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1.
《水文科学杂志》2013,58(3):513-525
Abstract The Water Erosion Prediction Project (WEPP) model was calibrated and evaluated for estimation of runoff and sediment yield in the data-scarce conditions of the Indian Himalaya. The inputs derived from remote sensing and geographic information system technologies were combined in the WEPP modelling system to simulate surface runoff and sediment yield from the hilly Kaneli watershed. The model parameters were calibrated using measured data on runoff volumes and sediment yield. The calibrated model was validated by producing the monthly runoff and sediment yield simulations and comparing them with data that were not used in calibration. The model was also used to make surface runoff and sediment yield simulations for each of the individual watershed elements, comprising 18 hillslopes and seven channels, and the detailed monthly results for each are presented. Although, no field data on hillslope runoff and sediment yield are currently available for the validation of distributed results produced by the model, the present investigation has demonstrated clearly the applicability of the WEPP model in predicting hydrological variables in a data-scarce situation. 相似文献
2.
XU JIONGXIN 《水文科学杂志》2013,58(2):187-202
Abstract The runoff and sediment of large rivers usually come from different source areas, which make different contributions to the sediment flux into the sea. This has been studied with the example of the Yellow River in China, whose suspended sediment flux into the Bohai Sea accounts for 19.4% of the world total. The drainage basin of this river can be divided into four major water and sediment source areas. The sediment flux into the sea is found to be closely related to the water and sediment from the different source areas in the drainage basin and, accordingly, an empirical regression model has been established to express this relationship. According to this model, in each tonne (t) of sediment from the fine sediment producing area (FSA), 0.85 t (for yearly series) and 0.72 t (for event series) can be transported into the sea; in each tonne of sediment from the coarse sediment producing area (CSA), only 0.21 t (for yearly series) and 0.34 t (for event series) can be transported into the sea. Since the 1970s, the Yellow River's sediment flux into the sea has declined markedly and this reduction can be attributed to a great degree to the soil control measures in the fine sediment producing area. Coupling the models of this study to the previously established models for estimating the impacts of soil control measures on water and sediment balance in the Yellow River basin, a quantitative prediction may be made for the change of sediment flux into the sea that might result from climate change and human activities in the future. 相似文献
3.
Seasonal and event‐based drivers of runoff and phosphorus export through agricultural tile drains under sandy loam soil in a cool temperate region 
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下载免费PDF全文 Frequent algal blooms in surface water bodies caused by nutrient loading from agricultural lands are an ongoing problem in many regions globally. Tile drains beneath poorly and imperfectly drained agricultural soils have been identified as key pathways for phosphorus (P) transport. Two tile drains in an agricultural field with sandy loam soil in southern Ontario, Canada were monitored over a 28‐month period to quantify discharge and the concentrations and loads of dissolved reactive P (DRP) and total P (TP) in their effluent. This paper characterizes seasonal differences in runoff generation and P export in tile drain effluent and relates hydrologic and biogeochemical responses to precipitation inputs and antecedent soil moisture conditions. The generation of runoff in tile drains was only observed above a clear threshold soil moisture content (~0.49 m3·m?3 in the top 10 cm of the soil; above field capacity and close to saturation), indicating that tile discharge responses to precipitation inputs were governed by the available soil‐water storage capacity of the soil. Soil moisture content approached this threshold throughout the non‐growing season (October – April), leading to runoff responses to most events. Concentrations of P in effluent were variable throughout the study but were not correlated with discharge (p > 0.05). However, there were significant relationships between discharge volume (mm) and DRP and TP loads (kg ha?1) for events occurring over the study period (R2 ≥ 0.49, p ≤ 0.001). This research has shown that the hydrologic and biogeochemical responses of tile drains in a sandy loam soil can be predicted to within an order of magnitude from simple hydrometric data such as precipitation and soil moisture once baseline conditions at a site have been determined. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
Abstract Using daily suspended sediment and water discharge data, we calculated the current mean annual runoff and Specific Suspended Sediment Yield (SSY) for 66 mountainous and piedmont catchments in Chile. These catchments are located from the extreme north of Chile to Southern Patagonia and cover an exceptionally wide range of climates, slopes, and vegetation. The SSY ranges mainly between 0 and 700 t km-2 year-1 with some exceptions as high as 1780 t km-2 year-1. The SSY increases between the extreme north and 33°S and then decreases toward the south. Sediment and water discharge north of 33°S occur mainly during summer. Farther south the contribution of winter precipitation increases and predominates. When the SSY database is correlated with topographic, climatic and vegetation indices, it is found to correlate significantly with runoff and mean slope only. In order to concentrate on erosion processes in the mountain range, 32 mountainous catchments were selected along a strong north–south SSY gradient between 27°S and 40°S. From north to south, SSY increases strongly with runoff and then decreases, even while runoff keeps increasing. In catchments where SSY is low, although runoff is high, the mean slope is less than 40% and the vegetation cover is greater than 8%. For the other catchments, runoff variations explain 67% of the variance in sediment yields. Thus, SSY seems to be controlled by vegetation cover and slope thresholds. In addition, SSY also correlates with glacier cover. However, a correlation between SSY and seismicity, although possible, is ambiguous. Citation Pepin, E., Carretier, S., Guyot, J. L. & Escobar, F. (2010) Specific suspended sediment yields of the Andean rivers of Chile and their relationship to climate, slope and vegetation. Hydrol. Sci. J. 55(7), 1190–1205. 相似文献
5.
V. HRISSANTHOU 《水文科学杂志》2013,58(2):279-292
Abstract Two mathematical models were used to estimate the annual sediment yield resulting from rainfall and runoff at the outlet of the Nestos River basin (Toxotes, Thrace, Greece). The models were applied to that part of the Nestos River basin (838 km2) which lies downstream of three dams. Both models consist of three submodels: a simplified rainfall-runoff submodel, a physically-based surface erosion submodel and a sediment transport submodel for streams. The two models differ only in the surface erosion submodel: that of the first model is based on the relationships of Poesen (1985) for splash detachment and splash transport, while the corresponding submodel of the second model is based on the relationships of Schmidt (1992) for the momentum flux exerted by the droplets and the momentum flux exerted by the overland flow. The degree of conformity between the annual values of sediment yield at the basin outlet according to both models is satisfactory. 相似文献
6.
This study examines runoff and sediment generation rates within the road prism on unsealed road segments in the Cuttagee Creek catchment near Bermagui in New South Wales, Australia. A large (600 m2) rainfall simulator was used to measure runoff and sediment yields from each of the potential sediment and runoff sources and pathways. These included the road surface, table‐drain, upslope contributing area and cutslope face, and the entire road segment as measured at the drain outlet. Experiments were conducted on two major types of road (ridge‐top and cut‐and‐fill) of varying traffic usage and maintenance standard for two 30‐minute simulations of increasing rainfall intensity. From the range of possible sources within the road prism, the road surface produced the dominant source of excess runoff and sediment at each site with limited contributions from the table‐drain, cutslope face or contributing hillslope. Sediment generation varied significantly with road usage and traffic intensity. Road usage was strongly related to the amount of loose available sediment as measured prior to the experiments. Table‐drains acted primarily as sediment traps during the low rainfall event but changes in sediment concentration within the drains were observed as runoff volumes increased during the higher rainfall event of 110 mm h?1, releasing sediment previously stored in litter and organic dams. The experiments demonstrate the potential roles of various features of the road prism in the generation and movement of sediment and water. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
7.
Decreasing trend of sediment transfer function of the Upper Yellow River,China, in response to human activity and climate change 总被引：1，自引：0，他引：1
Xu Jiongxin 《水文科学杂志》2013,58(2):311-325
AbstractAn index (Fs) for sediment transfer function is introduced, based on the sediment budget at the channel scale. The purpose of this study is two-fold: to gain a deeper insight into how Fs is influenced by natural and human factors, and to provide some new knowledge for decision making in the management of the Upper Yellow River, China. Since 1960, the Fs of the Lanzhou to Toudaoguai reach of the Upper Yellow River shows a decreasing trend. At the drainage basin level, the decreased Fs can be explained by changes in precipitation and air temperature, as well as by a number of variables describing human activity, such as reservoir regulation, water diversion, and soil and water conservation. The higher temperature reduces the transfer function, while the larger runoff coefficient increases it. At the channel level, the decreased Fs can be explained by a number of variables of flow and sediment input. Three countermeasures for restoration of the Fs are suggested.
Editor Z.W. Kundzewicz 相似文献
8.
Research on arable sandy loam and silty clay loam soils on 4° slopes in England has shown that tramlines (i.e. the unseeded wheeling areas used to facilitate spraying operations in cereal crops) can represent the most important pathway for phosphorus and sediment loss from moderately sloping fields. Detailed monitoring over the October–March period in winters 2005–2006 and 2006–2007 included event‐based sampling of surface runoff, suspended and particulate sediment, and dissolved and particulate phosphorus from hillslope segments (each ～300–800 m2) established in a randomized block design with four replicates of each treatment at each of two sites on lighter and heavier soils. Experimental treatments assessed losses from the cropped area without tramlines, and from the uncropped tramline area, and were compared to losses from tramlines which had been disrupted once in the autumn with a shallow tine. On the lighter soil, the effects of removal or shallow incorporation of straw residues was also determined. Research on both sandy and silty clay loam soils across two winters showed that tramline wheelings represented the dominant pathway for surface runoff and transport of sediment, phosphorus and nitrogen from cereal crops on moderate slopes. Results indicated 5·5–15·8% of rainfall lost as runoff, and losses of 0·8–2·9 kg TP ha?1 and 0·3–4·8 t ha?1 sediment in tramline treatments, compared to only 0·2–1·7% rainfall lost as runoff, and losses of 0·0–0·2 kg TP ha?1 and 0·003–0·3 t ha?1 sediment from treatments without tramlines or those where tramlines had been disrupted. The novel shallow disruption of tramline wheelings using a tine once following the autumn spray operation consistently and dramatically reduced (p < 0·001) surface runoff and loads of sediment, total nitrogen and total phosphorus to levels similar to those measured in cropped areas between tramlines. Results suggest that options for managing tramline wheelings warrant further refinement and evaluation with a view to incorporating them into spatially‐targeted farm‐level management planning using national or catchment‐based agri‐environment policy instruments aimed at reducing diffuse pollution from land to surface water systems. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
9.
Pedro H. A. Medeiros Andreas Güntner Till Francke George L. Mamede José Carlos de Araújo 《水文科学杂志》2013,58(4):636-648
Abstract Rainfall–runoff induced soil erosion causes important environmental degradation by reducing soil fertility and impacting on water availability as a consequence of sediment deposition in surface reservoirs used for water supply, particularly in semi-arid areas. However, erosion models developed on experimental plots cannot be directly applied to estimate sediment yield at the catchment scale, since sediment redistribution is also controlled by the transport conditions along the landscape. In particular, representation of landscape connectivity relating to sediment transfer from upslope areas to the river network is required. In this study, the WASA-SED model is used to assess the spatial and temporal patterns of water and sediment connectivity for a semi-arid meso-scale catchment (933 km2) in Brazil. It is shown how spatial and temporal patterns of sediment connectivity within the catchment change as a function of landscape and event characteristics. This explains the nonlinear catchment response in terms of sediment yield at the outlet. Citation Medeiros, P. H. A., Güntner, A., Francke, T., Mamede, G. L. & de Araújo, J. C. (2010) Modelling spatio-temporal patterns of sediment yield and connectivity in a semi-arid catchment with the WASA-SED model. Hydrol. Sci. J. 55(4), 636–648. 相似文献
10.
The spatial scale effect on sediment concentration in runoff has received little attention despite numerous studies on sediment yield or sediment delivery ratio in the context of multiple spatial scales. We have addressed this issue for hilly areas of the Loess Plateau, north China where fluvial processes are mainly dominated by hyperconcentrated flows. The data on 717 flow events observed at 17 gauging stations and two runoff experimental plots, all located in the 3906 km2 Dalihe watershed, are presented. The combination of the downstream scour of hyperconcentrated flows and the downstream dilution, which is mainly caused by the base flow and is strengthened as a result of the strong patchy storms, determines the spatial change of sediment concentration in runoff during flood events. At the watershed scale, the scouring effect takes predominance first but is subordinate to the downstream dilution with a further increase in spatial scale. As a result, the event mean sediment concentration first increases following a power function with drainage basin area and then declines at the drainage basin area of about 700 km2. The power function in combination with the proportional model of the runoff‐sediment yield relationship we proposed before was used to establish the sediment‐yield model, which is neither the physical‐based model nor the regression model. This model, with only two variables (runoff depth and drainage basin area) and two parameters, can provide fairly accurate prediction of event sediment yield with model efficiency over 0·95 if small events with runoff depth lower than 1 mm are excluded. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
11.
Abstract This paper presents a reach-scale sediment balance of a large impounded Mediterranean river (the lower Ebro, 1998–2008). Multi-temporal sediment storage and the influence of floods and tributaries on the sediment load were examined using continuous discharge and turbidity records. The mean annual suspended sediment load at the reach outlet (Xerta) is 0.12?×?106 t, corroborating previous results. Suspended sediment concentrations were low (SSCmean?=?13 mg L-1), attaining a maximum of 274 mg L-1. Erosion processes (channel-scour, bank erosion) are dominant, and net export of sediment occurs over the long term. Unexpectedly, ephemeral tributaries were found to contribute significantly: sediment delivered during torrential events attained 5% of the Ebro annual load, and was even larger than that in flushing flows. Overall, most of the suspended sediment load is transported by floods (up to 65% in some years). The results constitute basic information to underpin current management actions aiming to achieve the sustainability of the riverine and deltaic system. Editor D. Koutsoyiannis; Associate editor D. Hughes Citation Tena, A., Batalla, R.J. and Vericat, D., 2012. Reach-scale suspended sediment balance downstream from dams in a large Mediterranean river. Hydrological Sciences Journal, 57 (5), 831–849. 相似文献
12.
Previous studies have identified unpaved roads as the primary source of erosion on St John in the US Virgin Islands, but these studies estimated road erosion rates only as annual averages based primarily on road rill measurements. The goal of this project was to quantify the effect of unpaved roads on runoff and sediment production on St John, and to better understand the key controlling factors. To this end runoff and sediment yields were measured from July 1996 to March 1997 from three plots on naturally vegetated hillslopes, four plots on unpaved road surfaces and two cutslope plots. Sediment yields were also measured from seven road segments with contributing areas ranging from 90 to 700 m2. With respect to the vegetated plots, only the two largest storm events generated runoff and there was no measurable sediment yield. Runoff from the road surface plots generally occurred when storm precipitation exceeded 6 mm. Sediment yields from the four road surface plots ranged from 0·9 to 15 kg m−2 a−1, and sediment concentrations were typically 20–80 kg m−3. Differences in runoff between the two cutslope plots were consistent with the difference in upslope contributing area. A sprinkler experiment confirmed that cross‐slope roads intercept shallow subsurface stormflow and convert this into surface runoff. At the road segment scale the estimated sediment yields were 0·1 to 7·4 kg m−2 a−1. Road surface runoff was best predicted by storm precipitation, while sediment yields for at least three of the four road surface plots were significantly correlated with storm rainfall, storm intensity and storm runoff. Sediment yields at the road segment scale were best predicted by road surface area, and sediment yields per unit area were most strongly correlated with road segment slope. The one road segment subjected to heavy traffic and more frequent regrading produced more than twice as much sediment per unit area than comparable segments with no truck traffic. Particle‐size analyses indicate a preferential erosion of fine particles from the road surface and a rapid surface coarsening of new roads. Published in 2001 by John Wiley & Sons, Ltd. 相似文献
13.
Abdulvahed Khaledi Darvishan Seyed Hamidreza Sadeghi Mehdi Homaee Mahmood Arabkhedri 《水文研究》2014,28(15):4463-4471
The bulk of eroded soils measured at the outlets of plots, slopes and watersheds are suspended sediments, splash‐induced sheet erosion. It is depending on rainfall intensity and antecedent soil moisture contents and contributes to a significant proportion of soil loss that usually is ignored in soil erosion and sediment studies. A digital image processing method for tracing and measuring non‐suspended soil particles detached/transported by splash/runoff was therefore used in the present study. Accordingly, fine mineral pumice grains aggregated with white cement and coloured with yellow pigment powder, with the same size, shape and specific gravity as those of natural soil aggregates, called synthetic color‐contrast aggregates, were used as tracers for detecting soil particle movement. Subsequently, the amount of non‐suspended soil particles detached and moved downward the slope was inferred with the help of digital image processing techniques using MATLAB R2010B software (Mathworks, Natick, Massachusetts, USA). The present study was conducted under laboratory conditions with four simulated rainfall intensities between 30–90 mm h‐1, five antecedent soil moisture contents between 12–44 % v v‐1 and a slope of 30%, using sandy loam soils taken from a summer rangeland in the Alborz Mountains, Northern Iran. A range of total transported soil between 90.34 and 1360.93 g m‐2 and net splash erosion between 36.82 and 295.78 g m‐2were observed. The results also showed the sediment redeposition ratio ranging from 87.27% [sediment delivery ratio (SDR) = 12.73%] to 96.39% (SDR = 3.61%) in various antecedent soil moisture contents of rainfall intensity of 30 mm h‐1 and from 80.55% (SDR = 19.45%) to 89.42% (SDR = 10.58%) in rainfall intensity of 90 mm h‐1. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
Fluvial sediment delivery is the main form of sediment transfer from the land to the sea, but this process is currently undergoing significant variations due to the alteration of catchment and base level controls related to climate change and human activities, especially the widespread construction of dams. Using the lower Wei River as an example and an integrated approach, this study investigates the variation of fluvial sediment delivery, as well as the connectivity under the effects of both controls. Based on hydrological records and channel cross‐section surveys, sediment budgets were constructed for two periods (1960–1970, 1970–1990) after the dam was closed in 1960. In the period 1960–1969, due to the elevated base level (327.2 ± 1.62 m) caused by the dam, the aggradation rate was 0.451 × 108 t yr‐1 in the channel and 0.716 × 108 t yr‐1 on the floodplain, indicating that the positive lateral connectivity between these locations was enhanced. As a consequence, serious sediment storage resulted in a sediment delivery ratio (SDR) that was smaller than that occurring before 1960. In the period 1970–1990, sweeping soil and water conservation (SWC) measures were implemented, resulting in a reduction of the connectivity between the trunk and tributaries, and a decrease of ~31% in the mean sediment input. In addition, together with the base level fluctuation in the range of 327.47 ± 0.49 m, the annual variation in sediment storage was primarily dependent on the water–sediment regime affected by the SWC. The negative lateral connectivity was enhanced between the channel and floodplain via bank erosion. Consequently, the aggradation rate was reduced by 89% on the floodplain and by 96% in the channel. Sediment output continued to decrease primarily due to the SWC practices and climate changes in this period, whereas the SDR increased due to the enhanced longitudinal connectivity between the upstream and downstream. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
15.
《水文科学杂志》2013,58(2):457-465
Abstract Periodicity of the runoff and the sediment load, and possible impacts from human activities and climatic changes, in the Yangtze River basin during 1963–2004 are discussed based on the monthly sediment and runoff data, and using the wavelet approach. Research results indicated that: (a) Sediment load changes are severely impacted by the different types of human activity (e.g. construction of water reservoirs, deforestation/afforestation); and the runoff variability is the direct result of climatic changes, e.g. the precipitation changes. (b) The impacts of human activity and climatic changes on the sediment load and runoff changes are greater in smaller river basins (e.g. the Jialingjiang River basin) than in larger river basins. The response of sediment load and runoff changes to the impacts of human activities and climatic changes are prompt and prominent in the Jialingjiang River basin relative to those in the mainstem of the Yangtze River basin. (c) Construction of the Three Gorges Dam has already had obvious impacts on the sediment transport process in the middle and lower Yangtze River basin, but shows no obvious influence on the runoff changes. Construction of the Three Gorges Dam will result in further re-adjustment of the scouring/filling process within the river channel in the middle and lower Yangtze River basin, and have corresponding effects on the altered sediment load because of the Dam's operation for the river channel, ecology, sustainable social economy and even the development of the Yangtze Delta. This will be of concern to local governments and policy makers. 相似文献
16.
Despite widespread bench‐terracing, stream sediment yields from agricultural hillsides in upland West Java remain high. We studied the causes of this lack of effect by combining measurements at different spatial scales using an erosion process model. Event runoff and sediment yield from two 4‐ha terraced hillside subcatchments were measured and field surveys of land use, bench‐terrace geometry and storage of sediment in the drainage network were conducted for two consecutive years. Runoff was 3·0–3·9% of rainfall and sediment yield was 11–30 t ha−1 yr−1 for different years, subcatchments and calculation techniques. Sediment storage changes in the subcatchment drainage network were less than 2 t ha−1, whereas an additional 0·3–1·5 t ha−1 was stored in the gully between the subcatchment flumes and the main stream. This suggests mean annual sediment delivery ratios of 86–125%, or 80–104% if this additional storage is included. The Terrace Erosion and Sediment Transport (TEST) model developed and validated for the studied environment was parameterized using erosion plot studies, land use surveys and digital terrain analysis to simulate runoff and sediment generation on the terraced hillsides. This resulted in over‐estimates of runoff and under‐estimates of runoff sediment concentration. Relatively poor model performance was attributed to sample bias in the six erosion plots used for model calibration and unaccounted covariance between important terrain attributes such as slope, infiltration capacity, soil conservation works and vegetation cover. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
17.
Artificial subsurface (tile) drainage is used to increase trafficability and crop yield in much of the Midwest due to soils with naturally poor drainage. Tile drainage has been researched extensively at the field scale, but knowledge gaps remain on how tile drainage influences the streamflow response at the watershed scale. The purpose of this study is to analyse the effect of tile drainage on the streamflow response for 59 Ohio watersheds with varying percentages of tile drainage and explore patterns between the Western Lake Erie Bloom Severity Index to streamflow response in heavily tile-drained watersheds. Daily streamflow was downloaded from 2010 to 2019 and used to calculated mean annual peak daily runoff, mean annual runoff ratio, the percent of observations in which daily runoff exceeded mean annual runoff (TQmean), baseflow versus stormflow percentages, and the streamflow recession constant. Heavily-drained watersheds (>40% of watershed area) consistently reported flashier streamflow behaviour compared to watersheds with low percentages of tile drainage (<15% of watershed area) as indicated by significantly lower baseflow percentages, TQmean, and streamflow recession constants. The mean baseflow percent for watersheds with high percentages of tile drainage was 20.9% compared to 40.3% for watersheds with low percentages of tile drainage. These results are in contrast to similar research regionally indicating greater baseflow proportions and less flashy hydrographs (higher TQmean) for heavily-drained watersheds. Stormflow runoff metrics in heavily-drained watersheds were significantly positively correlated to western Lake Erie algal bloom severity. Given the recent trend in more frequent large rain events and warmer temperatures in the Midwest, increased harmful algal bloom severity will continue to be an ecological and economic problem for the region if management efforts are not addressed at the source. Management practices that reduce the streamflow response time to storm events, such as buffer strips, wetland restoration, or drainage water management, are likely to improve the aquatic health conditions of downstream communities by limiting the transport of nutrients following storm events. 相似文献
18.
Simultaneous field monitoring of runoff and suspended sediment loads from a 30 ha, artificially‐drained, mixed‐agricultural catchment in Herefordshire, UK indicates field drains are the dominant pathway for the transfer of runoff and sediment to the stream. Surface runoff pathways draining 6·2% of the catchment area transported around 1% of the catchment sediment load, while subsurface runoff in field drains draining 26·5% of the catchment transported around 24% of the sediment load. The explanations offered here for the dominance of drainflow—the spatial limitation of surface runoff generation and low hillslope‐stream connectivity of surface runoff compared with subsurface runoff—are also likely to apply to other artificially‐drained lowland agricultural catchments in the UK. These catchments are usually on poorly‐drained soils, and land management can have a considerable effect on the operation of runoff pathways and the transfer of sediment from hillslope to stream. As a result, subsurface inputs may also dominate sediment transfers in other underdrained catchments. The focus on sediment and pollutant losses via surface runoff pathways means that pollution inputs from subsurface, preferential pathways have been unfairly neglected, and it may be more important to focus on subsurface sediment and sediment‐associated pollution inputs for mitigation rather than inputs from surface pathways. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
19.
《水文科学杂志》2013,58(5):1068-1075
Abstract The present study aims to estimate the sediment yield due to storm rainfall and runoff at the outlet of the Khanmirza watershed (395 km2) located in western Iran. The estimation was made for six storm events using the Modified Universal Soil Loss Equation (MUSLE). All the inputs required for the application of the model were determined through runoff and sediment concentration monitoring at the time of storm events, and field surveys in the study area. The applicability of the model to the study area was then evaluated by comparison of its estimates with those calculated using the measured sediment data. The results of the study demonstrated the efficiency of the MUSLE in estimating storm-associated sediment yield except one storm event in the study area with a high level of agreement and non-significant differences between mean estimated and measured values in the study storm events. 相似文献
20.
Sugarcane is grown on the floodplains of northern Queensland adjacent to the Great Barrier Reef lagoon. Sediment and nutrient loss from these sugarcane areas is considered a potential threat to coastal and marine ecosystems. To enable sugarcane cultivation, farmers have structured the landscape into different elements, comprising fields, water furrows, ‘headlands’ and drains. In order to apply appropriate management of the landscape and reduce export of sediment, it is important to identify which of these elements act as sediment sources or sinks. In this study erosion and deposition rates were measured for the different landscape elements in a subcatchment of the Herbert River and used to create a sediment budget. Despite large uncertainties, the budget shows that the floodplain area is a net source of sediment. Estimated sediment export varies between 2 and 5 t ha?1 y?1. The relative importance of the landscape elements as sediment sources could also be determined. Plant cane is identified as the most important sediment source. Water furrows generate most sediment, but are a less important source of exported sediment due to their low connectivity. Headlands and minor drains act as sediment traps. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献