TY - CHAP A1 - Caviedes-Voullième, Daniel A1 - Jozefik, Zoltan A1 - Hinz, Christoph T1 - Towards a physically-based multi-scale ecohydrological simulator for semi-arid regions T2 - European Geosciences Union General Assembly 2017 Vienna, Austria, 23–28 April 2017 N2 - The use of numerical models as tools for describing and understanding complex ecohydrological systems has enabled to test hypothesis and propose fundamental, process-based explanations of the system system behaviour as a whole as well as its internal dynamics. Reaction-diffusion equations have been used to describe and generate organized pattern such as bands, spots, and labyrinths using simple feedback mechanisms and boundary conditions. Alternatively, pattern-matching cellular automaton models have been used to generate vegetation self-organization in arid and semi-arid regions also using simple description of surface hydrological processes. A key question is: How much physical realism is needed in order to adequately capture the pattern formation processes in semi-arid regions while reliably representing the water balance dynamics at the relevant time scales? In fact, redistribution of water by surface runoff at the hillslope scale occurs at temporal resolution of minutes while the vegetation development requires much lower temporal resolution and longer times spans. This generates a fundamental spatio-temporal multi-scale problem to be solved, for which high resolution rainfall and surface topography are required. Accordingly, the objective of this contribution is to provide proof-of-concept that governing processes can be described numerically at those multiple scales. The requirements for a simulating ecohydrological processes and pattern formation with increased physical realism are, amongst others: i. high resolution rainfall that adequately captures the triggers of growth as vegetation dynamics of arid regions respond as pulsed systems. ii. complex, natural topography in order to accurately model drainage patterns, as surface water redistribution is highly sensitive to topographic features. iii. microtopography and hydraulic roughness, as small scale variations do impact on large scale hillslope behaviour iv. moisture dependent infiltration as temporal dynamics of infiltration affects water storage under vegetation and in bare soil Despite the volume of research in this field, fundamental limitations still exist in the models regarding the aforementioned issues. Topography and hydrodynamics have been strongly simplified. Infiltration has been modelled as dependent on depth but independent of soil moisture. Temporal rainfall variability has only been addressed for seasonal rain. Spatial heterogenity of the topography as well as roughness and infiltration properties, has not been fully and explicitly represented. We hypothesize that physical processes must be robustly modelled and the drivers of complexity must be present with as much resolution as possible in order to provide the necessary realism to improve transient simulations, perhaps leading the way to virtual laboratories and, arguably, predictive tools. This work provides a first approach into a model with explicit hydrological processes represented by physicallybased hydrodynamic models, coupled with well-accepted vegetation models. The model aims to enable new possibilities relating to spatiotemporal variability, arbitrary topography and representation of spatial heterogeneity, including sub-daily (in fact, arbitrary) temporal variability of rain as the main forcing of the model, explicit representation of infiltration processes, and various feedback mechanisms between the hydrodynamics and the vegetation. Preliminary testing strongly suggests that the model is viable, has the potential of producing new information of internal dynamics of the system, and allows to successfully aggregate many of the sources of complexity. Initial benchmarking of the model also reveals strengths to be exploited, thus providing an interesting research outlook, as well as weaknesses to be addressed in the immediate future. Y1 - 2017 UR - http://meetingorganizer.copernicus.org/EGU2017/EGU2017-14851.pdf N1 - EGU2017-14851 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - CHAP A1 - Caviedes-Voullième, Daniel A1 - Domin, Andrea A1 - Hinz, Christoph T1 - Nonlinear effects of microtopography on macroscopic rainfall-runoff partitioning a the hillslope scale: a modelling study T2 - European Geosciences Union General Assembly 2017 Vienna, Austria, 23–28 April 2017 N2 - The quantitative description and prediction of hydrological response of hillslopes or hillslope-scale catchments to rainfall events is becoming evermore relevant. At the hillslope scale, the onset of runoff and the overall rainfall-runoff transformation are controlled by multiple interacting small-scale processes, that, when acting together produce a response described in terms of hydrological variables well-defined at the catchment and hillslope scales. We hypothesize that small scale features such microtopography of the land surface will will govern large scale signatures of temporal runoff evolution. This can be tested directly by numerical modelling of well-defined surface geometries and adequate process description. It requires a modelling approach consistent with fundamental fluid mechanics, well-designed numerical methods, and computational efficiency. In this work, an idealized rectangular domain representing a hillslope with an idealized 2D sinusoidal microtopography is studied by simulating surface water redistribution by means of a 2D diffusive-wave (zero-inertia) shallow water model. By studying more than 500 surfaces and performing extensive sensitivity analysis forced by a single rainfall pulse, the dependency of characteristic hydrological responses to microtopographical properties was assessed. Despite of the simplicity of periodic surface and the rain event, results indicate complex surface flow dynamics during the onset of runoff observed at the macro and micro scales. Macro scale regimes were defined in terms of characteristics hydrograph shapes and those were related to surface geometry. The reference regime was defined for smooth topography and consisted of a simple hydrograph with smoothly rising and falling limbs with an intermediate steady state. In constrast, rough surface geometry yields stepwise rising limbs and shorter steady states. Furthermore, the increase in total infiltration over the whole domain relative to the smooth reference case shows a strong non-linear dependency on slope and the ratio of the characteristic wavelength and amplitude of microtopography. The coupled analysis of spatial and hydrological results also suggests that the hydrological behaviour can be explained by the spatiotemporal variations triggered by surface connectivity. This study significantly extents previous work on 1D domains, as our results reveal complexities that require 2D representation of the runoff processes. Y1 - 2017 UR - http://meetingorganizer.copernicus.org/EGU2017/EGU2017-8115.pdf N1 - EGU2017-8115 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - CHAP A1 - Maurer, Thomas A1 - Caviedes-Voullième, Daniel A1 - Hinz, Christoph A1 - Gerke, Horst H. T1 - Dynamik der initialen (öko-) hydrologischen Entwicklung – Modellierung von Anfangsbedingungen und Wasserflüssen in einem exemplarischen Einzugsgebiet T2 - Abstract-Sammlung zu Posterbeiträgen, eingereicht zum Tag der Hydrologie in Trier 2017, 23. 03. – 24. 03. 2017 Y1 - 2017 UR - https://www.uni-trier.de/fileadmin/fb6/prof/PHY/PDF-Dateien/TdH2017_4Abstracts_Poster.pdf SP - S. 20 ER - TY - CHAP A1 - Maurer, Thomas A1 - Caviedes-Voullième, Daniel A1 - Hinz, Christoph A1 - Gerke, Horst H. T1 - Flow processes on the catchment scale – modeling of initial structural states and hydrological behavior in an artificial exemplary catchment T2 - European Geosciences Union General Assembly 2017 Vienna, Austria, 23–28 April 2017 N2 - Landscapes that are heavily disturbed or newly formed by either natural processes or human activity are in a state of disequilibrium. Their initial development is thus characterized by highly dynamic processes under all climatic conditions. The primary distribution and structure of the solid phase (i.e. mineral particles forming the pore space) is one of the decisive factors for the development of hydrological behavior of the eco-hydrological system and therefore (co-) determining for its – more or less – stable final state. The artificially constructed ‚Hühnerwasser‘ catchment (a 6 ha area located in the open-cast lignite mine Welzow-Süd, southern Brandenburg, Germany) is a landscape laboratory where the initial eco-hydrological development is observed since 2005. The specific formation (or construction) processes generated characteristic sediment structures and distributions, resulting in a spatially heterogeneous initial state of the catchment. We developed a structure generator that simulates the characteristic distribution of the solid phase for such constructed landscapes. The program is able to generate quasi-realistic structures and sediment compositions on multiple spatial levels (1 cm up to ∼ 100 m scale). The generated structures can be i) conditioned to actual measurement values (e.g., soil texture and bulk distribution); ii) stochastically generated, and iii) calculated deterministically according to the geology and technical processes at the excavation site. Results are visualized using the GOCAD software package and the free software Paraview. Based on the 3D-spatial sediment distributions, effective hydraulic van-Genuchten parameters are calculated using pedotransfer functions. The hydraulic behavior of different sediment distribution (i.e. versions or variations of the catchment’s porous body) is calculated using a numerical model developed by one of us (Caviedes-Voullième). Observation data are available from catchment monitoring are available for i) determining the boundary conditions (e.g., precipitation), and ii) the calibration / validation of the model (catchment discharge, ground water). The analysis of multiple sediment distribution scenarios should allow to approximately determine the influx of starting conditions on initial development of hydrological behavior. We present first flow modeling results for a reference (conditioned) catchment model and variations thereof. We will also give an outlook on further methodical development of our approach. Y1 - 2017 UR - http://meetingorganizer.copernicus.org/EGU2017/EGU2017-6639.pdf N1 - EGU2017-6639 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - CHAP A1 - Caviedes-Voullième, Daniel A1 - Domin, Andrea A1 - Fernández-Pato, Javier A1 - Hinz, Christoph T1 - A numerical study on the influence of mìcrotopography on raìnfall-runoff-infiltration partitioning T2 - 4th International Symposium of Shallow Flows (ISSF 2017), Eindhoven University of Technology, The Netherlands, 26.-28.06.2017 N2 - Microtopographic features, although minute relative to the hillslope scales, are not insignificant in terms of runoff generation, rain-runoff-infiltration partitioning and overall hillslope hydrological signals. As-sessing the effects of such small scale features, arguably requires mathematical models that can cope with microtopraphic complexity to adequately represent surface water dynamics, which in turn deter-mine hydrological signals at the hillslope scale. In this work, rain-runoff simulations are perfomed with a 2D shallow water model on a rectangular domain representing a hillslope with an idealized 2D sinusoidal microtopography. Several combinations of slope, wavelength and amplitudes were used to create over 500 surfaces on which simulations were performed in order to assess their hydrological response in terms of rainfallrunoff-infiltration partitioning. The results were analysed through several dimensionless indices which allow to observe the dependency of characteristic hydrological responses to mi-crotopography properties. They reveal a complex dependency of hydrological signatures to surface microtopography. In particular, the results show that the fraction of rainfall that results in infiltration is increased following a particular non-linear dependency on surface smoothness. Additionally, hydrograph properties and surface flow connectivity also show emerging patterns in response to microtopography. KW - shallow flows KW - microtopography KW - rainfall-runoff KW - onset of runoff KW - infiltration Y1 - 2017 UR - https://www.researchgate.net/publication/318226057_A_numerical_study_on_the_influence_of_microtopography_on_rainfall-runoff-infiltration_partitioning ER - TY - CHAP A1 - Caviedes-Voullieme, Daniel A1 - Andezhath Mohanan, Anju A1 - Brück, Yasemine A1 - Zaplata, Markus K. A1 - Hinz, Christoph ED - Schütze, Niels ED - Müller, Uwe ED - Schwarze, Robert ED - Wöhling, Thomas ED - Grundmann, Jens T1 - Effect of surface water redistribution on vegetation encroachment in the constructed Hühnerwasser catchment T2 - M³ - Messen, Modellieren, Managen in Hydrologie und Wasserressourcenbewirtschaftung. Beiträge zum Tag der Hydrologie am 22./23. März 2018 an der Technischen Universität Dresden N2 - The artificial Hühnerwasser catchment has experienced a significant and monitored evolution since 2005, changing from a post-mining landscape to an almost fully vegetated ecosystem. The early stages showed a fast rate of ecohydrological evolution with changing dominating processes and feedbacks. The evolution of rill vegetation encroachment is one of such complex co-evolving processes. We hypothesise that rill vegetation encroachment is driven by the evolution of the hydrologic/hydraulic regime of the rill network, which in turn affects the regime, potentially creating a stabilising positive feedback. We further hypothesise that rill vegetation occurs later than hillslope vegetation, and follows a particular establishment and encroachment timeline in response to the changing hydrological/hydraulic regimes. That is, the early runoff-dominated regime results in higher flows, velocities, transport and erosion capacity, thus favouring seed flushing and seedling uprooting. On the other hand, as the system transitions from a runoffdominated into an infiltration- and ET-dominated system, flow, velocity, transport and erosion capacity in the rill network are reduced, making seed establishment in the rills more likely. We explore these hypothesis with two complementary approaches: an analysis of the spatiotemporal distribution of vegetation and a process-based numerical modelling study. Firstly, we assess aerial photography of rill vegetation encroachment between 2007 and 2012 in terms of several vegetation types to derive temporal indicators of encroachment. The analysis reveals that in the initial stages, a rill network developed in the hillslope. Shortly after vegetation first established on hillslopes, the rill network became progressively vegetated. Different pioneering species established heterogeneously, at different times and encroached into the rills at different rates. However, despite the volume of data, it is difficult to assess which are the governing and limiting processes which respectively drive and constrain how and at which rate vegetation encroaches into the rills. In consequence, a pilot modelling study to identify the relative relevance of rill network geometry, bare soil infiltration, hillslope vegetation heterogeneity and intra-storm variability on the hydraulic response of the rill network and its possible impact on encroachment. The overall results suggest that vegetation encroachment may be controlled by the rill network hydraulic regime, but such regime is the result of a complex superposition of responses of all the aforementioned factors, of which rill geometry appears to be a dominant one. Furthermore, the simulations showed that vegetation spatial heterogeneity has an impact on the hydraulic regime coupled to the presence of temporal rainfall variability. Altogether, these results show that the governing coevolving ecohydrological processes are interacting and are strongly affected by spatial and temporal heterogeneities. Y1 - 2018 UR - https://tu-dresden.de/bu/umwelt/hydro/ihm/hydrologie/ressourcen/dateien/tdh2018/TdH_2018_Abstractband.pdf SP - S. 91 PB - Technische Universität CY - Dresden ER - TY - CHAP A1 - Caviedes-Voullieme, Daniel A1 - Martı́nez-Aranda, Sergio A1 - Fernández-Pato, Javier A1 - García-Palacín, Ignacio A1 - García-Navarro, Pilar ED - Schütze, Niels ED - Müller, Uwe ED - Schwarze, Robert ED - Wöhling, Thomas ED - Grundmann, Jens T1 - Measuring 2D transient shallow water surfaces: raising the benchmark challenges for 2D shallow water solvers T2 - M³ - Messen, Modellieren, Managen in Hydrologie und Wasserressourcenbewirtschaftung. Beiträge zum Tag der Hydrologie am 22./23. März 2018 an der Technischen Universität Dresden N2 - In the past decade, shallow water (SW) solvers have been dramatically improved both in terms of accuracy and computational power. The mathematical, numerical and computational improvements available in state-of-the-art solvers now allow for large scale, long term, high resolution simulations of river flooding, flash floods, dam-break phenomena, rainfall-runoff simulation and extensions into pollutants, substance and sediment transport, etc. SW solvers have been benchmarked against a set of test cases, ubiquitious in the literature. The solvers have been systematically verified against 1D and some 2D analytical solutions and validated further against 1D and 2D laboratory experiments, as well as some well-documented real-scale field cases. However, despite the 2D nature of many of these benchmark tests, none of them report 2D water surface elevation. Typically a few profiles are measured and reported, and more often, only a few points are available. Moreover, in field cases, often not even fully transient data is available. The reason for the inavailability of 2D transient water surface data is due to the technical difficulty of measuring a (fast) moving water surface. In most of the reported experiments, pressure gauges are often used to register water depth evolution, and sometimes PIV techniques have been used to obtain velocity fields. In experimental fluid mechanics, measuring the evolution of a free surface has received little attention, as it has been mainly understood as a problem for SW flows, and more recently for free surface granular flows. In consequence, this work aims to generate a new benchmarking dataset in which 2D transient water surfaces are available for SW model developers and users to further test and challenge these models. We argue that the availability of this new data can help identify limitations in the current generation of solvers, thus laying the ground for improvements in the near future. We present laboratory-scale experimental results on steady and unsteady 2D water surfaces performed in a laboratory flume, ranging from steady transcritical flow to dam-break flows around obstacles. The transient water surface was captured using a commercial-grade RGBD sensing device which allows to capture a high-frequency succession of 3D color-coded point clouds. The channel bed can also be registered in the same manner, thus also allowing to compute the 2D transient water-depth field. Color coding also allows to easily differentiate the channel bed, sidewalls and obstacles. The result of the experimental study is a novel collection of 2D benchmark SW cases, with transient water depth and water elevation data for the entire visible flow field. Furthermore, we compare the experimental measurements to 2D shallow water simulations performed with an extensively tested state-of-the-art solver to assess the suitability of this dataset to perform as benchmark test cases and identify some potential limitations of current models. Y1 - 2018 UR - https://tu-dresden.de/bu/umwelt/hydro/ihm/hydrologie/ressourcen/dateien/tdh2018/TdH_2018_Abstractband.pdf SP - S. 23 PB - Technische Universität CY - Dresden ER - TY - CHAP A1 - Caviedes-Voullième, Daniel A1 - Hinz, Christoph T1 - The role of topography and intra-annual rainfall variability in semi-arid vegetation self-organisation: a multi-scale modelling study T2 - European Geosciences Union, General Assembly 2018, Vienna, Austria N2 - Coevolution of hydrological and vegetation dynamics in semi-arid regions has been widely observed to result in vegetation self-organisation (VSO). Many hypothesis of VSO’s underlying ecohydrological processes and feedbacks have been studied relying on mathematical models, which have been key to evaluate the sensitivity of ecohydrological systems to environmental factors and drivers. Although this ecohydrological coevolution is essentially multiscale, researchers have continued to be constrained by the simplicity of the models which are unable to cope with the multiscale, process-based complexity of fast-moving surface water over complex topographies driven by varying rainfall, during decade-to-century long VSO processes. This limitation has not allowed deep exploration of the role and sensitivity of key environmental factors such as topography and rainfall variability, and the lack of proper hydrodynamics still constrains adequate sediment transport modelling and its feedback effects on VSO. We hypothesize that the intra-storm water redistribution by surface runoff at the hillslope scale is strongly controlled by both topography and storm intensity and may control VSO. This requires for these environmental factors to be accurately represented in models and their their hydraulic and hydrological effects properly reflected. This work provides the first systematic study of the effects of topography and intra-annual rainfall distributions on vegetation band formation at the hillslope scale. Simulations were performed with a physically-based numerical model solving the Zero-Inertia approximation to the shallow water equations for surface flow coupled to the HilleRisLambers-Rietkerk vegetation model, allowing to explicitly represent arbitrary topography. An idealized study of ecohydrological evolution over 30 years was performed, solving with a temporal resolution in the seconds scale. Plane, convex and convex hillslope topologies with different slopes were used, while forcing the model with different annual rainfalls along a semi-arid rainfall gradient, with discrete events of different frequencies. We describe results in terms of evolution of total biomass, hydrological water balance, and of the spatial properties of banded vegetation. Results show that both topography and intra-annual rainfall distribution can play a shaping and governing role in VSO by controlling surface water redistribution and the hydrologic water balance. Increasing slopes favours runoff over infiltration, reducing the available water for vegetation and resulting in different evolutions of vegetation band geometry and band migration. Hillslope topology plays a strong role in the internal water redistribution of the system. Plane and convex surfaces behave similarly, but concave surfaces exhibit a different ecohydrological behaviour, despite the very small topological differences. Different intra-annual rainfall distributions result in different rainfall intensities for the same total annual rainfall which strongly affect the band formation and evolution process: higher intensities lead to less available water, to which vegetation adapts by spatially clustering in bands with different geometrical properties. The study also shows that it is computationally feasible (a few hours runtime) to perform decade-to-century long simulations of these systems with physically-based numerical models paving the way to simulate natural systems with arbitrary topography and high-resolution rainfall data, and is a first step in introducing physically-based sediment transport processes and feedbacks in these studies. Y1 - 2018 UR - https://meetingorganizer.copernicus.org/EGU2018/EGU2018-17423.pdf N1 - EGU2018-17423 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - CHAP A1 - Brück, Yasemine A1 - Andezhath Mohanan, Anju A1 - Caviedes-Voullième, Daniel A1 - Hinz, Christoph A1 - Zaplata, Markus K. T1 - Spatio-temporal development of rill vegetation in the Hühnerwasser Catchment T2 - European Geosciences Union, General Assembly 2018, Vienna, Austria N2 - The artificial catchment “Hühnerwasser” was built in a post-mining landscape, as a field experiment to observe and monitor early-development ecosystems at hillslope scale. Early on, rain-induced rill and channels formation was observed, followed by vegetation growth in between rills, and later on inside the rills. In this work, we aim to describe the temporal evolution of the spatial distribution of rill vegetation. In general terms, we hypothesize four different encroachment patterns might occur: (1) The vegetation spreads from the top of the rills downstream. The underlying hypothesis would be a higher establishment probability due to a lower velocity of surface runoff and therefore less transport probability compared to downstream rill segments. (2) The vegetation starts growing downstream and moves upwards. In this case we can hypothesize that the spatial distribution of the vegetation is dominated by water availability, which is higher or more stable downstream. (3) The vegetation encroaches from the sides into the rills, meaning that inter-rill vegetation governs vegetation encroachment inside the rills. (4) If no patterns are detected it might mean that the encroachment process depends strongly on very local conditions, or perhaps that the underlying assumption of an initially homogeneous seed distribution is false. To investigate the rills formation and rill vegetation encroachment processes, rills and vegetation patches inside these rills were identified and digitized from aerial photographs of the catchment from 2007 to 2012. Different vegetation types were identified based on the colour and texture of the patches. The geometrical properties of the rill segments and vegetation patches were used to define how the different vegetation types have distributed in space and how this distribution has changed over time. Rill mapping reveals a large increase of rill area from 2007 to 2008 and only a small rise from 2008 to 2009. Starting in 2010 dense vegetation prevents a precise mapping of the rills in the aerial photographs, so we assume that there is no change in rill area from 2009 to 2012. In 2007 vegetation covered only 1.4% of the rill area. There is only a small increase of this area in 2008 compared to the later years. In 2012 more than 50% of the rill area is covered by plants. Ten different vegetation types have been identified in the aerial photographs, starting with two types in 2007. By 2012 nine types are spotted in the rills of the catchment. Some of these vegetation types show an encroachment from up- to downstream (e.g. Tussilago farfara), some from down- to upstream like Phragmites australis, whose creeping rhizomes can also promote such spreading. Others reveal no patterns. To better assess and identify the underlying processes leading to these encroachment processes shown by the different vegetation types further data analysis –e.g. comparison with ground based vegetation mapping– and process-based hydrological modelling is necessary to fully explain these observations and assessing additional competition effects, which may be at play. Y1 - 2018 UR - https://meetingorganizer.copernicus.org/EGU2018/EGU2018-13391.pdf N1 - EGU2018-13391 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - CHAP A1 - Caviedes-Voullième, Daniel A1 - Andezhath Mohanan, Anju A1 - Brück, Yasemine A1 - Hinz, Christoph T1 - Rill hydrodynamics and its impact on rill vegetation encroachment: a modelling study of the constructed Hühnerwasser catchment T2 - European Geosciences Union, General Assembly 2018, Vienna, Austria N2 - The Hühnerwasser catchment is a monitored, early-development constructed catchment within the Lower Lausatia post-mining landscape in Germany. Observations have shown that a sequence of landscape-forming processes occurred, including the initial vegetation establishment stages, which are the main interest of this study. In the initial stages of geomorphic development a surface drainage network of rills was formed as vegetation started to appear on the hillslopes and subsequently inside the rill network. Observations and analysis of the rill vegetation establishment suggest that different vegetation types encroach into the rill network at different times, rates and form different directions. We hypothesize that these encroachment processes may respond to the runoff properties of the catchment at such time: velocity distribution in the rills might play a significant role in flushing seeds in high-velocity reaches of the rill network, thus favouring the appearance of vegetation in low-velocity regions. Consequently, the goal of this study is to assess the magnitudes and spatiotemporal behaviour of velocity in the rill network, to assess its possible impact on seed flushing and rill vegetation encroachment. One rill subcatchment of Hühnerwasser was selected to perform an explorative study of rill hydrodynamics and their impact on vegetation establishment. Two vegetation states were simulated: bare hillslopes and vegetated hillslopes. The vegetated cover polygons were obtained from digitized aerial photography, and stochastically dissagregated 10-minute resolution precipitation data were used, selecting events with early, middle and late peak storm intensities. A 2D explicit finite volume scheme solving the Zero-Inertia approximation to the shallow water equations was used to simulate surface flow in the subcatchment. The preliminary modelling results suggest that that there is no clear overall velocity gradient in the downstream direction along the rills. In fact, velocity in the rills may increase or decrease along the rill following local topography and rill geometry. Consequently, no global trend for the probability of seeds being transported can be established. The results also shows that varying rainfall intensity and rainfall intrastorm distribution –in the absence of hillslope vegetation– does not affect the rill locations of maximum velocities, but mostly affect the magnitude of velocity. In the presence of hillslope vegetation –and thus heterogeneous infiltration conditions in the hillslopes– the spatial distribution of velocity is strongly affected, and can be in fact governed not by topography or rill geometry, but by the spatial heterogeneity of infiltration capacity. Furthermore, the time at which maximum discharge and velocities occur may not match that of maximum intensity. That is, emerging temporal dynamics arise due to the introduction of spatial heterogeneity, which also manifests in the fact that outflow from the subcatchment exhibits a intensity-thresholded behaviour. Y1 - 2018 UR - https://meetingorganizer.copernicus.org/EGU2018/EGU2018-13392.pdf N1 - EGU2018-13392 PB - European Geophysical Society CY - Katlenburg-Lindau ER -