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The first part of this review demonstrates that before the twentieth century, traditional irrigation schemes were widespread and a characteristic feature of European landscapes. Rapid decline in traditional irrigation practice ensued following the arrival of agricultural industrialization. Today working traditional irrigation systems are rare exceptions, yet relic features can still frequently be found in the field. Consequently, the tradition of irrigation is diminishing and comprehensive documentation and reconstruction are urgent issues. Moreover, full recognition of irrigation tradition as a rural patrimony of high complexity is needed. Irreversible demise of irrigation operation entails the loss of genuine traditional irrigation landscapes as they were a characteristic part of many regions once. Indeed, interest in traditional irrigation has reawakened recently. Beneficial functions and services of traditional irrigation have been recognized apart from purely agricultural profitability. Increasingly initiatives for revitalization of irrigation emerge, often from nature, biodiversity and landscape conservation circles. Due to conflicts and competing management demands local restoration projects face many challenges. Yet a great potential for creating win–win outcomes by adequate multifunctional landscape management is demonstrated by the existing projects, where the restoration of an extensive heritage landscape could be realized. Copyright © 2014 John Wiley & Sons, Ltd. RESUME La premiere partie de cet article demontre que, avant le XXeme siecle, les systemes d'irrigation traditionnelle etaient tres etendus et caracteristiques des paysages europeens. Avec l'arrivee de l'industrialisation agricole, un declin rapide de ces traditions a commence. Bien que les vestiges d'une irrigation traditionnelle soient frequemment visibles dans le paysage, rares sont ces systemes encore fonctionnels aujourd'hui. En consequence, la tradition dans l'irrigation se perd et une documentation complete ainsi qu'une reconstruction historique de ces systemes est urgente. De plus, le classement de l'irrigation traditionnelle comme un patrimoine rural d'une grande complexite est essentiel. Une perte irreversible des techniques d'irrigation engendrerait inevitablement une perte des paysages creuses par ces traditions et tres caracteristiques pour de nombreuses regions. Heureusement, on peut constater dernierement un retour de l'interet pour l'irrigation traditionnelle. Celle-ci a montre qu'elle pouvait apporter des services et fonctions benefiques en dehors d'une production agricole purement orientee vers le profit. Les initiatives pour la revitalisation des systemes d'irrigation sont de plus en plus frequentes, provenant souvent de groupes pour la conservation de la nature, de la biodiversite et du paysage. En raison de conflits ainsi que d'objectifs divergents dans la gestion des ressources, les projets de restauration sont souvent exposes a de nombreux challenges. Cependant, les projets de restauration de l'heritage paysager existants ont pu montrer que, lors d'une gestion multifonctionnelle adequate du paysage, un denouement ‘profit–profit’ est possible. Copyright © 2014 John Wiley & Sons, Ltd.

Whereas the importance of traditional irrigation in southern Europe is well known, its role in the ecological history of rural landscapes elsewhere in Europe is often overlooked. This two-part review aims to advance understanding of the historical and present role of traditional irrigation farming schemes in Europe. It confirms that, prior to the industrial era, irrigation had been an essential part of farming for centuries. It was practised in very different, often contrasting, environmental regions across Europe. The historical spread of the schemes is presented in a map. Two ‘golden ages’ of traditional irrigation in Europe can be identified: the first in the High Middle Ages along with the introduction and widespread adoption of the three-field system, and the second in the late eighteenth up to the first half of the twentieth century with reorganization of this agricultural system. Due to the complex character of past irrigation functioning, scientific understanding of processes and long-term impacts is difficult, but ultimately all irrigation farming enterprises were driven by the purpose of increasing yields. Apparently the traditional schemes were the result of an evolution process over the course of centuries characterized by steady optimization and adaptation to historic and local conditions. Copyright © 2014 John Wiley & Sons, Ltd. RESUME Alors que l'importance de l'irrigation traditionnelle en Europe du Sud est bien connue, ses impacts ecologiques sur le paysage rural du reste de l'Europe sont souvent oublies. Cet article en deux parties a pour but d'apporter une meilleure comprehension du role tant historique qu'actuel de l'irrigation traditionnelle dans le schema rural europeen. Le schema agricole europeen ainsi que son etendue sont presentes a l'aide d'une carte. Il y est mis en avant que, avant l'ere industrielle, l'irrigation etait une partie essentielle de l'agriculture pendant des siecles, pratiquee en Europe dans des regions aux caracteres environnementaux tres distincts. L'irrigation traditionnelle europeenne a connu deux ‘âges d'or’. Le premier se situe a la fin du Moyen Age et se caracterise par l'introduction de l'assolement triennal, alors que le second, s'etendant entre la fin du XVIIIe et la premiere moitie du XXe siecle, correspond a une reorganisation de ce systeme agricole. En raison du caractere complexe du fonctionnement de l'irrigation dans le passe, la comprehension scientifique de ses procedes et de son impact sur le long terme est difficile. Mais le besoin d'augmenter la productivite a toujours ete la motivation principale de tout systeme d'irrigation agricole. A l'evidence, le schema traditionnel etait le resultat d'un processus evolutif au cours des siecles caracterise par une optimisation constante et une adaptation aux conditions historiques et locales. Copyright © 2014 John Wiley & Sons, Ltd.

The stable isotopes deuterium ( 2 H, D) and oxygen 18 ( 18 O) were applied in water for use as tracers in column experiments and in two field studies. Their performance was compared against uranine and was used to characterize saturated and unsaturated water movement and depths of plant water uptake. Deuterium and 18 O are completely soluble and chemically and biologically stable. They are not subject to radioactive decay like tritium, nor photodegradation and sorption processes, like uranine. The column studies were conducted under saturated conditions; they explored variations of (i) flow rates (1.4– 3.5 ml min � 1 ), (ii) column lengths (0.5, 1.0, 1.5 m), and (iii) tracer concentrations (0.07, 0.14, 0.28 ml of a 99.8% D2O solution). A one dimensional dispersion model was used to generate parameters that allowed us to compare the tracers. The column experiments showed higher mean transport velocities and smaller dispersion coefficients for deuterium in comparison to uranine. The first field study, on a rain dominated floodplain, found unsaturated flow rates of 0.03–0.04 m day � 1 . The second field study examined snow

River water samples were analysed for stable isotopes (deuterium and oxygen-18) collected from 46 sites during spring 2008, and from monthly samples at the outlets of seven sub-basins of the River Weser (46,200 km(2) basin area in total) over a five year period from 2003 to 2007, to characterise temporal and spatial isotope patterns of river water. Results indicate a pronounced elevation effect (0.2 per thousand and 1 to 2 per thousand per 100 m for delta(18)O and delta(2)H, respectively) as well as influence of seawater mixing for a few coastal locations. A lumped parameter modelling approach was used to compare residence times and relative amounts of direct flow, fast and slow groundwater with those derived from a combined water balance and tritium balance modelling approach. Residence times of direct runoff were estimated to be between one and three and a half months. Much longer groundwater residence times are necessary to explain tritium recession in river water. The modelling fits for stable isotope data in river water, derived with residence times and base flow amounts combined from a water and tritium balance approach, emphasise that beneath a characterisation of a direct flow component, seasonal variations of stable isotope values in river water carry information on groundwater contribution.

Classical hydrometric measurements and detailed 2-D electrical resistivity imaging (ERI) surveys were combined with tracer sampling to identify the hydrological processes in a semi-arid headwater catchment in the Eastern Cape Province of South Africa. The analysis of precipitation and runoff events emphasized the strong link between precipitation and runoff formation characteristics. Soil water tension and groundwater level observations demonstrated the development of a perched water table within the soil layer. These results are supported by tracer-based runoff component separations and illustrate the important role of the shallow subsurface component. The ERI investigation permitted further insight into the structure of the subsurface. Finally, the ERI survey, in combination with time domain reflectometry (TDR) measurements, allowed the extrapolation of selective soil water content measurements. To summarize, the application and combination of different field methods led to the development of a conceptual model of the hydrological functioning of this catchment. The dominant role of the subsurface mechanisms was evaluated.

This study investigated the influence of meteorological, pedospheric and physiological factors on the water relations of Scots pine, as characterized by the origin of water taken up, by xylem transport as well as by carbon isotope discrimination (Delta13C) and oxygen isotope enrichment (Delta18O) of newly assimilated organic matter. For more than 1 year, we quantified delta2H and delta18O of potential water sources and xylem water as well as Delta13C and Delta18O in twig and trunk phloem organic matter biweekly, and related these values to continuously measured or modelled meteorological parameters, soil water content, stand transpiration (ST) and canopy stomatal conductance (G(s)). During the growing season, delta18O and delta2H of xylem water were generally in a range comparable to soil water from a depth of 2-20 cm. Long residence time of water in the tracheids uncoupled the isotopic signals of xylem and soil water in winter. Delta18O but not Delta13C in phloem organic matter was directly indicative of recent environmental conditions during the whole year. Delta18O could be described applying a model that included 18O fractionation associated with water exchange between leaf and atmosphere, and with the production of organic matter as well as the influence of transpiration. Phloem Delta13C was assumed to be concertedly influenced by G(s) and photosynthetically active radiation (PAR) (as a proxy for photosynthetic capacity). We conclude that isotope signatures can be used as effective tools (1) to characterize the seasonal dynamics in source and xylem water, and (2) to assess environmental effects on transpiration and G(s) of Scots pine, thus helping to understand and predict potential impacts of climate change on trees and forest ecosystems.

Analysis of water flow pathways from hillslopes to streams is essential for the optimal protection of water resources as well as for ecohydrological studies. This study addresses runoff generation processes at a hillslope and near-stream shallow groundwater system in the Black Forest Mountains, southwestern Germany. The changing spatial and temporal flow patterns during differing hydrological situations were examined using a combined hydraulic and hydrochemical approach. Groundwater levels at 10 wells, discharge at a near-stream saturated area, and several natural tracers (deuterium, dissolved silica, and major anions and cations) were observed at different locations during high and low flows. The importance of the groundwater component during flood formation was clearly demonstrated: its contribution was about 80% during a double peak flood event at the saturated area. In addition, a rapid change of the shallow groundwater levels was observed along two transects of groundwater wells in the floodplain. This led to an enhanced groundwater discharge into the saturated area located at the end of one study transect. The amount of groundwater additionally activated during the event was about 30% of total discharge recorded at the outlet of the saturated area. Two alternative hypotheses are discussed to explain this phenomenon: the establishment of locally confined conditions and the development of a pressure wave (hypothesis A), or the significant change of the three-dimensional groundwater flow lines that caused a large increase of the groundwater catchment at the saturated area during the investigated event (hypothesis B). Even if the exact flow paths and mechanisms could not be clearly identified, the importance of rapid responding hillslope groundwater was undoubtedly demonstrated by a combination of tracer and hydrometric methods. Copyright © 2004 John Wiley & Sons, Ltd.

With the implementation of the European Water Framework Directive (WFD) the achievement of a good ecological status of surface waters and a good quantitative and qualitative status of groundwater has become obligatory. The ecological status is defined by biological, chemical and physical criteria. In the River Basin Management Plans required by the WFD, all human impacts on the aquatic environment shall be quantified and evaluated. For this purpose catchment related assessment methods which describe the physical and chemical predictors of the ecological status in surface waters and the status of groundwater are needed. They will have to be combined with monitoring programs and assessments of the water bodies themselves. To complete the existing biological, chemical and morphological assessment methods a spatially orientated assessment procedure for the hydrological quality of meso-scale river basins was developed. In this procedure human impacts on hydrology, river morphology and water quality are quantified and assessed. The procedure is divided into the three assessment units “catchment properties”, “runoff dynamics” and “nutrient budget, water quality and solute dynamics”. It was applied to 22 meso-scale river basins in South-West Germany. The assessment results enable a quantification of the level of human impact on the aquatic environment.

Es wurden hydrologische Homogenbereiche (Hydrotopen) in einem mesoskaligen Einzugsgebiet auf der Basis breitenverfugbarer Daten mit Hilfe eines Geographischen Informationssystems (GIS) ausgewiesen. Insbesondere wurde hierfur ein Regionalisierungsansatz fur die flachenhafte Abschatzung der Struktur- und Lithovarianz von periglazialen Deckschichten entwickelt, welcher auf der Hangentwicklungsgenese basiert. Dies ist von besonderer Bedeutung, da diese Raumeinheit fur den lateralen Hangabfluss ein sehr bedeutender Herkunftsraum ist. Die Ergebnisse zeigen eine plausible Raumgliederung fur das 40 km 2 grose Bruggaeinzugsgebiet (Schwarzwald). Fur das ubergeordnete Dreisamgebiet (258 km 2 ) konnte zusatzlich die Eignung mit Hilfe der Bodenubersichtskarte BUK 200 belegt werden. Die Resultate stellen die Grundlage fur eine verbesserte prozessorientierte Niederschlags-Abfluss-Modellierung sowie fur eine holistische Umwelt- und Landschaftsplanung dar.

The stable isotope oxygen-18 is often used as a natural tracer in stream-flow separation studies in forested catchments. Knowledge about the 18 O content of throughfall and soil water is needed. The present study was conducted in order to assess the effect of vegetation structure on the stable isotope 18 O composition of rainwater input during its passage through the canopy and into the unsaturated zone. The research area was a small (0.1 km 2 ) forested catchment in the mountainous Black Forest' region of southern Germany. During the 3-month periods (September to December 1995 and April to July 1996) several structural units were instrumented according to tree species (beech and spruce) and canopy density. Overall throughfall was enriched compared with open rainfall by +0.38‰ and +0.36‰ for spruce and beech, respectively. Considerable differences existed in the results of the crown centre and the crown periphery sites. Throughfall in the crown centre showed a higher degree of enrichment, with a mean value of +0.30‰ for beech and +0.37‰ for spruce. Enrichment and depletion were observed in the lower canopy density locations. Mean results of the crown periphery were similar to those of open precipitation (+0.15‰ for beech and - 0.01‰ for spruce). Soil water was sampled at five different depths (0, 15, 60, 120 and 180 cm). The signals of individual rainfall events could be traced down to a depth of 60 cm. The soil water in the upper layers followed the seasonal trend in the precipitation input. At a depth of 180 cm, soil water had a very constant δ 18 O value. The 18 O composition of the soil water at various depths at different locations showed a similar behaviour. No detectable differences could be found between the structural units in the different layers, except at 180 cm depth. This might be attributed to downslope directed flow at that depth.

Resume Des mesures hydrometriques classiques et l'imagerie 2-D de resistivite electrique (IRE) detaillee ont ete combinees avec le prelevement de traceurs pour identifier les processus hydrologiques en jeu dans un bassin versant semi-aride de la province Cap-Oriental, en Afrique du Sud. L'etude des evenements de precipitation et d'ecoulement a souligne la forte relation qui existe entre les precipitations et les caracteristiques de la generation des ecoulements. L'observation du potentiel hydrique du sol ainsi que du niveau d'eau souterraine a mis en evidence le developpement d'une nappe perchee dans le sol. Ces resultats sont confirmes par des separations d'hydrogrammes a base de traceurs et illustrent le role important des ecoulements souterrains superficiels. L'etude par IRE a permis de mieux connaitre la structure du sous-sol. Finalement, l'etude par IRE, combinee avec des mesures obtenues par reflectometrie en domaine temporel (TDR), a permis d'extrapoler a des mesures selectives de teneur en eau. Po...

[1] The spatial and temporal (event and seasonal timescale) variability of major runoff components in the mountainous Brugga basin (Black Forest, Germany) were examined. The mesoscale (40 km2) study basin represented an extraordinary challenge as comparable studies have been undertaken mainly in smaller headwater basins. Discharge data, tracer concentrations of 18O, 3H, CFCs, and dissolved silica, and major anions and cations were analyzed during single events and over a period of 3 years. Three main runoff components were defined: event water with a residence time of several hours to a few days contributed up to 50% during flood peaks, quantified by a classical hydrograph separation technique using 18O. However, this component is of minor importance for longer periods, comprising ∼11.1% of total runoff as estimated for the period August 1995 to April 1998. The other two flow components originated from shallow and deep groundwater. Source areas for these are the upper drift and debris cover for the shallow groundwater and the deeper drift, weathering zone and hard rock aquifer for the deep groundwater. Mean residence times ranged from 28 to 36 months on the basis of 18O data for the shallow groundwater and from 6 to 9 years on the basis of 3H and CFC data for the deep groundwater. The importance of the upper drift and debris cover of the slopes for runoff generation at the test site was clearly demonstrated at the seasonal timescale, showing a contribution of 69.4% based on a mixing model with a monthly time step. The deep groundwater contribution was 19.5%. With this information a conceptual model of runoff generation for the study site was constructed.

The uncertainties arising from the problem of identifying a representative model structure and model parameters in a conceptual rainfall-runoff model were investigated. A conceptual model, the HBV model, was applied to the mountainous Brugga basin (39.9 km”) in the Black Forest, southwestern Germany. In a first step, a Monte Carlo procedure with randomly generated parameter sets was used for calibration. For a ten-year calibration period, different parameter sets resulted in an equally good correspondence between observed and simulated runoff. A few parameters were well defined (i.e. best parameter values were within small ranges), but for most parameters good simulations were found with values varying over wide ranges. In a second step, model variants with different numbers of elevation and landuse zones and various runoff generation conceptualizations were tested. In some cases, representation of more spatial variability gave better simulations in terms of discharge. However, good results could...