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In the context of the Sustainable Development Goals (SDG), understanding landscape evolution is essential to design long-term management plans. In agricultural fields, such as the vineyards on steep slopes, the terraces offer one of the most important morphological changes. However, it is not clear if the poorly managed agricultural terraces are optimal to reduce soil erosion and overland flow, although the trafficability is improved. Therefore, the main aim of this research is to compare the differences between initial soil erosion processes on poorly managed terraced vineyards and sloping vineyards at the pedon scale, considering the key role of the SSC (Soil Surface Components). To achieve this goal, twenty-six rainfall simulations were performed, considering the inclination, vegetation and stone covers, and surface roughness. Our research was carried out in the sloping vineyards (>20°) of the Almachar municipality, in the Montes de Malaga (Spain). Those vineyards are characterized by bare soils, low organic matter and high rock fragment contents. Our results showed that higher soil losses (42.2 g m−2 vs 9.4 g m−2) and runoff (4.9 l m−2 vs 1.6 l m−2) were detected in the plots of the poorly managed terraced vineyard than in the sloping one. Moreover, the time to runoff generation was lower in the poorly conserved terraces (232 s) than in the sloping vineyard (679 s), showing a faster saturation capacity. The SSC considered as the key factors were the reduction of the stone cover and an increase of roughness. As a conclusion, we confirm that the imminent transformation from sloping vineyards into terraced fields could lead several land degradation processes if a poor management is carried out, and no control measures are applied during the process, such as the conservation of stone walls or vegetation cover above the embankment, which is not in compliance with the SDG.

The endemic argan tree (Argania spinosa) in Morocco, which is the source of the valuable argan oil, forms open-canopy forests that are highly degraded due to overgrazing, illegal cutting of firewood and the expanding intensive agriculture. Because of the high grazing pressure young sprouts cannot establish themselves, reforestation measures are often unsuccessful and the bare areas between the isolated trees are expanding. In a previous study, we could already show that these intertree areas are more degraded than the areas under the trees, regarding various soil parameters as well as their erodibility and infiltration capacity.The spatial extent of argan trees on soil quality from the trunk to the intertree area is so far unknown. Hypothetically, the tree influences the soil of the intertree area by wind drift of tree litter and soil material towards the East, i.e. main wind direction, and downhill by runoff and erosion processes of soil material downslope. Tree shadow in the hot midday and afternoon sun should have positive influences on soil moisture in northern or northeastern directions. To test this hypothesis, we took 424 soil samples around 31 argan trees in four directions, uphill, downhill and in both directions parallel to the slope towards the nearest neighbouring tree in that direction. Samples along these transects were taken near the trunk, just inside and just outside the area covered by the tree crown and in the intertree area in the middle between two trees. The soil samples were analysed for various soil parameters (C/N, percolation stability, electrical conductivity, pH, soil moisture).The first results show that the influence of the trees is not limited to the crown-covered area but for some trees extends further into the intertree area in specific directions according to the hypothesis (East due to wind drift, North due to shade and downslope due to slope runoff). For other trees the influence of the trees does not even encompass the whole crown-covered area, where we found similarly lower soil quality as for the bare intertree areas. These differences may result from the degradation state of the tree as well as from the different characteristics of the study areas. Understanding the way argan trees influence their surrounding intertree areas would enable structured reforestation measures with a higher chance of successful rejuvenation of the argan forest.

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we pres ent a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wild land fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.

The argan tree (Argania spinosa) populations, endemic to South Morocco, have been highly degraded. Although the argan tree is the source of the valuable argan oil and is protected by law, overbrowsing and -grazing as well as the intensification and expansion of agricultural land lead to tree and soil degradation. Young stands cannot establish themselves; undergrowth is scarce due to the semiarid/arid climate and thus, goats, sheep and dromedaries continually browse the trees. Canopy-covered areas decrease and are degraded while areas without vegetation cover between the argan trees increase.On 30 test sites, 60 soil samples of tree and intertree areas were studied on their soil physical and chemical properties. 36 rainfall simulations and 60 single-ring infiltration measurements were conducted to measure potential differences between tree/intertree areas in their runoff/erosion and infiltration properties. Significant differences using a t-test were found for the studied parameters saturated hydraulic conductivity, pH, electric conductivity, percolation stability, total C-content, total N-content, K-content, Na-content and Mg-content. Surface runoff and soil erosion were not statistically significant, but showed similar trends due to the higher complexity of runoff formation. The soil covered by argan trees generally showed less signs of degradation than intertree areas. With ever-expanding intertree areas due to the lack of rejuvenation of argan trees a further degradation of the soil can be assumed.

The intensification of European agriculture leads to soil degradation, reduction of biodiversity and an increased economic risk for the farmers. An approach towards solving this problem is crop diversification and the optimized use of resources. Increasing agricultural efficiency/resilience through diversification and the associated falling environmental costs could contribute to the growth of the European agricultural sector by adapting the entire value chain.The EU-funded project DIVERFARMING (Horizon 2020 no 728003) aims to develop and deploy innovative farming and agribusiness models based on crop diversification. Germany is involved with a broad-based study in organic steep slope viticulture in Wawern (Saar Valley).A fundamental issue of steep slope viticulture is related to vegetation management below the vines. In order to overcome problems of soil erosion and soil organic matter depletion, an increasing number of winemakers is establishing cover crops such as grasses and legumes in driving lanes. On the contrary, the area underneath the vines is typically kept free of vegetation to avoid fungal diseases and competition on water. As cover crops do not benefit to the value chain and may compete with vines on water or have other adverse effects on vine performance, an alternative strategy for vegetation management underneath vines in steep slope viticulture is required.Therefore, intercropping vines with perennial herbs like Thyme and Oregano growing underneath is a promising cropping practice to address the abovementioned issues. Both herbs are economically valuable and originate from dry and warm environments, which are typical for most viticultural areas. Furthermore, their relatively low need for water and flat-growing habitus is assumed to be suitable to cover the soil underneath the vines in order to protect against erosion and suppress weeds without having adverse effects on vine growth and -health. They can be marketed directly or indirectly as a concentrate for cosmetics, perfumes, nutritional supplements and food.During the 5-year project, we will investigate impacts on and interactions between crops, soil ecological and physicochemical properties as well as erosion and emission of greenhouse gases to evaluate ecological benefits of crop diversification. Selected results obtained within the first two years of investigation will be presented.

A sound understanding of erosive processes at different scales can contribute substantially to the design of suitable management strategies. The main aim of this work was to evaluate key factors at the pedon scale that cause soil erosion to occur. To achieve this goal, we quantified infiltration, permeability, soil losses and runoff volumes in a small Southern Spanish catchment cultivated with olive orchards. To assess which factor contributed most to speeding up soil erosion, a Spearman rank coefficient and principal components analysis were carried out. The results confirmed low infiltration values (11.8 mm h−1) in the surface soil layers and high permeability values (24.6 mm h−1) in the sub-surface soil layers, and produced an average soil loss of 19.7 g m−2 and average runoff coefficients of 26.1%. Statistical analyses showed that: i) the generation of runoff was closely correlated with soil loss; and, ii) an increase in the vegetation cover helped reduce soil erosion. In comparison to larger areas such as a catchment, the pedon scale produced lower or similar soil losses and runoff coefficients in rainfall simulation conditions, although the influence of vegetation cover as a control factor was also detected.

Las unidades geomorfologicas estan relacionadas con ciertos procesos y con la historia de su formacion. Ademas, se definen por sus formas y materiales. En este estudio se investigan los procesos de erosion en diferentes unidades de relieve. Simulaciones de lluvia, experimentos en rigolas y seguimientos a traves de fotografia aerea se llevaron a cabo en dunas, glacis, rellenos holocenos, taludes y terrazas franco-arcillosos de origen cuaternario, con el objeto de conocer la variacion en la intensidad de los procesos. Para ello, se evaluaron el impacto de las gotas de lluvia, la generacion de escorrentia, la erosion en inter-rigolas y rigolas durante varios anos. Las areas de estudio se situaron en el NE y SE de Espana, sur de Marruecos y norte de Burkina Faso. Los resultados muestras claramente que los procesos medidos son muy diferentes entre si segun la formacion de las propias unidades de relieve. Las dunas y los rellenos holocenos en los valles son altamente susceptibles a la erosion por el impacto de las gotas de lluvia y la formacion de regueros. Por el contrario, las terrazas sobre materiales franco-arcillosos muestran baja susceptibilidad a los procesos de erosion. Por lo tanto, se puede concluir que las distintas unidades de relieve muestran diferentes dominancia e intensidad de procesos. Las diferencias son mas significativas con el incremento de la escala y la complejidad del proceso erosivo: el crecimiento de las carcavas varia mucho mas entre diferentes unidades que los efectos del impacto de la gota de lluvia y la formacion de rigolas.

Conventional Mediterranean vineyards from the Montes de Malaga (Axarquia region, Spain) are characterized by high average temperatures, extreme rainfall events during autumn and winter, elevated stoniness and steep slopes (20–50°). Traditionally, several problems of high soil loss, rill and ephemeral gully generation, and elevated runoff are observed by farmers, which are increasing land degradation processes and a decrease of the productivity. According to this, the main aims of this paper were: i) to quantify the initial soil loss, surface flow and infiltration processes; ii) to characterize and describe the hydrological and geomorphological dynamics; iii) to detect the key factors, which control the soil erosion processes. For this purpose, a combined methodology was applied, using soil analysis, a small portable rainfall simulator and a Guelph permeameter on one experimental plot cultivated with vineyards with steep slopes. Results showed a high variability of soil erosion and permeability processes. Soil analysis showed an elevated concentration of silt particles and stoniness, with higher contents of sand particles between 0 and 5 cm, and clays from 5 cm. With a Guelph permeameter, high average of permeability and saturated hydraulic conductivity with elevated standard deviation were observed. Furthermore, an increase of these parameters from the upper to the foot slope was registered. By using rainfall simulations, on the upper and the foot slope positions the highest runoff coefficient and soil loss were registered. The most elevated peak of sediment concentration was obtained on the middle slope. In general, high infiltration coefficients between 66.5 and 100% were observed. In conclusion it was observed that the activation of the soil erosion processes was due to the distribution of the surface soil components (high roughness, several cracks and high stoniness and silt content), the steep slopes and the impact of the soil traditional tillage practices. These Mediterranean hillslope vineyards registered a mixed Hortonian-Hewlettian model, which combines surface and sub-surface flow conditioned by the micro-topographical changes and its saturation degree.

In spring 2009, four rill experiments were accomplished on a fallow land. Most external factors as well as discharge quantity (9 L min-1) were held constant or at least in the same range. Following most process based soil erosion models, detachment or runoff values should therefore be similar, but the experimental results show clear differences in sediment concentration, runoff and other measured and calculated values. This fact underlines the problems of process based models: concerning rill erosion, different processes take part and the process described by the models is only responsible for a part of the eroded material.

For a long time, studies concerning erosion caused by concentrated overland flow mainly dealt with the erosion and the transport of fine material. More recent studies have shown that rock fragments reduce the intensity of soil erosion processes on the one hand, but on the other hand rock fragment movements also have been observed both in the rill- and interrill erosion processes. However, there is little knowledge about the movement process of rock fragments in shallow channel flow. Are certain movement patterns typical for different shapes? Are there relationships between movement patterns and slope and flow velocity? Are all these patterns and relationships reproducible? To answer these questions, we performed laboratory channel experiments. With these experiments, we could obtain information about movement patterns of pebbles, by varying the following parameters: shape (flat, ellipsoidal, nearly spherical), size (diameter between 1.97 and 4.0 cm) and channel slope (5°, 10°). During the experiments, a high-speed camera was used to capture the motion of eight specially painted pebbles. The resulting image sequences were processed using both automatic image processing and manual visual inspection. Besides the movement patterns, the pebbles velocity, the water velocity and the water depth were estimated. We could show that there were different movement patterns depending on the shape and the slope. For the 5° experiments, the big, flat pebbles lie at the beginning of the tests. After the following yawing, the pebbles mainly showed the movement form rolling around the longest axis. For the 10° experiments the big, flat pebbles showed the same movement pattern firstly, but later in the sequence, they started to roll around their shortest axis and in the end this movement form was combined with saltation. These patterns are described using a simple symbolic language: sequences of pictograms describe the consecutive movement forms. Furthermore, we detected five different velocity groups of the pebbles for each slope: different cross-section shapes of the pebbles result in different acceleration behavior. The methodology is limited to clear water in laboratory use. Even a larger water depth restricts the image processing. Thus, in the future the experiments will be combined with a small sensor that is implanted in the pebbles and measures forces (acceleration), compass (magnetic flux density) and rotations (gyroscope).

In the framework of the EU-INTERREG-IVb-project ForeStClim (Transnational Forestry Management Strategies in Response to Regional Climate Change Impacts) a combination of experimental methods has been applied for the investigation of the spatial and temporal variation and intensity of overland flow generation and soil erosion processes. In the presented study, the influences of land-use type and land-management practices on overland flow generation and soil erosion are investigated for three low mountain range catchments in Luxembourg and in Rhineland-Palatinate, Germany. The key questions of the study can be summarized as follows: Can Hortonian overland flow generation be observed on all land-use types in the investigated areas in the Central European low mountain range? How can the contribution of forested areas to the flood and erosion dynamics be evaluated under humid climate conditions in Central Europe and what are the most important factors of influence? The results of the presented study show that forest areas can also be sources for overland flow and sediment, particularly artificial linear structures like unpaved roads and harvester tracks, where runoff coefficients between 41.2 and 97.1%, and erosion values between 2.6 and 122.5 g m− 2 were determined using rainfall experiments. Another important factor is soil water repellency, this factor can pre-eminently be observed under rather dry soil moisture conditions in summer and can have severe influence on overland flow generation particularly in forested areas. The results of the rainfall experiments in coniferous forests show runoff coefficients ranging from 0 to 86.9%, here the high values can all be traced back to water repellency influence, as the field observations suggest. In the context of flood generation, it is becoming more and more important to improve knowledge on overland flow generation and soil erosion processes occurring in forested catchments, particularly considering the expected climate change.

The results from several rainfall simulations performed on two abandoned fields of different ages in the Central Ebro Depression have been analysed by application of the physically based hydraulic model HILLFLOW 1D. The data gained by the simulations was used to parame - terise the model. Afterwards, the runoff generation characteristics were determined by simulation of different rainfall intensities and different macroporosities of the soil. The young fallow land shows a minimum inten - sity for runoff generation of 6 mm h-1. An increase of the rainfall intensity leads rapidly to a growing runoff coefficient, being the value modelled for 30 mm h-1 nearly the same as the simulated one (40 mm h-1). Another con - clusion of the simulations and their modelling is the homogeneity of the soils on the young fallow land, with no macroporosity all over the profile. On the other hand, the rainfall simulations and the modelling on the old fallow land show a high variability of rainfall-runo ff response patterns, strongly conditioned by the presence of macropores. They are distributed very irregularly throughout the soil of the old fallow land. In both cases, water infiltrates only little into the soil matrix, for that measures for enhan- cing soil hydraulic properties are needed. RESUMEN: Se han analizado los resultados de numerosas simulacio - nes de lluvia en campos abandonados de diferente antuguedad en la Depresion central del Ebro aplicando el modelo hidrologico de base fisi ca HILLFLOW 1D. Los datos de las simulaciones se utilizaron para para - metrizar el modelo. A continuacion, las caracteristicas de la generacion de escorrentia se analizaron modelizando diferentes intensidades de lluvia y volumenes de macroporos en el suelo. En el campo recientemente aban - donado se pudo calcular una intensidad de llluvia minima para la gene- racion de escor rentia de 6 mm h-1. Una intensidad de precipitacion cr e - ciente produce un incremento muy fuerte del coeficiente de escor rentia, de modo que precipitaciones de 30 mm h-1 se diferencian poco de las simu- ladas con 40 mm h-1. Otra conclusion es que los suelos del campo recien - temente abandonado son muy homogeneos y estan caracterizados por la ausencia de macroporos. La respuesta de la generacion de escor rentia a la precipitacion es en cambio muy variable en el campo abandonado anti

The present paper is based on several field investigations (monitoring soil and rill erosion by aerial photography, rainfall simulations with portable rainfall simulators, and manmade rill flooding) in southern Spain. Experiments lead now to a closer understanding of the dynamics and power of different soil erosion processes in a gully catchment area. The test site Freila (Andalusia, Spain) covers an area of 10.01 ha with a rill density of 169 m ha−1, corresponding to a total rill length of 1694 m. Assuming an average rill width of 0.15 m, the total rill surface can be calculated at 250 m2 (0.025 ha). Given that, the surface covered by rills makes up only 0.25% of the total test site. Since the rill network drains 1.98 ha, 20% of the total runoff comes from rills. The rills’ sediment erosion was measured and the total soil loss was then calculated for detachment rates between 1685 g m−2 and 3018 g m−2. The interrill areas (99.75% of the test site) show values between 29 and 143 g m−2. This suggests an important role of rill erosion concerning runoff and soil detachment.

Within this paper a standardized method to quantify sediment transport and runoff in natural rills is described. In order to achieve this, several rill experiments (RE) were accomplished in March 2007 in the Arnás catchment in the Spanish Pyrenees. Both, anthropogenically initiated and naturally developed rills were flushed with a total water quantity of 72 l in 8 minutes (equivalent to 9 l min-1). For the characterisation of the rill, slope is measured and micromorphological features like scours are registered. The experiments are characterised by the flow velocities along the whole flushed rill, sediment concentrations at different points and different times during the experiment. Runoff is measured after 25 m continuously. With this data, a set of characteristic variables is generated, which reflects the infiltration and flow behaviour along the rill. By means of rainfall simulations within the rills catchments, their contributing runoff was estimated also. The tested rills were developed on average slopes oscillating between 7.6° and 11.3°, the steepest slope reached 16°. The sediment concentrations reached average values between 0.69 and 2.21 g l-1, the maximum values ranged between 1.59 and 6.31 g l-1. Comparing the sediment concentrations measured in the rills to the sediment concentrations in the runoff of the river Arnás, it can be stated that the concentrations in the rills are usually higher. Though, the runoff was to low to cause erosion. Accordingly, the runoff amount that can be produced within the rills catchments was found to be about 10-25 times higher. By means of the developed rill experiments, for which easy to handle devices were built and are described in detail, it becomes possible to assess the effectivity of individual rills in a catchment and to evaluate their hydraulic functioning as well as their geomorphodynamic activity

Steep slopes, erodible soils, rill and ephemeral gullies, compaction due to wheel. traffic and human trampling are common features in vineyards around the world and result in high soil erosion rates. However, little is known about seasonal and spatial variations of soil erosion rates due to factors such as the impact of the vine plantation, harvest, and tillage on the soil redistribution over the long-term temporal scale. The goal of this study is to assess long-term soil erosion rates and the impact of management on sediment and runoff yield by means of Gerlach troughs and a topographical approach based on botanic benchmarks in two paired vineyards with different ages (3 and 35 years) located on the hillslope of the Ruwer-Mosel Valley (Germany). We studied: i) soil profiles and properties at different hillslope locations and ii) soil redistribution and erosion by means of topsoil level maps applying botanic benchmarks using the Stock Unearthing Method (SUM), RUSLE (Revised Unviersal Soil Loss Equation) and Gerlach troughs. The SUM showed that the old vineyard's erosion rates ranged from 3.3 to 3.8 Mg ha(-1) yr(-1), which was similar to the Gerlach trough measurements, and we demonstrated that the soil erosion rates depended on rainfall characteristics and human disturbances due to tillage, harvest trampling, and compaction by heavy machinery. Data from the SUM in the young vineyard showed 62.5 Mg ha(-1) yr(-1) of soil loss, which is a consequence of severe soil disturbance during the planting of the new vineyard. Finally, to prove the reliability data, RUSLE showed higher soil loss in the young vineyards (19.46 Mg ha(-1) yr(-1)) than in the old ones (11.28 Mg ha(-1) yr(-1)).

Vineyards are one of the most German conditioned eco-geomorphological systems by human activity. Precisely, the vineyards of the Ruwer Valley (Germany) is characterized by high soil erosion rates and rill problems on steep slopes (between 23–26°) caused by the increasingly frequent heavy rainfall events, what is sometimes enhanced by incorrect land use managements. Soil tillage before and after vintage, application of vine training systems and anthropic rills generated by wheel tracks and footsteps are observed along these cultivated area. The objective of this paper is to determine and to quantify the hydrological and erosive phenomena in two chosen vineyards, during diverse seasons and under different management conditions (before, during and after vintage). For this purpose, a combined methodology was applied. Investigating climatic, pedological, geomorphological and botanic-marks variables was suggested on the two experimental plot in the village of Waldrach (Trier, region of Rhineland-Palatinate). First, high infiltration rates (near 100%) and subsurface flow was detected by rainfall simulations performed at different times of the year. The second method to investigate the geomorphological response of slope inclination, two 10 m and one 30 m long rills were measured using geometrical channel cross-section index, depth and width. The highest variations (lateral and frontal movements) were noted before and during vintage, when footsteps occurred in a concentrated short time. Finally, two maps were generated of soil loss, indicated by the botanic marks on the graft union of the vines. As results 62.5 t−1 ha−1 yr−1 soil loss rate was registered (one year) on the experimental plots of the new vineyards, while 4.3 t−1 ha−1 yr−1 on the old one.

This study presents the comparison of experimental results with assumptions used in numerical models. The aim of the field experiments is to test the linear relationship between different hydraulic parameters and soil detachment. For example correlations between shear stress, unit length shear force, stream power, unit stream power and effective stream power and the detachment rate does not reveal a single parameter which consistently displays the best correlation. More importantly, the best fit does not only vary from one experiment to another, but even between distinct measurement points. Different processes in rill erosion are responsible for the changing correlations. However, not all these procedures are considered in soil erosion models. Hence, hydraulic parameters alone are not sufficient to predict detachment rates. They predict the fluvial incising in the rill's bottom, but the main sediment sources are not considered sufficiently in its equations. The results of this study show that there is still a lack of understanding of the physical processes underlying soil erosion. Exerted forces, soil stability and its expression, the abstraction of the detachment and transport processes in shallow flowing water remain still subject of unclear description and dependence.

Despite many efforts over the last decades to understand rill erosion processes, they remain unclear. This paper presents the results of rill experiments accomplished in Andalusia in September 2008 using a novel experimental set up. 72 L of water are introduced with an intensity of 9 L min(-1) into a rill. Rill cross sections, slope values, flow velocities and sediment concentrations were measured and these values were used to calculate sediment detachment and transport. Each experiment was repeated once within 15 min. With this new experimental setup it is possible to calculate several hydraulic parameters like hydraulic radius, wetted perimeter, flow cross section, transport rate and transport capacity which are usually estimated from coarse flow and rill parameters. In rill experiments, four different natural rills were flooded with the same experimental setup. Several processes like transport of loose material, erosion, bank failure and knickpoint retreat and the runoff effectiveness showed different and variable intensities. The sediment concentrations ranged between 5.2 and 438 g L-1. most cases, detachment rates are close to the transport capacity and, in some cases, the transport capacity is even exceeded. This can be explained by the occurrence of different erosion processes within a rill (e.g. detachment, bank failure, and headcut retreat) which are not all explained by the given equations. The results suggest that the existing soil erosion equations based on shear forces exerted by the flowing water are not able to describe rill erosion processes satisfactory. Too many different processes with a high spatial and temporal variability are responsible for rill development. (C) 2010 Elsevier B.V. All rights reserved.

The state of river channels and their riparian zones in terms of geomorphology and vegetation has a significant effect on water and sediment transport in headwater catchments. High roughness in natural rivers due to vegetation and geomorphological attributes generate drag on flowing water. This drag will slow water discharge, which in turn influences the sediment dynamics of the flow. The impacts of changes in the management of rivers and their riparian zone (either by catchment managers or river restoration plans) impacts both up- as well as downstream reaches, and should be assessed holistically prior to the implementation of these plans.To assess the river's current state as well as any possible changes in geomorphology and vegetation in and around the river, effective approaches to characterise the river are needed. In this paper, we present a practical approach for making detailed surveys of relevant river attributes. This methodology has the benefit of being both detailed – describing river depth, width, channel morphology, erosive features and vegetation types – but also being practical in terms of time management. This is accomplished by identifying and describing characteristic benchmark reaches (typical sites) in detail against which the remainder of the river course can be rated. Using this method, a large river stretch can be assessed in a relatively short period while still retrieving high quality data for the total river course. In this way, models with high data requirements for assessing the condition of a river course, can be parameterised without major investments on field surveys.In a small headwater catchment (23 km2) in southwestern Poland, this field methodology was used to retrieve data to run an existing model (HEC-GeoRAS) which can assess the impact of changes in the riparian and channel vegetation and channel management on sedimentation processes and stream flow velocity. This model determines the impact of channel morphology and in-channel and riparian vegetation on stream flow and sediment transport. Using four return periods of flooding (2, 10, 20 and 100 years), two opposing channel management / morphology scenarios were run; a natural channel and a fully regulated channel. The modelling results show an increase in the effect of riparian vegetation / geomorphology with an increase in return period of the modeled peak discharge. More natural channel form and increased roughness reduces the stream flow velocity due to increasing drag from flow obstructions (vegetation and channel morphological features). The higher the flood water stage, the greater the drag due to vegetation on the floodplains of natural river reaches compared to channelised sections. Slower flow rates have an impact on sediment mobilisation and transport in the river.

22 Pag., 3 Tabl., 7 Fig., This paper studies the hydrological response to rainstorm events of a small experimental catchment in the Central Spanish Pyrenees. The Arnás catchment was cultivated until 40 years ago, and then abandoned and affected by plant recolonisation, especially shrubs. A rainfall of a few millimeters is enough to produce a sudden increase in discharge, due most probably to the steep gradients and the small size of the catchment and the extensive areas with low vegetation density and thin soils. The intensity of the response shows a very high variability, depending on the intensity of precipitation and soil humidity conditions before the flood. This paper identifies two types of floods according to the relationships between precipitation and discharge, and confirms that antecedent soil moisture explains much of the response. The shape of the hydrograph, very similar to the hyetograph, suggests that the Arnás catchment is dominated by overland flow processes. However, more intense rainstorms do not generate higher peak flows, thus demonstrating the existence of different runoff-generating areas., This paper has been supported by the following projects: “Water resources management in a changing environment: the impact of sediment on sustainability” (WARMICE, ENV4-CT98-0789) funded by the European Commission; and “Assessment of sediment sources and runoff generation areas in relation to land use changes” (HIDROESCALA, REN2000-1709-C04-01/GLO), “Hydrological processes in seminatural Mediterranean areas” (PROHISEM, REN 2001-2268-C02-01/HID), and “Hydrological processes in Pyrenean catchments in relation to land use and climate changes” (REN 2003-08678/HID), all funded by the CICYT. Monitoring of the catchment has been supported by agreement between the CSIC and the Spanish Ministry of Environment (RESEL).

Las cuencas experimentales de Arnás y San Salvador, localizadas en la cuenca alta del río Aragón, han sido equipadas con estación meteorológica completa, flume e instrumentos para la medición continua del caudal y del sedimentos transportado (en solución y en suspensión). Una trampa de sedimento a la entrada del flume permite controlar periódicamente la carga de fondo. Los resultados obtenidos confirman la existencia de grandes diferencias en la respuesta hidrológica y el transporte de sedimento entre la cuenca forestal (San Salvador) y la cuenca de campos abandonados (Arnás). La primera muestra una respuesta mucho más moderada debido básicamente a los procesos de interceptación y a la mayor profundidad de los suelos. Las relaciones entre precipitación y pico de caudal, así como entre este último y la concentración de sedimento en suspensión son muy bajas, aumentando notablemente si se contemplan por separado las crecidas de estación fría. La escorrentía se genera sobre todo por procesos de saturación. Las fuentes de sedimento se localizan en el cauce y sus proximidades.

Plans to increase the amount of irrigated land in Mediterranean countries should consider how changes in climate and land-use affect water resources. In this study, both precipitation and temperature were used to analyze regional trends in discharge in the basins of the Central Spanish Pyrenees since the mid-20th century. Annual variations in the relationship between precipitation and discharge suggested that discharge was relatively lower in the second half of the study period, coinciding with major changes in land use. On a monthly scale, precipitation increased significantly in October, April, and July, and decreased in March, and temperature increased in January and February and decreased in April. Nevertheless, discharge has decreased significantly in most months in the past 50 years. Land-use and plant-cover changes are the only nonclimatic factor that can explain the loss of around 30% of the average annual discharge., Funding for this research was provided by the following projects: "Water resources management in a changing environment: the impact of sediment in sustainability" (WARMICE, ENV4-CT98-0789), funded by the European Community, and "Assessment of sediment and runoff sources in relation to land-use changes", (HIDROESCALA, REN2000-1709-C04-01/GLO) and "Hydrological processes in semi-natural Mediterranean areas" (PROHISEM, REN2001-2268-C02-01/HID), both funded by CICYT.