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1.
Post‐logging changes in catchment sediment yield have traditionally been attributed to increases in hillslope erosion and delivery rates as a result of forest harvesting activities. Linking hillslope erosion to catchment yield in forestry environments remains difficult, however, primarily because of the scarcity of data on the nature of hillslope sediment storage and delivery processes. A large rainfall simulator (350 m2) was used to apply rainstorms to a logged hillslope containing a snig track (skid trail) and a general logging or harvesting area (GHA) on 10 forest compartments in south‐eastern Australia. The experiments confirmed that the compacted, disturbed surfaces, such as roads and tracks, are the dominant sources of sediment in forestry areas. Sediment transport rates were limited by available sediment supply on both the snig track and the GHA, introducing important implications for the modelling of these surfaces using sediment transport capacity theories. Sediment delivery from the snig track to the adjacent GHA, via a cross‐bank (drainage diversion), was strongly influenced by the percentage fine fraction in the eroded sediment. Preferential deposition of coarse aggregates was measured at erosion control structures and on the adjacent GHA. Over 50% of fine‐grained material were deposited on the hillslope over a relatively short, flow path length of <5 m, highlighting the effectiveness of runoff diversion as a practice in reducing sediment flux. The transfer of water and sediment from disturbed to less disturbed parts of the landscape, and the associated potential for sediment storage, needs to be considered as part of any catchment impact assessment. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

2.
Road survey and field rainfall simulation experiments have shown that the erodibility of a road surface is dynamic. In the absence of extreme runoff events, dynamic erodibility results from the generation and removal of easily entrained surface material by human road surface maintenance activities, vehicular detachment and overland flow events. Maintenance activities introduce easily transportable material to the road surface where it can be entrained by overland flow. Traffic in dry conditions detaches material that is quickly removed during subsequent overland flow events. The pre‐storm erodibility of a road is therefore largely a function of maintenance and vehicle activity since the last overland flow event. During rainstorms, vehicle passes increase sediment production by detaching/redistributing surface material and creating efficient overland flow pathways for sediment transport. However, if incision of tracks by overland flow does not occur, post‐pass sediment transport quickly returns to pre‐pass rates. Field rainfall simulation data suggest that sediment transport resulting from during‐storm vehicle passes is greatly influenced by the presence of existing loose material, which again is a function of prior road usage and maintenance activities. Incorporation of vehicular effects into physically based road erosion models may be possible by parameterizing both during‐storm and inter‐storm changes in the supply of loose surface material as changes in surface erodibility. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

3.
This paper reports results from field experiments and hydrological modelling on the dynamics of runoff generation in highly convergent parts of the landscape in a logged and burnt eucalypt forest in south‐eastern Victoria, Australia. Large‐scale rainfall simulation experiments were conducted to explore runoff generating mechanisms from harvested areas, and to assess the effectiveness of standard water quality protective measures, here a disturbed filter strip, in preventing accession of sediment to near‐stream areas. We then examined the likely effects of varying antecedent moisture conditions on surface and subsurface runoff generating mechanisms. Very small volumes of surface runoff were generated only at very high rainfall intensity rates that exceeded a 100 year recurrence interval event during the simulated experiments. There was little or no identifiable impact of either compaction from logging operations or fire‐induced hydrophobicity on surface infiltration or generation of surface runoff. Measured soil hydraulic properties and soil depths explained the paucity of surface runoff, and the dominance of subsurface storm flow as the prime runoff generating mechanism. Deep lateral subsurface flow was observed from the cut‐face of a fire access track and into a streamhead downslope of the experimental plots. Water balance modelling using Topog_Dynamic indicated the conditions under which saturated overland flow in this environment could be generated are rare, but that care should be taken in siting of roads and tracks in lower parts of convergent landscapes. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

4.
Hydrological and sediment fluxes were monitored for a 1 yr period in a tropical headwater catchment where a 3 yr old logging road caused substantial Hortonian overland flow (HOF) and intercepted subsurface flow (ISSF). On a 51·5 m road section, ISSF became an increasingly important component of total road runoff, up to more than 90% for large storms. The proportion of ISSF contributed by road cuts along more or less planar slopes compared with ISSF from a zero‐order basin (convergent slopes) truncated by the road declined with increasing rainfall. During the monitored storms that generated ISSF along the road, on average, 28% of sediment export and 79% of runoff from the road section were directly attributable to ISSF. Estimates of total sediment export from the road surface (170 t ha?1 yr?1) and suspended sediment export from the logging‐disturbed catchment (4 t ha?1 yr?1) were exceptionally high despite 3 yr of recovery. ISSF caused not only additional road‐generated sediment export, but also exacerbated HOF‐driven erosion by creating a poor foundation for vegetation recovery on the road surface. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

5.
This study integrates a simple overland flow module (isochronous cells model) with the river module of MODFLOW such that temporal and spatial interactions between stream flow and groundwater can be simulated using net rainfall data of a watershed. The isochronous cells model is an efficient travel time runoff approach based on geographic information system (GIS) that considers both spatial and temporal variations of net rainfall through hill slope of the watershed. This overland module is easily coupled with MODFLOW river routing module. Specifically, the stream flow from the isochronous cells model is directly assigned to both sides of river cells of the MODFLOW model. Such an integration of MODFLOW and isochronous cells model is especially useful in watersheds where river flow data are limited. The feasibility of this integrated model was demonstrated using a case study in the middle and downstream regions of the Yitong River watershed, China. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

6.
A replicated field study using rainfall simulation and overland flow application was conducted in central Oahu, Hawaii, on a clay‐dominated Oxisol with a 9% slope. Three main treatment groups were examined: a bare treatment, a group of four rolled erosion control systems (RECSs) with open weave designs, and a group of five randomly oriented fibre RECSs. A total of 1122 measurements of runoff and erosion were made to examine treatment differences and to explore temporal patterns in runoff and sediment flux. All erosion control systems significantly delayed the time required to generate plot runoff under both simulated rainfall (35 mm h?1) and the more intense trickle flow application (114 mm h?1). Once runoff was generated during the rainfall application phase, the bare treatment runoff coefficients were significantly lower than those from the two groups of RECSs, as surface seal disruption by rilling is inferred to have enhanced infiltration in the bare treatments. During the more intense phase of overland flow application, the reverse pattern was observed. Interrill contributing‐area roughness was reduced on the bare treatment, facilitating increased runoff to well‐developed rill networks. Meanwhile, the form roughness associated with the RECSs delayed interrill flow to the poorly organized rills that formed under some of the RECSs. Regardless of runoff variations between treatments, sediment output was significantly lower from all surfaces covered by RECSs. The median cumulative sediment output from the bare surfaces was 6·9 kg, compared with 1·2 kg from the open‐weave RECSs and 0·2 kg from the random‐fibre RECSs. The random‐fibre systems were particularly effective under the more stressful overland flow application phase, with 63 times less sediment eroded than the bare treatments and 12 times less than that from the open‐weave systems. Architectural design differences between the two groups of RECSs are discussed in light of their relation to erosion process dynamics and shear stress partitioning. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

7.
Channel curvature produces secondary currents and a transverse sloping channel bed, along which the depth increases towards the outer bank. As a result deep pools tend to form adjacent to the outer bank, promoting bank collapse. The interaction of sediment grains with the primary and secondary flow and the transverse sloping bed also causes meanders to move different grain sizes in different proportions and directions, resulting in a consistent sorting pattern. Several models have been developed to describe this process, but they all have the potential to over‐predict pool depth because they cannot account for the influence of erodible banks. In reality, bank collapse might lead to the development of a wider, shallower cross‐section and any resulting flow depth discrepancy can bias associated predictions of flow, sediment transport, and grain‐size sorting. While bed topography, sediment transport and grain sorting in bends will partly be controlled by the sedimentary characteristics of the bank materials, the magnitude of this effect has not previously been explored. This paper reports the development of a model of flow, sediment transport, grain‐size sorting, and bed topography for river bends with erodible banks. The model is tested via intercomparison of predicted and observed bed topography in one low‐energy (5·3 W m?2 specific stream power) and one high‐energy (43·4 W m?2) study reach, namely the River South Esk in Scotland and Goodwin Creek in Mississippi, respectively. Model predictions of bed topography are found to be satisfactory, at least close to the apices of bends. Finally, the model is used in sensitivity analyses that provide insight into the influence of bank erodibility on equilibrium meander morphology and associated patterns of grain‐size sorting. The sensitivity of meander response to bank cohesion is found to increase as a function of the available stream power within the two study bends. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

8.
Although unpaved roads are well‐recognized as important sources of Hortonian overland flow and sediment in forested areas, their role in agriculturally‐active rural settings still lacks adequate documentation. In this study, we assessed the effect of micro‐catchment size, slope, and ground cover on runoff and sediment generation from graveled roadbeds servicing a rural area in southern Brazil. Fifteen replications based on 30‐min‐long simulated rainfall experiments were performed at constant rainfall intensities of 22–58 mm h?1 on roadbeds with varying characteristics including ~3–7 m2 micro‐catchment areas, 2–11° slopes, 2–9.7‐m‐long shallow rill features, and 30–100% gravel cover. The contributions of micro‐catchment size and rill length were the most important physical characteristics affecting runoff response and sediment production; both the size of the micro‐catchment and the length of the rills were inversely related to sediment loss and this contradicts most of the rill erosion literature. The effect of micro‐catchment size on runoff and sediment response suggests a potentially problematic spatial‐scale subjectivity of experimental plot results. The inverse relationship between rill length and sediment generation is interpreted here as related to the predominance of coarse fragments within rills, the inability of the shallow flows generated during the simulations to erode this sediment, and their role as zones of net sediment storage. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

9.
Water is a major limiting factor in arid and semi‐arid agriculture. In the Sahelian zone of Africa, it is not always the limited amount of annual rainfall that constrains crop production, but rather the proportion of rainfall that enters the root zone and becomes plant‐available soil moisture. Maximizing the rain‐use efficiency and therefore limiting overland flow is an important issue for farmers. The objectives of this research were to model the processes of infiltration, runoff and subsequent erosion in a Sahelian environment and to study the spatial distribution of overland flow and soil erosion. The wide variety of existing water erosion models are not developed for the Sahel and so do not include the unique Sahelian processes. The topography of the Sahelian agricultural lands in northern Burkina Faso is such that field slopes are generally low (0–5°) and overland flow mostly occurs in the form of sheet flow, which may transport large amounts of fine, nutrient‐rich particles despite its low sediment transport capacity. Furthermore, pool formation in a field limits overland flow and causes resettlement of sediment resulting in the development of a surface crust. The EUROSEM model was rewritten in the dynamic modelling code of PCRaster and extended to account for the pool formation and crust development. The modelling results were calibrated with field data from the 2001 rainy season in the Katacheri catchment in northern Burkina Faso. It is concluded that the modified version of EUROSEM for the Sahel is a fully dynamic erosion model, able to simulate infiltration, runoff routing, pool formation, sediment transport, and erosion and deposition by inter‐rill processes over the land surface in individual storms at the scale of both runoff plots and fields. A good agreement is obtained between simulated and measured amounts of runoff and sediment discharge. Incorporating crust development during the event may enhance model performance, since the process has a large influence on infiltration capacity and sediment detachment in the Sahel. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

10.
In the semi‐arid Mediterranean environment, the rainfall–runoff relationships are complex because of the markedly irregular patterns in rainfall, the seasonal mismatch between evaporation and rainfall, and the spatial heterogeneity in landscape properties. Watersheds often display considerable non‐linear threshold behavior, which still make runoff generation an open research question. Our objectives in this context were: to identify the primary processes of runoff generation in a small natural catchment; to test whether a physically based model, which takes into consideration only the primary processes, is able to predict spatially distributed water‐table and stream discharge dynamics; and to use the hydrological model to increase our understanding of runoff generation mechanisms. The observed seasonal dynamics of soil moisture, water‐table depth, and stream discharge indicated that Hortonian overland‐flow was negligible and the main mechanism of runoff generation was saturated subsurface‐flow. This gives rise to base‐flow, controls the formation of the saturated areas, and contributes to storm‐flow together with saturation overland‐flow. The distributed model, with a 1D scheme for the kinematic surface‐flow, a 2D sub‐horizontal scheme for the saturated subsurface‐flow, and ignoring the unsaturated flow, performed efficiently in years when runoff volume was high and medium, although there was a smoothing effect on the observed water‐table. In dry years, small errors greatly reduced the efficiency of the model. The hydrological model has allowed to relate the runoff generation mechanisms with the land‐use. The forested hillslopes, where the calibrated soil conductivity was high, were never saturated, except at the foot of the slopes, where exfiltration of saturated subsurface‐flow contributed to storm‐flow. Saturation overland‐flow was only found near the streams, except when there were storm‐flow peaks, when it also occurred on hillslopes used for pasture, where soil conductivity was low. The bedrock–soil percolation, simulated by a threshold mechanism, further increased the non‐linearity of the rainfall–runoff processes. Copyright © 2013 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.
To analyse suspended sediment sources in unmanaged Japanese cypress plantation watersheds, field measurements and fingerprinting of the suspended sediment was conducted in the Shimanto River basin in southern Japan. For sediment fingerprinting, 137Cs and 210Pbex were detected by means of gamma‐ray spectrometry in the surface soil of the forest floor, stream bank and truck trail and mobilized sediment by interrill erosion. The 137Cs and 210Pbex activities associated with the forest floor materials were considerably higher than those of the stream bank and truck trail. The 137Cs and 210Pbex activities associated with the suspended sediment were found to vary with the sampling period. Evidently, the suspended sediment can comprise materials generated from the forest floor by interrill erosion and those from the truck trail and/or stream bank. The multivariate sediment‐mixing model using 137Cs and 210Pbex showed that the contribution of the forest floor varied periodically, ranging from 23–56% in the Hinoki 156 subwatershed and from 18–85% in the Hinoki 155 subwatershed. The difference in the average contribution of the forest floor between Hinoki 156 (46%) and Hinoki 155 (69%) may relate to the presence of truck trail networks in the watershed. The truck trail network can play roles of sediment source and pathway for sediment from forest floor to stream channel due to the concentrated overland flow on the truck trail during heavy rainfall events. These results indicate that the forest floor should be recognized as a major source of suspended sediment in unmanaged Japanese cypress plantation watersheds. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

13.
Fire is an important and natural process in the lifecycle of chaparral systems, removing old growth and recycling nutrients. Recent catastrophic wildfires in southern California chaparral have heightened concerns about increased runoff and nutrient export. The goal of this study was to improve understanding of how overland flow is generated in unburned and post‐fire chaparral watersheds. Samples of overland flow were collected from burned and unburned watersheds after rainfall events and multiple regression analysis was used to examine the influence of individual storm characteristics and system moisture on overland flow volume. The results indicate that variation in overland flow generation in the unburned watershed is best explained by storm size, while overland flow in the burned watershed was positively related to storm size and time between storms. These findings suggest that the burned system had decreased infiltration rates and increased soil water repellency. In contrast, there is a statistically significant negative relationship between overland flow 1 year after a fire against different system and precipitation factors revealed a negative correlation with drying period and a positive relationship with rainfall intensity, a combination that suggests reduced repellency. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

14.
G. Desir 《水文研究》2002,16(13):2685-2700
A 9‐year rainfall, sediment yield and runoff generation record from four experimental plots has been studied. Plots are located in the central Ebro Basin over smooth hillslope developed over gypsum and marl Miocene deposits. The hydrological response of these areas is a function of soil properties, final infiltration capacity and permeability of soils and rainfall characteristics, such as intensity and amount. Results show that there are two types of hydrological response in these areas. First is Hortonian like, which takes place during wet periods and it is responsible for the main part of total sediment yield. Second is like saturation excess overland flow, and it appears after long period. The presence of either type is controlled by a double threshold, starting from when runoff is significant. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

15.
I. Takken  J. Croke  P. Lane 《水文研究》2008,22(2):254-264
This paper outlines a conceptual and methodological approach to evaluating the risk of road derived runoff delivery, which is based on the principle of hydrological connectivity. Three different types of runoff delivery pathways are identified (stream crossings, gullied pathways and diffuse pathways) and the volume of runoff that may reach the stream through these pathways during a one in 10 year 30 minute event is estimated. The methodology is applied to three catchments of contrasting forest use, both plantation and native. Results show that degree of connectivity of a road depends on catchment characteristics such as the topography, road placement, drain spacing and road and drainage density. Maps outlining the distribution of different delivery pathways within a catchment are used to assess the potential for runoff connectivity. In one of the selected study catchments, the Albert River, greatest potential connectivity can be isolated to a single road. The upper part of this road crosses many tributaries resulting in high connectivity via stream crossings, whereas the lower part of the road is located within the valley bottom, where the majority of drains will contribute runoff during a one in 10 year event through diffuse overland flow. The presented methodology is also used to highlight hot‐spots in terms of runoff and sediment delivery through the creation of risk assessment maps, which allows for the evaluation of different procedures for road rehabilitation. Using examples from the Albert River catchment, we demonstrate that minimizing diffuse overland flow can generally be achieved by the placement of additional road drains, whereas at highly connected road segments the relocation of the road might be the only option. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

16.
Interrill erosion processes on gentle slopes are affected by mechanisms of raindrop impact, overland flow and their interaction. However, limited experimental work has been conducted to understand how important each of the mechanisms are and how they interact, in particular for peat soil. Laboratory simulation experiments were conducted on peat blocks under two slopes (2.5° and 7.5°) and three treatments: Rainfall, where rainfall with an intensity of 12 mm h?1 was simulated; Inflow, where upslope overland flow at a rate of 12 mm h?1 was applied; and Rainfall + Inflow which combined both Rainfall and Inflow. Overland flow, sediment loss and overland flow velocity data were collected and splash cups were used to measure the mass of sediment detached by raindrops. Raindrop impact was found to reduce overland flow by 10 to 13%, due to increased infiltration, and reduce erosion by 47% on average for both slope gradients. Raindrop impact also reduced flow velocity (80–92%) and increased roughness (72–78%). The interaction between rainfall and flow was found to significantly reduce sediment concentrations (73–85%). Slope gradient had only a minor effect on overland flow and sediment yield. Significantly higher flow velocities and sediment yields were observed under the Rainfall + Inflow treatment compared to the Rainfall treatment. On average, upslope inflow was found to increase erosion by 36%. These results indicate that overland flow and erosion processes on peat hillslopes are affected by upslope inflow. There was no significant relationship between interrill erosion and overland flow, whereas stream power had a strong relationship with erosion. These findings help improve our understanding of the importance of interrill erosion processes on peat. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

17.
A series of large rainfall simulator experiments was conducted in 2002 and 2003 on a small plot located in an experimental catchment in the North Island of New Zealand. These experiments measured both runoff and sediment transport under carefully controlled conditions. A physically based hydrological modelling system (SHETRAN) was then applied to reproduce the observed hydrographs and sedigraphs. SHETRAN uses physically based equations to represent flow and sediment transport, and two erodibility coefficients to model detachment of soil particles by raindrop erosion and overland flow erosion. The rate of raindrop erosion also depended on the amount of bare ground under the simulator; this was estimated before each experiment. These erodibility coefficients were calibrated systematically for summer and winter experiments separately, and lower values were obtained for the summer experiments. Earlier studies using small rainfall simulators in the vicinity of the plot also found the soil to be less erodible in summer and autumn. Limited validation of model parameters was carried out using results from a series of autumn experiments. The modelled suspended sediment load was also sensitive to parameters controlling the generation of runoff from the rainfall simulator plot; therefore, we found that accurate runoff predictions were important for the sediment predictions, especially from the experiments where the pasture cover was good and overland flow erosion was the dominant mechanism. The rainfall simulator experiments showed that the mass of suspended sediment increased post‐grazing, and according to the model this was due to raindrop detachment. The results indicated that grazing cattle or sheep on steeply sloping hill‐country paddocks should be carefully managed, especially in winter, to limit the transport of suspended sediment into watercourses. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

18.
An experimental landscape simulator has been developed which uses a rainfall simulator to create overland flow and erosion. The simulator uses rainfall sprinklers that eliminate rainsplash and an artificial soil which has little cohesion. Experimental landscapes developed in the simulator evolved according to Howard's headward growth model. Elements of Glock's model could be identified during evolution (i.e. initiation and maximum extension), but other stages of this model were not observed (i.e. extension and integration). The Horton concept of cross‐grading and micropiracy and stream piracy was not observed despite the dominance of overland flow, nor the groundwater headward growth mechanism proposed by Dunne, the latter due to experimental design, which eliminated any perched groundwater table. The experimental apparatus produced model landscapes that are scaled‐down analogues of real world processes. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

19.
This study examines the release of dissolved organic carbon (DOC) from upland peat during the period of the autumn flushing. Hydroclimatic conditions were monitored in conjunction with measurements of absorbance and the E4/E6 ratio of the stream draining an 11·4 km2 upland peat catchment in northern England. During two months of monitoring the effects of 67 separate rainfall events were examined showing that:
  • The peat behaves hydrologically as if it were a two end‐member system consisting of old, interevent, and new, event, water. Runoff is initiated by percolation excess of new water at the acrotelm–catotelm interface.
  • The discharge of dissolved organic matter behaves like a three end‐member system with the between‐event water being low in DOC and storm events being characterized by two types of water. Initial runoff being characterized by new water rich in DOC that gives way to new water depleted in DOC. This transition can be ascribed to the runoff progressing from throughflow within the acrotelm progressing to saturation‐excess overland flow.
  • Depletion of DOC during storm events is accompanied by a change in the character of the DOC as the E4/E6 ratio changes. This suggests that the decrease in DOC during events is the result of exhaustion of reserves rather than changes in the flowpaths being utilized by runoff.
  • The amount of carbon released in any event is critically dependent upon the time between events during which oxidation processes generate a reservoir of available carbon. Production of available carbon in the catchment is as high as 4·5 g C per day per m3 of peat, suggesting a turnover rate of peat of the order of 42 years. Copyright © 2002 John Wiley & Sons, Ltd.
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20.
Two distributed parameter models, a one‐dimensional (1D) model and a two‐dimensional (2D) model, are developed to simulate overland flow in two small semiarid shrubland watersheds in the Jornada basin, southern New Mexico. The models are event‐based and represent each watershed by an array of 1‐m2 cells, in which the cell size is approximately equal to the average area of the shrubs. Each model uses only six parameters, for which values are obtained from field surveys and rainfall simulation experiments. In the 1D model, flow volumes through a fixed network are computed by a simple finite‐difference solution to the 1D kinematic wave equation. In the 2D model, flow directions and volumes are computed by a second‐order predictor–corrector finite‐difference solution to the 2D kinematic wave equation, in which flow routing is implicit and may vary in response to flow conditions. The models are compared in terms of the runoff hydrograph and the spatial distribution of runoff. The simulation results suggest that both the 1D and the 2D models have much to offer as tools for the large‐scale study of overland flow. Because it is based on a fixed flow network, the 1D model is better suited to the study of runoff due to individual rainfall events, whereas the 2D model may, with further development, be used to study both runoff and erosion during multiple rainfall events in which the dynamic nature of the terrain becomes an important consideration. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

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