is essen- tial and this certainly applies to water. The call for contributions to this symposium was so suc- cessful that it was expanded and so the selected papers were divided, according to topic, be- tween two books, IAHS publications 280 and 281. Water Resources Systems– Water Availability and Global Change edited by Stewart Franks, Günter Blöschl, Michio Kumagai, Katumi Musiake & Dan Rosbjerg Publ. 280 (2003) ISBN 1-901502-27-9; 322 + xiv pp. Price £54.90 As greater demands are placed upon limited water resources, it becomes increasingly important to safeguard water resource systems from encroaching pollution, over- exploitation, the vagaries of natural climate variability, and the threat of anthropogenic climate change. Continued population growth over the coming decades can only exacerbate the existing global water crisis. This volume compiles a representative sample of the range of activities currently engaging the international hydrological science community, focusing on: © Hokkaido Shimbun Press – Water resources assessment case studies and methodologies, – Observations of hydrological change, – Coupled climate–land surface modelling approaches, – Water quality threats to water resources, and – Modelling approaches to water resource assessment. Contents

Preface by Stewart Franks, Günter Blöschl, Michio Kumagai, Katumi Musiake, v Dan Rosbjerg

1 Water Resources Assessment: Case Studies and Methodologies

Small hydrological basins in delta regions, past and future (climatic) changes, the 3 Mark–Vliet basin Victor Jan Witter Water problems and sustainability in North China Xia Jun, Heung Wong & 12 Wai Cheung Ip Utilization of water resources and its effects on the hydrological environment of 23 the Tarim River basin in Xinjiang, China Changyuan Tang, Shizuo Shindo, Yas- uo Sakura & Xin Li Water resources in Bulgaria under climate variability and change Ves- 30 selin Alexandrov & Marin Genev Implications of climatic variability and climate change on water resources avail- 37 ability and water resources management in West Africa Oyediran Ojo, Feyi Oni & O. Ogunkunle Structure of ecological indicators and indices for sustainable groundwater devel- 48 opment Anna P. Belousova Assessment of the vulnerability of water resource systems in China with the run- 54 off sensitivity factor Lihua Xiong & Shenglian Guo

2 Observations of Hydrological Change

Impacts of global warming on large lakes Michio Kumagai, Kanako Ishikawa & 65 Naoko Ishiguro Analysis of water resources in the Yellow River basin in the last century 70 Dawen Yang, Chong Li, Katumi Musiake & Tetsuya Kusuda Patterns of runoff change in Bulgaria Marin Genev 79 Long-term variations in runoff and temperature in Sweden Göran Lindström & 86 Sten Bergström The impacts of human activity on hydrological processes in the arid zones of the 93 Hexi Corridor, northwest China, in the past 50 years Wang Genxu, Cheng Guodong & Du Mingyuan Recent variability of the climate and glaciers in China’s monsoon region 104 He Yuanqing, Zhang Zhonglin, Wilfred H. Theakstone, Chen Tuo, Yao Tandong, David D. Zhang & Pang Hongxi

3 Coupled Climate–Land Surface Modelling Approaches

Utilisation de modèles hydrologiques pour évaluer les ressources en eau de 117 surface et leur évolution spatio-temporelle—application à l’Afrique de l’Ouest Jean-Emmanuel Paturel, Mahaman Ouedraogo, Gil Mahé, Eric Servat & Alain Dezetter Global water resources assessment under climatic change in 2050 using TRIP 124 Taikan Oki, Yasushi Agata, Shinjiro Kanae, Takao Saruhashi & Katumi Musiake Prediction of hydrological extremes by air circulation indices 134 Joanna Pociask-Karteczka, Zenon Nieckarz & Danuta Limanówka Comparison of flow forecasts by runoff models: a case study from southern 142 Brazil Carlos E. M. Tucci, Pedro Dias, Robin Clarke, Walter Collischonn & Gilvan Sampaio Investigation of feedback mechanisms between soil moisture, land use and 149 precipitation in West Africa Harald Kunstmann & Gerlinde Jung The effect of downscaling techniques on assessing water resources impacts from 160 climate change scenarios Johan Andréasson, Sten Bergström, Bengt Carlsson & L. Phil Graham Generation of rainfall scenarios using daily patterns of change from GCMs 165 Timothy I. Harrold & Roger N. Jones

4 Water Quality Threats to Water Resources

A step in the right direction: towards integrated natural resource management in 175 Sarawak, Malaysia Tina Svan Hansen Groundwater pollution vulnerability and groundwater protection strategy for the 184 Owerri area, southeastern Nigeria K. M. Ibe Sr, G. I. Nwankwor & S. O. Onyekuru Modelling nitrogen dynamics in an agricultural-forested catchment Baolin Su, 195 So Kazama, Minjiao Lu & Masaki Sawamoto Assessment of groundwater quality and climatic water balance studies in the 205 Pageru River basin, Andhra Pradesh, India P. D. Sreedevi & Shakeel Ahmed Effect of irrigation on groundwater chemistry in the lower Chambal Command 213 area, Madhya Pradesh, India L. P. Chourasia Cumulative environmental change in the lower Niger Shakirudeen Odunuga, 221 Olufemi Tejuoso & Fasona Mayowa The origin of water salinity on the Annaba coast (NE Algeria) L. Djabri, 229 R. Laouar, A. Hani, J. Mania & J. Mudry

5 Modelling Approaches to Water Resource Assessment

Identifying human induced pressures and their impact on water resources—the 239 assessment of hydrological quality in river basins Michael Eisele, Andreas Steinbrich & Christian Leibundgut Estimating land cover changes and associated environmental impacts on 247 wetlands by coupling remote sensing and hydrological modelling Zacharias Ierotheos, E. Dimitriou & Th. Koussouris Streamflow generation using a multivariate hybrid time series model 255 Seung Yup Rieu, Young-Oh Kim & Dong Ryul Lee Radial basis function network for prediction of hydrological time series 260 A. W. Jayawardena, Pengcheng Xu & W. K. Li Long-term estimation of evapotranspiration from a tropical rain forest in 267 Peninsular Malaysia Makoto Tani, Abdul Rahim Nik, Yukio Yasuda, Shoji Noguchi, Siti Aisah Shamsuddin, Mohd Md Sahat & Satoru Takanashi Evaporation of intercepted precipitation in unlogged and logged forest areas of 275 central Kalimantan, Indonesia Chay Asdak Estimating the snow distribution in a subalpine region using a distributed 282 snowmelt model Kentaro Matsui & Takeshi Ohta The influence of snow depth on the variation of vegetation activity and 292 evapotranspiration Yoshihiro Asaoka, So Kazama & Masaki Sawamoto Some problems in regionalization of watersheds A. Ramachandra Rao & 301 V. V. Srinivas Effect of snow interception on the energy balance above deciduous and 309 coniferous forests during a snowy winter Kazuyoshi Suzuki, Yuichiro Nakai, Takeshi Ohta, Tsutomu Nakamura & Tetsuo Ohata

Key word index 319 Preface

The provision of adequate water supply is of fundamental importance to social and economic security worldwide. As greater demands are placed upon limited water resources, it becomes increasingly important to safeguard water resource systems from encroaching pollution, over-exploitation, the vagaries of natural climate variability and the threat of anthropogenic climate change. The challenges of water security are felt most acutely in the less developed countries, where it is estimated that 1.2 billion people lack access to safe drinking water and 4 million children are lost to water-borne diseases each year. Continued population growth over the coming decades can only exacerbate the existing global water crisis, so readily apparent in many parts of the world. The task of addressing this water crisis can only be achieved through a true consensus for action at every level of society. In this light, the hydrological sciences will have a key role to play in providing deeper insight into the sustainability and suitable management of water resource systems.

During the 2003 General Assembly of the International Union of Geodesy and Geophysics, 30 June–11 July 2003 in Sapporo, Japan, a symposium was held entitled “Water Resources Systems—Global Change, Risk Assessment and Water Management”. The symposium was organized by the International Association of Hydrological Sciences (IAHS) through a number of its constituent commissions. The response to the initial call for papers was so great that the proceedings of this symposium have been compiled into two volumes, the first relating to water availability and change (this volume), whilst the second volume focuses on hydrological risk and water management (IAHS Publication no. 281*).

The present volume contains 37 papers from the international hydrological community, reflecting a range of issues being faced in many different regions of the world. The diversity of the problems faced and their potential solution is well demonstrated through the range of contributions. They are arranged in a series of sections:

Section 1 – Water Resources Assessment: Case Studies and Methodologies, Section 2 – Observations of Hydrological Change, Section 3 – Coupled Climate–Land Surface Modelling Approaches, Section 4 – Water Quality Threats to Water Resources, and Section 5 – Modelling Approaches to Water Resource Assessment.

Whilst we cannot hope to provide definitive methodological approaches to each and every water resource issue faced across the globe, this volume compiles a representative sample of the range of activities currently engaging the international hydrological science community. It is through this sharing of experience and insight that we hope that lessons may be drawn from which the current and future problems of water security may be mitigated or avoided.

Editor in chief: Stewart Franks University of Newcastle, Australia

Co-editors: Günter Blöschl Vienna University of Technology, Austria Michio Kumagai Lake Biwa Research Institute, Uchidehama Otsu, Japan Katumi Musiake University of Tokyo, Japan Dan Rosbjerg Technical University of Denmark, Lyngby, Denmark

*Available from IAHS Press: Water Resources Systems–—Hydrological Risk, Management and Development, edited by Günter Blöschl, Stewart Franks, Michio Kumagai, Katumi Musiake & Dan Rosbjerg. IAHS Publ. no. 281. ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 3–11. Small hydrological basins in delta regions, past and future (climatic) changes, the Mark–Vliet basin

VICTOR JAN WITTER Water authority “Hoogheemraadschap van West-Brabant” PO Box 2212, NL-4800 CE Breda, The Netherlands [email protected]

Abstract The paper gives an overview of past and provisioned changes in climate, land use, and measures affecting the hydrology of the Dutch/Belgian basin of the Mark and the Vliet rivers. This is a small hydrological basin (~1400 km2) situated in the delta of the rivers Rhine, Meuse and Scheldt. The basin is of recent origin. The period of study starts about the year 1820, when sluices were built at the outlets of the rivers draining the basin, and extends to the year 2050. The changes are analysed with respect to their effect on drainage and water supply. Key factors in hydrological change are identified: land use, drainage basis and layout and resistance of the open water system. Changes are analysed with respect to water levels and discharges during mean conditions as well as high flood and low flood conditions. The paper demonstrates: (a) the profound changes that took place in the hydrology of small basins like the Mark–Vliet basin, changes that in large river basins are flattened out; (b) the magnitude of future changes in the region’s hydrology due to autonomous developments and due to the effects of climatic change; and (c) that the magnitude of future changes considerably exceeds that of changes in the past. The results for the Mark–Vliet basin are generalized to small hydrological basins in delta regions. It is argued that these basins are particularly vulnerable to climatic change. Key words climatic change; delta regions; droughts; floods; hydrological change; water management

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Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 12–22. Water problems and sustainability in North China

XIA JUN Institute of Geographical Science & Natural Resources, Chinese Academy of Science, 100101 Beijing, China, and Wuhan University, 430072 Wuhan, China [email protected]

HEUNG WONG, WAI CHEUNG IP Department of Applied Mathematics, Polytechnic University, Hong Kong, China

Abstract The problems of water shortage and related eco-environmental issues in North China have become the most significant issue to impact sustainable development in this very important region that is the political, cultural and economic centre of China. This paper addresses these emergent issues using the case study of the Haihe River basin in North China. The new developments in international water study and the background causing these problems, natural change and particular human activities, are analysed. Key points are addressed as four aspects: (a) study of the water cycle process as impacted by climate change and high intensity human activity, focusing on the influence of climate change on continued drought in the region, and human activity; (b) water utilization in relation to new economic changes, such as water saving models; (c) study of ecohydrology, and interaction of water and ecology impacted by climate change and human activity; and (d) reasonable water allocation, including water diversion from south to north, and water saving issues in local areas. Several suggestions for both study of the water cycle, which is a very important base for water security in North China, and applied studies of water resources and eco-environmental rehabilitation, are proposed. These key issues will benefit both water science and sustainable development in China. Key words environmental change; North China; sustainability; water security ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 23–29. Utilization of water resources and its effects on the hydrological environment of the Tarim River basin in Xinjiang, China

CHANGYUAN TANG, SHIZUO SHINDO, YASUO SAKURA Graduate School of Science and Technology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan [email protected])

XIN LI Suzhou College for Urban Construction and Environmental Protection, Suzhou, China

Abstract This paper describes the characteristics of water resources utilization in the Tarim River basin in terms of both its quality and quantity. It is found that the water cycle and water qualities have changed greatly because of human activities in the last 50 years. Many canals have been built to transfer almost all stream waters for irrigation and farmland desalinization. 2+ – As a result, about 37% of stream waters were Ca HCO3 type and more than 40% were either + – + 2– Na Cl type or Na SO4 type. The former can be found in natural hydrological conditions, while the latter was affected by agriculture activities. The relationships between water use, desertification and salinization are discussed, based on the water table, soil water content and evaporation in the study region. When the groundwater table is 4 m below the surface, evapo- ration almost stops. Soil moisture will decrease without supply by groundwater. It is therefore possible to cause desertification when the groundwater table is deeper than 4 m in the Tarim basin. Therefore, water resources issues concerning desertification and salinity must be dealt with at the same time with respect to water and mass balances. Key words China; desertification; ecology; salinization; Tarim River; utilization of water; water resource management

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Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 30–36. Water resources in Bulgaria under climate variability and change

VESSELIN ALEXANDROV & MARIN GENEV National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, 66 Tsharigradsko Chaussee, 1784 Sofia, Bulgaria [email protected]

Abstract Variability of air temperature, precipitation and river runoff during the twentieth century in Bulgaria was investigated. Possible scenarios for air temperature, precipitation and annual runoff in the country were created. According to GCMs (Global Circulation Models) air temperature is expected to increase by between 3 and 5°C before the end of the twenty- first century. Precipitation is expected to increase during the winter and to decrease during the warm half-year. The total precipitation amount during the actual crop-growing season is projected to decrease due to the GCM simulated decrease of precipitation and because of shortening of the actual crop-growing season. The Decision Support System for Agrotechnology Transfer (DSSAT) was used to simulate the impact of climate variability and climate change scenarios on the parameters of the soil water balance during the maize growing season. Adaptation strategies and options in respect to water resources including irrigation under climate change are also considered. Key words Bulgaria; climate variability and change; Decision Support System for Agrotechnology Transfer (DSSAT); maize; river runoff; soil water balance ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p.37–47. Implications of climatic variability and climate change on water resources availability and water resources management in West Africa

OYEDIRAN OJO, FEYI ONI & O. OGUNKUNLE Department of Geography, University of Lagos, Lagos, Nigeria

Abstract This paper discusses the implications of climatic variability and change for water resources systems in West Africa, with particular reference to hydrological systems, water resources availability, and water resources management. The paper in particular discusses issues related to rainfall trends, seasonal variations in river flows, mean annual trends in river flows and discharges, and local variations and extremes of river discharges. The paper also discusses the climate change implications for groundwater variations, water resources availability and climatic events (including droughts and floods). The results show that a lot of spatial and temporal variations occur regionally and locally, but in general there have been downward trends in rainfall and increases in water deficits and drought events. The paper then discusses the response strategies needed to adapt to the climate change impacts on water resources, and emphasizes the need for both water supply-demand adaptations, details of which are discussed in the paper. The paper finally discusses the mechanisms needed for the implementation of the adaptation measures. Such mechanisms include: (a) building capacity and manpower development of water institutions in the region for producing hydrological and hydroclimatological data; (b) public participation and the involvement of stakeholders; (c) the establishment of both national and regional cooperation; and (d) the need for climate and other environmental data collection and monitoring. Key words adaptation measures; climate change; climatic variability; rainfall; water resources ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 48–53. Structure of ecological indicators and indices for sustainable groundwater development

ANNA P. BELOUSOVA Water Problems Institute, Russian Academy of Sciences, 3 Gubkina Str., 117735 Moscow, Russia [email protected]

Abstract A system of indicators and indices of groundwater quality sustainability is described. A system of indicators (Pressure–State–Response) worked out by the European Organization for Economic Co-operation and Development was taken as a basis, but was widened due to addition of a new indicator of foresight and also by subdividing all the indicators according to the time of their manifestation (present/future). The response indicator has a more complex structure; it indicates the level of accepted decisions (international, national, regional) and rate of response (planning, operational, proposed). Classification of groundwater sustainability indices has been worked out for authropogenic conditions. These indices characterizing indicators of Pressure and State are subdivided into the following groups: indices of damage, indices of pollution (chemical indices), static indices (hydrogeochemical indices), dynamic indices and indices of interaction. The use of these indicators and indices when assessing and compiling maps of groundwater sustainability has an advantage over other methods due to its representation of complexity and the fact that it is also a stage in a general structure of assessing sustainable development in the studied regions. Key words groundwater; indicators; indices; sustainable development ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 54–62.

Assessment of the vulnerability of water resource systems in China with the runoff sensitivity factor

LIHUA XIONG & SHENGLIAN GUO Department of Hydrology and Water Resources, Wuhan University, Wuhan 430072, China [email protected]; [email protected]

Abstract Based on the relationship of watershed long-term runoff change rate with both long- term precipitation and potential evaporation rates of change, the expressions for the sensitivity factor of watershed runoff to climate change were derived for the watersheds in China. By using information on average annual precipitation, potential evaporation, discharge and land surface properties of the watershed, the sensitivity factors of runoff to precipitation for the nine major hydrological regions and 82 hydrological sub-regions of China were calculated. It was found that the sensitivity factor of runoff to precipitation in the humid watersheds such as southwest China was much smaller than that in the arid regions such as the Yellow River region. Based on these sensitivity factors, the vulnerabilities of water resources systems of all regions in China were assessed and the results were very consistent with what people have recognized in reality. Key words climate change; runoff; sensitivity factor; vulnerability; water resources system ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 65–69. Impacts of global warming on large lakes

MICHIO KUMAGAI Lake Biwa Research Institute, 1-10 Uchidehama, Otsu 520-0806, Japan [email protected]

KANAKO ISHIKAWA Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan

NAOKO ISHIGURO Department of Geography, Limoges University, F-87038 Limoges, France

Abstract Global warming is now having serious impacts on large lakes (100– 1000 km2 in area). Large lakes are not as sensitive as small lakes (<100 km2), however, they are more reactive than lakes with surface areas >1000 km2. We have been studying large lakes of the world and found that some of these are facing a very serious situation. Lake Geneva, between Switzerland and France, has lost almost all oxygen from the hypolimnion over the last two decades. Lake Fuxian in Yunnan Province, China, is also suffering from deoxygenation. Lake Biwa, the largest lake in Japan, appears unaffected to the casual observer, but actually the benthic ecosystem and water quality are deteriorating due to oxygen depletion year by year. We found that the oxygen depletion and benthic ecosystem changes of these lakes are due to insufficient overturning, a result of global warming rather than increases of organic matter related to eutrophication. Key words ecosystem; global warming; hypolimnion; Lake Biwa; Lake Fuxian; Lake Geneva; organic matter; overturning; oxygen depletion ______Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 70–78. Analysis of water resources in the Yellow River basin in the last century

DAWEN YANG Department of Civil Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan [email protected]

CHONG LI Japan Science and Technology Corporation (JST), Tokyo, Japan

KATUMI MUSIAKE Institute of Industrial Science, University of Tokyo, Tokyo, Japan TETSUYA KUSUDA Graduate School of Engineering, Kyushu University, Fukuoka, Japan

Abstract A statistical analysis on the precipitation and river discharge was carried out to explore annual and seasonal changes of water resources in the Yellow River basin in the last century. Together with a distributed hydrological model, this research examined the reason for river dry-up along the lower reaches of the Yellow River. In the upper basin up to the Lanzhou station, it was found that the observed runoff decreased by 23% from the 1950s to the 1990s; climate change contributed about 20% of this decrease, taking into account artificial water use. It was known that the river flow in the lower reaches downstream of the Huayuankou gauge during the dry season, was mainly supplied by the runoff generated from the upper basin above the Lanzhou gauge. The river dry-ups along the lower reaches were caused by both climate change and artificial water use. Key words hydrological analysis; hydrological modelling; river dry-up; Yellow River basin ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 79–85. Patterns of runoff change in Bulgaria

MARIN GENEV National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, Tsharigradsko Chaussee 66, 1784 Sofia, Bulgaria [email protected]

Abstract Variations in temperature, precipitation and runoff complex over the territory of Bulgaria are considered. The analysis is made on the basis of a sufficiently large number of stations broadly distributed across the country. Basic structures such as phases, cycles and long-term tendencies of the variations are found. A positive phase in temperature variations, as well as a negative phase in precipitation and runoff, are estimated after 1981. The degree of the changes in the different years is determined by their percentage deviation towards the norm for the period 1961–1990. The numbers of years of appearance in the temperature, precipitation and runoff variations are also determined. Key words Bulgaria; cycles; phases; precipitation and runoff variations; probabilistic processes; temperature ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 86–92. Long-term variations in runoff and temperature in Sweden GÖRAN LINDSTRÖM & STEN BERGSTRÖM Swedish Meteorological and Hydrological Institute, SE-601 76 Norrköping, Sweden [email protected]

Abstract The objective of this paper is to study long-term variations in runoff and flood frequency in Sweden. Runoff over the 20th century increased by about 4% on average, but the trend was not statistically significant. The runoff during 1981–2000 was about 8% above the century average, but runoff in the 1920s was also as high. Records from the 19th century indicate that runoff was higher then, but temperatures were lower. The combination of high temperatures and high runoff in recent years is quite different from earlier records. The increase in the average level of annual floods in northern Sweden was larger, about +10%, but problems with the reliability of older data made it difficult to conclude that the change is in fact significant. The average increase at a selection of the most reliable stations was considerably smaller. Key words floods; peaks; runoff; Sweden; temperature; trends ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 93–103. The impacts of human activity on hydrological processes in the arid zones of the Hexi Corridor, northwest China, in the past 50 years

WANG GENXU1, CHENG GUODONG1 & DU MINGYUAN2 1 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, and College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China [email protected] 2 National Institute for Agro-Environmental Sciences, Tsukuba, Japan

Abstract The Hexi Corridor, like other arid zones in northwest China, is characterized by alternating high mountains and plains. The mountain areas have abundant precipitation and glaciers that provide surface water flow to the plains and form numerous inland river systems. The hydrological regimes of the groundwater and springs, to a large extent, depend on the surface runoff. The regional hydrology and ecosystems of the Hexi Corridor region have changed over the last half century under the driving force of intense human activity. This paper aims to show the characteristics of hydrological changes resulting from human activities in the last 50 years from several points of view, such as: surface runoff changes at the mountain front and in the lower reaches of streams, both annual and inter-annual, the changes of the groundwater table and spring water volume, and temporal and spatial hydro- chemical regimes. Streamflow issuing from mountains in the eastern section of the Corridor by way of the Shiyang River has decreased significantly. Annual mountain outflow from the Heihe and Shule rivers in the central and western portions of the Corridor, respectively, have tended to increase. However, river discharge in the lower reaches is decreasing, terminal lakes are contracting or drying up and water quality is getting worse due to expanding large-scale exploitation of water resources. Many small rivers disappear soon after flowing from mountain valleys, river courses are shortening, the spring water volume is continually reducing, and the groundwater table is falling in most parts of the middle and lower reaches. These hydrological changes exacerbate the water supply–demand paradox, and result in serious environmental problems. Understanding the characteristics of hydrological processes and regime change is important for driving the solutions to rational use of the limited water resources and the limiting of environmental degradation in the northwest China. Key words Hexi Corridor, northwest China; human impact; hydrological change; hydrological processes; water exploitation ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 104–114. Recent variability of the climate and glaciers in China’s monsoon region

HE YUANQING1,2, ZHANG ZHONGLIN1, WILFRED H. THEAKSTONE2, CHEN TUO1, YAO TANDONG1, DAVID D. ZHANG3 & PANG HONGXI1 1 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China [email protected] 2 Department of Geography, University of Manchester, Manchester M13 9PL, UK 3 Department of Geography, University of Hong Kong, Hong Kong, China

Abstract Climatic data, ice core records, the tree-ring index and recorded glacier variations have been compared, and used to reconstruct a history of climatic and glacial changes in the monsoonal temperate-glacier region of southwestern China during the last 400 years. The results indicate that the region’s temperature has increased in a fluctuating manner during the 20th century, after the two cold stages of the Little Ice Age of the 17th–19th centuries, with a corresponding retreat of most of the glaciers during the 20th century, against a background of global warming. Rates of retreat accelerated after the 1980s. The few advancing glaciers that did exist have started to retreat in recent years. The amount, trend and amplitude of variation of precipitation have differed in different parts of the region. The climatic records in the Dasuopu ice core, from the Himalaya area in the western part of the region, show a decreasing trend in precipitation, the converse of the trend in temperature. However, in the Hengduan Mountains and other areas of the eastern part of the region, a rising trend in rainfall has accompanied increasing temperatures, a result of the variable atmospheric circulations from different sources. The data indicate that the Southwest Monsoon, which is the principal controlling factor in the Chinese monsoonal temperate-glacier region, can be classified into two parts. One is the Indian Monsoon from the Arabian Sea, passing across the Indian Peninsula. This transports the vapour for precipitation in the Himalaya area, the western part of the monsoonal temperate-glacier region. The other part is the Bengal Monsoon originating in the Bay of Bengal, passing over Bengal and Burma. This is the major source of precipitation in the Hengduan Mountains and other areas in the eastern part of the region. In addition, the eastern part is influenced by the Southeast Monsoon arriving from the western Pacific, whilst the western part is affected in winter by the southern branch of the westerly circulation. This complex atmospheric situation results in differing patterns of precipitation in the western and eastern zones. Although it is clear that both temperature and precipitation affect the glaciers, further work is needed to confirm which is the major factor influencing present glacier change. Key words climatic change; temperate glaciers; monsoon region; China ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 117–123. Utilisation de modèles hydrologiques pour évaluer les ressources en eau de surface et leur évolution spatio-temporelle—application à l’Afrique de l’Ouest

JEAN-EMMANUEL PATUREL, MAHAMAN OUEDRAOGO, GIL MAHÉ IRD, UMR HydroSciences Montpellier (IRD-UM2-UM1-CNRS) et IRD, 01 BP 182, Ouagadougou 01, Burkina Faso

ERIC SERVAT, ALAIN DEZETTER IRD, UMR HydroSciences Montpellier (IRD-UM2-UM1-CNRS), BP 64501, F-34394 Montpellier Cedex 5, France [email protected]

Résumé Cette étude couple trois modèles hydrologiques (GR2M, Water Balance Model modifié et Yates) à un Système d’Information Géographique, afin d’analyser l’impact de la péjoration climatique observée en Afrique de l’Ouest sur la ressource en eau de surface à un pas d’espace de 0.5° × 0.5° et à un pas de temps mensuel. Les modèles de relation pluie–débit utilisés nécessitent des données peu nombreuses et assez facilement disponibles en Afrique mais permettent cependant d’atteindre des niveaux de performance satisfaisants. La transposition des résultats obtenus sur certains bassins versants se révèle difficile sur d’autres, non jaugés, et pour lesquels on ne dispose d’aucune information. Seul, le modèle de Yates permet de prédéterminer les valeurs de ses paramètres sans aucune procédure de calage et validation. La cartographie des lames d’eau écoulées rend possible de dresser une répartition spatiale des écoulements à l’échelle régionale et d’apprécier l’impact de la variabilité du climat sur les ressources en eau. Mots clefs Afrique de l’Ouest; cartographie; hydrologie regionale; ressources en eau; SIG; variabilite climatique Key words West Africa; mapping; regional hydrology; water resources; GIS; climate variability ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 124–133. Global water resources assessment under climatic change in 2050 using TRIP

TAIKAN OKI Research Institute for Humanity and Nature, Kyoto 602-0878, Japan t aikan @iis.u-tokyo.ac.jp

YASUSHI AGATA, SHINJIRO KANAE, TAKAO SARUHASHI & KATUMI MUSIAKE Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan

Abstract Annual water availability was derived from annual runoff estimated by land surface models using Total Runoff Integrating Pathways (TRIP) with 0.5° × 0.5° longitude/latitude resolution globally. Global distribution of water withdrawal for each sector in the same horizontal spatial resolution was estimated based on country-base statistics. Based on this framework, future projections of the global water resources considering population growth, climatic change, and the increase of water consumption per capita were carried out. Change in annual runoff was estimated based on the climatic simulation by a general circulation model coupled with TRIP. With the increase of population only, the future population under strong water scarcity, (water scarcity index is larger than 0.4), will increase by 90% in 2050 compared to the situation in 1995. Consideration of the climatic change due to global warming will relax this situation, and only 74% will be under strong water scarcity according to the future projection used in this study. Key words downscaling GCM simulation; global warming; global water balance; Total Runoff Integrating Pathways, TRIP; water scarcity; water withdrawal ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 134–141. Prediction of hydrological extremes by air circulation indices

JOANNA POCIASK-KARTECZKA Institute of Geography and Spatial Management, Jagiellonian University, ul. Grodzka 64, 31-044 Kraków, Poland [email protected]

ZENON NIECKARZ Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Kraków, Poland

DANUTA LIMANÓWKA Institute of Meteorology and Water Management, ul. Borowego 14, 30-215 Kraków, Poland Abstract The study of air circulation variability is important for a better understanding of river runoff. Research presented in this paper describes an attempt to find a link between air circulation on a large regional scale, and hydrological extremes of Carpathian river discharges in warm and cold seasons. The relationship between the North Atlantic Oscillation in winter, the Scandinavian baric system, and maximum and minimum river discharges was investigated over the period 1951–2000. Multiple correlation analysis was used. Some interesting relationships were found and multiple correlation formulae were developed for a few Carpathian basins. They may be used for hydrological forecasts of Carpathian extreme river discharges and they may allow the implementation of a warning system for extreme river events. Key words Carpathian Mountains; hydrological extremes; multiple regression; North Atlantic Oscillation; river discharge; SCAND; teleconnections; winter Hurrell index ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 142–148. Comparison of flow forecasts by runoff models: a case study from southern Brazil

CARLOS E. M. TUCCI1, PEDRO DIAS2, ROBIN CLARKE1, WALTER COLLISCHONN1 & GILVAN SAMPAIO3 1 Institute for Hydraulic Research, Federal University of Rio Grande do Sul, Brazil [email protected] 2 Institute for Atmospheric and Geophysical Research (IAGCA), University of São Paulo, Brazil 3 Center for Climatic Research (CPTEC), Brazilian Agency for Space Research (INPE), Cachoeira Paulista, Brazil.

Abstract Over 80% of Brazil’s energy demand is supplied at present by hydropower. It is therefore essential for purposes of future planning to have good estimates of reservoir inflows, and the longer the lead time of streamflow forecasts, the more distant is the planning horizon for decisions concerning the costing, production and distribution of power. Whilst it is relatively easy to forecast river basin response to precipitation that has already fallen, forecasts for periods beyond this immediate response time must be based upon estimates of future precipitation. This paper describes the results of work which combines forecasts of future rainfall given by a model of global climate with a detailed, distributed model of river basin response in the Brazilian part of the River Uruguay basin, an area of intensive hydropower production. Comparison of predicted and observed rainfall over the period of model calibration showed that it was necessary to apply a statistical correction to eliminate a spatial trend in predicted rainfall. Data from a two-year period were set aside for model validation. Results show that the combined use of models of climate and river-basin response has been successful for the River Uruguay basin, in that the root mean square error (RMSE), between observed flows and flows predicted by the combined model, is substantially less than the RMSE between observed flows and the historic mean monthly flows. Key words climate models; flow forecasts; rainfall–runoff models; River Uruguay ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 149–159. Investigation of feedback mechanisms between soil moisture, land use and precipitation in West Africa

HARALD KUNSTMANN & GERLINDE JUNG Institute for Meteorology and Climate Research (IMK-IFU), Forschungszentrum Karlsruhe GmbH, Kreuzeckbahnstraße 19, D-82418 Garmisch-Partenkirchen, Germany [email protected] Abstract To investigate the effects on precipitation of the ongoing intensification of agri- culture in West Africa, we applied the mesoscale meteorological model MM5 for the identification of feedback mechanisms between land surface (soil and vegetation) and atmosphere. Great differences in the ability to quantitatively describe the observed meteorological data were found between different model parameterizations. The main research question was to what extent regional (intra-domain) evapotranspiration determines rainfall within the domains (precipitation recycling ratio and precipitation efficiency). The effect of decreased and increased initial soil moisture on the total rainfall was investigated. Scale-dependent, positive as well as negative, feedback mechanisms were found. Sensitivity of precipitation with respect to soil moisture was found to be very variable over space and takes on negative as well as positive values. To investigate the effect of land-use change, we computed the total rainfall distribution under the assumption of the observed land use substitution from cropland–woodland mosaic into shrubland and finally into grassland, Ceteris paribus. Again, the resulting precipitation change response was found to be very heterogeneous over space. Key words land-use change effects; mesoscale meteorological modelling; precipitation recycling; soil moisture– precipitation feedbacks ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 160–164. The effect of downscaling techniques on assessing water resources impacts from climate change scenarios

JOHAN ANDRÉASSON, STEN BERGSTRÖM, BENGT CARLSSON & L. PHIL GRAHAM Swedish Meteorological and Hydrological Institute, SE-601 76 Norrköping, Sweden [email protected]

Abstract Assessing the impact of climate change on water resources is often based on simulations from global climate models (GCMs) that have been downscaled. Downscaling of GCMs, to improve representation over a limited region, can be done either by use of a regional climate model (RCM) or by statistical downscaling of the GCMs. Although both of these techniques are common, they are seldom compared. This paper investigates the effect of using different downscaling techniques for the assessment of climate change impacts on water resources. The results show that both dynamical and statistical downscaling are useful methods to downscale GCM output. However, when there are orographic influences that affect the local climate, such as mountains, the method of statistical downscaling should be used more carefully. Key words climate change; downscaling techniques; HBV model; hydrological impacts; RCA model; Sweden ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 165–172. Generation of rainfall scenarios using daily patterns of change from GCMs

TIMOTHY I. HARROLD Research Institute for Humanity and Nature, 335 Takashima-cho, Kamigyo-ku, Kyoto 602-0878, Japan [email protected]

ROGER N. JONES CSIRO Atmospheric Research, PMB 1, Aspendale, Victoria 3195, Australia

Abstract This paper proposes a modification of the perturbation approach to downscaling GCM rainfall. The proposed approach uses a daily pattern of change in ranked rainfalls from the GCM, and then scales the ranked point daily rainfall by this pattern of change. This new approach can produce sequences of “climate change impacted” point daily rainfall that are very different in magnitude to sequences that are produced by simpler perturbation methods, especially in terms of rainfall that will produce runoff. We argue that the proposed method is superior to simpler methods, because the method can produce sequences of “climate change impacted” point rainfall that are consistent with the changes in extreme daily rainfalls and changes in the frequency of wet days that occur in the GCM. Key words downscaling; daily rainfall; global climate models; perturbation methods ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p.175–183. A step in the right direction: towards integrated natural resource management in Sarawak, Malaysia

TINA SVAN HANSEN Institute of Geography, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark [email protected]

Abstract This paper analyses the effect of recent changes in natural resource management policies in Sarawak, Malaysia. Within the time period of the new policies, institutions have been created to administer the new legislation, leading to an overlap in the mandates of the key institutions managing natural resources. Results from an ongoing study in the Niah catchment show that the pace of large-scale land conversion from forest into oil palm plantations has increased, yet new environmental monitoring programmes have improved the natural resource management in the oil palm plantations. Still, the land-use changes have caused a significant decrease in water quality. So far there has been no attempt to plan or coordinate an integrated natural resource management at catchment level in the study area. Nevertheless, the process of changing the approach towards integrated natural resource management has started. Key words integrated management; land-use changes; river; Sarawak, Malaysia; water ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 184–194. Groundwater pollution vulnerability and groundwater protection strategy for the Owerri area, southeastern Nigeria

K. M. IBE Sr, G. I. NWANKWOR & S. O. ONYEKURU Department of Geology Federal University of Technology, Owerri, Nigeria [email protected]

Abstract The vulnerability to pollution of the Owerri regional water supply in, Nigeria, was assessed as the basis for proposing an appropriate strategy for protecting the groundwater resources. The vulnerability assessment was accomplished using the LeGrand, GOD, SIGA, and DRASTIC computer models. The model techniques generally involve parameter rating and point-count systems, based on evaluation of various hydrogeological parameters in relation to their capacity to influence the flow of contaminants in the groundwater system. The Owerri area is generally flat and groundwater recharge is relatively high. The area is underlain by predominantly sandy strata in the north, which grade into gravelly sequences towards the southwest. The southeastern part of the area is underlain in part by a thick clayey faces that thins and interfingers into the gravelly strata. Effective hydraulic conductivity ranges from 5.6  10-9 to 1.44  10-3 m s-1, the higher value being in the coarse sand and gravel units. The depth to the water table is about 60 m in the north decreasing southward to less than 20 m; the hydraulic-head gradient is 9–22%. The southwestern part of the Owerri area including the Owerri conurbation has a high vulnerability to groundwater pollution and therefore waste disposal sites should not be located there. The northern and southeastern areas have moderate and low vulnerabilities, respectively, and carefully selected and engineered sites within those areas could be considered for future waste disposal. Policies should be instituted to facilitate the closing of pollution sources in the area of high vulnerability such as open disposal pits, leaking petrol stations, effluent discharge from industries, and use of pit latrines, and to locate future disposal site in areas of lower vulnerability. Key words groundwater development; groundwater protection; groundwater vulnerability assessment models; hydraulic head distribution

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Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 195–204. Modelling nitrogen dynamics in an agricultural-forested catchment

BAOLIN SU, SO KAZAMA Department of Civil Engineering, Tohoku University, Aoba-yama 06, Sendai 980-8579, Japan [email protected]

MINJIAO LU Department of Civil and Environmental Engineering, Nagaoka University of Technology, Kamitomioka 1603-1 Nagaoka, Niigata 940-21, Japan

MASAKI SAWAMOTO Department of Civil Engineering, Tohoku University, Aoba-yama 06, Sendai 980-8579, Japan

Abstract A spatially distributed nitrogen simulation (DNS) model has been developed to simulate daily nitrogen concentration variation in an agricultural-forested catchment. The model can simulate hydrological processes and various nitrogen processes at the grid cell level, continuously considering plant uptake, atmospheric wet deposition, fertilizer application, mineralization, nitrification and denitrification. The hydrological component is based on the distributed Xinanjiang (DXAJ) rainfall–runoff model, and the nitrogen component simulates key sources and sinks using a series of first-order kinetic equations. In particular, plant growth indices for land-use classes are incorporated to simulate plant uptake variation in accordance with seasonal vegetation cover variations. Model calibrations showed that there is a reasonable agreement between simulated and observed stream nitrate-nitrogen concentration. Sensitivity analysis showed that plant uptake is the key nitrogen sink, whereas agricultural fertilizer application is the key source of nitrogen. Key words kinetic equations; nonpoint source; nitrogen modelling; plant uptake; Xinanjiang model ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 205–212. Assessment of groundwater quality and climatic water balance studies in the Pageru River basin, Andhra Pradesh, India

P. D. SREEDEVI & SHAKEEL AHMED Indo-French Centre for Groundwater Research, National Geophysical Research Institute, Hyderabad-500007, India [email protected]; [email protected]

Abstract An analysis of the climatic water balance and drought in the Pageru River basin, a chronically drought prone area in south India, has been prepared using rainfall data from eight raingauge stations located in and around the basin. The values of rainfall and temperature have been collected and the water balance parameters have been computed using the Thornthwaite and Mather method. In addition, 99 water samples were collected during both pre- and post-monsoon seasons and analysed for major ions to assess the water quality in relation to agriculture and domestic uses in the basin. The results indicate that the annual water deficit of the basin is 821 mm. The maximum water deficit is observed during the months of March and June and it is minimal in September. The analysis of the data revealed that the annual distribution is mainly controlled by the physiography of the region. A comparison of the water balance and cropping pattern used in the villages indicates that the basin area is only suitable for cultivation of drought resistant crops such as Sorghum bicolor, Eleusine coracana and Pennisetum typhoides. Assessment of water samples from various methods proved that most of the water is good for drinking as well as for agriculture in both seasons. Key words climate; crops; drought; groundwater quality; Pageru River basin, India; water balance ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 213–220. Effect of irrigation on groundwater chemistry in the lower Chambal Command area, Madhya Pradesh, India

L. P. CHOURASIA Department of Applied Geology, Dr H. S. Gour University, Sagar 470003 (M.P.), India [email protected]

Abstract The study area is a part of the Chambal and Sind River basin, in the Bhind and Morena districts of Madhya Pradesh, India. It is irrigated by the Chambal canal system. The area comprises alluvium in which groundwater occurs under unconfined and semi-confined conditions. To determine the effect of irrigation on groundwater chemistry, 45 groundwater samples from a non-irrigated area, and 45 samples from an irrigated area, were collected during May–June 1998 from the existing dug wells. The major cations and anions were determined from the samples. The statistical analysis of these data suggests that irrigation does have an effect on groundwater chemistry. At the 99% confidence level, the concentrations of the chemical constituents are much higher in the irrigated area than the non- irrigated area. These areas are identical except in their agricultural development. Although most of the groundwater samples are of good quality for irrigation purposes, some of them are unsuitable for irrigation. The processes associated with surface water irrigation and involved in modifying the concentration of chemical constituents in groundwater are evaporation and transpiration, mineral dissolution, dissolution of fertilizers, mixing with existing groundwater, CO2 uptake and ion exchange. In addition, calcite precipitation is likely to be a control on Ca and HCO3 concentrations at several stages. Although the method has only examined one “snap shot” in time, the approach to data analysis adopted here is simple enough to be incorporated as routine following field collection of data but it is representative of a longer- term average. Key words Chambal District, Madhya Pradesh, India; effect; groundwater chemistry ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 221–228. Cumulative environmental change in the lower Niger

SHAKIRUDEEN ODUNUGA, OLUFEMI TEJUOSO & FASONA MAYOWA Department of Geography, University of Lagos, Lagos, Nigeria [email protected]

Abstract The Niger–Benue waterway, with a total water-route distance of about 2200 km, provides a natural artery and has great potential for water transportation from the coastal area of Warri and Port Harcourt to the middle belt and from there to the northeastern and northwestern frontiers of Nigeria. The long period of the neglect of the lower Niger has resulted in blockage of the channel of the waterway. The blockage and seasonal fluctuation of the river has confined the effective service of even small ferries to particular areas and periods of the year. In view of this, the present project of dredging was conceptualized to improve the navigability of the water route so as to promote both local and international economic integration. Statistical methods (regression) were used to aid understanding of the water resource dynamics of the lower Niger. Uncertainty in the water resource processes as a result of large scale deforestation, due to dredging activities, was reduced through the adoption of a water balance approach for the local catchments of three stations (Onitsha, Lokoja and Baro). Ranges of parameters of about 20–15% reduction in evapotranspiration contribution to rainfall at Onitsha, to 15–10% reduction at Baro were assumed. The response of the water resource to the expected change was estimated and the trend in water resources properly determined and suggestions made for sustainable use of the excess water resources. Key words deforestation; evapotranspiration; environmental change; River Niger ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 229–235. The origin of water salinity on the Annaba coast (NE Algeria)

L. DJABRI 11 Rue Asla Hocine, Annaba 23000, Algeria [email protected]

R. LAOUAR, A. HANI, J. MANIA & J. MUDRY LML URA CNRS 1441 EUDIL, Ave Paul Langevin, F-59655 Villeneuve d’Ascq, Cedex, France

Abstract Water wells located on the Annaba City coast are characterized by high salinity. The origin of this may be attributed to several factors such as the geological features of the region, the climate and the salted bevel. A number of analyses were carried out during October 1990, November 1998, December 1998, January 1999 and February 1999, in order to locate the origin of this high salinity. Principal component analyses show that the chloride- rich, Na-rich water is located near the sea. This indicates that seawater is the most likely contaminant of freshwater and that the sand can contribute highly to the observed high chloride contents. Our results also show that the salinity increases steadily when approaching the sea, and indicates the influence of marine water. Away from the coast, the observed Sr/Ca ratios (< 1) is due to the absence of the evaporitic formation which outcrops further south of the region. Key words Algeria; climatic changes; dryness; geology; geophysical; hydrochemical; interface; Mediterranean Sea; salt level ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 239–246. Identifying human induced pressures and their impact on water resources—the assessment of hydrological quality in river basins

MICHAEL EISELE, ANDREAS STEINBRICH & CHRISTIAN LEIBUNDGUT Institute of Hydrology, University of Freiburg, Fahnenbergplatz, D-79098 Freiburg, Germany [email protected]

Abstract The assessment procedure presented in this paper is a combination of tools, by which identification and quantification of human impacts on the quantity and quality of water resources within a catchment can be carried out. The application of the procedure is demonstrated in a meso-scale catchment. Quantitative pressures on water resources are identified using criteria of land-use structure, river morphology, water consumption, water abstraction and transfer, and the storage volume of dams and reservoirs. Additionally, human induced alterations of runoff dynamics are evaluated using statistical methods, taking into account climatic effects. Pressures on water quality are characterized using criteria for land use, agricultural intensity, population density, sewage system and urban runoff, as well as a detailed water and nutrient balance. To examine the human impact on water quality, different scenarios are calculated and compared to the actual status. The potential range of error in the predictions is estimated based on a sensitivity analysis. Key words assessment; pressures; runoff dynamics; water quality ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 247–254. Estimating land cover changes and associated environmental impacts on wetlands by coupling remote sensing and hydrological modelling

ZACHARIAS IEROTHEOS, E. DIMITRIOU & Th. KOUSSOURIS National Centre for Marine Research/Institute of Inland Waters, Mavro Lithari, GR-19013 Anavissos-Attiki, Greece [email protected]

Abstract Land-use changes and associated hydrological disturbances are common reasons for wetland degradation today. This necessitates the development of a method to identify and quantify potential ecological impacts from specific land-use alterations in order to avoid environmental deterioration. This scientific project used remotely sensed data, GIS techniques and hydrological modelling to estimate land cover modifications during a 40-year period, as well as associated changes in hydrological parameters, such as overland flow, soil moisture, evapotranspiration and water storage on the ground surface. Present and past land cover maps have been developed with the use of remote sensing and GIS software, and have been the basis of hydrological modelling simulations that indicate differences in these parameters during the study period. The modelling results illustrated significant variations in the hydrological regime caused mainly by the considerable increase of agricultural land and urban areas that posed adverse effects on the regional wetlands. Key words land use; Greece; hydroecology; hydrological modelling; remote sensing; wetlands ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 255–259. Streamflow generation using a multivariate hybrid time series model

SEUNG YUP RIEU, YOUNG-OH KIM School of Civil, Urban, Geosystem Engineering, Seoul National University, San 56-1 Shillim-dong, Gwanak-gu, Seoul, Korea Republic [email protected]

DONG RYUL LEE Water Resources and Environmental Research Division, Korea Institute of Construction Technology, 2311 Daewha-dong, Ilsan-gu, Koyang-shi, Kyonggi-do, Korea Republic

Abstract The long-term water resources plan in Korea is usually established on the basis of the so-called water balance analysis that estimates the water availability over an entire basin. The analysis generally uses only a single 30-year historical record of natural streamflow. This study suggested that the water balance analysis should include the hydrological uncertainty in its results. For this purpose, a multivariate streamflow generation model called the multivariate contemporaneous PAR(1)NT-hybrid model was proposed and applied to a multi- site monthly streamflow generation problem for the Han River basin in Korea. The proposed model was then compared with a multivariate PAR(1) and a disaggregation model. This study showed that the proposed model reproduces cross-correlations at various lags better than the traditional parametric generation models. Key words bootstrap; generation; Han River, Korea; hybrid; multivariate; stochastic process ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 260–266. Radial basis function network for prediction of hydrological time series

A. W. JAYAWARDENA Department of Civil Engineering, The University of Hong Kong, Hong Kong, China [email protected]

PENGCHENG XU Academy of Mathematics and System Sciences, Chinese Academy of Sciences, Beijing, China

W. K. LI Department of Statistics and Actuarial Science, The University of Hong Kong, Hong Kong, China

Abstract In this study, a network using radial basis functions as the mapping function in the evolutionary equation for prediction of time series is presented. A radial basis function network requires the determination of the number of centres of the radial basis functions, their receptive field widths, and the linear weights of the network output layer. Methods to estimate the widths of the receptive fields, and the number of centres for the radial basis functions are introduced in the study. The latter is based on the concept of the Generalized Degrees of Freedom. The linear weights are determined by the least squares method. The predictions by the proposed method when compared with the actual values of four hydrometeorological data sets, are better than those by the traditional approach of fixing the number of centres. Key words Chao Phraya River, chaos; generalized degrees of freedom; Mekong River; phase space; radial basis functions; S-index ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 267–274. Long-term estimation of evapotranspiration from a tropical rain forest in Peninsular Malaysia

MAKOTO TANI1, ABDUL RAHIM NIK2, YUKIO YASUDA3, SHOJI NOGUCHI4, SITI AISAH SHAMSUDDIN2, MOHD MD SAHAT2 & SATORU TAKANASHI1 1 Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan [email protected] 2 Forest Research Institute Malaysia, Kepong, 52109 Kuala Lumpur, Malaysia 3 Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan 4 Japan International Research Center for Agricultural Sciences, 1-1,Ohwashi, Tsukuba, Ibaraki 305-8686, Japan Abstract Field observations for estimating long-term evapotranspiration from a tropical rain forest were made in the Pasoh Forest Reserve, Peninsular Malaysia. The Penman-Monteith- Rutter model was applied to four-years of meteorological records to enable continuous estimation of evapotranspiration during dry and wet canopy conditions. The estimates show that the annual average total evapotranspiration, transpiration and interception loss for 1996– 1999 were 1548 mm, 1218 mm and 331 mm, respectively, cf. annual rainfall of 1571 mm and net radiation of 1744 mm (water equivalent). Although a long dry period was included as a result of the strong El Niño in 1997 and 1998, evapotranspiration always accounted for a large portion of the net radiation. Key words El Niño; evapotranspiration; Pasoh Forest Reserve, Malaysia; Penman-Monteith-Rutter model; tropical forest ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 275–281. Evaporation of intercepted precipitation in unlogged and logged forest areas of central Kalimantan, Indonesia

CHAY ASDAK Institute of Ecology, Padjadjaran University, Jl. Sekeloa Selatan 1, Bandung 40132, Indonesia [email protected]

Abstract The effect of logging practices on rainfall interception loss was monitored for 12 months and related to vegetation and rainfall characteristics at the Wanariset Sangai, Central Kalimantan. The results show that evaporation of intercepted rainfall is higher in the unlogged forest (11% of total gross rainfall) than in the logged forest (6%). These results were closely associated with the reduction in number of trees per hectare from 581 in the unlogged plot to 278 (52%) in the logged plot, or a reduction in terms of basal area from 38.6 to 13.8 m 2 ha-1 (65%). The evaporation rate during and after rainfall has ceased, in canopy-saturated conditions, was calculated by an energy balance method, which relied on the modified Penman equation using directly determined microclimatic and canopy structure variables as inputs. The results obtained showed that the evaporation from wet canopies in this research area is driven more by advected energy than by radiative energy. In the unlogged plot, advective energy accounted for 0.38 mm h-1 of the 0.50 mm h-1 of evaporation, whereas radiative energy accounted for only 0.13 mm h-1. Key words boundary layer conductance; energy balance equations; evaporation rate; humid tropical rainforest; Indonesia; volume balance method ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 282–291. Estimating the snow distribution in a subalpine region using a distributed snowmelt model

KENTARO MATSUI Graduate School of Agriculture, Iwate University, Uyeda 3-18, Morioka, Iwate 020-8550, Japan and Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan

TAKESHI OHTA Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan [email protected]

Abstract A distributed snowmelt model was applied to a subalpine region. The model is based on an energy budget method and evaluates topography and vegetation cover. In the Akagawa basin, Japan, the model reproduced the proportion of snow coverage and snow water equivalent in the snowmelt season exactly. The simulated results agreed better at forest sites than at open sites, and at lower sites rather than at higher sites. This suggests that the snow redistribution caused by wind cannot be ignored in predicting snow distribution in a subalpine zone. Key words distributed snowmelt model; heat balance; spatial snow distribution; subalpine; temporal snow distribution ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 294–300. The influence of snow depth on the variation of vegetation activity and evapotranspiration

YOSHIHIRO ASAOKA, SO KAZAMA & MASAKI SAWAMOTO Department of Civil Engineering, Graduate School of Engineering, Tohoku University,Aoba-yama 06, Aoba-ku, Sendai City, Miyagi 980-8579, Japan [email protected]

Abstract The influence of snow conditions on the seasonal variation of vegetation and evapotranspiration were investigated in a low snow year (1998), a normal snow year (1999) and a heavy snow year (2000). First, a NDVI (Normalized Difference Vegetation Index), evapotranspiration and a snow cover map were composed with NOAA/AVHRR data. The Warm Index (WI) was compiled with meteorological data. Secondly, seasonal variation of NDVI and evapotranspiration were evaluated considering WI and the snow area map. Finally, the spatial distribution of vegetation growth ratio to temperature increase was calculated with the proposed new index. The results indicate that vegetation activity and evapotranspiration in the snowmelt season are related to the area of the remaining snow-covered area because snow cover restrains plants from vegetating. Next, the vegetation growth ratio to temperature increase is greater in the low elevation area, less in the middle elevation area and greater in the high elevation area. This shows the relationship between snow condition and vegetation types. Key words NDVI; NOAA/AVHRR; snow condition; snow cover; Warm Index ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 301–308. Some problems in regionalization of watersheds

A. RAMACHANDRA RAO School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, USA [email protected]

V. V. SRINIVAS Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India

Abstract Because of the paucity of flood data, it is not always possible to use methods of frequency analysis to estimate flood values corresponding to specified recurrence intervals. To alleviate this problem, hydrologists have used information from watersheds in a region to estimate the magnitude of floods. Several regionalization procedures, which attempt to identify watersheds with a similar hydrological response, have been developed in the literature. However, as no single procedure has been demonstrated to yield universally acceptable results, several methods of regionalization are in use. In this study, three hybrid-cluster algorithms, which are a blend of agglomerative hierarchical and partitional clustering procedures, are tested to determine their potential in combining watersheds in Indiana, USA, into homogeneous regions. The problems encountered in this investigation are discussed. Key words clustering algorithms; flood flows; regionalization ______

Water Resources Systems—Water Availability and Global Change (Proceedings of symposium HS02a held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 280, 2003. p. 309–317. Effect of snow interception on the energy balance above deciduous and coniferous forests during a snowy winter

KAZUYOSHI SUZUKI Frontier Observational Research System for Global Change, 3173-25 Showa-machi, Kanazawa-ku, Yokohama 236-0001, Japan [email protected]

YUICHIRO NAKAI Hokkaido Center, Forestry and Forest Products Research Institute, Sapporo, Japan

TAKESHI OHTA Nagoya University/Frontier Observational Research System for Global Change, Nagoya, Japan

TSUTOMU NAKAMURA Iwate University, Morioka, Japan

TETSUO OHATA Institute for Low Temperature Sciences of Hokkaido University/Frontier Observational Research System for Global Change, Sapporo, Japan

Abstract We discuss how snow intercepted by deciduous and coniferous forests affects their water and energy balances. Intensive micrometeorological observations above and below the canopy were carried out in deciduous (DF) and coniferous (CF) forests in the winter of 1996– 97 in Sapporo, Hokkaido Island, Japan. Compared with the DF, large amounts of intercepted snow on the canopy of the CF caused a relatively large latent heat flux, which depended on the aerodynamic and canopy resistance. When the intercepted snow on the canopy disappeared from the CF, the sensible and latent heat fluxes were the same at the two sites. Canopy resistance determined the latent heat flux above the DF because the aerodynamic resistance was insignificantly small. The canopy resistance for the DF was correlated with the snow surface temperature. Differences in the amounts of intercepted snow and in the canopy and aerodynamic resistance affected the partition of the input radiative energy above the two canopies. Furthermore, the site of effective energy exchange differed in the CF and DF because the effective energy exchange in the DF occurred at the forest floor. Keywords aerodynamic and canopy resistance; coniferous forest; deciduous forest; energy balance; snow interception