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1.
In the Dolomitic region, abundant coarse hillslope sediment is commonly found at the toe of rocky cliffs. Ephemeral channels originate where lower permeability bedrock surfaces concentrate surface runoff. Debris flows initiate along such channels following intense rainfall and determine the progressive erosion and deepening of the channels. Sediment recharge mechanisms include rock fall, dry ravel processes and channel-bank failures. Here we document debris flow activity that took place in an active debris flow basin during the year 2015. The Cancia basin is located on the southwestern slope of Mount Antelao (3264 m a.s.l.) in the dolomitic region of the eastern Italian Alps. The 2.5 km2 basin is incised in dolomitic limestone rocks. The data consist of repeated topographic surveys, distributed rainfall measurements, time-lapse (2 s) videos of two events and pore pressure measurements in the channel bed. During July and August 2015, two debris flow events occurred, following similarly intense rainstorms. We compared rainfall data to existing rainfall triggering thresholds and simulated the hydrological response of the headwater catchment with a distributed model in order to estimate the total and peak water discharge. Our data clearly illustrate how debris entrainment along the channel is the main contributor to the overall mobilized volume and that erosion is dominant when the channel slope exceeds 16°. Further downstream, sediment accumulation and depletion occurred alternately for the two successive events, indicating that sediment availability along the channel also influences the flow behaviour along the prevailing-transport reach. The comparison between monitoring data, topographical analysis and hydrological simulation allows the estimation of the average solid concentration of the two events and suggests that debris availability has a significant influence on the debris flow volume. © 2020 John Wiley & Sons, Ltd.  相似文献   

2.
Abstract

The concept of “catchment-scale storm velocity” quantifies the rate of storm motion up and down the basin accounting for the interaction between the rainfall space–time variability and the structure of the drainage network. It provides an assessment of the impact of storm motion on flood shape. We evaluate the catchment-scale storm velocity for the 29 August 2003 extreme storm that occurred on the 700 km2-wide Fella River basin in the eastern Italian Alps. The storm was characterized by the high rate of motion of convective cells across the basin. Analysis is carried out for a set of basins that range in area from 8 to 623 km2 to: (a) determine velocity magnitudes for different sub-basins; (b) examine the relationship of velocity with basin scale and (c) assess the impact of storm motion on simulated flood response. Two spatially distributed hydrological models of varying degree of complexity in the representation of the runoff generation processes are used to evaluate the effects of the storm velocity on flood modelling and investigate model dependencies of the results. It is shown that catchment-scale storm velocity has a non-linear dependence on basin scale and generally exhibits rather moderate values, in spite of the strong kinematic characteristics of individual storm elements. Consistently with these observations and for both models, hydrological simulations show that storm motion has an almost negligible effect on the flood response modelling.

Editor Z.W. Kundzewicz; Guest editor R.J. Moore

Citation Nikolopoulos, E.I., Borga, M., Zoccatelli, D., and Anagnostou, E.N., 2014. Catchment-scale storm velocity: quantification, scale dependence and effect on flood response. Hydrological Sciences Journal, 59 (7), 1363–1376. http://dx.doi.org/10.1080/02626667.2014.923889  相似文献   

3.
Floods in small mountainous watersheds cover a wide spectrum of flow. They can range from clear water flows and hyperconcentrated flows to debris floods and debris flows, and calculation of the peak discharge is crucial for predicting and mitigating such hazards. To determine the optimal approach for discharge estimation, this study compared water flow monitoring hydrographs to investigate the performance of five hydrological models that incorporate different runoff yields and influx calculation methods. Two of the models performed well in simulating the peak discharge, peak time, and total flow volume of the water flood. The ratio (γ) of the monitored debris flood discharge (Qd) to the simulated water flow discharge (Qw) was investigated. Qualitatively, γ initially increased with Qw but then decreased when Qw exceeded a certain threshold, which corresponded to rainfall of 95 and 120 mm in a 6- and 24-h event with a normal distribution of precipitation, respectively. The decrease might be attributable to a threshold of sediment availability being reached, beyond which increased flow rate is not matched by increased sediment input in the large watershed. Uncertainty of hydrological calculation was evaluated by dividing the catchment into sub-basins and adopting different rainfall time steps as input. The efficiency of using a distributed simulation exhibited marginal improvement potential compared with a lumped simulation. Conversely, the rainfall time step input significantly affected the simulation results by delaying the peak time and decreasing the peak discharge. This research demonstrates the applicability of a discharge estimation method that combines a hydrological water flow simulation and an estimation of γ. The results were verified on the basis of monitored flow densities and videos obtained in two watersheds with areas of 2.34 and 32.4 km2.  相似文献   

4.
Radar rainfall estimation for flash flood forecasting in small, urban catchments is examined through analyses of radar, rain gage and discharge observations from the 14.3 km2 Dead Run drainage basin in Baltimore County, Maryland. The flash flood forecasting problem pushes the envelope of rainfall estimation to time and space scales that are commensurate with the scales at which the fundamental governing laws of land surface processes are derived. Analyses of radar rainfall estimates are based on volume scan WSR-88D reflectivity observations for 36 storms during the period 2003–2005. Gage-radar analyses show large spatial variability of storm total rainfall over the 14.3 km2 basin for flash flood producing storms. The ability to capture the detailed spatial variation of rainfall for flash flood producing storms by WSR-88D rainfall estimates varies markedly from event to event. As spatial scale decreases from the 14.3 km2 scale of the Dead Run watershed to 1 km2 (and the characteristic time scale of flash flood producing rainfall decreases from 1 h to 15 min) the predictability of flash flood response from WSR-88D rainfall estimates decreases sharply. Storm to storm variability of multiplicative bias in storm total rainfall estimates is a dominant element of the error structure of radar rainfall estimates, and it varies systematically over the warm season and with flood magnitude. Analyses of the 7 July 2004 and 28 June 2005 storms illustrate microphysical and dynamical controls on radar estimation error for extreme flash flood producing storms.  相似文献   

5.
Rainfall and flood data are relatively sparse in semi‐arid areas; hence there have been relatively few investigations into the relationships between rainfall inputs and flood generation in these environments. Previous work has shown that flood properties are influenced by a combination of precipitation characteristics including amount, intensity, duration and spatial distribution. Therefore floods may be produced by high intensity, short duration storms, or longer duration, low intensity rainfall. Most of this research has been undertaken in small catchments in either hyper‐arid or relatively high rainfall Mediterranean climates. This paper presents results from a 6 year data record in south‐east Spain from research conducted in two basins, the Rambla Nogalte (171 km2) and the Rambla de Torrealvilla (200 km2). Data cover an area of approximately 500 km2 and an annual average rainfall of 300 mm. At coarse temporal resolutions gauges spread over large areas record similar patterns of rainfall, although spells of rain show much more complexity; pulses of rain within storms can vary considerably in total rainfall, intensity and duration over the same area. The analysis for south‐east Spain shows that most storms occur over a period of less than 24 h, but that the number of rainfall events declines as the duration exceeds 8 h. This is at odds with data on floods for the study area suggesting that they are produced by storms lasting longer than 18 h. However, one flood event was produced by a very short (15 min) storm with high intensity rainfall. Most floods tended to occur in May/June or September, which coincides with wetter months of the year (September, October, December and May). Floods are also more highly related to the total rainfall occurring in a spell of rain, than to intensity. The complexity of storm rainfall increases with the storm total, which makes it difficult to generalize on the importance of rainfall intensity for flood generation. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

6.
We develop a simple model to evaluate the daily flow discharges in the ablation season for the 11 km2 Pantano basin in the Retiche Italian Alps, based upon the data gathered during a three years field campaign. The Pantano basin embeds the Venerocolo debris covered and the Avio debris free glaciers, covering 2.14 km2 in the Adamello Group, where the widest Italian glacier Adamello is located. First, degree-day models based upon air temperature are tuned to calculate snow and ice melt at daily scale. Glaciers’ meteorological data are collected from an automatic weather station (AWS), operating on the glacier during summer 2007. The melt factors in the debris covered areas of the glacier are estimated against debris thickness, using a data driven parameterization. The flow discharge from the catchment is estimated using semi distributed flow routing for the ablation seasons of four years, from 2006 to 2009. The predicted discharges are compared to those derived from inverse reservoir's routing at the Benedetto lake, catching the basin outflow. The proposed approach is valuable as a tool to investigate the hydrology of poorly gauged glacierized areas, including those with debris covered ice, widely diffused and yet poorly understood. Pending accurate parameterization the approach is usable for water resources evaluation and for long term assessment of the climate change impact on the glacierized areas within the Alps.  相似文献   

7.
A model‐based method is proposed for improving upon existing threshold relationships which define the rainfall conditions for triggering shallow landslides but do not allow the magnitude of landsliding (i.e. the number of landslides) to be determined. The SHETRAN catchment‐scale shallow landslide model is used to quantify the magnitude of landsliding as a function of rainfall return period, for focus sites of 180 and 45 km2 in the Italian Southern Alps and the central Spanish Pyrenees. Rainfall events with intensities of different return period are generated for a range of durations (1‐day to 5‐day) and applied to the model to give the number of landslides triggered and the resulting sediment yield for each event. For a given event duration, simulated numbers of landslides become progressively less sensitive to return period as return period increases. Similarly, for an event of given return period, landslide magnitude becomes less sensitive to event duration as duration increases. The temporal distribution of rainfall within an event is shown to have a significant impact on the number of landslides and the timing of their occurrence. The contribution of shallow landsliding to catchment sediment yield is similarly quantified as a function of the rainfall characteristics. Rainfall intensity–duration curves are presented which define different levels of landsliding magnitude and which advance our predictive capability beyond, but are generally consistent with, published threshold curves. The magnitude curves are relevant to the development of guidelines for landslide hazard assessment and forecasting. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

8.
An Erratum has been published for this article in Hydrological Processes 16(5) 2002, 1130–1131. Humid tropical regions are often characterized by extreme variability of fluvial processes. The Rio Terraba drains the largest river basin, covering 4767 km2, in Costa Rica. Mean annual rainfall is 3139±419sd mm and mean annual discharge is 2168±492sd mm (1971–88). Loss of forest cover, high rainfall erosivity and geomorphologic instability all have led to considerable degradation of soil and water resources at local to basin scales. Parametric and non‐parametric statistical methods were used to estimate sediment yields. In the Terraba basin, sediment yields per unit area increase from the headwaters to the basin mouth, and the trend is generally robust towards choice of methods (parametric and LOESS) used. This is in contrast to a general view that deposition typically exceeds sediment delivery with increase in basin size. The specific sediment yield increases from 112±11·4sd t km?2 year?1 (at 317·9 km2 on a major headwater tributary) to 404±141·7sd t km?2 year?1 (at 4766·7 km2) at the basin mouth (1971–92). The analyses of relationships between sediment yields and basin parameters for the Terraba sub‐basins and for a total of 29 basins all over Costa Rica indicate a strong land use effect related to intensive agriculture besides hydro‐climatology. The best explanation for the observed pattern in the Terraba basin is a combined spatial pattern of land use and rainfall erosivity. These were integrated in a soil erosion index that is related to the observed patterns of sediment yield. Estimated sediment delivery ratios increase with basin area. Intensive agriculture in lower‐lying alluvial fans exposed to highly erosive rainfall contributes a large part of the sediment load. The higher elevation regions, although steep in slope, largely remain under forest, pasture, or tree‐crops. High rainfall erosivity (>7400 MJ mm ha?1 h?1 year ?1) is associated with land uses that provide inadequate soil protection. It is also associated with steep, unstable slopes near the basin mouth. Improvements in land use and soil management in the lower‐lying regions exposed to highly erosive rainfall are recommended, and are especially important to basins in which sediment delivery ratio increases downstream with increasing basin area. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

9.
In much of western United States destructive floods after wildfire are frequently caused by localized, short‐duration convective thunderstorms; however, little is known about post‐fire flooding from longer‐duration, low‐intensity mesoscale storms. In this study we estimate and compare peak flows from convective and mesoscale floods following the 2012 High Park Fire in the ungaged 15.5 km2 Skin Gulch basin in the northcentral Colorado Front Range. The convective storm on 6 July 2012 came just days after the wildfire was contained. Radar data indicated that the total rainfall was 20–47 mm, and the maximum rainfall intensities (upwards of 50 mm h?1) were concentrated over portions of the watershed that burned at high severity. The mesoscale storm on 9–15 September 2013 produced 220–240 mm of rain but had maximum 15‐min intensities of only 25–32 mm h?1. Peak flows for each flood were estimated using three independent techniques. Our best estimate using a 2D hydraulic model was 28 m3 s?1 km?2 for the flood following the convective storm, placing it among the largest rainfall‐runoff floods per unit area in the United States. In contrast, the flood associated with the mesoscale flood was only 6 m3 s?1 km?2, but the long‐duration flood caused extensive channel incision and widening, indicating that this storm was much more geomorphically effective. The peak flow estimates for the 2013 flood had a higher relative uncertainty and this stemmed from whether we used pre‐ or post‐flood channel topography. The results document the extent to which a high and moderate severity forest fire can greatly increase peak flows and alter channel morphology, illustrate how indirect peak flow estimates have larger errors than is generally assumed, and indicate that the magnitude of post‐fire floods and geomorphic change can be affected by the timing, magnitude, duration, and sequence of rainstorms. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

10.
Field observations on hydraulics and sediment dynamics during extreme floods in two mountain torrents show the influence of man-made constructions such as bridges and check dams, in addition to the sediment supplied naturally by the basin and the channel network, on the formation of hyperconcentrated flows. In the Pyrenean Arás basin, hyperconcentrated flow occurred after collapse of a bridge, which in turn mobilized large volumes of sediment from the stream channel and, subsequently, destroyed a series of check dams. Boulders up to several metres in size were transported in a mixture of sand and fine material. A minimum of 100000 tonnes of sediment were deposited on the alluvial fan during the event. Prior to bridge destruction, mean bedload transport rates had reached 0.4t m−1 s−1 upstream. In the alpine Lainbach basin, the flood was characterized by transportation of large amounts of slope material, including debris flows. Along its main tributary an intensive hyperconcentrated flow occurred during the rising stage, whereas in the main valley smaller flows occurred after failure of check dams. The depth of coarse material deposited reached 80 cm. The effectiveness of the Aràs and Lainbach floods was attained due to exceptional rates of energy expediture. Flood power ranged from 20000 W m−2 to 40000 W m−2 on average. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

11.
Taiwan suffers from heavy storm rainfall during the typhoon season. This usually causes large river runoff, overland flow, erosion, landslides, debris flows, loss of power, etc. In order to evaluate storm impacts on the downstream basin, a real‐time hydrological modelling is used to estimate potential hazard areas. This can be used as a decision‐support system for the Emergency Response Center, National Fire Agency Ministry, to make ‘real‐time’ responses and minimize possible damage to human life and property. This study used 34 observed events from 14 telemetered rain‐gauges in the Tamshui River basin, Taiwan, to study the spatial–temporal characteristics of typhoon rainfall. In the study, regionalized theory and cross‐semi‐variograms were used to identify the spatial‐temporal structure of typhoon rainfall. The power form and parameters of the cross‐semi‐variogram were derived through analysis of the observed data. In the end, cross‐validation was used to evaluate the performance of the interpolated rainfall on the river basin. The results show the derived rainfall interpolator represents the observed events well, which indicates the rainfall interpolator can be used as a spatial‐temporal rainfall input for real‐time hydrological modelling. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

12.
Robert E. Criss 《水文研究》2018,32(11):1607-1615
The rainfall–run‐off convolution integral is analytically solved for several models for the elementary hydrograph. These solutions can be combined with available rainfall frequency analyses to predict flood flows along streams for different recurrence intervals, using no free parameters for gauged streams and one estimable parameter for ungauged streams. Extreme discharge magnitudes at gauged sites can be typically estimated within a factor of two of actual records, using no historical data on extreme flows. The flow predictions reproduce several important characteristics of the flood phenomenon, such as the slope of the regression line between observed extreme flows and basin area on the conventional logQ versus logA plot. Importantly, for the models and data sets investigated, the storm duration of greatest significance to flooding was found to approximate the intrinsic transport timescale of the particular watershed, which increases with basin size. Thus, storms that deliver extraordinary amounts of rainfall over a particular time interval will most greatly activate basins whose time constants approximately equal that interval. This theoretical finding is supported by examination of the regional hydrological response to the massive storms of September 14, 2008, and April 28–30, 2017, which caused extraordinary record flooding of basins of about 5–100 km2 and 500–4,000 km2, respectively, but produced few records in basins that were larger or smaller than those ranges.  相似文献   

13.
Rainfall, peak discharges, and suspended sediment transport were surveyed for 280 events in three small (0.8 to 10 km2) catchments in a hilly area derived from Neogene marls, silts, and sands. Under similar hydrological input conditions, stream flow behaviour and sediment delivery differed considerably from one catchment to another, depending on topography, lithology, land use, and especially sediment availability. Analytical treatment of data showed a good fit between sediment yield and peak flow discharge. Less good, although still significant, was the correlation between sediment concentration and discharge values for different flow stages. Rainfall peak/basin lag time and rainfall/discharge showed poor or no correlation, mainly due to strong variations in rainfall distribution. Sediment concentration in the catchments varied enormously according to season, from zero up to 334 g 1?1; sediment yield was 160-900 tonnes km?2 yr?1 in the two major catchments, and over 5200 tonnes km?2 yr?1 in the headwater catchment, stressing the importance of small tributaries not only in inducing floods in downstream channels, but also in sediment supply.  相似文献   

14.
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15.
Abstract

Sediment is transported in the form of debris flows in major gullies dissecting permeable volcanic slopes as exemplified by the Kami-kamihori Valley in the northern Japan Alps. Four years of hydrological observations in the headwater area of the gully showed that the surface runoff which triggers debris flows is related to peak 10- to 20-minute rainfall. Sediment production in such a short time is not sufficient to prepare a debris flow. Therefore, debris must have been accumulated at a particular section by repeated sediment discharge due to minor rainstorms. The volume of the debris produced in the headwaters was evaluated and correlated to an effective rainfall. The quantity of sediment transport at seven sections along the gully by debris flows in three periods was evaluated through the measurement of the topographic changes. It was compared with the total effective rainfall for the pertinent period, and the mean “sediment concentration” in the debris flow was calculated for each section and for each period. It was shown that the change in the sediment concentration along the gully reflects the entrainment of debris from the gully floor in the acceleration zone and the deposition in the deceleration zone. It was also demonstrated that the sediment delivery of a debris flow depends on the time distribution of rainfall, because rainfall time bases appropriate to prediction of the sediment transport at different reaches vary.  相似文献   

16.
Research into torrent erosion has focused on bedload transport dynamics, debris flow propagation during flood events, and fan sedimentation. Studies have frequently been biased towards specific events and have not considered sediment delivery in the catchment as a whole. The aim of this study is to examine spatial variations and process controls on sediment transfer in an upland torrent system (hillslopes, channel and fan). The study site is Iron Crag, a small torrent system (catchment area 2·4 ha) situated in the northern Lake District, UK. Particle size analysis of hillslope sediments trapped during transport suggests sediment calibre is controlled primarily by sediment source. Freeze–thaw and rainfall processes impart a weak but recognizable size sorting signature on the trapped sediments. However, these variations are less significant in determining sediment supply to the basal fan, than those operating in the channel system. Channel sediment movement is strongly influenced by storm events, the type of flow process (debris flow or fluvial flow), the sediment characteristics, and the local channel topography. The importance of the channel–fan coupling is clearly demonstrated in that more than 90 per cent of fan sedimentation is derived from channel sediment sources. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

17.
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18.
The Whangaehu fan is the youngest sedimentary component on the eastern ring plain surrounding Ruapehu volcano. Fan history comprises constructional (830–200 years bp) and dissectional (<200 years bp) phases. The constructional phase includes four aggradational periods associated with both syneruptive and inter-eruptive behavior. All four aggradational periods began when deposition by large lahars changed flow conditions on the fan from channelized to unchannelized. Subsequent behavior was a function of the rate of sediment influx to the fan. The rate of sediment influx, in turn, was controlled by frequency and magnitude of volcanic eruptions, short-term climate change, and the amount of sediment stored on the volcano flanks. Fanwide aggradation occurred when rates of sediment influx and deposition on the fan were high enough to maintaìn unchannelized flow conditions on the fan surface. Maintenance of an undissected surface required sedimentation from frequent and large lahars that prevented major dissection between events. These conditions were best met during major eruptive episodes when high frequency and magnitude eruptions blanketed the volcano flanks with tephra and rates of lahar initiation were high. During major eruptive episodes, volcanism is the primary control on sedimentation. Climatic variations do not influence sediment accumulation. Local aggradation occurred when lahars were too small to maintain unchannelized flow across the entire fan. In this case, only the major channel system received much sediment following the deposition from the initial lahar. This localized aggradation occurred if (1) the sediment reservoir on the flank was large enough for floods to bulk into debris flows and (2) sedimentation events were frequent enough to maintain sediment supply to only some parts of the fan. These conditions were met during both minor eruptive and inter-eruptive episodes. In both cases, a large sediment reservoir remained on the volcano flanks from previous major eruptive intervals. Periods of increased storm activity produced floods that bulked to relatively small debris flows. When the sediment reservoir was depleted, the fan entered the present dissectional phase. Syneruptive and noneruptive lahars are mostly channelized and sediment bypasses the fan. Fan deposits are rapidly reworked. This is the present case at Ruapehu, even though the volcano is in a minor eruptive episode and the climate favors generation of intense storm floods.  相似文献   

19.
This study analyzes the flash flood event of two ungauged ephemeral streams in Olympiada region (Chalkidiki, North Greece), which occurred at the 21–22 of November 2019. Aim of the study is to reconstruct the specific flash flood event, investigate the causes of flood generation mechanisms, evaluate the performance of SCS-CN hydrological and HEC-RAS hydraulic models, investigate the relation between extreme flash floods and human intervention, using the combination of ground and aerial observations obtained from the field survey and unmanned aerial vehicles (UAVs), respectively. The results of the specific discharge ranged between 9 and 11 m3 s−1 km2, values that are typical for flash flood events in Mediterranean region. The comparison between the observed and simulated values of flood extent showed sufficiently good performance of the hydraulic model (CSI = 82%). However, the statistical analysis of the observed and simulated flood depths displayed a flood depth overestimation by the applied model, despite that the values of the used statistic indexes are acceptable (RMSE = 0.35 m, SD = 0.53, NSE = 0.56, PBIAS = 11.26%). The model overestimation of flood depth was attributed to the DEM low resolution and quality. Ground and aerial observations depicted the alluvial fan activation, the alternation of flow paths and the huge sediment transport. Human intervention in main streams, urban sprawl, wet AMC and sediment transport were among the main factors that contributed to the flash flood generation. This integrated approach revealed the necessity of the constant evaluation and validation of hydrological and hydraulic models in small ungauged Mediterranean watersheds and ephemeral streams. The use of UAVs in combination with ground observations and hydraulic simulation could significantly contribute to the enhanced understanding of flash flood mechanisms, in the direction of flood risk mitigation, improvement of the planning efficiency of flood prevent measures, flood hazard estimation, evolution of flood warning systems and floodplain geomorphology analysis.  相似文献   

20.
The variability of rainfall in space and time is an essential driver of many processes in nature but little is known about its extent on the sub‐kilometre scale, despite many agricultural and environmental experiments on this scale. A network of 13 tipping‐bucket rain gauges was operated on a 1·4 km2 test site in southern Germany for four years to quantify spatial trends in rainfall depth, intensity, erosivity, and predicted runoff. The random measuring error ranged from 10% to 0·1% in case of 1 mm and 100 mm rainfall, respectively. The wind effects could be well described by the mean slope of the horizon at the stations. Except for one station, which was excluded from further analysis, the relative differences due to wind were in maximum ±5%. Gradients in rainfall depth representing the 1‐km2 scale derived by linear regressions were much larger and ranged from 1·0 to 15·7 mm km?1 with a mean of 4·2 mm km?1 (median 3·3 mm km?1). They mainly developed during short bursts of rain and thus gradients were even larger for rain intensities and caused a variation in rain erosivity of up to 255% for an individual event. The trends did not have a single primary direction and thus level out on the long term, but for short‐time periods or for single events the assumption of spatially uniform rainfall is invalid on the sub‐kilometre scale. The strength of the spatial trend increased with rain intensity. This has important implications for any hydrological or geomorphologic process sensitive to maximum rain intensities, especially when focusing on large, rare events. These sub‐kilometre scale differences are hence highly relevant for environmental processes acting on short‐time scales like flooding or erosion. They should be considered during establishing, validating and application of any event‐based runoff or erosion model. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

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