__________________________________________________________hydrologie.org/redbooks/a314/p314...

Water Quality and Sediment Behaviour of the Future: Predictions for the 21st CenturyEdited by Bruce W. Webb & Dirk De Boer

IAHS Publ. 314 (2007) ISBN 978-1-901502-14-5; 322 + x pp price £62.00The abstracts of the papers in this volume can be seen at: www.iahs.info, with information about other IAHS publications and IAHS activities.

This volume is an outcome of a symposium organized by the IAHS International Commissions on Water Quality (ICWQ), Continental Erosion (ICCE), and Groundwater (ICGW), and the Predictions in Ungauged Basins (PUB) Working Group, with the objective of bringing together experts to provide a state-of-the-art review of our current understanding of how water quality and sediment behaviour might alter as a result of climate and land-use change during the 21st century. The aim was to examine, for both surface water and groundwater systems, not only the nature and controls of future changes in water quality and sediment behaviour, but also what the implications of these will be for human use of water and for freshwater ecosystems, and how well our science is equipped to predict the future in this regard. Thirty-six reviewed papers were accepted for publication. They are grouped in three sections in this volume: Sediment and Nutrient Behaviour in Surface Waters; Metals and Other Water Quality Problems; and Management Issues.

http://www.iahs.info/

Contents

Preface by Bruce W. Webb v

1 Sediment and Nutrient Behaviour in Surface Waters

Suspended sediment yields in the Amazon basin of Peru: a first estimation Jean Loup Guyot, Hector Bazan, Pascal Fraizy, Juan Julio Ordonez, Elisa Armijos & Alain Laraque

3

Impacts of human activities on the sediment regime of the Yangtze River Qiongfang Li, Zhenhua Zou, Ziqiang Xia, Wei Zhang & Huiqing Wang

11

Modelling extreme suspended sediment concentrations in North America: fre-quency analysis and correlations with watershed characteristics Yves Tramblay, André Saint-Hilaire & Taha B. M. J. Ouarda

20

Predicting the impact of projected change in agriculture by 2015 on annual mean fluvial suspended sediment concentrations across England and Wales Adrian L. Collins, Steven G. Anthony, Tony Turner & Julia Hawley

28

Neuroevolution methodologies applied to sediment forecasting Alison J. Heppenstall, Linda M. See & Robert J. Abrahart

38

Modelling discharge, water chemistry and sediment load from a subarctic river basin: the Tanana River, Alaska Kazuhisa A. Chikita, Tomoyuki Wada, Isao Kudo, Daisaku Kido, Yu-Ichi Narita & Yongwon Kim

45

Measuring the fluxes of suspended sediment, trace elements and nutrients for the City of Atlanta, USA: insights on the global water quality impacts of increasing urbanization Arthur J. Horowitz, Kent A. Elrick & James J. Smith

57

Assessing the effects of design and climate change on sediment removal in urban stormwater ponds Catherine T. Morgan, Kate V. Heal, Steve G. Wallis & Rebecca J. Lunn

71

Scale-related sediment and phosphorus transfers in small agricultural catchments Clare Deasy, Richard E. Brazier, A. Louise Heathwaite & Robin Hodgkinson

79

Modelling climate change impact on phosphorus load in Swedish rivers Jörgen Rosberg & Berit Arheimer

90

Groundwater–surface water exchange fluxes in a Pleistocene lowland and the impacts on riparian zone water balance and nitrate conditions Stefan Krause, Axel Bronstert & Erwin Zehe

98

Contents

Effect of frequent storms on nutrient discharge in a mountainous coastal catchment, western Japan Shin-ichi Onodera, Misa Sawano, Mitsuyo Saito & Hidehiro Takahashi

108

Evaluation des méthodes d’estimation de flux événementiels des nitrates et d’atrazine sur un bassin agricole / Evaluation of estimation methods for nitrate and atrazine loads during rainfall events in agricultural catchments Adilson Pinheiro, Flavie Cernesson & Jean François Dubernet

117

Modelling catchment-scale nitrate transport using a combined process-based and data-driven approach Rajesh Raj Shrestha & Michael Rode

125

2 Metals and Other Water Quality Problems

Long-term trend of uranium concentrations in Beaverlodge Lake, Saskatchewan, Canada, under mine decommissioning Huaxia Yao, Robert Kidd & Michio Hashino

137

The distribution of heavy metals in a highly regulated river: the River Murray, Australia Martin C. Thoms

145

Assessing water–sediment processes for metals in rivers polluted by mining to predict environmental impacts in developing countries M. Aurora Armienta, Azucena Dótor, Flor E. Arcega-Cabrera, Oscar Talavera, Alejandra Aguayo, Nora Ceniceros & Olivia Cruz

155

The distribution of metals (Co, As and Zn) in a residential urban watershed, typical of the Brazilian suburbs Cristiano Poleto & Gustavo Henrique Merten

163

Quantifying sediment deposition and the spatial variability of sediment-associated metals in ponds treating urban diffuse pollution Alan J. Jones, Kate V. Heal, Neil Stuart, Steve G. Wallis, Rebecca J. Lunn & Barbara Barbarito

173

Kohonen self-organising map (KSOM) extracted features for enhancing MLP-ANN prediction models of BOD5 Rabee Rustum, Adebayo Adeloye & Aurore Simala

181

Simulation by the IPTM-CS model of pesticides found in surface water and groundwater of the Fucino Plain, Italy Eva Pacioni, Marco Petitta & Miguel A. Mariño

188

Some reflections on the future of the water quality of the Corumbataí River basin, São Paulo State, Brazil Daniel Marcos Bonotto & Jorge Luis Nepomuceno De Lima

197

An assessment of water quality changes within the Athi and Nairobi river basins during the last decade Shadrack Mulei Kithiia

205

Contents

Flood flow water quality analysis using low-cost samplers in small rivers Janaína Bezerra Mesquita Lima & Sérgio Koide

213

Community-based monitoring and the science of water quality C. Conrad 217

3 Management Issues, Groundwater Contamination and Soil Erosion

Future impacts of freshwater resource management: sensitivity of coastal deltas Charles J. Vörösmarty, Jason P. Ericson, S. Lawrence Dingman, Larry G. Ward & Michel Meybeck

231

Appropriate use of catchment models for water-quality target setting and land-use management Bradford S. Sherman, Jon Brodie, Lex Cogle & Chris Carroll

239

Development and application of a Watershed Information System (WIS) for wa-ter quality analyses Conceicao De Maria Albuquerque Alves & Daniel Pete Loucks

251

Groundwater of the future in the Roussillon flood plain: present-day situation and solutions for the 21st century Pierre Serrat

261

Nitrate contamination in groundwater of the Yellow River Delta and its effect on the marine environment Mitsuyo Saito, Shin-ichi Onodera, Kunihide Miyaoka, Jianyao Chen, Makoto Taniguchi, Guanqun Liu & Yoshihiro Fukushima

271

The assessment of groundwater vulnerability in China Tang Lihua, Zhang Sicong & Yao Wenfeng

278

Hydrogeochemistry of groundwater in a part of the hard rock terrain of central India L. P. Chourasia

286

Runoff erosion control for a sustainable water supply in Niamey, Niger Republic Issoufou Abdoulkader

293

The effect of parent material and land use on soil erosion: a case study of the Taleghan drainage basin, Iran Sadat Feiznia & Kazem Nosrati

300

Sediment yield in the Daryacheh-Namak drainage basin, Iran, and its relation to land-use changes Sadat Feiznia, Abdolhossein Mohammadi & Sepideh Zakikhani

306

Implications of changes in river sediments during the 21st century for freshwater ecosystems in northeast India U. C. Sharma & Vikas Sharma

312

Key word index 321

Water Quality and Sediment Behaviour of the Future: Predictions for the 21st Century (Proceedings of Symposium HS2005 at IUGG2007, Perugia, July 2007). IAHS Publ. 314, 2007, 3-10

Suspended sediment yields in the Amazon basin of Peru: a first estimation

JEAN LOUP GUYOT1, HECTOR BAZAN2, PASCAL FRAIZY1, JUAN JULIO ORDONEZ3, ELISA ARMIJOS4 & ALAIN LARAQUE5

1 IRD – LMTG (Institut de Recherche pour le Développement – Laboratoire des Mécanismes de Transfert en Géologie), Casilla 18-1209, Lima 18, [email protected]

2 UNALM – FIA (Universidad Nacional Agraria La Molina – Facultad de Ingeniería Agrícola), Avenida La Molina s/n, Lima 12, Peru

3 SENAMHI – DGH (Servicio Nacional de Meteorología e Hidrología – Dirección General de Hidrología), Casilla 11-1308, Lima 11, Peru

4 INAMHI, Iñaquito700 y Corea, Quito, Ecuador5 IRD – OBHI (Institut de Recherche pour le Développement – OBHI), Centre Martinique-Caraibe, BP 8006, 97259

Fort de France Cedex, France

Abstract The Amazon basin represents 76% of the area of Peru. From north to south, the Andean tributaries of the Amazonas River in Peru are: the Napo River (100 520 km2, 6300 m3 s-1), the Marañón River (360 550 km2, 14 700 m3 s-1) and the Ucayali River (360 490 km2, 13 800 m3 s-1). The total suspended sediment yield exported from Peru to Brazil by these rivers is about 450 106 t year-1 for the 2004–2006 period (12% from the Napo River, 40% from the Marañón River and 48% from the Ucayali River). As the Amazon flood plain traverses the Andean piedmont and reaches its mouth, sediment yield increases along the Napo and Marañón rivers. This suggests the occurrence of erosion processes in the lowlands as observed in Ecuador, rather than the occurrence of sedimentation as observed along the Madeira River in Bolivia. At all the study stations, discharge and suspended sediment yield show a very high degree of seasonal variation.Key words Amazon basin; hydrology; Peru; suspended sediment


Impacts of human activities on the sediment regime of the Yangtze River

QIONGFANG LI, ZHENHUA ZOU, ZIQIANG XIA, WEI ZHANG & HUIQING WANGState Key Laboratory of Hydrology, Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, [email protected]

Abstract The Yangtze River (Changjiang) is one of the most important rivers in the world, and the alterations in its hydrological regime have global-scale impacts. However, with population increase and economic growth, the sediment regime of the Yangtze River has been altered to some extent by human activities, including dam construction, deforestation, soil and water

conservation, etc. The alteration in the sediment regime of the Yangtze River will unavoidably influence its morphology and geomorphology, the delta evolution and the ecosystem health and stability. To assess dam-induced alterations in the sediment regime of the Yangtze River quantitatively, the Danjiangkou Reservoir, the Gezhouba Reservoir and the Three Gorges Reservoir have been selected as case study sites, and the whole study period was divided into four sub-periods according to the years when these three reservoirs started to store water. On the basis of the time series of daily sediment discharge from six key hydrological stations (Wanxian, Yichang, Hankou, Datong, Baihe and Xiantao), the changes in annual, seasonal and monthly sediment load in different sub-periods, and the driving forces, were explored. The results in this paper could provide a reference for the assessment of impacts of human activities on the health and stability of the Yangtze River ecosystem.Key words Yangtze River; Danjiangkou Reservoir; Gezhouba Reservoir; Three Gorges Reservoir; sediment regime; hydrological changes


Modelling extreme suspended sediment concentrations in North America: frequency analysis and correlations with watershed characteristics

YVES TRAMBLAY, ANDRÉ SAINT-HILAIRE & TAHA B. M. J. OUARDA INRS-ETE, 490 rue de la Couronne, Québec, Québec G1A9A9, Canada [email protected]

Abstract Suspended sediment concentration (SSC) is an important abiotic variable for river habitats. Inspired by the statistical methods developed for flood frequency analysis, the probabilistic approach adopted in this paper is used to quantify extreme SSC events. Probability distributions were fitted to 149 series of annual maxima of SSC in Canada and the USA in order to estimate quantiles of SSC for different return periods. The most adequate probability distributions for modelling extreme events of SSC were selected based on the Bayesian information criteria. Seasonal patterns of occurrence of extreme concentrations were also analysed. Then, in order to investigate the links between magnitude of extreme SSC and drainage basin characteristics, correlations between annual maximum SSC, discharge, and a large range of physiographic variables were calculated, and the most significant ones were highlighted.Key words extremes; frequency analysis; physiographic influences; suspended sediment concentrations

________________________________________________________________________________________Water Quality and Sediment Behaviour of the Future: Predictions for the 21st Century (Proceedings of Symposium HS2005 at IUGG2007, Perugia, July 2007). IAHS Publ. 314, 2007, 28-37

Predicting the impact of projected change in agriculture by 2015 on annual mean fluvial suspended sediment concentrations across England and Wales

ADRIAN L. COLLINS1, STEVEN G. ANTHONY1, TONY TURNER2 & JULIA HAWLEY2

1 Environment Systems, ADAS, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, [email protected]

2 Rural Management Group, ADAS, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UK

Abstract With respect to achieving “good ecological status” (GES) for freshwaters by 2015, ADAS has recently been commissioned by the Department for Environment, Food and Rural Affairs (Defra) to estimate the gap between current and target losses of suspended sediment from diffuse agricultural sources across England and Wales. The work required a model for predicting mean annual total suspended sediment loads (SSL) and time-weighted mean fluvial suspended sediment concentrations (SSC). GES was defined in terms of the guideline annual average SSC of 25 mg L-1 cited by the EC Freshwater Fish Directive. National scale sediment source apportionment was undertaken to estimate the contributions of diffuse agricultural and urban sector sediment losses, channel bank erosion and point source discharges to the total SSL in all rivers. Landscape sediment retention was taken into account. The total SSL estimated for each Water Framework Directive (WFD) sub-catchment across England and Wales was used in conjunction with predicted flow exceedence to derive corresponding SSC time-exceedence plots. Baseline (year 2000) sediment load reductions required from the agricultural sector for meeting the target threshold SSC of 25 mg L-1 were estimated at national scale. Projected change in agriculture (structural and uptake of sediment mitigation methods) by 2015 was incorporated in the modelling exercise to predict the associated changes in SSL and mean annual SSC. The findings suggest that in addition to current agri-environment schemes, e.g. Countryside Stewardship, Catchment Sensitive Farming (CSF), further mitigation will be necessary under the River Basin Management Plans (RBMPs) of the WFD to reduce diffuse agricultural sediment losses for achieving GES in some parts of England and Wales. Key words agriculture; sediment; good ecological status


Neuroevolution methodologies applied to sediment forecasting

ALISON J. HEPPENSTALL1, LINDA M. SEE1 & ROBERT J. ABRAHART2

1 School of Geography, University of Leeds, Leeds LS2 9JT, UK [email protected]

2 School of Geography, University of Nottingham, Nottingham NG7 2RD, UK

Abstract Sediment forecasting represents a significant modelling challenge. This is due to the combined effects of suspended sediment transfer and throughput being source limited and subject to hysteresis effects. Recent approaches to modelling and forecasting have involved the use of neural networks. Despite yielding good results, this method has its own set of limitations, for example lack of guidance in parameter setting and the potential to overtrain. This paper reports on the application of a neuroevolutionary toolbox, JavaSANE. This toolbox is applied to two catchments in Puerto Rico that have been previously studied by Kisi (2005), who used a range of different methods including a neuro-fuzzy approach and neural networks to model suspended sediment in these catchments. These experiments are replicated using JavaSANE and compared to the results reported in Kisi (2005). These results show that JavaSANE produces estimates that are better or comparable to those of Kisi (2005).Key words genetic algorithm; JavaSANE; neural network; neuroevolution; Puerto Rico; sediment


Modelling discharge, water chemistry and sediment load from

mailto:[email protected]

a subarctic river basin: the Tanana River, Alaska

KAZUHISA A. CHIKITA1, TOMOYUKI WADA1, ISAO KUDO2, DAISAKU KIDO1, YU-ICHI NARITA1 & YONGWON KIM3

1 Laboratory of Physical Hydrology, Faculty of Science, Hokkaido University, Sapporo 060-0810, [email protected]

2 Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan3 International Arctic Research Center, the University of Alaska, Fairbanks, Alaska 99775-7340, USA

Abstract With reference to elevation effects on air temperature and rainfall, the time series of discharge, suspended sediment concentration (SSC) and SiO2 in the Tanana River, Alaska, are simulated by a conceptual model, the tank model. The simulations are reasonable (correlation coefficient r = 0.684 to 0.953) for all the time series obtained in the glacier-melt periods of 2002, 2004 and 2005. The smog from large forest fires in the summers of 2004 and 2005 sporadically covered the glacierized regions in the river basin, which were defined by field observation and using satellite imagery. The correlation for the discharge series was relatively low in or around the smog-covered periods. This is caused by the overestimation of calculated glacier-melt discharge. The runoff analyses revealed that, in spite of the 5.6% glacierized area, the glacier-melt discharge comprises 35.2 to 54.2% of the river discharge. The simulations of the SSC and SiO2 series suggest that the suspended sediment originates mostly from glacierized regions, and SiO2 mainly from the mineral layer in the permafrost regions.Key words forest fires; glacier; permafrost; sediment load; Tanana River; tank model


Measuring the fluxes of suspended sediment, trace elements and nutrients for the City of Atlanta, USA: insights on the global water quality impacts of increasing urbanization

ARTHUR J. HOROWITZ, KENT A. ELRICK & JAMES J. SMITHUS Geological Survey, Peachtree Business Center, 3039 Amwiler Road, Atlanta, Georgia 30360, [email protected]

Abstract During 2004 and 2005, suspended sediment fluxes from the City of Atlanta amounted to about 150 000 t year-1; 94% of the transport occurred in conjunction with stormflow, which also accounted for 65% of the annual discharge; typically, stormflow occurred during 20% of the year. Based on annual median chemical concentrations for baseflow and stormflow, the annual fluxes of 75% of trace elements (e.g. Cu, Pb, Zn), major elements (e.g. Fe, Al) and total P were sediment-associated; in turn, 90% of this transport was storm-related. As such, baseflow sediment-associated and all dissolved contributions represent a relatively insignificant portion of the total annual load. An exception is total N, whose sediment-associated fluxes range from 50 to 60%; even so, storm-related transport exceeded 80% of the total. Key words Atlanta City; global water quality; suspended sediment; trace elements; urbanization


Assessing the effects of design and climate change on sediment

removal in urban stormwater ponds

CATHERINE T. MORGAN1, KATE V. HEAL2, STEVE G. WALLIS1 & REBECCA J. LUNN3

1 School of the Built Environment, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK2 School of GeoSciences, The University of Edinburgh, Crew Building, The King's Buildings, West Mains Road,

Edinburgh EH9 3JN, [email protected]

3 Department of Civil Engineering, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG, UK

Abstract Urban stormwater pond design normally only considers single storm events, does not explicitly consider climate change and is often inconsistent, with some approaches emphasising flow attenuation and others emphasising water quality enhancement. These design issues were explored for sediment removal (by settling) through modelling generic cylindrical ponds sized using current UK guidance. Results showed that ponds designed for flow attenuation had a higher sediment removal efficiency than those designed for water quality enhancement (78% vs 21% removal of incoming sediment, respectively, for the 1 in 2 year storm event). Sediment removal efficiency remained almost unchanged when multiple rather than single storm events were routed through ponds, but decreased with increasing storm event magnitude. Overall, decreased sediment removal is likely from the more frequent and intense storm events predicted due to climate change. Urban stormwater ponds designed for flow attenuation are more successful for both flow and sediment attenuation.Key words climate change; design; modelling; ponds; retention basins; Scotland; sediment; SUDS; urban stormwater


Scale-related sediment and phosphorus transfers in small agricultural catchments

CLARE DEASY1,3, RICHARD E. BRAZIER2, A. LOUISE HEATHWAITE3 & ROBIN HODGKINSON4

1 Department of Geography, University of Sheffield, Winter Street, Sheffield S10 2TN, UK2 Department of Geography, University of Exeter, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, UK3 The Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK

[email protected] ADAS Gleadthorpe Research Centre, Meden Vale, Mansfield, Nottinghamshire NG20 9PF, UK

Abstract Gaining a better understanding of the processes and linkages operating in agricultural catchments is essential in understanding how diffuse sources of pollution influence the water quality of fluvial systems. One of the key limitations is the lack of available data at a range of spatial scales, which is necessary in order to improve process understanding and model develop-ment. Carefully designed field-based research has the potential to improve predictions of water quality in agricultural catchments, which is particularly important given the context of changing climate and land use. Event-based fluxes of sediment and phosphorus were monitored at different scales in a first-order agricultural catchment in Herefordshire, UK, and the data have enabled characterisation of their behaviour and identification of relationships at various scales from hillslope patches of 60 m length to a 30 ha first-order catchment. The results shown here indicate

the differing behaviour of both sediment and phosphorus over six events throughout two hydrological years between two scales of observation: the hillslope and the catchment.Key words field monitoring; catchment; sediment; phosphorus; soil erosion; scale


Modelling climate change impact on phosphorus load in Swedish rivers

JÖRGEN ROSBERG & BERIT ARHEIMERSwedish Meteorological and Hydrological Institute (SMHI), SE-60176 Norrköping, [email protected]

Abstract Climate change impact on phosphorus load is modelled and compared for two Swedish rivers with different characteristics. The modelling was based on the ECHAM4/OPYC3 B2 scenario, downscaled with the RCA3 model and a complementary scaling procedure. Hydrology and phosphorus concentrations were simulated for the time period 1961–2100, using the ICECREAM model for arable leaching, and HBV-NP model for integrated catchment analysis including all sources, erosion and major turnover processes at the catchment scale. The results show 10% increased load, and 25% reduced load, respectively, for the rivers. In both catchments, phosphorus leaching from crops was found to increase; however, this load was only a minor fraction in one river. For the other river, a suggested plan of measures for reducing load was found to be less effective in a future climate. Finally, the study concludes that climate change impact studies are based on a chain of assumptions and uncertainties which should be emphasised in future research.Key words catchments; climate change impact study; phosphorus; river load; Sweden

Water Quality and Sediment Behaviour of the Future: Predictions for the 21st Century (Proceedings of Symposium HS2005 at IUGG2007, Perugia, July 2007). IAHS Publ. 314, 2007, 98-107.

Groundwater–surface water exchange fluxes in a Pleistocene lowland and the impacts on riparian zone water balance and nitrate conditions

STEFAN KRAUSE1, AXEL BRONSTERT2 & ERWIN ZEHE2

1 Centre for Sustainable Water Management, Lancaster Environment Centre, Lancaster LA1 4YQ, UK [email protected]

2 Institute for Geoecology, Potsdam University, PO Box 601553, D-14415 Potsdam, Germany

Abstract Water balance and groundwater nitrate dynamics within the riparian flood plain of the Havel River in northeast Germany are investigated by experimental analyses as well as by model simulations, using a coupled soil water balance and groundwater model approach. The model simulations indicate a substantial impact of exchange fluxes across the groundwater–surface water interface on the riparian water balance, the river discharge, as well as on the nitrate dynamics within the groundwater and river. Experimental and model-based results give evidence

that the impact of groundwater contributions and associated nitrate fluxes from the riparian flood plain are temporally very variable. Substantial seasonal variations in the riparian groundwater-borne nitrate contributions to river discharge are observed. Hence, nitrate contributions from the groundwater represent a significant proportion of the observed loads in the Havel River during summer, when discharge and nutrient conditions in the surface waters are crucial for the ecological health of the lowland river. Key words riparian; flood plain; nitrate; groundwater; surface water; coupled model


Effect of frequent storms on nutrient discharge in a mountainous coastal catchment, western Japan

SHIN-ICHI ONODERA1, MISA SAWANO1, MITSUYO SAITO2 & HIDEHIRO TAKAHASHI3

1 Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, Japan [email protected]

2 JSPS research fellowship, Graduate School of Biosphere Sciences, Hiroshima University, Higashi-Hiroshima, 7398521, Japan

3 National Agricultural Research Center for Western Region, Fukuyama, 7218514, Japan

Abstract In order to forecast the variation of nutrient load with climate change, the long-term change in rainfall and its effect on river runoff in a study catchment were investigated and related to change in nutrient discharge to the ocean. In the study area there has been a decreasing rainfall trend for 40 years but the frequency of large rainfall events has remained constant. The annual runoff decreased by 60 mm in the last 40 years, but large annual runoff amounts were observed in years with large rainfall events. The nutrient discharge also reflected the rainfall and runoff trends. DN load has increased in the long term, while in drought years DP load has increased, reflecting the dominant groundwater contribution with significantly higher DP concentrations in such conditions.Key words groundwater; heavy storm event; nutrient discharge; river


Evaluation des méthodes d’estimation de flux événementiels des nitrates et d’atrazine sur un bassin agricole

ADILSON PINHEIRO1, FLAVIE CERNESSON2 & JEAN FRANÇOIS DUBERNET3

1 Universidade Regional de Blumenau, rua São Paulo, 3250 CP 1507, 89030-350 Blumenau, SC, Bré[email protected]

2 UMR TETIS Cemagref–AgroParisTech ENGREF-CIRAD, Maison de la Télédétection, 500 rue JF Breton, F-34093 Montpellier Cedex 5, France

3 CEMAGREF, Groupement de Bordeaux – UR Réseau Epuration Qualité des Eaux, 50 Avenue de Verdun, F-33612 Cestas Cedex, France

Resumé L’estimation des flux de polluants sur un bassin versant est un problème récurrent pour les gestionnaires des ressources en eau. La littérature présente différentes méthodes d’estimation de ces flux. Ce travail a pour objectif l’évaluation de l’utilisation de quatre méthodes pour l’estimation de flux de nitrate et d’atrazine lors d’évènements pluvieux générateurs de crues. On évalue ensuite la précision des estimations de ces flux pour différents pas d’échantillonnage. Le flux calculé avec les données horaires est pris comme référence. Deux critères d’évaluation sont utilisés: la différence entre le flux estimé et le flux de référence, et le RMSE (racine carrée de la moyenne des erreurs carrées). On constate des différences significatives, qui augmentent avec le pas de temps d’échantillonnage. On démontre qu’il est intéressant de prendre en compte les incertitudes liées à la méthode adoptée pour l’estimation des flux. Mots clefs incertitude; flux de polluants; nitrates; atrazine

Evaluation of estimation methods for nitrate and atrazine loads during rainfall events in agricultural catchments Abstract To estimate pollutant loads on a catchment is a recurring problem for water resources managers. The literature presents many different methods for estimating these pollutant loads. The aim of this paper is to assess four methods used to estimate nitrate and atrazine loads during rain events. Then, the precision of these estimations for various sampling time steps is assessed. The reference load is calculated using hourly data. Two criteria of evaluation are used: the difference between the estimated and reference loads, and the RMSE (root mean squared error). Significant differences are observed and they increase with the length of the sampling time step. It is demonstrated that it is important to take into account uncertainties related to the method adopted to estimate pollutant load.Key words uncertainty; pollutant loads; nitrate; atrazine


Modelling catchment-scale nitrate transport using a combined process-based and data-driven approach

RAJESH RAJ SHRESTHA & MICHAEL RODEDepartment of Hydrological Modelling, UFZ – Helmholtz Centre for Environmental Research, Brueckstrasse 3a, D-39114 Magdeburg, Germany [email protected]

Abstract Diffuse nitrate pollution in catchments is mainly driven by hydrological flow components characterised by complex relationships with streamflow nitrate concentration. This paper demonstrates a combined process-based–artificial neural network (ANN) approach for the simulation of streamflow nitrate concentration based on the relationships between driving and resultant variables. The simulated hydrological flow components from a process based WaSiM-ETH model, together with observations, are used to train two different ANNs. The results show a reasonable match between observed and simulated streamflow and nitrate-N concentration. The ANN with temperature as an input performed better than the ANN without it, indicating the effect of seasonal variability. Nash-Sutcliffe coefficients of 0.746 and 0.856 were obtained for streamflow in calibration and test periods, respectively, while these coefficients were 0.819, 0.629 and 0.627 for nitrate-N concentration in training, cross-validation and test periods, respectively. Hence, the combined approach offers an effective and efficient methodology for modelling catchment scale nitrate dynamics.Key words artificial neural network; hybrid model; nitrate transport; water balance


Long-term trend of uranium concentrations in Beaverlodge Lake, Saskatchewan, Canada, under mine decommissioning

HUAXIA YAO1, ROBERT KIDD1 & MICHIO HASHINO2

1 Environmental Protection Branch, Department of Environment, Box 3003, 800 Central Ave, Prince Albert, Saskatchewan S6V 6G1, [email protected]

2 Department of Civil Engineering, The University of Tokushima, 2-1 Minami-josanjima, Tokushima 770-8506, Japan

Abstract The annual mass balance of uranium for Beaverlodge Lake (which is impacted by uranium mining) was analysed using limited observation data. Annual water discharges of the basin, or discharges at the lake outlet are estimated using the discharge ratios of a sub-basin from 1985 to 2006. Uranium loadings are determined using observed concentrations and discharges from two creeks flowing into Beaverlodge Lake. The relationships between inflow loadings, outflow volumes and lake concentration changes are established. Then, given the trends of loading, the long-term trends of outflows from the lake and concentrations in the lake are predicted. Along with a continuous reduction in loadings from 3473 kg/year in 1985 to 0 kg/year in 2092, uranium concentration of the lake decreases from 125 g/L in 1985 to 10 g/L in 2118. The natural restoration of the lake water would need 112 years to reach the 10 g/L Canadian drinking water standard.Key words trend; uranium; lake; mine decommissioning; Saskatchewan; mass balance; loading; discharge


The distribution of heavy metals in a highly regulated river: the River Murray, Australia

MARTIN C. THOMS Riverine Landscapes Research Laboratory, Resource and Environmental Sciences, University of Canberra, ACT 2601, [email protected]

Abstract Dams and weirs are efficient traps for sediments and associated pollutants. They interrupt the downstream movement of material, leading to changes in sediment composition. The lower reach of the River Murray, in southeast Australia, is regulated along its 830 km length by a series of ten weirs constructed between 1929 and 1935. Large amounts of sediment have accumulated in each weir pool, and in response to flow regulation the river has initiated a series of channel adjustments. Surface sediment samples taken along 154 km of the river between Locks 2 and 4 reveal the impact of these structures on the textural and geochemical composition of the sediment. Downstream of each weir, surficial sediments were found to be well-sorted medium sands, while poorly sorted fine sands, silts and clays were found downstream (above the next successive weir). Concentrations of sediment-associated chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) were up to five times background levels, presumably as a result of increased agricultural and urban development. Peak heavy metal loadings in the sediment were found in the depositing areas above each weir. It thus appears that maximum environmental

disturbance occurred some distance from urbanization. Since heavy metal loads are amplified by changes in sediment texture, the spatial concentrations of these pollutants reflect sediment-transport factors associated with the presence of weirs. We also calculate, for this section of the River Murray, the long-term heavy metal concentrations arising from unabated pollutant runoff from urban areas, and the results provide cause for concern.Key words serial impoundments; sediment quality; urbanization


Assessing water–sediment processes for metals in rivers polluted by mining to predict environmental impacts in developing countries

M. AURORA ARMIENTA1, AZUCENA DÓTOR1, FLOR E. ARCEGA-CABRERA2, OSCAR TALAVERA3, ALEJANDRA AGUAYO1, NORA CENICEROS1 & OLIVIA CRUZ1

1 Instituto de Geofísica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, CU, México 04510 DF, México [email protected]

2 Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autonoma de Mexico, CU, México 04510 DF, México

3 Escuela Regional de Ciencias de la Tierra, UA de Guerrero, Taxco El Viejo, Guerrero, México

Abstract Water–sediment geochemical processes influencing As, Pb, Zn, Cu and Fe mobilization were investigated in a river within the historic mining area of Taxco, México. Tailings wash off and acid mine drainage have led to concentrations of metals in sediments well above the regional background. Zinc and lead associate with the carbonate fraction, followed by Fe oxi-hydroxides. Arsenic and Fe concentrate in the residual fraction, followed by organic matter/sulphide and Fe oxi-hydroxides. Metals are mainly transported as particulates in the water. Calcium, silicate and iron minerals are oversaturated in the river water. Limestones play a key role in the contaminant behaviour. Principal components analysis indicated that Zn, Cu and Pb may be released to the water following small changes in physico-chemical and/or hydrogeological conditions. Application of straightforward analytical techniques jointly with geochemical and statistical evaluation, is an affordable alternative to clarify the environmental impact of mining wastes in developing countries. Key words mining; contamination; metals; river; sediments; Mexico; hydrogeochemistry; principal components; limestones; Taxco


The distribution of metals (Co, As and Zn) in a residential urban watershed, typical of the Brazilian suburbs

CRISTIANO POLETO & GUSTAVO HENRIQUE MERTENHydraulic Research Institute - IPH, Federal University of Rio Grande do Sul - UFRGS, Avenida Bento Gonçalves 9500, Caixa Postal 150.29, Porto Alegre, [email protected]

Abstract Environmental contamination by heavy metals has been a constant concern in areas with industrial activity. However, little research has been devoted to the presence of metals in residential areas, especially in the urban periphery. In Brazil, these areas are characterized by disordered urban development and mixed land use, including homes, businesses and services. There is normally no control over point source pollution (domestic sewage, motor oils) in these areas, much less non-point source pollution (sediment from paved and unpaved roads). This study seeks to investigate the concentrations of Co, As and Zn in soil and aquatic environments in a 0.83 km2 urban watershed in the metropolitan region of Porto Alegre, in southern Brazil. Forty-seven samples per km2 were collected from paved and unpaved roads, vegetated areas, the riverbed and its banks. The presence of metals in suspended fluvial sediment was also studied, and sequential extraction was performed to evaluate the geochemical fractions occupied by these metals. Analysis indicates that the metals in question are widely distributed throughout the study area, with higher concentrations in streets with more intense automobile traffic. The metals were found in concentrations above the background values in fluvial sediment; however, sequential extractions showed that both Co and As are found mainly (>50%) in the crystalline phase, offering little risk to the aquatic environment. On the other hand, Zn was distributed among the easily reducible (12%), oxides (41%) and carbonates (20%), representing greater mobility in the aquatic environment in the event of changes in the pH and/or Eh of the water. This non-industrial study area presented high concentrations of the three metals studied, but only Zn poses significant risk of contaminating the aquatic environment.Key words urban sediments; metals; sequential extraction


Quantifying sediment deposition and the spatial variability of sediment-associated metals in ponds treating urban diffuse pollution

ALAN J. JONES1, KATE V. HEAL1, NEIL STUART2, STEVE G. WALLIS3, REBECCA J. LUNN4 & BARBARA BARBARITO5

1 Institute of Atmospheric & Environmental Science, School of GeoSciences, The University of Edinburgh, Crew Building, The King's Buildings, West Mains Road, Edinburgh EH9 3JN, [email protected]

2 Institute of Geography, School of GeoSciences, The University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, UK

3 School of the Built Environment, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK4 Department of Civil Engineering, University of Strathclyde, John Anderson Building,

107 Rottenrow, Glasgow G4 0NG, UK5 Scottish Water, Castle House, 6 Castle Drive, Carnegie Campus, Dunfermline KY11 8GG, UK

Abstract Studies examining the accumulation of sediments within retention ponds have tended to provide spatially averaged estimates of deposition rates and have not accounted for the spatial variability of deposition and the potential role that developing morphological and sedimentary structures play in the routing of flow and potential contaminants within retention ponds. Additionally, studies examining the potential metal contamination of retention pond sediments have tended to examine individual cores at metre intervals. In this paper, the utility of ground-penetrating radar to provide a rapid means of delineating present pond-morphology and to also provide an estimate of sediment deposit thickness within retention ponds is explored. The spatial variability of metals in pond sediments at the centimetre-scale is also examined. Results show

that metal variability around the inlet is high at the centimetre-scale, and that a degree of dependence exists between direction of flow and metal contamination.Key words morphology; ponds; retention basins; Scotland; sediment; sediment deposition; spatial variability; SUDS; urban stormwater


Kohonen self-organising map (KSOM) extracted features for enhancing MLP-ANN prediction models of BOD5

RABEE RUSTUM1, ADEBAYO ADELOYE1 & AURORE SIMALA2

1 School of the Built Environment, Heriot-Watt University, Edinburgh EH14 4AS, UK [email protected]

2 15 bis, allée Marie, F-93360 Neuilly-Plaisance, France

Abstract This paper presents the results of developing a model to predict the concentrations of biological oxygen demand (BOD5), in the effluent of the primary clarifier of an activated sludge wastewater treatment plant, using other easily measurable water quality parameters. The model is based on the Kohonen self-organising map (KSOM) and multi-layered perceptron artificial neural networks (MLP-ANN). The KSOM was used to extract the features of the measured data and to deal with the effects of noise and missing values. The best map units of the measurement vectors over the KSOM were used as inputs to the MLP-ANN to reduce the effects of noise and uncertainty in the measurement data, and to replace the missing elements in these measurements. The results of the KSOM-ANN modelling strategy were found to be better than those obtained by the MLP-ANN trained using the raw measurement data. Key words wastewater treatment plant; primary clarifier modelling; neural networks; Kohonen self-organising map


Simulation by the IPTM-CS model of pesticides found in surface water and groundwater of the Fucino Plain, Italy

EVA PACIONI1, MARCO PETITTA1 & MIGUEL A. MARIÑO2

1 Dipartimento di Scienze della Terra, Università di Roma “La Sapienza”, P. le Aldo Moro 5, Roma, Italy [email protected]

2 Hydrology Program and Department of Civil and Environmental Engineering, University of California, Davis, California 95616, USA

Abstract The agricultural area of the Fucino Plain, Italy, has recently had a transition to intensive agriculture characterized by increased horticultural production with a double or sometimes a triple harvest, and accompanied by high water demand and wide use of pesticides. Water sampling conducted in 2004 and 2006 showed the presence of pesticides, mainly Linuron, Dicloran and Carbaryl. By taking into account pesticide application, irrigation practice, rainfall, evapotranspiration and soil characteristics, mathematical simulations were conducted using the IPTM-CS pesticide transport model. The aim of the simulations is to verify if measured pesticide concentrations agree with a conceptual model based on the amount of pesticide application and its

transport into the water system by runoff or infiltration. Simulations of Linuron, the use of which has been banned in Italy since 2005, showed a higher persistence. This pesticide is mobilized partly by runoff, while infiltration rates allow its transport to shallow groundwater in concentrations up to the limits specified by law.Key words mathematical models; pesticides; runoff; unsaturated zone; groundwater pollution; Italy


Some reflections on the future of the water quality of the Corumbataí River basin, São Paulo State, Brazil

DANIEL MARCOS BONOTTO1 & JORGE LUIS NEPOMUCENO DE LIMA2

1 Instituto de Geociências e Ciências Exatas, UNESP-Universidade Estadual Paulista Júlio de Mesquita Filho, Av. 24-A, No. 1515, CP 178, CEP 13506-900, Rio Claro, São Paulo, [email protected]

2 Departamento de Ciências Exatas, UNIR-Fundação Universidade Federal de Rondônia, Campus de Ji-Paraná, Estrada Itapirema, CEP 78961-170, Ji-Paraná, Rondônia, Brasil

Abstract The waters of Corumbataí River in the middle and eastern part of São Paulo State, Brazil, are extensively used for human consumption; their water quality has been modified mainly due to increasing pressure caused by population growth, accompanied by a more accentuated industrial development for the whole São Paulo State in the early 1970s. The Corumbataí River basin has, over time, received significant emissions of municipal waste products and discharges of wastewater, sludge, sewage, sanitary and industrial effluents, but the first effluent treatment plant at Rio Claro city was only inaugurated at the end of the 1990s. Data on river water quality from two widely spaced locations in the Corumbataí River basin are reported in this paper; they indicate the need for continuous initiatives and efforts by decision makers in order to improve and preserve the water quality in the basin for the 21st century.Key words Corumbataí River basin; water quality; physical and chemical parameters; surface water; rainwater


An assessment of water quality changes within the Athi and Nairobi river basins during the last decade

SHADRACK MULEI KITHIIAPostgraduate Programme in Hydrology, Department of Geography and Environmental Studies, University of Nairobi, PO Box 30197, 00100 GPO, Nairobi, [email protected]

Abstract This paper examines the changes in water quality that have occurred within the Athi and Nairobi river basins in the last decade. The main focus is to examine the trends in water quality degradation, pollutant sources and pollution levels since the early 1990s to year 2000 and beyond. It draws its major findings from two research projects done within the basins over the same period. The two research projects revealed increasing trends in water quality degradation due to changes in land-use systems. Industrial, population (rural–urban migration) growth and


agricultural activities were found to contribute significant amounts of water pollutants, thus degrading the water quality status in the two river basins investigated. This is of major concern to national water policy makers and environmentalists, as well as the Kenyan government in general. This paper reviews some of the possible mitigation strategies as means of mitigating against future water quality degradation trends and to abate the problem in good time. The use of riverine vegetation (macrophytes) and stormwater in the basins are recommended for reducing water quality degradation status in the two basins and other similar catchment areas in the country. Plant species Commelina benglensius, Sphaeranthus napirae and Xanthium pungens proved useful in adsorbing some of the pollutants, and especially heavy metals.Key words trends; water quality degradation; pollution levels; pollutants; riverine vegetation; stormwater; mitigation strategies


Flood flow water quality analysis using low-cost samplers in small rivers

JANAÍNA BEZERRA MESQUITA LIMA1 & SÉRGIO KOIDE2

1 SHIN CA8, LT.03, casa 16, Lago Norte, 71.503-508 Brasilia, DF, [email protected]

2 University of Brasilia, Department of Civil and Environmental Engineering, 70.910-900 Brasilia, DF, Brazil

Abstract Water quality studies require field data for assessment and mathematical simulation. Manual collection of water samples during floods in small rivers is very difficult due to the short event duration and quick response to rainfall. Some low cost siphon samplers presented in the literature have been developed and adapted to collect event-based samples, but they only collect samples when the stream stage is rising. This work presents a new design of a low cost siphon sampler developed to allow collection when the stream stage is decreasing. It was tested in the laboratory and also installed in a river with flood flows strongly dominated by urban runoff. The major problem faced in the field work was to keep the samplers in place due to the amount of debris carried by the floods. Laboratory tests showed water intrusion into the sampler during the rising stage and further improvement is proposed to solve the problem.Key words low cost sampler; water quality sampling; sampler


Community-based monitoring and the science of water quality

C. CONRADDepartment of Geography, Saint Mary’s University, Halifax, Nova Scotia, [email protected]

Abstract Reductions in funding for hydrological monitoring by government agencies, the recognition of the need to involve communities and stakeholders in the planning and delivery of

sustainability, increasing mistrust of the government’s care of the environment and the continued rise in environmental consciousness are all factors which have led to the proliferation of community based monitoring (CBM) initiatives. CBM is a process in which concerned citizens, government agencies, industry, academia, community groups and local institutions collaborate to monitor, track, and respond to issues of common community concern. The UNEP has stated that public participation is an essential component of sustainability, and it has been argued that the integration of community-based monitoring into resource management is one of the most significant developments in this area since the environmental movement itself. The Predictions in Ungauged Basins (PUB) Science Plan, among other purposes, intends to “actively promote capacity building activities in the development of appropriate scientific knowledge and technology to areas and communities where is it needed”. This paper draws on the expertise and experience of working on CBM initiatives through Environment Canada’s Ecological Monitoring and Assessment Network (EMAN) as well as the Community-Based Environmental Monitoring Network in Nova Scotia. Examples are drawn from Nova Scotia, where community watershed groups have undertaken water quality monitoring activities in more than 10 of Nova Scotia’s watersheds. Since the early 1990s they have gathered in excess of 55 monitoring-years of water quality data at over 200 sampling sites. CBM initiatives, in close collaboration with government and academia, following standardized monitoring protocols with careful quality assurance and quality control programmes, have the ability to address otherwise uncertain changes as a result of land-use alterations and climate change. Science alone is not well equipped to model and understand future changes and scientists are even less equipped to reach decision-makers. The community serves a role and a purpose here.Key words community; environment; monitoring; public participation; volunteers; sustainability; watersheds; water quality


Future impacts of freshwater resource management: sensitivity of coastal deltas

CHARLES J. VÖRÖSMARTY1,2, JASON P. ERICSON3, S. LAWRENCE DINGMAN2, LARRY G. WARD2 & MICHEL MEYBECK4

1 Water Systems Analysis Group, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire 03824, [email protected]

2 Earth Sciences Department, University of New Hampshire, Durham, New Hampshire 03824, USA3 Virginia Department of Conservation and Recreation, 101 N. 14th Street, Richmond, Virginia 23219, USA 4 UMR Sisphe, Université de Paris VI, France Case 123, Tour 26, 4 Place Jussieu, F-75257 Paris Cedex 05, France

Abstract We present an assessment of contemporary and future effective sea-level rise (ESLR) using a sample of 40 deltas distributed worldwide. For any delta, ESLR is a net rate defined by eustatic sea-level rise, natural gross rates of fluvial sediment deposition and subsidence, and accelerated subsidence due to groundwater and hydrocarbon extraction. Present-day ESLR, estimated from geospatial data and a simple model of deltaic dynamics, ranges from 0.5 to 12.5 mm year-1. Reduced accretion of fluvial sediment from upstream siltation of reservoirs and freshwater consumptive irrigation losses are primary determinants of ESLR in nearly 70% of the deltas, while for only 12% eustatic sea-level rise predominates. Future scenarios indicate a much larger impact on deltas than previously estimated. Serious challenges to human occupancy of deltas worldwide are conveyed by upland watershed factors, which have been studied less comprehensively than the climate change and sea-level rise question.Key words deltas; sea-level rise; sediment flux; water resource management; siltation; reservoirs


Appropriate use of catchment models for water-quality target setting and land-use management

BRADFORD S. SHERMAN1, JON BRODIE2, LEX COGLE3 & CHRIS CARROLL4

1 CSIRO Land and Water, GPO Box 1666, Canberra, ACT 2601, [email protected]

2 Australian Centre for Tropical Freshwater Research, James Cook University, Douglas, Queensland 4811, Australia3 Queensland Department of Natural Resources, Mines and Water, Mareaba, Queensland 4880, Australia4 Queensland Department of Natural Resources, Mines and Water, Rockhamption,

Queensland 4700, Australia

Abstract Management of land use and the setting of water-quality targets on the whole-catchment scale are typically constrained by a lack of observational data on which to base decisions. Typically, GIS-based models are used to interpolate and extrapolate a limited observational data set to cover an entire catchment and these derived values (pseudo-data) are used as input to catchment contaminant generation and transport models. We examine the impact of the intrinsic uncertainty in pseudo-data on predictions made using the catchment sediment and nutrient model, SedNet/ANNEX, and the consequences of this uncertainty for land-use management planning. The use of pseudo-data to estimate bulk soil properties (% clay, % phosphorus, % nitrogen) exhibited both a high bias and high standard deviation when compared with direct measurements. The high bias limits the usefulness of model predictions for setting quantitative targets. The high standard deviation requires model results to be aggregated over scales considerably larger than the intrinsic model grid to facilitate comparison of contaminant export rates between spatial units. Assessment of competing land management scenarios is not severely impacted by model uncertainty provided the interpretation of results is limited to relative changes in contaminant export.Key words catchment modelling; decision making; uncertainty; Great Barrier Reef; water quality; sediment; nitrogen; phosphorus


Development and application of a Watershed Information System (WIS) for water quality analyses

CONCEICAO DE MARIA ALBUQUERQUE ALVES1 & DANIEL PETE LOUCKS2

1 FUNCEME – Fundação Cearense de Meteorologia e Recursos Hídricos, Av Rui Barbosa, 1246 Fortaleza 60115-221, CE, Brazil [email protected]

2 Cornell University, Hollister Hall, 301, Ithaca, New York 14850, USA [email protected]

Abstract This paper describes the development, implementation and evaluation of a watershed information system (WIS) to assist in the planning of programmes for water quality control in river basins incorporating both point and nonpoint pollutant sources. The system simulates rainfall–runoff processes and the transport of water quality constituents and sediment. WIS includes two nonpoint source models, a network design component, a flow and sediment routing component and a water quality component. Simple models of rainfall–runoff and water quality were selected for WIS. The models in the system are integrated through their inputs and outputs. Friendly Graphical User Interfaces (GUI) facilitate the interaction with user-models. WIS was applied in a watershed in Delaware County, New York. The results showed that the system is a suitable computational tool to identify source areas of pollution in river basins and indicate where more complex modelling and analysis might be recommended.Key words water quality; information system; nonpoint source models; sediment


Groundwater of the future in the Roussillon flood plain: present-day situation and solutions for the 21st century

PIERRE SERRAT

Université de Nancy 2, CERPA - EA-1135 – 23, boulevard Albert 1er, F-54 000 Nancy, France pierre.s [email protected]

Abstract In the Roussillon flood plain (France), as all around the Mediterranean Sea, water resources are not very important. However, for three decades, groundwater pumping has become very excessive. The consequences are clear: the levels of all aquifers are falling and the quality of water is getting worse. This is a serious problem because this water is renewed with an average period of about 5000 to 7000 years. In some wells of the plain, the signs are alarming with low aquifer levels and pollution by nitrates. Near the Mediterranean Sea, penetration by a salt wedge has been recorded. Better management of this resource is required. Several solutions can be put forward, such as the use of water coming from the karst reserves of the Corbieres Mountains, as well as the treatment of river water, stored by means of the existing dams. These solutions have a real cost: the price of sustainable management of the water.Key words groundwater; overexploitation; Mediterranean regions; Roussillon flood plain; water pollution; sustainable development; demography


Nitrate contamination in groundwater of the Yellow River Delta and its effect on the marine environment

MITSUYO SAITO1, SHIN-ICHI ONODERA2, KUNIHIDE MIYAOKA3, JIANYAO CHEN4, MAKOTO TANIGUCHI5, GUANQUN LIU6 & YOSHIHIRO FUKUSHIMA5

1 Graduate School of Biosphere Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 7398521, Japan [email protected]


2 Graduate School of Integrated Arts and Sciences, Hiroshima University, Japan3 Faculty of Education, Mie University, Japan4 School of Geography Sciences and Planning, Zhongshan University, China5 Research Institute for Humanity and Nature (RIHN), Japan6 College of Environmental Science and Engineering, Ocean University of China, China

Abstract The current condition of nitrate (NO3-) contamination in groundwater and its effect on the

marine environment were evaluated in the Yellow River Delta, northeastern China. In the groundwater recharge area, NO3

- contamination is suggested to be more severe compared with that in the groundwater discharge area. Also a relatively large amount of nitrogen is estimated to have accumulated in the aquifer of the recharge area. However, distribution of nitrate-nitrogen (NO 3

--N) concentrations and δ15N implied a denitrification process in the aquifer of the coastal area. In addition, a high rate of denitrification was indicated there by in situ experiments involving injected tracer water with high concentrations of NO3

--N. Based on these results, it is suggested that a large amount of nitrate will be removed before it reaches the sea. Key words Yellow River Delta; nitrate contamination; denitrification process; marine environment


The assessment of groundwater vulnerability in China

TANG LIHUA1,2, ZHANG SICONG1 & YAO WENFENG1

1 Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, [email protected]

2 State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China

Abstract China is one of the countries suffering severely from water shortage. Its water availability per capita is only 25% of the world average. According to new statistics for 2000–2002, the fresh groundwater resource is about 883.7 billion m3, which amounts to 33% of the total water resources in China. Moreover, groundwater plays an important role in water supply. Nearly 20% of the total water consumption is from groundwater, especially in northern China where the percentage of supply from groundwater exceeds 50%, and in some cases even up to 80%. With such a great degree of exploitation, as well as excessive development, many environmental problems have been caused, such as groundwater pollution and overexploitation, which greatly affect humans. In order to further understand the characteristics of groundwater quantity and quality, and to protect groundwater resources, a research assessment of groundwater vulnerability for the whole of China was carried out during the second Comprehensive National Water Resources Planning (CNWRP) exercise that commenced in 2002. Based on abundant data and GIS technology, an integrated assessment model was developed and applied to evaluate the groundwater vulnerability. The results show trends of increasing groundwater vulnerability from north to south, as well as from west to east. Terrain slope, shallow groundwater depth and aquifer media are the three most dominant factors influencing groundwater vulnerability in China as a whole.Key words assessment of groundwater vulnerability; integrated assessment model; GIS


Hydrogeochemistry of groundwater in a part of the hard rock terrain of central India

L. P. CHOURASIADepartment of Applied Geology, Dr H. S. Gour University, Sagar 470003, M. P., Indialpc55@ rediffmail.com

Abstract Hydrogeochemical investigations have been carried out to determine the sources of dissolved ions in groundwater in a part of the hard rock terrain of central India. The high concentration of SiO2 and various geochemical signatures reflect the weathering of minerals. The groundwater chemistry favours the formation of clay minerals due to evaporation. The positive saturation index of calcite and the higher ratio of Mg/Ca and Na/Ca also support the occurrence of evaporation. The evaporation enhances the concentration of ions in groundwater during the summer. The high content of sulphate and chloride in some groundwater, and the occurrence of kankar in the area suggest a long history of evaporation. Greater ion concentrations in the groundwater of the post-monsoon period compared with the pre-monsoon period indicates the increasing addition of leachates into the groundwater from the soil and anthropogenic activities, which leads to a deteriorating quality of groundwater. The Gibbs diagram shows that the groundwater chemistry is controlled by rock weathering to some extent and that evaporation is a dominant factor leading to the deterioration of the quality of groundwater in the area.Key words hydrogeochemistry; groundwater; terrain; central India


Runoff erosion control for a sustainable water supply in Niamey, Niger Republic

ISSOUFOU ABDOULKADERFACOM, Save the Children UK, Tessaoua, Niger [email protected]

Abstract Runoff erosion is very detrimental to soils and their use, especially in semi-arid countries, and controlling it is a day-to-day preoccupation of people and governments. The flowing water erodes farmland and destroys infrastructures. Also, overland flow transports silt and deposits it in depresssions. Silting is one of the most important causes of flow reduction in the River Niger, which serves as the source of domestic water supply for Niamey and other riverside towns and villages. In order to protect this river and its riparian communities, the Niger Republic and the Niamey Urban Communality (CUN) governments adopted a number of measures to control runoff erosion so as to guarantee three million cubic metres of domestic water supply, the need of only a few days. These were mostly structural and/or agronomic methods. The present study examines the control measures in Niamey Township from 2000 to 2006. The methodology used included interviews with the local population, technicians and engineers handling the erosion control activities. Some field investigations were also undertaken to determine the sediments caught upstream of the constructions, and view the effectiveness of the control measures. After a critical examination of the techniques implemented, it emerges that not all were effectively constructed. The efficiency of any erosion control measure is conditioned by the total involvement of the local population. There is, therefore, a need for a large-scale campaign to enlighten the people of the importance of the control activities so as encourage them to fully participate in the control work and in maintaining the existing constructions.Key words erosion control; River Niger flow; CUN (Niamey Urban Communality)


The effect of parent material and land-use on soil erosion: a case study of the Taleghan drainage basin, Iran

SADAT FEIZNIA1 & KAZEM NOSRATI2 1 Faculty of Natural Resources, University of Tehran, PO Box 31585/4314, Karaj, Iran

[email protected] Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran

Abstract The objective of this study was to investigate the effect of parent rock and different land-uses on soil erosion in the Taleghan drainage basin. For this purpose, a geological map of the area was prepared by photogeological studies and field control. Soil profiles were investigated and soil samples were taken on uniform morphological units of each lithological unit. Samples were then analysed for physical and chemical characteristics. Based on physical and chemical characteristics, they were classified and analysed using factor analysis. Three parent materials, including gypsum, alluvial deposits, and basalt, and three land-uses, including rangeland, agriculture and dry-farming cultivation were examined, and soil erodibility factors were derived for each and analysed by variance analysis. The results show that erodibility increases as lithology changes from basalt to alluvial deposits and to gypsum. Erodibility was also highest in areas of dry farming and least for rangelands. Key words erodibility; factor analysis; Iran; land-use; parent material

Water Quality and Sediment Behaviour of the Future: Predictions for the 21st Century (Proceedings of Symposium HS2005 at IUGG2007, Perugia, July 2007). IAHS Publ. 314, 2007., 306-311

Sediment yield in the Daryacheh-Namak drainage basin, Iran, and its relation to land-use changes

SADAT FEIZNIA1, ABDOLHOSSEIN MOHAMMADI2 & SEPIDEH ZAKIKHANI3

1 Faculty of Natural Resources, University of Tehran, Karaj, [email protected]

2 Jehad –Agriculture Research Center of Markazy Province, Iran 3 Faculty of Civil Engineering, Sharif University of Technology, Tehran, Iran

Abstract Monthly and annual variations in sediment yield during a 24-year period were analysed for 10 sub-catchments in the Daryacheh-Namak drainage basin, Iran. Highest specific suspended sediment yields were recorded at Razin and the lowest at Solan, reflecting large land-use changes in the former, and the presence of relatively resistant formations in the latter sub-catchment. Highest sediment yields were observed in the months of April, March, May and November, and the lowest in September and August. At almost all stations, the highest sediment yield occurs in the spring, reflecting higher rainfall in that season.Key words Daryacheh-Namak drainage basin; monthly and annual variation; sediment yield


Implications of changes in river sediments during the 21st century for freshwater ecosystems in northeast India

U. C. SHARMA1 & VIKAS SHARMA2

1 Center for Natural Resources Management, PO Tarore, District Jammu-181133, J & K, India [email protected]

2 S. K. University of Agricultural Sciences & Technology, Chatha, Jammu-180009, J & K, India

Abstract Sediment delivery to the river and stream network in the northeastern region of India is expected to increase from 601 million tonnes in 2001, to about 981 and 1167 million tonnes by the years 2050 and 2100, respectively. This will substantially increase the river sediments, thereby increasing flood incidence and magnitude and affecting freshwater resources and environmental quality. The Doolittle method was used to develop a model based on a partial regression equation: runoff (% of rainfall) = 9.293 + 0.147 slope (%) + 0.048 rainfall (cm) – 1.469 vegetation + 0.054 soil moisture (%) – 0.125 soil clay (%), for runoff generation. In pursuit of increasing agricultural production, a rapid increase in the use of agricultural chemicals will further degrade the freshwater resources, affect the health of humans and aquatic ecosystems, and alter the carbon cycle and biological and life support ecosystem in the region.Key words implications; river sediments; freshwater resources; northeastern region of India; 21st century

__________________________________________________________hydrologie.org/redbooks/a314/p314...

Documents