In a recent development in the literature, a new temporal rainfall model,
based on the Bartlett-Lewis clustering mechanism and intended for sub-hourly
application, was introduced. That model replaced the rectangular rain cells of
the original model with finite Poisson processes of instantaneous pulses,
allowing greater variability in rainfall intensity over short intervals. In the
present paper, the basic instantaneous pulse model is first extended to allow
for randomly varying storm types. A systematic comparison of a number of key
model variants, fitted to 5-minute rainfall data from Germany, then generates
further new insights into the models, leading to the development of an
additional model extension, which introduces dependence between rainfall
intensity and duration in a simple way. The new model retains the original
rectangular cells, previously assumed inappropriate for fine-scale data,
obviating the need for the computationally more intensive instantaneous pulse
La méthode SHYREG est une approche développée pour la connaissance régionale de l’aléa pluvial (SHYREG pluie) et hydrologique (SHYREG débit) en tout point du territoire français. Elle est basée sur le couplage d’un générateur stochastique de pluie horaire et d’un modèle hydrologique. Cet article présente les résultats de la mise en œuvre de la méthode sur 1605 bassins versants répartis sur la France métropolitaine. Sur les fréquences courantes (c.à.d. périodes de retour inférieures à 10 ans), la méthode restitue correctement les quantiles de débit de crue ajustés à une loi statistique sur les observations (loi GEV, selon le critère de Nash-Sutcliffe). Plusieurs critères sont utilisés pour valider l’extrapolation des débits à des fréquences extrêmes: (a) en la confrontant à de longues chroniques de débits observés, (b) en analysant dans le modèle hydrologique la saturation du réservoir de production synonyme de comportement asymptotique avec les pluies, et (c) en étudiant la stabilité de la méthode à travers les critères statistiques. Editeur Z.W. Kundzewicz; Editeur associé G. MahéCitation Aubert, Y., Arnaud, P., Ribstein, P., et Fine, J.-A., 2014. La méthode SHYREG débit, application sur 1605 bassins versants en France Métropolitaine. Hydrological Sciences Journal, 59 (5), 993–1005.
Les recherches sur l'hydrologie, l'hydrochimie et les phénomènes d'érosion mécanique menées dans le bassin versant du Rimbaud (1,46 km2) après l'incendie de forêt d'août 1990, ont permis la mise au point d'une méthode de décomposition des hydrogrammes entre les eaux fournies par le ruissellement sur les versants et les eaux ayant effectué un trajet souterrain. La décomposition utilise comme traceur le sodium ou les ions chlorures, deux éléments dont les concentrations mesurées dans la pluie ne subissent pas de modification au contact du sol après la destruction du couvert végétal. Les essais conduits avec l'oxygène-18 n'ont pas été concluants. Deux crues, les plus représentatives du comportement impulsionnel du ruisseau du Rimbaud après l'incendie, ont été décomposées. L'une s'est produite en début d'année hydrologique (27 septembre 1992 – P : 72,0 mm), l'autre à la fin des pluies d'automne (9 décembre 1990 – P : 87,7 mm). Ces deux épisodes diffèrent très nettement par l'abondance des écoulements générés par les précipitations (coefficient d'écoulement total : 18,6 % en septembre 1992 ; 87,5 % en décembre 1990). Mais elles se ressemblent par les débits maxima (7,7 et 7,8 m3/s) et par l'importance des eaux fournies par le ruissellement sur les versants pendant la crue elle-même. Cette source d'alimentation représente 89 % du débit de pointe et 76 % du volume d'eau écoulé pendant la crue du 27 septembre 1992 ; 89 % du débit de pointe et 47 % du volume d'eau écoulé pendant la crue du 9 décembre 1990.
The lower course of the Acheloos River is an important hydrosystem in Greece, heavily modified by a cascade of four hydropower dams upstream, which is now being extended by two more dams in the upper course. The design of the dams and hydropower facilities that are in operation has not considered any environmental criteria. However, in the last 50 years, numerous methodologies have been proposed to assess the negative impacts of such projects to both the abiotic and biotic environment, and to provide decision support towards establishing appropriate constraints on their operation, typically in terms of minimum flow requirements. In this study, seeking a more environmentally-friendly operation of the hydrosystem, we investigate the outflow policy from the most downstream dam, examining alternative environmental flow approaches. Accounting for data limitations, we recommend the basic flow method, which is parsimonious and suitable for Mediterranean rivers, whose flows exhibit strong variability across seasons. We also show that the wetted perimeter–discharge method, which is an elementary hydraulic approach, provides consistent results, even without using any flow data. Finally, we examine the adaptation of the proposed flow policy (including artificial flooding) to the real-time hydropower generation schedule, and the management of the resulting conflicts. Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Efstratiadis, A., Tegos, A., Varveris, A., and Koutsoyiannis, D., 2014. Assessment of environmental flows under limited data availability: case study of the Acheloos River, Greece. Hydrological Sciences Journal, 59 (3–4), 731–750.
Sulphide mine waste extensively contaminates the Odiel River (Pyrite Belt, Huelva, SW Spain), releasing sulphuric acid in running water. Acidic water in this river precipitates and dissolves variably hydrated iron sulphate in a complex geological pattern controlled by climate. Imaging spectroscopy using Hymap data is used to assess the monitoring of environmental parameters in water. Local abrupt changes in water pH in the vicinity of highly contaminated tributaries can be mapped using Hymap data. Also, increased pH through mixing acidic river water with marine water can be detected when the river reaches the area influenced by sea tides. Mapping the quality of water with hyperspectral data is confounded by vegetation, dry or wet, rooted or floating. The spectral features of acidic water measured with a field spectrometer revealed the spectral influence of green vegetation, similar to the influence of the depth and transparency of water. A careful map of such parameters with hyperspectral Hymap data must precede any spectral evaluation of water related to acidity in a river course. The spectral features detectable by Hymap data associated with pH changes related to the intensity of contamination in river water by iron sulphide mine waste and their controls are described, establishing references for routine monitoring through hyperspectral image processing.
Quantifying the reliability of distributed hydrological models is an important task in hydrology to understand their ability to estimate energy and water fluxes at the agricultural district scale as well the basin scale for water resources management in drought monitoring and flood forecasting. In this context, the paper presents an intercomparison of simulated representative equilibrium temperature (RET) derived from a distributed energy water balance model and remotely-sensed land surface temperature (LST) at spatial scales from the agricultural field to the river basin. The main objective of the study is to evaluate the use of LST retrieved from operational remote sensing data at different spatial and temporal resolutions for the internal validation of a distributed hydrological model to control its mass balance accuracy as a complementary method to traditional calibration with discharge measurements at control river cross-sections. Modelled and observed LST from different radiometric sensors located on the ground surface, on an aeroplane and a satellite are compared for a maize field in Landriano (Italy), the agricultural district of Barrax (Spain) and the Upper Po River basin (Italy). A good ability of the model in reproducing the observed LST values in terms of mean bias error, root mean square error, relative error and Nash-Sutcliffe index is shown.
Editor Z.W. Kundzewicz; Associate editor D. Gerten
This article addresses the critical need for a better quantitative understanding of how water resources from the Herault River catchment in France have been influenced by climate variability and the increasing pressure of human activity over the last 50years. A method is proposed for assessing the relative impacts of climate and growing water demand on the decrease in discharge observed at various gauging stations in the periods 1961-1980 and 1981-2010. An annual water balance at the basin scale was calculated first, taking into account precipitation, actual evapotranspiration, water withdrawals and water discharge. Next, the evolution of the seasonal variability in hydroclimatic conditions and water withdrawals was studied. The catchment was then divided into zones according to the main geographical characteristics to investigate the heterogeneity of the climatic and human dynamics. This delimitation took into account the distribution of climate, topography, lithology, land cover and water uses, as well as the availability of discharge series. At the area scale, annual water balances were calculated to understand the internal changes that occurred in the catchment between both past periods. The decrease in runoff can be explained by the decrease in winter precipitation in the upstream areas and by the increase during summer in both water withdrawals and evapotranspiration in the downstream areas, mainly due to the increase in temperature. Thus, water stress increased in summer by 35%. This work is the first step of a larger research project to assess possible future changes in the capacity to satisfy water demand in the Herault River catchment, using a model that combines hydrological processes and water demand.
The objectives of this study were to discover the relationship between variables in a water reservoir and the hydrochemical variations related to acid mine drainage (AMD), and to describe the horizontal stratification related to vertical salinity and variations in metals present in the region. The information obtained may be used for establishing risk evaluation criteria and to design future remediation strategies, which could be useful for new dams. The hydrochemical characterization was based on a sampling campaign performed in October 2011. A total of 28 samples, at 1-m-deep intervals, were obtained. The hydrogeochemical study of the polluted reservoir shows that the dilution effect is not sufficient to neutralize AMD contributions from mining activity. Sampling carried out from the surface water to the deepest points reveals stratification of the reservoir that allows it to be included in the group of monomictic and holomitic lakes. Editor D. Koutsoyiannis; Associate editor M.D. FidelibusCitation Cerón, J.C., Grande, J.A., de la Torre, M.L., Borrego, J., Santisteban, M., and Valente, T., 2014. Hydrochemical characterization of an acid mine drainage-affected reservoir: the Sancho Reservoir, Huelva, southwest Spain. Hydrological Sciences Journal, 59 (6), 1213–1224. http://dx.doi.org/10.1080/02626667.2013.834341
Ce travail est une synthèse des connaissances actuelles du bilan des transports en solution et en suspension sur un grand bassin forestier équatorial. Une large place est faite aux mesures effectuées dans le cadre de l'opération grands bassins fluviaux du programme PIRAT. Les résultats obtenus sur le fleuve Congo à Brazzaville (95% de la superficie totale du bassin soit 3.5 X 10 puissance 6 km2) chiffrent les exportations moyennes de la façon suivante : matières dissoutes : 61.1 X 10 puissance 6 t an -1; et matières en suspension : 30.6 X 10 puissance 6 t an -1. La caractérisation hydrochique de la matière dissoute révèle une faible minéralisation des eaux du fleuve. (Résumé d'auteur)
An approach is presented for desktop-level environmental flow requirement (EFR) determination that is aligned with the Habitat Flow–Stressor Response (HFSR) method which evolved in South Africa over recent years. The HFSR method integrates hydrological, hydraulic and ecological habitat data, involves ecological and hydraulic specialists and is data-intensive and time-consuming. The revised desktop method integrates hydrological information with estimates of channel hydraulic cross-sectional characteristics to generate habitat-type frequencies under changing flow conditions. This information is used with the expected natural habitat requirements to determine acceptable habitat availability under different levels of ecological protection, which is then used with the hydraulic data to define flow regime characteristics that meet the ecological objectives. The paper describes the model components, discusses the assumptions, data requirements and limitations and presents some example results. The revised desktop approach uses approaches that are aligned with the more complex methods and generates results that are similar.Editor D. Koutsoyiannis; Guest editor M. AcremanCitation Hughes, D.A., Desai, A.Y., Birkhead, A.L., and Louw, D., 2014. A new approach to rapid, desktop-level, environmental flow assessments for rivers in South Africa. Hydrological Sciences Journal, 59 (3–4), 673–687.
Available data on suspended sediment transported by rivers in the Maghreb are reviewed for 130 drainage basins. These data allow a new estimate to be proposed for the delivery of river sediment to both the Atlantic Ocean and the Mediterranean Sea from the Maghreb region. The influences of several environmental factors (precipitation, runoff, drainage area size and lithology) on mechanical erosion and fluvial sediment transport are analysed. Finally, a multiple regression model is proposed to estimate the river sediment yields in the Maghreb.
Environmental flow provisions are a legal obligation under South Africa’s National Water Act (1998) where they are known as the “ecological reserve”, which is now being realized in river operations. This article presents a semi-quantitative method, based on flow–duration curve (FDC) analysis, used to assess the compliance of the Crocodile (East) River with the reserve in an historical context. Using both monthly and daily average flow data, we determine the extent and magnitude of non-compliant flows against environmental water requirements (EWRs) for three periods (1960–1983, 1983–2000, and 2000–2010). The results suggest a high degree of non-compliance, with the reserve increasing with each of these periods (14%, 35%, and 39% of the time), respectively, where effects were most pronounced in the low-flow season. The results also suggest that, whilst the magnitudes of reserve infringements for the latter period are relatively high, there appears to have been some improvement since the implementation of the river’s operating rules. Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Riddell, E., Pollard, S., Mallory, S., and Sawunyama, T., 2014. A methodology for historical assessment of compliance with environmental water allocations: lessons from the Crocodile (East) River, South Africa. Hydrological Sciences Journal, 59 (3–4), 831–843.
Ce travail établit les signaux cohérents de la variabilité climatique de l'Afrique centrale grâce à une base de données pluviométriques originale, vérifiée et couvrant la période 1951-1990. Les résultats statistiques indiquent que l'Afrique centrale n'est pas un ensemble pluviométrique uniforme qui varie de façon homogène à l'échelle interannuelle. Il est tout de même possible d'observer plusieurs analogies avec la variabilité d'autres régions africaines, notamment les transitions interannuelles enregistrées sur la période 1951-1990. Il semble également que les principales fluctuations pluviométriques de l'Afrique centrale correspondent à des modifications de l'amplitude saisonnière. (Résumé d'auteur)
Des bilans hydriques comparatifs ont été établis par des mesures (pluies, ruissellement, humidité du sol) et des calculs (évapotranspiration, drainage) dans six parcelles expérimentales d'Afrique Occidentale le long d'une séquence bioclimatique allant de la Basse Côte d'Ivoire à la Haute-Volta Centrale. Ces bilans montrent l'évolution de termes du bilan hydrique en fonction du bioclimat, de l'utilisation du sol et des caractéristiques pédologiques. Dans les parcelles non aménagées (végétation naturelle), le terme ruissellement reste faible quel que soit le couvert végétal (1% à 2% des pluies annuelles). Le drainage profond tend vers zéro quand les pluies annuelles deviennent inférieures à 900–1000 mm (régions équatoriales) et à 700–800 mm (régions tropicales). Dans les parcelles cultivées, le ruissellement augmente beaucoup, mais l'écoulement total (ruissellement + écoulement de base) n'augmente pas nécessairement. Les sols profonds, à forte réserve hydrique, favorisent l'augmentation de l'évapotranspiration aux dépens d'un drainage profond.
Les pays sub-sahariens basent principalement leur économie sur l’agriculture pluviale. Les projections démographiques à moyen ou long terme montrent que la pression démographique va s’accroître très fortement. A l’avenir, il faudra soutenir encore plus fortement le développement de stratégies agricoles de ces pays : cela nécessite une meilleure connaissance de leurs ressources en eau futures. Cette connaissance de la ressource en eau dans le futur passe par l’élaboration de scenarios climatiques et hydrologiques qui font intervenir différents acteurs, compétents dans des activités très variées, qu’ils soient scientifiques de divers domaines (climatologues, hydrologues, sociologues, …) mais aussi financiers, politiques, acteurs sociaux et décideurs. Ce processus d’élaboration de scenarios s’accompagne de nombreuses incertitudes, plus ou moins bien maitrisées, avec lesquelles doivent s’accommoder les gestionnaires d’ouvrages et planificateurs d’aménagements régionaux. Illustré par l’exemple du bassin du Bani, affluent du fleuve Niger, ce travail propose une réflexion sur la « scénarisation hydrologique » et la prédétermination des paramètres d’un modèle hydrologique dans un contexte global non stationnaire. Le choix de jeux de paramètres a de nombreux impacts sur les résultats de la scénarisation comme l’estimation de la ressource et la variabilité de cette ressource. Ces deux éléments sont fondamentaux pour qui doit conduire un processus de décision en réponse à une demande de stratégie d’aménagement ou à une demande de stratégie de développement. Nous proposons une méthodologie de détermination des jeux de paramètres se basant sur la construction de plusieurs jeux de paramètres issus de calages glissants, qui permet d’aller dans le sens de ce que de plus en plus de gestionnaires préconisent : ne pas essayer de prévoir le futur mais plutôt des futurs envisageables qui forceront des modèles d’impact, ce qui leur permettra de fournir des éléments de décision afin de s’adapter ou d’adapter des solutions d’aménagement aux conditions de ces futurs. Editeur Z.W. Kundzewicz; Editeur associé C. PerrinCitation Paturel, J.-E., 2014. Exercice de scénarisation hydrologique en Afrique de l’Ouest—Bassin du Bani. Hydrological Sciences Journal, 59 (6), 1135–1153. http://dx.doi.org/10.1080/02626667.2013.834340
Une étude d’analyse de sensibilité globale d’une application du modèle hydrologique CATHY (CATchment HYdrology) sur un bassin sous influence de drains agricoles a été réalisée en utilisant les méthodes Morris, FAST99 (Fourier Amplitude Sensitivity Test) et Sobol2002. Ces analyses ont permis d’identifier les paramètres les plus sensibles sur : (a) l’écoulement aux drains et (b) les flux sortant du micro-bassin agricole Bras d’Henri (Québec, Canada). Des 24 paramètres évalués par la méthode de Morris, les neuf et huit paramètres ayant été respectivement très influents sur les deux variables de sortie, ont été analysés par les méthodes FAST99 et Sobol2002. Il s’ensuit que la conductivité hydraulique horizontale à saturation dans les couches sous les drains est la propriété hydrodynamique la plus influente sur les deux variables de sortie. Cette étude démontre que des efforts devraient être portés sur la caractérisation de l’anisotropie du sol, car celle-ci n’est pas à négliger lors d’une modélisation hydrologique tridimensionnelle. Editeur Z.W. KundzewiczCitation Muma, M., Gumiere, S.J., et Rousseau, A.N., 2014. Analyses de sensibilité globale du modèle CATHY aux propriétés hydrodynamiques du sol d’un micro-bassin agricole drainé. Hydrological Sciences Journal, 59 (8), 1606–1623. http://dx.doi.org/10.1080/02626667.2013.843778
We developed a water-use conflict analysis framework to determine environmental flows that optimally balance water requirements for ecosystems and human activities. This framework considers trade-offs between water use for ecosystem health and agricultural processes and considers temporal variations in hydrological processes. It comprises three separate models that (a) analyse water balance between agriculture and initial environmental flows, (b) identify outcomes of varying balances in water use, and (c) determine recommended environmental flows for sustainable water use. We applied the framework to a region downstream of the Yellow River in China. Based on our results, we recommend a water management plan that allocates more water to ecosystem services than is currently allocated and that does not increase predicted economic losses. In addition, we found that recommended flows change depending on the ecological objectives considered and whether technologies or methodologies that improve water-use efficiency are employed. Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Pang, A., Sun, T., and Yang, Z., 2014. A framework for determining recommended environmental flows for balancing agricultural and ecosystem water demands. Hydrological Sciences Journal, 59 (3–4), 890–903.
This paper presents a calibration framework for a precipitation–runoff model for flood prediction in a mesoscale Alpine basin with discharges strongly influenced by hydraulic works. The developed methodology addresses two classical hydrological calibration challenges: computational limitations to run optimization algorithms for distributed hourly models and the absence of concomitant meteorological and natural discharge time series. The presented processes-oriented, multi-signal approach is based on hydrological data from a variety of sources and for different periods, corresponding to various spatial scales. The model parameters are calibrated by sequentially minimizing differences between observed and simulated values for different hydrological signals and signatures such as: (a) the phase of precipitations, (b) the time evolution of point-scale snow heights, (c) the mean inter-annual cycle of daily discharges, and (d) timing of snowmelt-induced spring runoff. We compare the model performance to a benchmark model obtained by simply using the globally optimal parameter values from the nearest gauged and non perturbed catchment. For prediction of flow seasonality and also extreme events, the calibration methodology outperforms the benchmark.
Citation Hingray, B., Schaefli, B., Mezghani, A. & Hamdi, Y. (2010) Signature-based model calibration for hydrological prediction in mesoscale Alpine catchments. Hydrol. Sci. J. 55(6), 1002–1016.
Flood frequency estimation is crucial in both engineering practice and
hydrologic research. In this context, regional analysis of flood peak
discharges is used for more accurate estimates of flood quantiles in
ungauged or poorly gauged catchments. This is based on the
identification of homogeneous zones, where the probability distribution
of annual maximum peak flows is invariant, except for a scale factor
represented by an index flood. The numerous applications of this method
have highlighted as a critical step obtaining reliable estimates of
index flood, above all in ungauged or poorly gauged sections, where
direct estimation by sample mean of annual flood series AFS is not
possible or inaccurate. Therein indirect methods have to be used. Most
indirect methods are based upon empirical relationships, developed by
means of multiregression analysis, or simplified lumped representation
of the process of transformation of intense rainfall into runoff. Limits
of these approaches are more and more evident as the size and spatial
variability of the catchment increases. In these cases use of a
spatially distributed physically based hydrological model for time
continuous simulation of discharge can improve estimation of index
flood. This work presents an application of FEST-WB model for the
reconstruction of 30-years hourly stream flows for an Alpine snow fed
catchment in Northern Italy, to be used for index flood estimation. To
extend length of simulated discharge time series, meteorological forcing
given by daily precipitation and temperature at ground automatic weather
stations are downscaled hourly by way of novel method, and then fed to
FEST-WB. Accuracy of the method in estimating index flood is discussed,
and suggestions for use of the methodology provided.
On propose un modèle analogique de ruissellement á stockage de surface, dans lequel l'infiltration est une fonction croissante de la lame d'eau en surface du sol. Le calage numérique des trois paramètres du modèle permet de reproduire correctement, y compris en régime transitoire d'écoulement, le ruissellement mesuré sur sept parcelles de 1 m, pour un total de 40 averses simulées à intensité variable. L'extrapolation du modèle le long d'une pente homogène permet de suivre l'évolution du ruissellement dans le temps et l'espace, sous une averse à intensité variable. On met en évidence l'existence d'une abscisse limite comptée depuis le sommet de pente, à l'aval de laquelle le ruissellement est uniforme à tout instant. La limite et son asymptote augmentent avec l'intensité de pluie et le degré d'imperméabilité du sol.
Les données recueillies à 13 stations hydrométriques des réseaux du SENAMHI et de ENDE, de 1975 à 1983, permettent d'estimer les flux des matières particulaires et dissoutes dans les bassins andins des rios Pilcomayo et Bermejo, formateurs du Rio Paraguay. Les résultats obtenus en Bolivie sur le bassin versant du Rio Pilcomayo, montrent que l'essentiel de l'exportation est le fait de matières en suspension (90%). Le flux de sédiments mesuré à la sortie des Andes sur le Rio Pilcomayo (80 x 10 puissance 6 t an-1) est du même ordre de grandeur que celui observé 2 000 kilomètres à l'aval sur le Moyen Parana. (Résumé d'auteur)
The potential impacts of future climate change on the evolution of groundwater recharge are examined at a local scale for a 546-km2 watershed in eastern Canada. Recharge is estimated using the infiltration model Hydrologic Evaluation of Landfill Performance (HELP), with inputs derived from five climate runs generated by a regional climate model in combination with the A2 greenhouse gas emissions scenario. The model runs project an increase in annual recharge over the 2041–2070 period. On a seasonal basis, however, a marked decrease in recharge during the summer and a marked increase during the winter are observed. The results suggest that increased evapotranspiration resulting from higher temperatures does not offset the large increase in winter infiltration. In terms of individual water budget components, clear differences are obtained for the different climate change scenarios. Monthly recharge values are also found to be quite variable, even for a given climate scenario. These findings are compared with results from two regional-scale studies. Editor D. Koutsoyiannis; Associate editor M. BesbesCitation Rivard, C., Paniconi, C., Vigneault, H., and Chaumont, D., 2014. A watershed-scale study of climate change impacts on groundwater recharge (Annapolis Valley, Nova Scotia, Canada). Hydrological Sciences Journal, 59 (8), 1437–1456. http://dx.doi.org/10.1080/02626667.2014.887203
A new structured approach is presented to derive groundwater baseline conditions, in this case for a dolomitic limestone aquifer suffering from salinization and other anthropogenic impacts. It builds on the HydroChemical System Analysis (HCSA) to map different groundwater bodies (hydrosomes) and hydrochemical zones within them, each of which show significant differences in baseline conditions. It also comprises a rigorous elimination scheme for samples affected by bias or pollution. The method is applied to the Damour coastal aquifer system, south of Beirut (Lebanon). Concentrations of Cl, Cl/Br, 2H, 18O and Ca/Sr were used to discern five hydrosomes and to determine mixing ratios. The dominant hydrochemical facies was (sub)oxic, calcareous and salinized, indicating a very low reduction capacity of the aquifer system, strong dissolution of dolomitic limestone and clear traces of seawater encroachment. The method proposed was capable of filtering out baseline conditions for 16 main constituents, 64 trace elements and two isotopes.
Effective policies to protect groundwater-dependent ecosystems require robust methods to determine the environmental flows and levels required to support species and processes. Frameworks to support groundwater management must incorporate the relationships between hydrology and species and ecological processes. These hydro-ecological relationships can be used to develop quantitative, measurable thresholds that are sensitive to changes in groundwater quantity. Here we provide a case study from a group of fens in central Oregon, USA, that are used for cattle watering, but also support numerous sensitive species. We developed quantitative relationships between the position of the water table and wetland indicator plant species and the process of peat development, to propose groundwater withdrawal thresholds. A maximum depth to water table of –0.9 to –34.8 cm for fen plants and –16.6 to –32.2 cm for peat accretion can be tolerated in these wetlands. Defining hydro-ecological relationships as thresholds can support management decisions. Editor D. Koutsoyiannis; Guest editor M. AcremanCitation Aldous, A.R. and Bach, L.B., 2014. Hydro-ecology of groundwater-dependent ecosystems: applying basic science to groundwater management. Hydrological Sciences Journal, 59 (3–4), 530–544.
The glaciers in the Nepalese Himalayas are retreating due to rising temperatures. Lack of data and information on Nepal’s cryosphere has impeded scientific studies and field investigations in the Nepalese Himalayas. Therefore, IRD France and Ev-K2 CNR Italy have conducted the PAPRIKA (CryosPheric responses to Anthropogenic PRessures in the HIndu Kush-Himalaya regions: impacts on water resources and society adaptation in Nepal) project in Nepal with the financial support of the French and Italian scientific agencies. This project aims to address the current and future evolution of the cryosphere in response to overall environmental changes in South Asia, and its consequences for water resources in Nepal. Thus, two hydrological models, the GR4J lumped precipitation–runoff model and the snowmelt runoff model (SRM), were used in the Dudh Koshi basin. The GR4J model has been successfully applied in different parts of Europe. To obtain better results in such a harsh and rugged topography, modifications needed to be made, particularly in the snow module. The runoff pattern is analysed herein both for past years and, in a sensitivity analysis, for possible future climatic conditions (i.e. precipitation and temperature) using the SRM and GR4J modelling approaches. The results reveal a significant contribution of snow- and glacier-melt to runoff, and the SRM model shows better performance in Nepalese catchments than the GR4J model. Editor D. Koutsoyiannis; Associate editor D. GertenCitation Pokhrel, B.K., Chevallier, P., Andréassian, V., Tahir, A.A., Arnaud, Y., Neppel, L., Bajracharya, O.R., and Budhathoki, K.P., 2014. Comparison of two snowmelt modelling approaches in the Dudh Koshi basin (eastern Himalayas, Nepal). Hydrological Sciences Journal, 59 (8), 1507–1518. http://dx.doi.org/10.1080/02626667.2013.842282
With climate change happening, hydraulic engineering design could play an important role in vulnerability assessment. Thus, we compute with the most recent daily data available the 10-year, 20-year and 100-year rainfall for 51 stations and the 10-year, 20-year and 100-year discharge for 6 stations of the Bani basin in Mali (129 000 km²). These values are computed using L-moments method and dividing the watershed in homogeneous regions. Finally, an empirical formula to calculate 10-year discharge is computed, considering the important rupture in discharges' values around 1970. Values computed show that period selected for computation is important, as few years could change results significantly.
We introduce a groundwater sustainability index offering a novel combination of features. It is holistic in the sense that it incorporates both water quantity and water quality indicators. The former employs the signal-to-noise ratio of long-term trends estimated via robust regression; the latter uses concentration of the primary contaminant of concern. A fuzzy inference system integrates these unlike metrics. The system also explicitly encodes expert knowledge and stakeholder values, and directly acknowledges subjectivity in environmental condition “grading,” through the use of linguistic rules and fuzzy sets, respectively. The fuzzy rule base is constructed such that poor environmental conditions captured by one measure are not hidden by good performance in another. A standard Mamdani (max–min) inference engine is used with centroid defuzzification. The outcome is an intuitively accessible index ranging from 0 to 100. The method is demonstrated using examples from the Abbotsford-Sumas aquifer, an important and managerially challenging transboundary (Canada–US) water resource. Editor D. Koutsoyiannis; Associate editor E. RozosCitation Fleming, S.W., Wong, C., and Graham, G., 2014. The unbearable fuzziness of being sustainable: an integrated, fuzzy logic-based aquifer health index. Hydrological Sciences Journal, 59 (6), 1154–1166. http://dx.doi.org/10.1080/02626667.2014.907496
New and previously published data sets including stable and radiogenic isotope measurements (18O, 2H, 3H, 13C and 14C) were used to investigate, conceptualize and compare groundwater hydrodynamics within three major multilayer aquifer systems located in central and southern Tunisia. It has been demonstrated that the investigated aquifer systems contain modern and palaeoclimatic waters. Modern groundwaters, which refer to contemporaneous and post-nuclear recharge waters, are characterized by enriched stable isotope contents, high carbon-14 activities and high to moderate tritium concentration. While palaeoclimatic groundwaters, which refer to Late Pleistocene and Early Holocene recharge waters, are distinguished by their depleted stable isotope contents, low carbon-14 activities and insignificant tritium concentrations. Established conceptual models have elucidated the groundwater hydrodynamics within the studied aquifer systems. They show that groundwater mixing occurs between end-members from the shallow and deep aquifers that migrate by downward and upward leakage towards the intermediate aquifer.Editor D. Koutsoyiannis; Associate editor S. FayeCitation Dassi, L. and Tarki, M., 2014. Isotopic tracing for conceptual models of groundwater hydrodynamics in multilayer aquifer systems of central and southern Tunisia. Hydrological Sciences Journal, 59 (6), 1240–1258. http://dx.doi.org/10.1080/02626667.2014.892206
L’aquifère du Trarza s’étend sur environ 40 000 km2 dans le Sud-Ouest mauritanien, entre le fleuve Sénégal au Sud, l’Océan Atlantique à l’Ouest et la chaîne métamorphique des Mauritanides au Nord et à l’Est. La nappe libre est contenue dans les sédiments du Continental Terminal et du Quaternaire. Les campagnes de terrain menées entre 2010 et 2012 ont significativement complété les quelques mesures anciennes. Le croisement d’approches hydrodynamiques et géochimiques a montré que, dans cette zone semi-aride, la dynamique de la nappe est influencée par les multiples changements, actuels et anciens, de l’environnement (depuis les transgressions quaternaires jusqu’aux différents barrages régulant le cours du fleuve Sénégal). La nappe est principalement alimentée par l’infiltration latérale des eaux de surface du fleuve Sénégal et, dans une moindre proportion, par les précipitations. La minéralisation des eaux souterraines résulte d’interactions eau-roches et minéraux silicatés et alumino-silicatés et est localement influencée par des traces des transgressions quaternaires. L’évaporation marque fortement les eaux de surface avant et durant leur infiltration. Des calculs encore très préliminaires suggèrent une recharge annuelle inférieure ou égale à 5% des précipitations, soit de 5 à 10 mm.Editeur Z.W. KundzewiczCitation Mohamed, A.-S., Marlin, C., Leduc, C., et Jiddou, M., 2014. Modalités de recharge d’un aquifère en zone semi-aride: cas de la nappe du Trarza (Sud-Ouest Mauritanie). Hydrological Sciences Journal, 59 (5), 1046–1062.
This study modified the BTOPMC (Block-wise TOPMODEL with the Muskingum-Cunge routing method) distributed hydrological model to make it applicable to semi-arid regions by introducing an adjustment coefficient for infiltration capacity of the soil surface, and then applied it to two catchments above the dams in the Karun River basin, located in semi-arid mountain ranges in Iran. The application results indicated that the introduced modification improved the model performance for simulating flood peaks generated by infiltration excess overland runoff at a daily time scale. The modified BTOPMC was found to fulfil the need to reproduce important signatures of basin hydrology for water resource development, such as annual runoff, seasonal runoff, low flows and flood flows. However, it was also very clear that effective model use was significantly constrained by the scarcity of ground-gauged precipitation data. Considerable efforts to improve the precipitation data acquisition should precede water resource development planning.Editor D. Koutsoyiannis
This investigation presents a new approach to estimate the costs resulting from the introduction of environmental flows in the arid Huasco River basin, located in the Atacama Region of Chile, one of the most sophisticated private water markets worldwide. The aim is to provide information to the water users, who hold the right to decide on water use, and thereby support the inclusion of environmental flows into decision-making. Costs are estimated by calculating the loss of agricultural productivity resulting from a trade-off between users and environmental flow requirements in times of water scarcity. Based on environmental flow requirements calculated by International Union for Conservation of Nature (IUCN), and hydrological supply-and-demand modelling using the Water Evaluation and Planning (WEAP) model, economic parameters of water productivity are calculated for the main economic sectors and then included in hydrological analysis. The study presents concrete costs that might be imposed on the water users during times of water scarcity, and confirms that there are significant variations in water productivity between different sectors. Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Wagnitz, P., Núñez, J., and Ribbe, L., 2014. Cost of environmental flow during water scarcity in the arid Huasco River basin, northern Chile. Hydrological Sciences Journal, 59 (3–4), 700–712.
t Spatio-temporal storm properties have a large impact on catchment hydrological response. The sensitivity of simulated flash floods to convective rain-cell characteristics is examined for an extreme storm event over a 94 km2 semi-arid catchment in southern Israel. High space–time resolution weather radar data were used to derive and model convective rain cells that then served as input into a hydrological model. Based on alterations of location, direction and speed of a major rain cell, identified as the flooding cell for this case, the impacts on catchment rainfall and generated flood were examined. Global sensitivity analysis was applied to identify the most important factors affecting the flash flood peak discharge at the catchment outlet. We found that the flood peak discharge could be increased three-fold by relatively small changes in rain-cell characteristics. We assessed that the maximum flash flood magnitude that this single rain cell can produce is 175 m3/s, and, taking into account the rest of the rain cells, the flash flood peak discharge can reach 260 m3/s. Editor Z.W. Kundzewicz; Guest editor R.J. MooreCitation Morin, E. and Yakir, H., 2013. Hydrological impact and potential flooding of convective rain cells in a semi-arid environment. Hydrological Sciences Journal, 59 (7), 1275–1284. http://dx.doi.org/10.1080/02626667.2013.841315
Artificial neural networks (ANNs) have recently been used to predict the hydraulic head in well locations. In the present work, the particle swarm optimization (PSO) algorithm was used to train a feed-forward multi-layer ANN for the simulation of hydraulic head change at an observation well in the region of Agia, Chania, Greece. Three variants of the PSO algorithm were considered, the classic one with inertia weight improvement, PSO with time varying acceleration coefficients (PSO-TVAC) and global best PSO (GLBest-PSO). The best performance was achieved by GLBest-PSO when implemented using field data from the region of interest, providing improved training results compared to the back-propagation training algorithm. The trained ANN was subsequently used for mid-term prediction of the hydraulic head, as well as for the study of three climate change scenarios. Data time series were created using a stochastic weather generator, and the scenarios were examined for the period 2010–2020. Editor Z.W. Kundzewicz; Associate editor L. SeeCitation Tapoglou, E., Trichakis, I.C., Dokou, Z., Nikolos, I.K., and Karatzas, G.P., 2014. Groundwater-level forecasting under climate change scenarios using an artificial neural network trained with particle swarm optimization. Hydrological Sciences Journal, 59(6), 1225–1239. http://dx.doi.org/10.1080/02626667.2013.838005
Soil erosion and eroded sediment are serious threats to sound land management. However, less attention has been given to quantifying the importance of different soil erosion features based on appropriate control measures that could be designated. Accordingly, this research was planned to quantify the contribution of potential sediment sources, i.e. sheet, rill and gully erosion, in Idelo watershed in Zanjan Province, Iran, using composite fingerprinting. Toward this aim, 16 geochemical and organic tracers were detected in sediment sources and sediment deposited at the outlet. The results of applying the composite fingerprinting technique, with a relative error of 16%, showed that sheet, rill and gully sources contributed 56%, 44% and 0%, respectively, to sediment yield. It was also apparent from the results that the composite fingerprinting approach could be successfully utilized to assess the provenance of sediment deposited at the main outlet of the study watershed by soil erosion type.Editor Z.W. Kundzewicz
The hydrology of water-dependent ecosystems around the world has been altered as a result of flow regulation and extraction for a variety of purposes including agricultural and urban water supply. The flow regime of the Murray-Darling Basin in Australia is no exception, with attendant impacts on the health of the environment. Restoration of parts of the flow regime is a key feature of environmental flow delivery. However, environmental flow delivery in a system that is managed primarily to provide a secure and stable supply for irrigation presents challenges for managers seeking to return more natural flow variability in line with ecosystem requirements. The institutional arrangements governing releases of water from storage can influence the ability of managers to respond to natural cues, such as naturally rising flows in a river. As such, the legal and governance aspects of environmental flow delivery are likely to be important influences on the outcomes achieved. Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Banks, S.A. and Docker, B.B., 2014. Delivering environmental flows in the Murray-Darling Basin (Australia)—legal and governance aspects. Hydrological Sciences Journal, 59 (3–4), 688–699.
If management of water resources is to fully take into account the requirements of the environment, it will benefit from quantitative predictions of the ecological effects of river flow alterations. A significant relationship between flow reductions caused by groundwater abstraction and ecological conditions (as measured by relevant biotic indices) has been shown in streams in the midlands of England. In this article, we combine this relationship with hydrological indices derived from calibrated regional groundwater models to assess river reaches that are likely to be ecologically impacted by abstraction and might consequently be at risk of failing to meet EC Water Framework Directive standards. We demonstrate the application of this method within the framework of the Ecological Limits of Hydrologic Alteration (ELOHA) approach to making water resource decisions. We provide examples of how this approach can be used to assess the implications of different groundwater abstraction scenarios for river water bodies. Editor D. Koutsoyiannis; Guest editor M. AcremanCitation Streetly, M.J., Bradley, D.C., Streetly, H.R., Young, C., Cadman D., and Banham, A., 2014. Bringing groundwater models to LIFE: a new way to assess water resource management options. Hydrological Sciences Journal, 59 (3–4), 578–593.
Terraced paddy fields play a crucial role in water and soil conservation because their water-storage capacity reduces flood peaks in mountainous areas. The water-storage capacity of a paddy field is mainly dependent on the size of the field, the height of the bund, and the outlet within the bund. However, the height of the bund and outlet can be reduced due to a lack of maintenance, especially when rice paddies have been abandoned. This study assessed the flood-control function of a terraced paddy field during heavy-rainfall events. The four-layered tank model calibrated by in situ rainfall–runoff measurements was applied to determine the effects of reducing the height of the bund and the outlet within the bund, on the drainage peak flow of terraced fields. The simulation results from two heavy-rainfall events indicated the excellent flood-control function of terraced paddy fields. The simulation results showed that the drainage peak flow underwent considerable changes when the height of the bund and outlet was reduced by more than 50%. Therefore, sustainable rice planting in the terraced paddies or maintenance of the water-storage capability in abandoned arable land is necessary to release downstream flood pressure. Editor D. Koutsoyiannis; Associate editor S. YueCitation Chen, S.-K., Chen, R.-S., and Yang, T.-Y., 2014. Application of a tank model to assess the flood-control function of a terraced paddy field. Hydrological Sciences Journal, 59 (5), 1020–1031.
This study was carried out in the framework of the Surface Water and Ocean Topography (SWOT) programme of the French National Centre of Space Studies (CNES). Based on discharge measurements and Gravity Recovery and Climate Experiment (GRACE) determination of total water storage (TWS), we have investigated the hydrological variability of the main French drainage basins (Seine, Loire, Garonne and Rhône) using a wavelet approach (continuous wavelet analyses and wavelet coherence analyses). The results of this analysis have shown a coherence ranging between 82% and 90% for TWS and discharge, thus demonstrating the potential use of TWS for characterization of the hydrological variability of French rivers. Strong coherence between the four basin discharges (between 73% and 92%) and between their associated TWS data (from 82% to 98%) suggested a common external influence on hydrological variability. To determine this influence, we investigated the relationship between hydrological variability and the North Atlantic Oscillation (NAO), considered as an index of prevailing climate in Europe. Basin discharges show strong coherence with NAO, ranging between 64% and 72% over the period 1959–2010. The coherence between NAO and TWS was 62% to 67% for 2003–2009. This is similar to the coherence between NAO and basin discharges detected for the same period. According to these results, strong influence of the NAO was clearly observed on the TWS and discharges of the major French river basins. Editor Z.W. Kundzewicz
Flow regimes play an important role in sustaining biodiversity in river ecosystems. However, the effects of flow regimes on riverine fish have not been clearly described. Therefore, we propose a new methodology to quantitatively link habitat conditions (such as flow indices and physical habitat conditions) to the occurrence probability (OP) of fish species. We developed a basin-scale fish distribution model by integrating the concept of habitat suitability assessment with a distributed hydrological model in order to estimate the OP of fish, with particular attention to flow regime. A generalized linear model was used to evaluate the relationship between the probabilities of fish occurrence and major environmental factors in river sections. A geomorphology-based hydrological model was adopted to simulate river discharge, which was used to calculate 10 flow indices. The occurrence probabilities of 50 fish species in the Sagami River in Japan were modelled. For the prediction accuracy, field survey results that included at least five observations of both the presence and the absence of each species were required to obtain relatively reliable prediction (accuracy > 60%). Using the developed model, important habitat conditions for each species were identified, which showed the importance of low-flow events for more than 10 species, including Hypomesus nipponensis and Rhinogobius fluviatilis. The model also confirmed the positive effects of natural flow and the negative effect of river-crossing structures, such as dams and weirs, on the OP of most species. The suggested approach enables us to evaluate and project the ecological consequences of water resource management policy. The results demonstrate the applicability of the fish distribution model to provide quantitative information on the flow required to maintain fish communities.
This work aims to identify wetland water sources for environmental flow assessment of three wetlands located in the area of Miguel Ibáñez (Segovia, Spain), known as Fuente Santa, Balsa de la Ermita and San Pedro ponds. These are remnants of wetland systems that were larger in the past. The methodology used involved four seasonal field campaigns conducted in 2012 at eight main and three additional surface water or groundwater sampling points. The interpretation of the physico-chemical and isotopic data obtained, and daily monitoring of changes in the water level of the Fuente Santa pond over 5 months provided an initial understanding of the environmental flows needed to sustain these wetlands in appropriate conditions. The arsenic values provided an additional auxiliary tool, although a single dominant cause of its presence in these three ponds could not be identified. The results show that the interactions between the wetlands and groundwater are hydrogeologically different despite their proximity to one another. These findings will enable the improved management and conservation of these wetlands. Editor D. Koutsoyiannis; Guest editor M. AcremanCitation de la Hera Portillo, A. and Murillo Díaz, J.M., 2014. Identification of wetland water sources for environmental flow assessment: a case study of the Miguel Ibáñez wetlands (Segovia, Spain). Hydrological Sciences Journal, 59 (3–4), 466–487.
The combined analysis of precipitation and water scarcity was done with the use of the Standardized Precipitation Index (SPI) and the Standardized Runoff Index (SRI), developed as a monthly, two-variable SPI-SRI indicator to identify different classes of hydrometeorological conditions. Stochastic analysis of a long-term time series (1966–2005) of monthly SPI-SRI indicator values was performed using a first-order Markov chain model. This provided characteristics of regional features of drought formation, evolution and persistence, as well as tools for statistical long-term drought hazard prediction. The study was carried out on two subbasins of the Odra River (Poland) of different orography and land use: the mountainous Nysa Kłodzka basin and the lowland, agricultural Prosna basin. Classification obtained with the SPI-SRI indicator was compared with the output from the NIZOWKA model that provided identification of hydrological drought events including drought duration and deficit volume. Severe and long-duration droughts corresponded to SPI-SRI Class 3 (dry meteorological and dry hydrological), while severe but short-term droughts (lasting less than 30 days) corresponded to SPI-SRI Class 4 (wet meteorological and dry hydrological). The results confirm that, in Poland, meteorologically dry conditions often shift to hydrologically dry conditions within the same month, droughts rarely last longer than 2 months and two separate drought events can be observed within the same year.
In the centre of Morocco, the High Atlas mountain range represents the most important water storage for the neighbouring arid plains through liquid and solid precipitation. In this context, we evaluated the performance of the Snowmelt Runoff Model (SRM) on the five main tributary watersheds of the High Atlas range. Due to the very low density of climate stations in the High Atlas, snowfall and snowmelt processes are difficult to monitor using meteorological data alone. In order to compensate for the lack of in situ data, snow maps are also derived from remotely-sensed data. We compared the streamflow forecasting performance when the model is driven by one or the other estimate of snow-covered area. Both estimates are generally comparable in all watersheds, and satisfactory streamflow simulations were obtained at seasonal time scales using both snow-cover products. However, significant differences can be observed for selected storms, with more accurate streamflow predictions being obtained when the remotely-sensed data are used.
We evaluate flood magnitude and frequency trends across the Mid-Atlantic USA at stream gauges selected for long record lengths and climate sensitivity, and find field significant increases. Fifty-three of 75 study gauges show upward trends in annual flood magnitude, with 12 showing increases at p < 0.05. We investigate trends in flood frequency using partial duration series data and document upward trends at 75% of gauges, with 27% increasing at p < 0.05. Many study gauges show evidence for step increases in flood magnitude and/or frequency around 1970. Expanding our study area to include New England, we find evidence for lagged positive relationships between the winter North Atlantic Oscillation phase and flood magnitude and frequency. Our results suggest hydroclimatic changes in regional flood response that are related to a combination of factors, including cyclic atmospheric variability and secular trends related to climate warming affecting both antecedent conditions and event-scale processes.Editor Z.W. Kundzewicz; Associate editor H. Lins. This material is published by permission of the U.S. National Oceanic and Atmospheric Administration Restoration Center under Contract No. WC133F-10-BU-0036/01.The US Government retains for itself, and others acting on its behalf, a paid -up, non-exclusive, and irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.
Cet article propose une méthodologie d’étude de sensibilité pour cerner l’incertitude d’estimation de la période de retour d’une crue maximale annuelle exceptionnelle connue seulement par la cote des plus hautes eaux. Deux autres contraintes ont présidé au choix méthodologique. Tout d’abord, nous ne disposions pas des débits maximaux de crue à la station (hors ceux de la crue annuelle) et nous disposions d’une courte série des débits maximaux annuels. L’étude a ainsi été focalisée sur les débits moyens journaliers dont la série est complète avec une seule lacune qui est celle de la crue qui nous intéresse. La taille de la série des débits moyens journaliers la plus complète étant assez modérée, un modèle statistique à dépassement de seuil POT (Peaks Over Threshold) a été adopté. A partir de la laisse de crue, le débit maximal de la crue non jaugée a été estimé par cinq approches différentes (méthodes d’extrapolation par régression statistique à partir des paramètres hydrauliques de la station, deux modèles de Manning-Strickler en lit homogène, et deux modèles de Manning-Strickler en lit composé) en adoptant des valeurs de rugosité du lit couvrant l’incertitude reflétée d’après les jaugeages existants. Nous avons proposé d’étudier la distribution statistique du rapport α du débit maximum instantané de la crue annuelle à son débit moyen journalier. Par ce biais, l’observation de la laisse de crue a été mise à profit pour compléter la série des débits moyens journaliers moyennant une hypothèse sur la valeur de α. L’article traite l’incertitude sur α pour diverses hypothèses sur la rugosité du lit. Une distribution lognormale a été ajustée pour α et des simulations de Monte Carlo ont été entreprises. Une valeur du débit moyen journalier a alors été attachée à chaque simulation de Monte Carlo de α. Cinquante (50) simulations ont été effectuées dans chaque cas. Le modèle à dépassement de seuil a été appliqué à chaque série de débits moyens journaliers ainsi complétée par simulation. Les quantiles des débits moyens journaliers pour différentes périodes de retour ont été estimés pour chaque série complétée. La dispersion de ces derniers a été représentée par une boite à moustaches et a été quantifiée par l’intervalle interquartile. L’application a porté sur une station hydrométrique contrôlant un bassin de 9000 km2 en région semi-aride nord africaine. Les séries d’observation ont été étudiées pour la période 1984–2006 pour laquelle 114 jaugeages étaient disponibles. La médiane du quantile quinquagennal du débit moyen journalier varie de 1410 à 1840 m3/s en fonction du seuil de dépassement retenu et de la valeur du coefficient de rugosité du lit. Les différentes méthodes, en considérant les différents seuils de troncature, conduisent à un intervalle interquartile de la période de retour du débit moyen journalier de cette crue variant entre 30 et 70 ans. Editeur Z.W. Kundzewicz; Editeur associé C. LeducCitation Aridhi, H., Bargaoui, Z., et Assia Chebchoub, F., 2014. Etude de la sensibilité d’estimation de la période de retour d’une crue connue seulement par la cote atteinte. Hydrological Sciences Journal, 59 (5), 978–992.
The scarcity of water in mediterranean-climate regions makes flow management in the rehabilitation of urban streams problematic. To explore potential applications of using recycled water for stream enhancement, we examine streams in the San Francisco Bay Area of California, USA, to characterize: (a) historic flow regimes at the regional scale, (b) potential unintended ecological effects and (c) specific issues related to recycled water. We analysed historic flow regimes in five basins, performed a streamflow augmentation experiment and monitored benthic macroinvertebrates above and below a recycled-water discharge. Streamflow augmentation with recycled water can provide improved aesthetics and aquatic habitat, but there are caveats to consider. Implications of inputs of recycled water in streams, whether direct or indirect, require detailed analysis of trade-offs. Augmentation is unlikely to harm the ecology of urban streams that are now just barely flowing perennially with pools of stagnant, contaminated water, and it may reduce public health problems from mosquitoes. Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Lawrence, J.E., Pavia, C.P.W., Kaing, S., Bischel, H.N., Luthy, R.G., and Resh, V.H., 2014. Recycled water for augmenting urban streams in mediterranean-climate regions: a potential approach for riparian ecosystem enhancement. Hydrological Sciences Journal, 59 (3–4), 488–501.
In this paper, using Sicilian and Australian rainfall intensity data, a comparison between different estimators (modified Fournier index F, FF index) of the rainfall erosivity factor in the USLE was made. The relationship between the modified Fournier index and the mean annual rainfall, P, was theoretically derived. The K constant, linking the FF index and P, and its cumulative distribution function (CDF) were used to establish hydrological similitude among different geographical regions of southern Italy and southeastern Australia. To predict the erosion risk for an event of given average recurrence interval, the probability distribution of the annual value F a.j of the Arnoldus index was studied. In order to establish the theoretical CDF to use as a regional parent distribution, the descriptive ability of LN2 and EV1 distributions was studied by both an at-site analysis and a hierarchical regional procedure. The analysis showed that for each sub-region of southern Italy and southeastern Australia, characterized by a constant coefficient of variation, the erosion risk index is constant. Yes Yes
The Pimpama coastal plain is situated in southern Moreton Bay, in subtropical eastern Australia. The plain is low lying and tidal and is situated behind a large sand barrier island. Largely due to recent (30 years) drainage networks within the flood plain, surface water quality has declined. Groundwater hydrographs have enabled the determination of different flow systems: a deeper system responding to seasonal weather patterns and a shallower flow system more responsive to individual rainfall events. Elevated potentiometric heads in semi-confined aquifers reflect upward movement of saline to hypersaline groundwaters. However, interaction of this deeper groundwater with shallower groundwater and the surface drains is yet to be determined. Recharge to the shallower system is by direct infiltration while recharge to the deeper system includes a component from landward ranges or bedrock outcrops within the plain. Discrimination between groundwater bodies is possible using salinity, ionic ratios and stable isotopes. Features of groundwater hydrology, the distribution of salinity and variations in water chemistry all suggest that under current conditions infiltration has increased, plus there is a greater landward migration of groundwaters of marine origin.
Reservoir operation is studied for the Daule Peripa and Baba system in Ecuador, where El Niño events cause anomalously heavy precipitation. Reservoir inflow is modelled by a Markov-switching model using El Niño–Southern Oscillation (ENSO) indices as input. Inflow is forecast using 9-month lead time ENSO forecasts. Monthly reservoir releases are optimized with a genetic algorithm, maximizing hydropower production during the forecast period and minimizing deviations from storage targets. The method is applied to the existing Daule Peripa Reservoir and to a planned system including the Baba Reservoir. Optimized operation is compared to historical management of Daule Peripa. Hypothetical management scenarios are used as the benchmark for the planned system, for which no operation policy is known. Upper bounds for operational performance are found via dynamic programming by assuming perfect knowledge of future inflow. The results highlight the advantages of combining inflow forecasts and storage targets in reservoir operation. Editor D. Koutsoyiannis; Associate editor I. NalbantisCitation Gelati, E., Madsen, H., and Rosbjerg, D., 2014. Reservoir operation using El Niño forecasts—case study of Daule Peripa and Baba, Ecuador. Hydrological Sciences Journal, 59 (8), 1559–1581. http://dx.doi.org/10.1080/02626667.2013.831978
In this paper we analyse all currently available simulated climate scenarios, proposed by the Spanish Agency of Meteorology (AEMET), for the period 2010-2040 on the geographical area covered by the Jucar River basin, located in eastern Spain. This is done through the validation of these scenarios using historical records, and by assessing the impact on water resources for the next 30 years by means of a hydrological model. By taking the period 1960-1990 as the control period, a careful comparison of its historical records against AEMET scenarios is performed. Although temperature records are modelled properly, precipitation data are widely underestimated in a range from 8% to 29%. This wide variability observed in the control period is also found in the precipitation scenarios for the period 2010-2040. The impact on water resources shows a great degree of dispersion, ranging from -13.45% to 18.1% with a mean value of -2.13%. [GRAPHICS] Editor Z.W. Kundzewicz; Associate editor F. Hattermann