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1.
为分析黄河水沙成因并预测未来水沙情势,选取黄河中游多沙粗沙区昕水河和朱家川2条流域为研究对象,依据水文站及雨量站1956—2018年降雨和径流泥沙实测数据,采用Mann-Kendall趋势及突变检验、累积距平法和Morlet连续小波分析等方法探讨流域水沙变化趋势,并利用双累积曲线法对水沙变化进行归因分析,量化气候变化及人类活动对水沙变化的相对贡献。结果表明:1956—2018年,昕水河和朱家川小流域年均径流量分别为11.9×107,1.7×107 m3,年均输沙量分别为12.3×106,9.8×106 t,径流和输沙量均呈显著减少趋势;2条流域的径流量突变年分别为1980年和1984年,输沙量突变年分别为1980年和1972年;选取的2条流域水沙变化存在明显周期性,径流变化的第1主周期分别为45年和16年,输沙量变化的第1主周期分别为9年和15年;降雨对昕水河和朱家川小流域径流量减少的贡献率分别为19%,8%,对输沙量减少的贡献率分别为25%,35%,远不及人类活动的贡献率,人类活动是径流和输沙量锐减的主导因素。研究结果可为黄河水沙治理提供科学性建议。 相似文献
2.
Using the modified agricultural non-point source pollution model in German watersheds 总被引：2，自引：0，他引：2
The modified agricultural non-point source pollution model (AGNPSm) was used in this study to predict runoff volume, peak flow rate, and sediment yield in three different watersheds in Germany. It is a distributed parameter soil erosion model which uses simple approaches to hydrological and sediment calculations. Simulations were carried out in the Glonn G1 (1.2 km2), and Glonn G2 (1.6 km2), and the Salzboede (81.7 km2) watersheds in Germany. Runoff volume was predicted reliably in all three watersheds. Sediment yield predictions were excellent in the Glonn G1 and acceptable in the Glonn G2 watersheds. There were some uncertainties in the sediment yield calculations for the Salzboede watershed. This study shows that a less complex soil erosion model such as AGNPSm is able to produce reliable assessments of non-point source pollution for planning purposes. 相似文献
3.
Miriam Fernanda Rodrigues José Miguel Reichert Jean Paolo Gomes Minella Leandro Dalbianco Rodrigo Luiz Ludwig Rafael Ramon Lilian Alessandra Rodrigues Norton Borges Júnior 《Journal of Soils and Sediments》2014,14(7):1311-1324
Purpose
Information on the effects of eucalyptus forests on hydrosedimentological processes is scarce, particularly at the catchment scale. Monitoring and mathematical modeling are efficient scientific tools used to address the lack of information for natural resource management and the representation and prediction of those processes. This study evaluates the effects of eucalyptus cultivation on hydrosedimentological processes in watersheds and to use the Limburg soil erosion model (LISEM) to represent and predict hydrological processes.Material and methods
The study was conducted in two forested watersheds: the main watershed (94.46 ha) and a nested sub-watershed (38.86 ha), both cultivated with eucalyptus and residual riparian native forest, located in southern Brazil. Hydrosedimentalogical monitoring was conducted from 16th February 2011 to 31st December 2012, and LISEM model calibrations were performed on the bases of six storms events.Results and discussion
The sediment yield for 2011 was 41.6 Mg km?2 and 38.5 Mg km?2 for the watershed and sub-watershed, respectively. An extreme event in 2012 provided greater sediment yield for the sub-watershed (99.8 Mg km?2) than that for the watershed (51.7 Mg km?2). Rainfall events with a greater maximum intensity generated rapid discharge and suspended sediment concentration responses in the sub-watershed due to the smaller drainage area and steeper landscape. In the main watershed, the accumulation of flood waves occurred for most events, with less steep hydrographs, and a later occurrence of the discharge peak after that of the sub-watershed. The LISEM adequately reproduced the peak discharge and runoff for the calibrated events; however, the peak time and the shape of the hydrograph were not adequately represented.Conclusions
The hydrosedimentological patterns of the watershed and sub-watershed, both cultivated with eucalyptus, was characterized by sedimentographs preceding hydrographs during rainfall–runoff events where scale effects occur, with maximum discharge and specific sediment yield greater in the watershed than that in the sub-watershed. Empirical models based on hydrologic variables may be used for estimating the suspended sediment concentration and sediment yield. Therefore, LISEM may be used for the prediction of hydrological variables in these forested watersheds. 相似文献4.
Carla Sofia Santos Ferreira Rory Peter Dominic Walsh João Pedro Carvalho Nunes Tammo S. Steenhuis Manuel Nunes João Luís Mendes Pedroso de Lima Celeste Oliveira Alves Coelho António José Dinis Ferreira 《Journal of Soils and Sediments》2016,16(11):2580-2593
Purpose
Relatively little is known in the Mediterranean environment about changes in streamflow during urban development in partially urbanized peri-urban catchments. This paper explores the modification of streamflow regime as a consequence of the construction of an enterprise park, a major road, and expansion of residential areas, leading to urban areas increase from 32 to 40 % in a small catchment (6.2 km2), located in the periphery of one of the main cities in central mainland Portugal.Materials and methods
The study was carried out over five hydrological years (October 2008–September 2009 to October 2012–September 2013), including two initial years of pre- and three following years of post-additional urban development. Streamflow was recorded by a V-notch weir at the catchment outlet at 5-min intervals. Rainfall was recorded at a weather station 0.5 km north of the catchment and by five tipping-bucket raingauges installed in January 2011 within the study catchment. Streamflow was converted into runoff and split into baseflow and stormflow components by applying a mathematical low-pass digital filter. Streamflow differences were investigated through changes in (i) annual runoff coefficients, (ii) annual baseflow index, (iii) seasonal baseflow index and stormflow coefficient, and (iv) storm event analysis.Results and discussion
Annual runoff coefficient ranged from 14 to 21 % and storm runoff coefficient from 9 to 14 %, both between the driest 2011/12 and wettest 2012/13. Although these differences were influenced by inter-annual weather variability, a comparison between years with similar rainfall before and after additional urban development showed a 43 % increase in storm runoff. Impacts on streamflow were also noticed through changes on hydrograph: (i) regression lines of storm runoff against rainstorm parameters exhibited higher vertical positions in 2012/13 than 2008/09, (ii) gradual increase in peak flow but with a clear distance between pre- and post- additional urbanization, (iii) quicker response time from 60–75 min to 40–45 min between both periods, and (iv) decrease in recession time from 21–29 h to 7–9 h for the same periods.Conclusions
The dispersed urban pattern and permeable soils provide many overland flow sinks, favouring relatively low storm runoff of the catchment. Nevertheless, the enlargement of impervious surfaces (from 12.8 to 17.0 %) and particularly the storm drainage system installed in new urban areas led to great changes on rainfall–runoff event responses. Urban planning should consider the landscape mosaic of peri-urban areas in order to maximize water infiltration and minimize the impacts on streamflow regime.5.
The impact of storm water runoff on a small urban stream 总被引：2，自引：0，他引：2
Vilmantė Karlavičienė Sigita Švedienė Danutė Elena Marčiulionienė Peter Randerson Mindaugas Rimeika William Hogland 《Journal of Soils and Sediments》2009,9(1):6-12
Background, aim, and scope In urban areas, storm water runoff often transports various pollutants, some of which settle and form sediments. In order
to have the comprehensive view of the ecological state of storm water runoff recipients, both water and sediments of the stream
must be assessed. In the Baltic Sea Area, the Water Framework Directive & HELCOM Recommendations aim to prevent or minimise
pollution caused by harmful substances arising from storm water runoff, in order to promote the ecological restoration of
the Baltic Sea—one of the most vulnerable seas. The aim of the study was to investigate the toxicity of bottom sediments of
a small storm water runoff recipient focusing on the potential impact of successive discharges of urban storm water. Some
storm water runoff quality parameters and the toxicity of bottom sediments of recipients was studied in this research.
Materials and methods During 9 years, at four discharge points, minimum four grab samples per year at each discharge point were taken for chemical
characterisation. General parameters (pH, SS, BOD7, CODCr and TPH) in liquid phase samples were analysed according to standard methods. Annual limit values were taken from the Lithuanian
EPA requirements for the management of storm water runoff with a focus on prevention and control of contamination. Eleven
composite samples of stream bottom sediments, each consisting of ten sub-samples, were collected in 2006. Toxicity screening
from sediments was performed using the plant Lepidium sativum according to modified I. Magone’s methodology (Magone I, Bioindication of phytotoxicity of transport emission. In: Kachalova
O-L, Zinatne (eds) Bioindication of toxicity of transport emissions in the impact of highway emissions on natural environment. Riga, pp 108–116, 1989). The level of toxic impact of Lepidium sativum (compared to control) was assessed according to the modified method of Wang (Rev Environ Contam Toxicol 126:88–127, 1992).
Results The mean pH of urban storm water runoff does not vary much from neutral, but range values are quite different, from 4.0 up
to 8.7. The highest concentration of SS reached 800 mg L−1, TPH—2.4 mg L−1, BOD7—300 mg O2 L−1 and CODCr—1,400 mg L−1. The SS was above the limit in 64% of total amount of grab samples, TPH—37%, BOD7—41% and CODCr—55%. The toxicity analysis of the bottom sediments showed varying toxicity of bottom sediments along the stream. From nine
analysed samples of bottom sediments, 30% had weak toxicity, 30% medium and 30% strong toxicity on the test organism plant
L. sativum. There was one single sample with no toxic effects, so that the results showed that urban storm water has an unacceptable
environmental impact on recipients. It was also indicated that storm water runoff discharge alone is not the potential source
of toxicity of bottom sediments. The litter demonstrated a weak toxicity of bottom sediments as well.
Discussion Most local authorities do not consider storm water runoff discharges to be a matter of great concern because they believe
that surface runoff arising from rainfall is still relatively clean. The study showed that the current method of monitoring
storm water runoff quality by chemical analyses is not the best tool for environmental impact assessment and must be combined
with toxicity tests of bottom sediments of recipients.
Recommendations and perspectives To avoid the environmental impact of storm water runoff more attention should be paid to the development and implementation
of storm water runoff pollution prevention measures. The study implies that future research concerning the relationships between
storm water runoff deposit characteristics and biological activities must be developed to evaluate the contamination potential
of stream sediment deposits for local aquatic ecosystems. Further studies should be developed to characterise the activities
of the microbial community of storm water runoff sediments, and to monitor bioremediation in situ. 相似文献
6.
Melaku Nigus Demelash Renschler Chris S. Holzmann Hubert Strohmeier Stefan Bayu Wondimu Zucca Claudio Ziadat Feras Klik Andreas 《Journal of Soils and Sediments》2018,18(4):1743-1755
Purpose
Land degradation due to soil erosion is a serious threat to the highlands of Ethiopia. Various soil and water conservation (SWC) strategies have been in use to tackle soil erosion. However, the effectiveness of SWC measures on runoff dynamics and sediment load in terms of their medium- and short-term effects has not been sufficiently studied.
Materials and methodsA study was conducted in 2011 to 2015 in the Gumara-Maksegnit watershed to study the impacts of SWC structures on runoff and soil erosion processes using the soil and water analysis tool (SWAT) model. The study was conducted in two adjacent watersheds where in one of the watersheds, SWC structures were constructed (treated watershed (TW)) in 2011, while the other watershed was a reference watershed without SWC structures (untreated watershed (UW)). For both watersheds, separate SWAT and SWAT-CUP (SWAT calibration and uncertainty procedure) projects were set up for daily runoff and sediment yield. The SWAT-CUP program was applied to optimize the parameters of the SWAT using daily observed runoff and sediment yield data.
Results and discussionThe runoff simulations indicated that SWAT can reproduce the hydrological regime for both watersheds. The daily runoff calibration (2011–2013) results for the TW and UW showed good correlation between the predicted and the observed data (R 2?=?0.78 for the TW and R 2?=?0.77 for the UW). The validation (2014–2015) results also showed good correlation with R 2 values of 0.72 and 0.70 for the TW and UW, respectively. However, sediment yield calibration and validation results showed modest correlation between the predicted and observed sediment yields with R 2 values of 0.65 and 0.69 for the TW and UW for the calibration and R 2 values of 0.55 and 0.65 for the TW and UW for the validation, respectively.
ConclusionsThe model results indicated that SWC structures considerably reduced soil loss by as much as 25–38% in the TW. The study demonstrated that SWAT performed well for both watersheds and can be a potential instrument for upscaling and assessing the impact of SWC structures on sediment loads in the highlands of Ethiopia.
相似文献7.
泥沙输移比是定量表征流域内侵蚀产沙-河道输沙特征的重要指标。探讨了不同尺度流域泥沙输移比计算的可能性与方法,以黄土丘陵沟壑区的径流小区、小流域、水文站实测资料为基础,利用径流小区观测资料和单元小流域侵蚀模数2种方法,对4种空间尺度流域的泥沙输移比进行了估算。结果表明:(1)对于面积在10~100km2的小流域,利用2种方法计算的泥沙输移比结果非常接近,说明在没有小区观测资料时,用单元小流域计算流域泥沙输移比是可行的。(2)对于土壤侵蚀类型单一的水文站控制流域,在没有面积>1km2单元小流域资料的情况下,可以用面积1~10km2小流域或面积10~100km2小流域作为单元小流域来计算泥沙输移比而对于侵蚀类型不同的支流其误差范围有些偏大。(3)流域治理措施的实施对于泥沙输移比的减少具有明显的效果,但治理措施减沙效应的发挥具有一定的滞后性。 相似文献
8.
T. Bisantino R. Bingner W. Chouaib F. Gentile G. Trisorio Liuzzi 《Land Degradation \u0026amp; Development》2015,26(4):340-355
In this paper, the Annualized Agricultural Non‐Point Source (AnnAGNPS) model has been used to estimate runoff, peak discharge and sediment load at the event scale in a Mediterranean watershed. The study area is the Carapelle torrent, Southern Italy (area = 506 km2), where continuous rainfall, streamflow and sediment load data are available. Nineteen flood events have been registered in the period 2007–2009 and were used for the application of the model. The aim of the paper is to evaluate the predictive accuracy of the model at the event scale, in a medium‐size watershed, given the specific conditions of the semi‐arid environments. A sensitivity analysis has been carried out to assign the correct parameterization: the mean normalized output variation of the most meaningful input parameters pointed out the influence of the curve number on runoff, peak discharge and sediment load predictions (values greater than 1); the MN Manning's roughness coefficient and K, C and P factors of the universal soil loss equation showed a moderate influence on sediment load simulations (values between 0·5 and 1). The selection of the Soil Conservation Service synthetic storm types has been based on the observed storm events analysis to improve the peak discharge simulations. The model prediction has proved to be good for runoff (R2 = 0·74, NSE = 0·75, W = 0·92) and peak discharge (R2 = 0·85, NSE = 0·70, W = 0·94), and satisfactory for sediment yield (R2 = 0·70, NSE = 0·63, W = 0·91). The relative error is lower for high events; this result is quite interesting in semi‐arid environments, where most of the annual sediment yield is concentrated in a few, severe events. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
《Land Degradation \u0026amp; Development》2017,28(5):1506-1518
The development of reliable tools to quantify long‐term sediment budgets is critical to establish adequate environmental and management policies in semiarid Mediterranean regions. In this study, we apply a multidisciplinary methodology to estimate water and sediment yields in ungauged Mediterranean watersheds over a period of scarce instrumental data (i.e. second half of 19th and first half of 20th centuries). Runoff and precipitation reconstructions have been obtained using an integrative approach involving synoptic reanalysis models, regional climatic datasets, historical archives and palaeoflood proxies from natural archives. The resulting hydrological reconstruction has been implemented on a hydro‐sedimentary distributed model (i.e. TETIS) to understand the hydro‐sedimentary dynamics in the studied watershed. We highlight that, in our study area, regional‐data (instrumental, historical and sedimentary) based models show higher accuracy in the sediment yield and runoff reconstruction than synoptic reanalysis climate models. The modelled sedimentary dynamics for the studied period respond to a complex interplay between human activities and climate variability. During the 19th century deforestation and grazing activities combined with higher frequency on extreme runoff events resulted in higher runoff and sediment yield in the period 1863–1900. Over the 20th century, reduced precipitation and land abandonment led to a decrease in erosion rates and sediment yield although increased in 1945–1960 coinciding with a period of higher frequency of heavy rainfalls. This hydrological response to climate and human activities in the study watershed improves our understanding of plausible future trends of environmental degradation in small Mediterranean watersheds under different land use and climate change scenarios. This article includes supporting information which features an explanation of GILMCLIM downscaling model, The precipitation series resulting from the reanalysis data (Figure S1), an analysis of the different precipitation series used (Table S1) and an extensive explanation of how the relation between Puentes and Valdeinfierno reservoirs was considered. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
10.
Keesstra Saskia D. Davis Jason Masselink Rens Hein Casalí Javier Peeters Edwin T. H. M. Dijksma Roel 《Journal of Soils and Sediments》2019,19(3):1598-1612
Purpose
Rain storm events mobilise large proportions of fine sediments in catchment systems. Sediments from agricultural catchments are often adsorbed by nutrients, heavy metals and other (in)organic pollutants that may impact downstream environments. To mitigate erosion, sediment transport and associated pollutant transport, it is crucial to know the origin of the sediment that is found in the drainage system, and therefore, it is important to understand catchment sediment dynamics throughout the continuity of runoff events.
Materials and methodsTo assess the impact of the state of a catchment on the transport of fine suspended sediment to catchment outlets, an algorithm has been developed which classifies rain storm events into simple (clockwise, counter-clockwise) and compound (figure-of-eight; complex) events. This algorithm is the first tool that uses all available discharge and suspended sediment data and analyses these data automatically. A total of 797 runoff events from three experimental watersheds in Navarre (Spain) were analysed with the help of long-term, high-resolution discharge and sediment data that was collected between 2000 and 2014.
Results and discussionMorphological complexity and in-stream vegetation structures acted as disconnecting landscape features which caused storage of sediment along the transport cascade. The occurrence of sediment storage along transport paths was therefore responsible for clockwise hysteresis due to the availability of in-stream sediment which could cause the “first flush” affect. Conversely, the catchment with steeper channel gradients and a lower stream density showed much more counter-clockwise hysteresis due to better downstream and lateral surface hydrological connectivity. In this research, hydrological connectivity is defined as the actual and potential transfer paths in a catchment. The classification of event SSC-Q hysteresis provided a seasonal benchmark value to which catchment managers can compare runoff events in order to understand the origin and locations of suspended sediment in the catchment.
ConclusionsA new algorithm uses all available discharge and suspended sediment data to assess catchment sediment dynamics. From these analyses, the catchment connectivity can be assessed which is useful to develop catchment land management.
相似文献11.
The influence of land use on runoff and soil loss was assessed on two small watersheds in the Eastern Caribbean island of St Lucia, under contrasting land management regimes. The data generated from these watersheds revealed that the soil losses from an intensively cultivated agricultural watershed were 20‐times higher in magnitude than that of a forested watershed both for peak rainfall event and for total duration of analysis. This was due to higher surface runoff rates and exposure of soil to direct raindrop impact within cultivated areas. Whereas the forest canopy cover in combination with higher infiltration capacities of the forested land reduced the erosive runoff from the forest watershed and thus the soil loss. Moreover, the energy intensities of large storms in excess of 40 mm were estimated and found to range between 400 MJ mm ha−1 h−1 and 1834 MJ mm ha−1 h−1. 1 1 Megajoules‐millimeters per hectare‐hour. Soil loss from the agricultural watershed was strongly correlated (R2 = 0·85) to storm energy‐intensity (EI30). However, the correlation of soil loss with the EI30 (R2 = 0·71) was poor for the forest watershed due to the effect of canopy vegetation, which significantly reduced the energy of raindrop impact. Over the study period, cumulative soil losses were 10·0 t ha−1 for the agricultural site and 0·5 t ha−1 for the forest site. 2 2 Metric tons per hectare. The largest storm observed during the study period resulted in erosion losses of 3·78 t ha−1 and 0·2 t ha−1 from the agricultural and forest sites respectively. The regression models were developed using the measured data for prediction of runoff and soil loss over the watersheds of St Lucia under similar conditions. This study contributed towards efficient watershed management planning and implementation of suitable water conservation measures in St Lucia. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
12.
Predicting runoff from semi-arid hillslopes as source areas for water harvesting in the Sierra de Gador, southeast Spain 总被引：2，自引：0，他引：2
The effectiveness of water harvesting systems collecting surface runoff form rangeland hillslopes in semi-arid regions is difficult to predict, since the hydrological response at the outlet depends on the heterogeneity of hydrological processes. The lack of continuous runoff pathways, due to the irregular spatial patterns of soil properties and the variety of antecedent soil moisture conditions directly influence runoff generation and control discharge into the water harvesting cisterns. The aim of this paper is to evaluate the effectiveness of semi-arid hillslopes in generating runoff for water harvesting systems. Runoff was estimated by the STREAM expert-based model which was applied to three semi-arid hillslopes (0.4 to 6 ha). On the one hand the STREAM model rules were adapted to the regional conditions i.e. an antecedent precipitation index was adjusted to local soil moisture conditions and the rainfall duration was defined as the total rainfall event quantity and the effective rainfall duration (Ptot/teff). On the other hand, the distribution of rock outcrop and vegetation cover along the slopes was used to define homogeneous hydrological units. Final infiltration capacities were attributed to these hydrological units based on values found in the literature. The prediction performances are acceptable for the three water harvesting systems with an RMSE of 13.9 m3. It was shown that the rainfall/runoff model was more sensitive to the duration of the storm than to the antecedent soil moisture conditions. The use of a unique set of hydrological parameters for the three water harvesting systems on representative hillslopes allows the runoff prediction from any rangeland hillslope within the same region. Furthermore, the spatial patterns of soil surface characteristics are crucial for collecting runoff at the outlet of the system. Model runs demonstrated that degradation of vegetation and sealing of very small areas within flow paths can lead to an increase of annual runoff by as much as a factor two. 相似文献
13.
Masahiro Sakata Tomoharu Takagi Satoshi Mitsunobu 《Water, air, and soil pollution》2010,213(1-4):363-373
The loads and sources of heavy metals (Cd, Co, Cu, Mn, Mo, Ni, Pb, V, and Zn) in the midstream of Tama River were evaluated on the basis of their chemical analyses in ordinary and stormwater runoff from July 2007 to November 2008. Tama River is one of the three major rivers flowing into Tokyo Bay. The total annual water discharges differed largely for 2007 and 2008, depending on the scales of typhoon rainfalls and other heavy rainfalls in each year. The concentrations of the metals other than Mo in the river did not change markedly at a flow rate of less than approximately 200 m3 s?1, but at higher flow rates, the concentrations of all the metals increased linearly with the increase in the log of flow rate (r 2?=?0.94–0.99). The annual loads of heavy metals for 2007 and 2008 were estimated using regression equations between the above parameters and the hourly flow rate data for each year. For the metals other than Mo, the contribution of the loads at higher flow rates (>200 m3 s?1) was much larger than that at lower flow rates (<200 m3 s?1), showing the importance of the particulate loads (primarily crustal materials) during storm runoff following typhoon rainfalls and other heavy rainfalls. In contrast, the loads of Mo at lower flow rates accounted for major portions (56–78%) of the total loads, because of a relatively small contribution of particulate load during storm runoff. The contribution of the loads of Mo, Zn, Cd, Cu, and Ni at lower flow rates to the annual loads was larger than that of other metals. It was found that the concentrations of these metals in ordinary runoff are strongly affected by the discharge of treated water from sewage treatment plants which are located along the catchment. Thus, treated water from sewage treatment plants may be the primary source contributing to the present pollution of Mo, Zn, Cd, Cu, and Ni in Tokyo Bay. 相似文献
14.
Purpose
The trends in runoff and sediment transportation in typical Loess Plateau basins and the factors causing the changes need to be clarified.
Materials and methodsIn this study, the runoff and sediment transportation data from 1960 to 2016, from hydrological stations (Wenjiachuan, Baijiachuan, Ganguyi, and Zhuangtou) based in four typical basins, were analyzed systematically using linear regression, anomaly accumulation, the Mann–Kendall test, and double accumulation curve. The characteristics of the runoff and sediment transportation and their responses to climatic and anthropogenic activities were investigated using several hydrological analytical and statistical methods.
Results and discussionThe results indicate that both runoff and sediment transportation in the four typical basins have decreased sharply from 1960 to 2016. Since the implementation of the Grain-for-Green Project in 1999, the reduction has been more marked, in particular the runoff and sediment discharge of the Kuye River (Wenjiachuan station). Compared with the period 1960–1999, the average annual runoff and sediment discharge in 2000–2016 had decreased by 76.72% and 94.50%, respectively. Apart from the Wuding River (Baijiachuan station), an abrupt change in runoff and sediment transportation in the basins occurred within 2–7 years of the implementation of the Grain-for-Green Project.
ConclusionsIn general, returning farmland to forests (grass) has had a more pronounced effect on the reduction of runoff and sediment in the more northerly Kuye River (Wenjiachuan station) and Wuding River (Baijiachuan station) basins, compared with the more southerly Yanhe River (Ganguyi station) and Beiluo River (Zhuangtou station) basins.
相似文献15.
Runoff and soil loss from bench terraces. 1. An event-based model of rainfall infiltration and surface runoff 总被引：2，自引：0，他引：2
Overland flow resulting from an excess of rain over infiltration is an essential component of many models of runoff and erosion from fields or catchments. The spatially variable infiltration (SVI) model and a set of associated equations relating depth of runoff and maximum rate of ‘effective’ runoff (as used in the GUEST erosion model) to storm depth, depth‐averaged intensity of rainfall, average maximum infiltration capacity and an additional amount of initial infiltration were validated and tested on back‐sloping bench terraces in volcanic upland West Java, Indonesia. Data used were runoff rate and depth from 31 small (1.0–8.2 m2) bounded plots representing sections of terrace beds or risers and from six larger (53–231 m2) terrace units with hydrologically defined boundaries. Modelled runoff rates using rainfall intensity data corresponded well with observed patterns and the storm‐based equations were used successfully to model runoff depths and maximum effective runoff rates for individual events. Resulting values for maximum average infiltration rate (Im) varied between 18 and 443 mm hour?1 and reflected effects of vegetation or mulch cover and soil compaction. We conclude that the SVI model and the derived equations provide a robust and accurate method for predicting runoff at the investigated scale. 相似文献
16.
Longxi Cao Keli Zhang Hailun Dai Yin Liang 《Land Degradation \u0026amp; Development》2015,26(8):825-832
Unpaved roads play an important role in soil loss in small watersheds. In order to assess the impact of these unpaved roads in the Loess Plateau of China, runoff and sediment yields from road‐related sources must be quantified. Field rainfall simulation experiments were conducted under three slope gradients and five rainfall intensities on unpaved loess roads in a small watershed. Results showed that the runoff generation was very fast in loess road surface (time to runoff < 1 min) and produced a high runoff coefficient (mean value > 0·8). Soil loss rates were decreased as surface loose materials were washed away during a rainstorm. Rainfall intensity, initial soil moisture, and slope gradient are key factors to model surface runoff and sediment yield. Soil loss on loess road surface could be estimated by a linear function of stream power (R2 = 0·907). Four commonly interrill erosion models were evaluated and compared, and the interrill erodibility adopted in the Water Erosion Prediction Project model was determined as 1·34 × 106 (kg s m−4). A new equation taking into account different parameters like rainfall intensity, surface flow discharge, and slope gradient was established. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
17.
汾河上游流域分布式水文模型的构建 总被引：2，自引：0，他引：2
根据汾河上游流域的水文特性,采用以坡度、坡向为主要因素,按照集水区自然分水线划分子流域的流域离散方法,将SCS产、汇流模型与马斯京根法结合用于计算该地区的径流过程,建立了适于该地区,基于流域尺度的次降雨-径流分布式水文模型.选用该地区的典型流域--岚河流域与分布式模型耦合,进行模拟.经实测资料与模拟结果的分析比较,结果表明,该模型具有一定的精度,径流量合格率及汇流合格率分别达到70%和80%,且计算流量过程与实测流量过程吻合较好,所建模型基本适用于该地区的降雨一径流计算. 相似文献
18.
黄龙山区不同类型小流域的产流过程及其特征 总被引：1，自引：1，他引：1
在黄龙山区选择自然条件基本相似的森林小流域、森林采伐小流域和荒坡草灌小流域,利用量水堰,于1999—2003年对流域的产流及其过程进行了系统的研究。结果表明:不同类型小流域径流的年际和年内变化不同。森林小流域全年产流,产流量主要与降水量有关;荒坡草灌小流域则仅在暴雨季节产流,产流量主要与雨强有关。除发生特大暴雨年份外,森林小流域的产流量均超过荒坡草灌小流域,5年内平均前者比后者多3倍。不同类型小流域对降水的调节作用不同,5年平均森林小流域比荒坡草灌小流域减少洪水径流94.9%,达5.2mm,增加枯水期径流0.5mm,占年径流量的8.7%,从而使流域径流保持相对均匀和稳定。采伐森林可以改变小流域的径流分布,常年径流被暴雨径流所代替,但其量比荒坡草灌小流域少。不同类型小流域产流过程不同,森林小流域产流过程平缓,洪水起伏程度小;而荒坡草灌小流域产流曲线陡峭,洪峰形成迅速,回落也较快。 相似文献
19.
Cassandre R. Stirpe Mary Ann Cunningham Kirsten M. Menking 《Water, air, and soil pollution》2017,228(9):362
Salt applied to roads for de-icing can persist for decades in watersheds, and understanding rates of salt accumulation and export is important for anticipating the magnitude and duration of its environmental impacts. Salt removal is affected by storm frequency and intensity, both of which are projected to change as a result of anthropogenic climate change. To examine the potential outcomes of changing storm regimes on rates of salt export from watersheds, we studied chloride concentrations in baseflow and surface runoff in 5 years of streamflow data (taken at 20-min intervals) in a headwater tributary of the Hudson River. Baseflow, with chloride concentrations of 200–230 mg/L year-round, dominated streamflow, except during and after large storms, and accounted for about 90% of chloride export from the watershed. Extreme precipitation events (e.g., tropical storms) increased salt export mainly by increasing baseflow discharge, which remained elevated long after storms ended. While intense events accomplished more salt export per storm, they did not produce disproportionately higher export per volume of precipitation, compared to smaller rain events. Chloride export in a wet year was almost twice that in a dry year, despite less than a doubling of rainfall. Under future climate conditions, if winter precipitation shifts toward a higher proportion of rainfall, or summers experience a greater frequency of tropical storms, then long-term residence time of road salt in watersheds may be shorter than previously anticipated. Conversely, if climate becomes drier, with increased evapotranspiration, reduced infiltration and baseflow discharge may prolong salt storage, which could exacerbate biotic stresses from high chloride concentrations in streams. 相似文献
20.
Pedro Henrique Augusto Medeiros José Carlos de Araújo 《Journal of Soils and Sediments》2014,14(7):1216-1223