Introducing the recharge–discharge relationship to evaluate the recharge coefficient of karstic aquifers: thematic and indexing approaches

ABSTRACT

Karst aquifers and springs are important with respect to their potential for supplying drinking water in regions suffering from water scarcity in Iran. Accordingly, it is essential to determine the recharge potential of the catchment and the regions with higher obtainability potential. This study provides a road map for the Sheshpeer catchment in southern Iran. A recharge potential (RP) map was produced from which a recharge index (RI) was computed for several selected springs in the catchment. Furthermore, the unit discharge (q) – defined as the average annual discharge for a given catchment area and unit rainfall depth for each spring – was calculated. The plot of q versus RI for the springs showed a linear positive relationship between the two variables (R ² = 0.9). Applying the trend equation of this plot to the whole Sheshpeer karstic catchment reveals that its long-term recharge coefficient is 0.74.     

Evaluation of temperature trends over India / Evaluation de tendances de température en Inde

Abstract

Abstract The impact of climate change is projected to have different effects within and between countries. Information about such change is required at global, regional and basin scales for a variety of purposes. An investigation was carried out to identify trends in temperature time series of 125 stations distributed over the whole of India. The non-parametric Mann-Kendall test was applied to detect monotonic trends in annual average and seasonal temperatures. Three variables related to temperature, viz. mean, mean maximum and mean minimum, were considered for analysis on both an annual and a seasonal basis. Each year was divided into four principal seasons, viz. winter, pre-monsoon, monsoon and post-monsoon. The percentages of significant trends obtained for each parameter in the different seasons are presented. Temperature anomalies are plotted, and it is observed that annual mean temperature, mean maximum temperature and mean minimum temperature have increased at the rate of 0.42, 0.92 and 0.09°C (100 year)^-1, respectively. On a regional basis, stations of southern and western India show a rising trend of 1.06 and 0.36°C (100 year)^-1, respectively, while stations of the north Indian plains show a falling trend of –0.38°C (100 year)^-1. The seasonal mean temperature has increased by 0.94°C (100 year)^-1 for the post-monsoon season and by 1.1°C (100 year)^-1 for the winter season.     

The aquifer systems of the Dominican Republic / Les systèmes de nappes aquiféres de la République Dominicaine

Abstract

Surface water resources, although abundant, are unevenly distributed in the tropical Dominican Republic. Despite large surface water regulation schemes, some of the semiarid regions remain deficient in water resources. A preliminary appraisal of the aquifer systems of the country, with emphasis on the three major regional aquifers, suggests how these deficiencies may be compensated.     

Modelling daily suspended sediment of rivers in Turkey using several data-driven techniques / Modélisation de la charge journalière en matières en suspension dans des rivières turques à l'aide de plusieurs techniques empiriques

Abstract

The transport of sediment load in rivers is important with respect to pollution, channel navigability, reservoir filling, longevity of hydroelectric equipment, fish habitat, river aesthetics and scientific interest. However, conventional sediment rating curves cannot estimate sediment load accurately. An adaptive neuro-fuzzy technique is investigated for its ability to improve the accuracy of the streamflow—suspended sediment rating curve for daily suspended sediment estimation. The daily streamflow and suspended sediment data for four stations in the Black Sea region of Turkey are used as case studies. A comparison is made between the estimates provided by the neuro-fuzzy model and those of the following models: radial basis neural network (RBNN), feed-forward neural network (FFNN), generalized regression neural network (GRNN), multi-linear regression (MLR) and sediment rating curve (SRC). Comparison of results reveals that the neuro-fuzzy model, in general, gives better estimates than the other techniques. Among the neural network techniques, the RBNN is found to perform better than the FFNN and GRNN.     

Incorporating groundwater recharge and discharge functions into an existing monthly rainfall–runoff model/Incorporation de fonctions de recharge et de vidange superficielle de nappes au sein d’un modèle pluie-débit mensuel existant

Abstract

Abstract There is an urgent need for an integrated surface water and groundwater modelling tool that is suitable for southern African conditions and can be applied at various basin scales for broad strategic water resource planning purposes. The paper describes two new components (recharge and groundwater discharge) that have been added to an existing monthly time-step rainfall–runoff model that is widely used in the southern African subcontinent. The new components are relatively simple, consistent with the existing model formulation, but based on accepted groundwater flow principles and well understood groundwater parameters. The application of the revised model on two basins in southern Africa with quite different baseflow characteristics has demonstrated that the new components have a great deal of potential, even if the improvement is only to be able to simulate the groundwater baseflow component of total runoff more explicitly. More comprehensive testing and comparison of the results with existing groundwater and geohydrological data is required, while some extensions to the new components need to be considered to ensure that the model can be considered applicable to a wide range of basin and climate types.     

Surface and subsurface water balance estimation by the groundwater recharge model and a 3-D two-phase flow model/Estimation de bilan hydrologique de surface et de subsurface à l’aide de modèles de recharge de nappe et d’écoulement diphasique 3-D

Abstract

Abstract Land development often results in adverse environmental impact for surface and subsurface water systems. For areas close to the coast, land changes may also result in seawater intrusion into coastal aquifers. Due to this, it is important to evaluate potential adverse effects in advance of any land development. For evaluation purposes a combined groundwater recharge model is proposed with a quasi three-dimensional unconfined groundwater flow equation. The catchment water balance for a planned new campus area of Kyushu University in southern Japan, was selected as a case study to test the model approach. Since most of the study area is covered with forest, the proposed groundwater recharge model considers rainfall interception by forest canopy. The results show that simulated groundwater and surface runoff agree well with observations. It is also shown that actual evapotranspiration, including rainfall interception by forest canopy, is well represented in the proposed simulation model. Several hydrological components such as direct surface runoff rate, groundwater spring flow rate to a ground depression, trans-basin groundwater flow etc., were also investigated.     

La phase de la composante annuelle des niveaux des rivières de la plaine de l'Est Européen

Résumé L'étude publiée intéresse l'ensemble des échelles hydrométriques de la plaine de l'Est européen. Les moyennes mensuelles des niveaux ont été élaborées par la méthode d'analyse par combinaisons linéaires d'ordonnées, due à M. et MmeLabrouste, afin de définir la phase de la composante annuelle. La carte de la répartition de la phase et les profils de celle-ci le long des cours d'eau, montrent que cette répartition est commandée par le relief, ainsi que par la marche saisonnière des températures, ce qui permet d'expliquer les particularités constatées par les causes naturelles: altitudes, forme et extension du bassin, etc.

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Summary The research deals with the hydrographic observations of the East-Europe's plain. The monthly means of the water level have been elaborated after the method of Mr. and Mrs.Labrouste with the aim to determine the phase of the yearly component. The map of the phase distribution and the profiles along the streams shows that this distribution is governed by the physiography, as well as by the seasonal course of the temperatures, what can permit to explain the observed particularities.

     

Explicit algebraic influence coefficients: two-dimensional aquifer model / Coefficients d'influence algébriques explicites: modèle d'aquifère bidimensionnel

Abstract

This work extends the algebraic expression of influence coefficients developed for one-dimensional aquifer models to a two-dimensional (2-D) case. First, the partial differential equation governing the flow in a 2-D semi-confined aquifer is discretized using a finite difference scheme. This results in a system of discrete equations presented in the form of water balance equations associated with a network of interconnected compartments centred on the grid nodes. The foregoing system is transformed into a series of uncoupled 1-D equations stated in terms of some generalized hydraulic head for which they are also solved. Second, the original hydraulic head is recovered from the generalized one via an appropriate linear transformation. Whence, the algebraic expression making the hydraulic head explicit versus sources and boundary conditions is derived. This discrete expression, mapped onto its continuous counterpart, helps to deduce an algebraic form of the inter-compartment influence coefficients. Finally, a comparison with the analytical Green function is carried out.     

DETERMINATION OF AQUIFER PARAMETERS FOR A MULTIPLE WELL SYSTEM / Détermination des paramètres d'aquifère pour un système à puits-multiples

Abstract

A curve-fitting method is described to determine the storage coefficient and transmissivity of an extensive confined aquifer.     

Approvisionnement futur en plantes forestières en suisse: préparation de compost

Sans résumé Institut fédéral de recherches forestières     

‘Overshooting’ effects due to hydrodispersive mixing of saltwater layers in aquifers

In computation of saltwater intrusion processes transient effects, wherein an elevation of salinity above a final steady state occurs, have been observed and termed as ‘overshooting’. To clear the overshooting phenomena a paradigmatic saltwater layer problem is studied. A new analytical solution for two-dimensional unsteady convective and hydrodispersive saltwater spreading in a bilayered aquifer is presented. A good agreement between analytical predictions and numerical results obtained by finite elements is exhibited. Using the analytical solution it has been found that the major factors for the existence and the development of overshooting are the initial conditions of saltwater layering and the difference of the flow velocities between the layers. The results presented in the paper can provide better insight into the mixing process of flowing saltwater layers.     

Modalités de recharge d’un aquifère en zone semi-aride : cas de la nappe du Trarza (Sud-Ouest Mauritanie)

Résumé

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. Kundzewicz

Citation 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.     

Application des outils chimiques et isotopiques à l'étude de la relation hydrodynamique entre les aquifères profonds de Sfax et de la Djeffara de Gabès Nord (Sud-Est tunisien)

Résumé

L'étude des bassins côtiers de Sfax et de la Djeffara de Gabès Nord, basée sur l'interprétation des données hydrochimiques (éléments majeurs) et isotopiques (¹⁸O, ²H et ¹⁴C), a permis une meilleure compréhension du fonctionnement hydrodynamique de l'aquifère Miocène le long de la frange côtière. En effet, d'après les données géochimiques, apparaît la présence de deux types de faciès chimiques: chloruré sodique dans le bassin de Sfax et mixte à chloruré sodique dans le bassin de Gabès Nord. Cette transition d'un faciès à un autre souligne la variabilité des origines de minéralisation des eaux. L'utilisation des outils isotopiques a permis l'identification d'une eau relativement ancienne à l'exception de quelques poches de recharge récente matérialisées à partir du relief de Zemlet El Beida en amont du bassin de Gabès Nord. Ceci a été vérifié par les fortes activités en¹⁴C des eaux dans cette région. Par conséquent, on peut noter que le passage du Sud au Nord le long de la côte est marqué par une grande variation latérale de lithologie et d'épaisseur de la formation aquifère, soulignant ainsi l'indépendance de chacun des deux réservoirs de Sfax et de la Djeffara de Gabès en absence de toute continuité hydrodynamique entre les deux bassins.

Editeur Z.W. Kundzewicz; Editeur associé S. Faye

Citation Ben Cheikh, N., Zouari, K., et Abidi, B., 2012. Application des outils chimiques et isotopiques à l'étude de la relation hydrodynamique entre les aquifères profonds de Sfax et de la Djeffara de Gabès Nord (Sud-Est tunisien). Hydrological Sciences Journal, 57 (8), 1662–1671.     

Détermination de la valeur du compost d'ordures ménagères destiné à l'agriculture

Sans résumé Station Experimentale T.N.O. d'Agronomic et Instituts pour l'Etude des Sols, Groningen.