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1.
Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of China. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest China, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors, i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large ar- eas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 28.12%, a base flow decline of 35.32%, a drop in the maximum peak discharge of 35.77%, and mean discharge decreases in spring and autumn of 36.05% and 24.87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73%-81%, and that to the influence of base flow reaching 62%-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water resources and the proper development of the entire catchment.  相似文献   

2.
Changes in climate and land use can significantly influence the hydrological cycle and hence affect water resources. Understanding the impacts of climate and land‐use changes on streamflow can facilitate development of sustainable water resources strategies. This study investigates the flow variation of the Zamu River, an inland river in the arid area of northwest China, using the Soil and Water Assessment Tool distributed hydrological model. Three different land‐use and climate‐change scenarios were considered on the basis of measured climate data and land‐use cover, and then these data were input into the hydrological model. Based on the sensitivity analysis, model calibration and verification, the hydrological response to different land‐use and climate‐change scenarios was simulated. The results indicate that the runoff varied with different land‐use type, and the runoff of the mountain reaches of the catchment increased when grassland area increased and forestland decreased. The simulated runoff increased with increased precipitation, but the mean temperature increase decreased the runoff under the same precipitation condition. Application of grey correlation analysis showed that precipitation and temperature play a critical role in the runoff of the Zamu River basin. Sensitivity analysis of runoff to precipitation and temperature by considering the 1990s land use and climate conditions was also undertaken. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

3.
ABSTRACT

Climate change alters hydrological processes and results in more extreme hydrological events, e.g. flooding and drought, which threaten human livelihoods. In this study, the large-scale distributed variable infiltration capacity (VIC) model was used to simulate future hydrological processes in the Yarlung Zangbo River basin (YZRB), China, with a combination of the CMIP5 (Coupled Model Intercomparison Project, fifth phase) and MIROC5 (Model for Interdisciplinary Research on Climate, fifth version) datasets. The results indicate that the performance of the VIC model is suitable for the case study, and the variation in runoff is remarkably consistent with that of precipitation, which exhibits a decreasing trend for the period 2046–2060 and an increasing trend for 2086–2100. The seasonality of runoff is evident, and substantial increases are projected for spring runoff, which might result from the increase in precipitation as well as the increase in the warming-induced melting of snow, glaciers and frozen soil. Moreover, evapotranspiration exhibits an increase between 2006–2020 and 2046–2060 over the entire basin, and soil moisture decreases in upstream areas and increases in midstream and downstream areas. For 2086–2100, both evapotranspiration and soil moisture increase slightly in the upstream and midstream areas and decrease slightly in the downstream area. The findings of this study could provide references for runoff forecasting and ecological protection for similar studies in the future.  相似文献   

4.
The effect of forests on annual water yield is an unresolved central issue in forest hydrology despite years of study. There has been a particular shortage of research in the mountains of arid inland river basins. In the present study, we examined the effects of forests on hydrology using data on precipitation, evaporation, canopy interception, transpiration, and runoff from 1994 to 2008 for the Pailugou catchment of northwestern China's Qilian Mountains. We modelled the water balance to assess the contribution of different vegetation types to annual water yield. In our study area, Picea crassifolia forest covered 38·5% of the catchment area, but contributed little to annual water yield. For an annual average precipitation of 407·1 mm (from 2003 to 2008) at an elevation of 2700 m, the runoff depth from the forest was 11·6 mm, accounting for only 3·5% of total annual water yield of the catchment. For an annual average precipitation of 374·1 mm (from 1994 to 2002), the runoff depth from the forest was ? 14·3 mm (i.e. 5·9% of total annual water yield of the catchment was consumed to sustain tree growth). This has significant implications, because forests are increasingly being planted in the Qilian Mountains, and this may decrease the downstream water supply. Thus, the relationship between the forest and water yield must be better understood to permit the establishment of an appropriate regional level of forest cover. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

5.
The assessment of surface water resources (SWRs) in the semi‐arid Yongding River Basin is vital as the basin has been in a continuous state of serious water shortage over the last 20 years. In this study, the first version of the geomorphology‐based hydrological model (GBHM) has been applied to the basin over a long period of time (1956–2000) as part of an SWR assessment. This was done by simulating the natural hydrological processes in the basin. The model was first evaluated at 18 stream gauges during the period from 1990 to 1992 to evaluate both the daily streamflows and the annual SWRs using the land use data for 1990. The model was further validated in 2000 with the annual SWRs at seven major stream gauges. Second, the verified model was used in a 45‐year simulation to estimate the annual SWRs for the basin from 1956 to 2000 using the 1990 land use data. An empirical correlation between the annual precipitation and the annual SWRs was developed for the basin. Spatial distribution of the long‐term mean runoff coefficients for all 177 sub‐basins was also achieved. Third, an additional 10‐year (1991–2000) simulation was performed with the 2000 land use data to investigate the impact of land use changes from 1990 to 2000 on the long‐term annual SWRs. The results suggest that the 10‐year land use changes have led to a decrease of 8·3 × 107 m3 (7·9% of total) for the 10‐year mean annual SWRs in the simulation. To our knowledge, this work is the first attempt to assess the long‐term SWRs and the impact of land use change in the semi‐arid Yongding River Basin using a semi‐distributed hillslope hydrological model. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

6.
Understanding the mechanisms of river runoff variation is important for the effective management of water resources in arid and semi‐arid regions. This study uses long‐term observational data as a basis for examining the effects of human activities and climate change on the runoff variation of Jinghe River Basin, a typical arid inland basin in northwest China. A distributed hydrological model called the Soil and Water Assessment Tool, combined with a sequential cluster method and a separation approach, was used to quantify and distinguish the effects of human activities and climate change on runoff. The hydrological sequence before 1981 can be considered natural. However, human activities have significantly affected runoff since 1981. The runoff reduction caused by human activities between 1981 and 2008 accounted for 85.7% of the total reduction in the downstream of Jinghe River, whereas that caused by climatic variation was only 14.3%. This observation suggests that human activities are the major driver of runoff variation in the basin. Although the role of climate change in driving runoff variation has been identified to be prevalent and dominant in arid regions, this study highlights the importance of human activities. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

7.
The upstream regions of the Three Gorges Reservoir (TGR) have undergone significant changes in land use during recent years, and these changes have strongly influenced runoff generation downstream. In this study, the relationships between land use changes and corresponding hydrological responses in the Dong and Puli River basins in the upstream region of the TGR were quantified using the runoff coefficient. Empirical regression equations between the runoff coefficient and the percentage of land use types were developed for the study area using partial least squares regression (PLSR). The Soil and Water Assessment Tool was used to simulate the runoff generation processes in the two basins, and land use maps developed using Landsat Thematic Mapper images from 2000, 2005, and 2010 were compared to extract information on changes in land use. The results showed that the total area of forest and pasture decreased over the 10‐year study period, while paddy fields and upland increased in both basins. These land use changes dramatically affected hydrological processes. Evapotranspiration decreased by 2.13% and 2.41% between 2000 and 2010 in the Dong and Puli River basins, respectively, whereas quickflow, infiltration, and baseflow increased to varying degrees. The PLSR modeling results showed that upland had a negative effect on the runoff coefficient and was the most influential land use type in the study area. In contrast, a positive effect of forest on runoff generation was found in most of the regression models. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

8.
The Dissolved Organic Carbon (DOC) content of rivers is the most significant part of the carbon cycle migration in the basin under consideration, and it is the basis for a comprehensive understanding of the regional carbon cycle. In this study, we periodically collected samples from four monitoring stations in the Xiying River Basin of the Qilian Mountains in the northern Qinghai-Tibet Plateau. We calculated the fluxes of organic carbon in the rivers within the study area and have discussed the influencing factors of DOC concentration in these rivers. The results showed that: (a) The DOC concentration and transport flux of the Xiying river showed significant seasonal changes. The DOC concentration during summer and autumn was higher than that in winter and spring, and the output flux in summer and autumn accounted for approximately 88.3% of the total annual output. (b) Precipitation runoff has a higher DOC concentration than meltwater runoff. Climate factors, river-water chemical characteristics, and seasonal frozen-soil changes in the river basin have significant effects on the river DOC concentration and transport flux. (c) Larger runoff causes higher DOC concentrations in rivers. Runoff is the primary means of carbon migration in the inland river basin. Carbon migration is significant from the upstream to the middle and downstream sections of the inland river basin.  相似文献   

9.
Climate changes brought on by increasing greenhouse gases in the atmosphere are expected to have a significant effect on the Pacific Northwest hydrology during the 21st century. Many climate model simulations project higher mean annual temperatures and temporal redistribution of precipitation. This is of particular concern for highly urbanized basins where runoff changes are more vulnerable to changes in climate. The Rock Creek basin, located in the Portland metropolitan area, has been experiencing rapid urban growth throughout the last 30 years, making it an ideal study area for assessing the effect of climate and land cover changes on runoff. A combination of climate change and land cover change scenarios for 2040 with the semi‐distributed AVSWAT (ArcView Soil and Water Assessment Tool) hydrological model was used to determine changes in mean runoff depths in the 2040s (2030–2059) from the baseline period (1973–2002) at the monthly, seasonal, and annual scales. Statistically downscaled climate change simulation results from the ECHAM5 general circulation model (GCM) found that the region would experience an increase of 1·2 °C in the average annual temperature and a 2% increase in average annual precipitation from the baseline period. AVSWAT simulation shows a 2·7% increase in mean annual runoff but a 1·6% decrease in summer runoff. Projected climate change plus low‐density, sprawled urban development for 2040 produced the greatest change to mean annual runoff depth (+5·5%), while climate change plus higher‐density urban development for 2040 resulted in the smallest change (+5·2%), when compared with the climate and land cover of the baseline period. This has significant implications for water resource managers attempting to implement adaptive water resource policies to future changes resulting from climate and urbanization. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

10.
The change of annual stream flow in the Shiyang river basin, a typical arid‐inland basin in north‐west China, was investigated using hydrological, meteorological and water‐related human activities' data of the past 50 years. The long‐term trends of the hydrological time series were examined by non‐parametric techniques, including the Pettitt and Mann–Kendall tests. Double cumulative curves and multi‐regression methods were used to separate and quantify the effects of climate changes and human activities on the stream flows. The results show that the study area has been experiencing a significant upward warming trend since 1986 and precipitation shows a decreasing trend in the mountainous region but an increasing trend in the plains region. All stream flows in the upper reach and lower reaches of the Shiyang river exhibit decreasing tendencies. Since 1970, human activities, such as irrigation, have had a significant effect on the upstream flow, and account for 60% of total flow decreases in the 1970s. However, climate changes are the main reason for the observed flow decreases in the 1980s and 1990s, with contributions to total flow decrease of 68% and 63%, respectively. Before 1975, flow decreases in the upper reaches were the main factor causing reduced flows in the lower reaches of the Shiyang river. After 1975, the effect of human activities became more pronounced, with contributions of 63%, 68% and 56% to total flow decreases in the lower reaches of the Shiyang river in the periods 1975 to 1980, 1980s and 1990s, respectively. As a result, climate change is responsible for a large proportion of the flow decreases in the upstream section of the catchment during the 1980s and 1990s, while human activities have caused flow decreases downstream during the same period. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

11.
The Ejina basin, which is located in arid and semi‐arid areas of northwest China, has experienced severe environmental deterioration in the past several decades, and an exploratory project was launched by the Chinese Government in 2001 to restore this degraded ecosystem. In this study, multi‐scale remotely sensed data and field investigations were used to quantify the responses of vegetation to the implementation of integrated water management under this project. In terms of the seasonal accumulated Normalized Difference Vegetation Index (SAN) variation, (1) the vegetation in 80·4% of the oasis regions showed an increasing or recovering trend, and increasing SAN trends with a magnitude greater than 0·14 a?1 mainly resulted from cultivated land reclamation; (2) the vegetation in 91·5% of the desert regions presented an increasing trend, and the statistically significant trends mainly appeared in the middle and lower Ejina basin; (3) the vegetation in 19·6% of oasis and 5·1% of desert regions showed a decreasing or degrading trend, mainly where rivers diminished and along artificial concrete canals; and (4) opposite signs of vegetation trends occurred simultaneously along some natural rivers experiencing water reduction, with a decreasing trend generally appearing in the high SAN regions, whereas an increasing trend was seen in the low SAN regions. The broad vegetation recovery observed was due to the comprehensive improvement of the water environment, which was attributed to both the increase in runoff entering the Ejina basin and the adoption of engineering measures. Vegetation degradation in the area mainly resulted from deterioration of the local water environment, which was closely related to the problems of water management. The results of this study can be used as a reference for adjusting the current water resource management strategy to effectively restore this ecosystem. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

12.
Data collected in 4 years of field observations were used in conjunction with continuous simulation models to study, at the small‐basin scale, the water balance of a closed catchment‐lake system in a semi‐arid Mediterranean environment. The open water evaporation was computed with the Penman equation, using the data set collected in the middle of the lake. The surface runoff was partly measured at the main tributary and partly simulated using a distributed, catchment, hydrological model, calibrated with the observed discharge. The simplified structure of the developed modelling mainly concerns soil moisture dynamics and bedrock hydraulics, whereas the flow components are physically based. The calibration produced high efficiency coefficients and showed that surface runoff is greatly affected by soil water percolation into fractured bedrock. The bedrock reduces the storm‐flow peaks and the interflow and has important multi‐year effects on the annual runoff coefficients. The net subsurface outflow from the lake was calculated as the residual of the lake water balance. It was almost constant in the dry seasons and increased in the wet seasons, because of the moistening of the unsaturated soil. During the years of observation, rainfall 30% higher than average caused abundant runoff and a continuous rise in the lake water levels. The analysis allows to predict that, in years with lower than the average rainfall, runoff will be drastically reduced and will not be able to compensate for negative balance between precipitation and lake evaporation. Such highly unsteady situations, with great fluctuations in lake levels, are typical of closed catchment‐lake systems in the semi‐arid Mediterranean environment. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

13.
The Yiluo River is the largest tributary for the middle and lower reaches of the Yellow River below Sanmenxia Dam. Changes of the hydrological processes in the Yiluo River basin, influenced by the climatic variability and human activities, can directly affect ecological integrity in the lower reach of the Yellow River. Understanding the impact of the climatic variability and human activities on the hydrological processes in the Yiluo River basin is especially important to maintain the ecosystem integrity and sustain the society development in the lower reach of the Yellow River basin. In this study, the temporal trends of annual precipitation, air temperature, reference evapotranspiration (ET0) and runoff during 1961–2000 in the Yiluo River basin were explored by the Mann‐Kendall method (M‐K method), Yamamoto method and linear fitted model. The impacts of the climatic variability and vegetation changes on the annual runoff were discussed by the empirical model and simple water balance model and their contribution to change of annual runoff have been estimated. Results indicated that (i) significant upwards trend for air temperature and significant downwards trend both for precipitation and ET0 were detected by the M‐K method at 95% confidence level. And the consistent trends were obtained by the linear fitted model; (ii) the abrupt change started from 1987 detected by the M‐K method and Yamamoto method, and so the annual runoff during 1961–2000 was divided into two periods: baseline period (1961–1986) and changeable period (1987–2000); and (iii) the vegetation changes were the main cause for change of annual runoff from baseline period to changeable period, and climatic variability contributed a little to the change of annual runoff of the Yiluo River. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

14.
Most studies on runoff and soil loss from olive orchards were performed on plots, despite the fact that measurements that examine a range of erosive processes on different scales are essential to evaluate the suitability of the use and soil management of this type of land. The main environmental limitations of much of the land used for olive orchards in the Mediterranean are the steep slopes and the shallow soil depth – and this was the case in the study area. Soil erosion and runoff over two hydrological years (2005–2006 and 2006–2007) were monitored in an olive orchard microcatchment of 6·1 ha under no‐tillage with spontaneous grass in order to evaluate its hydrological and erosive behaviour. Moreover, soil parameters such as organic matter (%OM), bulk density (BD) and hydraulic saturated conductivity (Ks) were also examined in the microcatchment to describe management effects on hydrological balance and on erosive processes. In the study period, the results showed runoff coefficients of 6·0% in the first year and 0·9% in the second. The differences respond to the impact of two or three yearly maximum events which were decisive in the annual balances. On the event scale, although maximum rainfall intensity values had a big influence on peak flows and runoff, its importance on mean sediment concentrations and sediment discharges was difficult to interpret due to the likely control of grass cover on volume runoff and on soil protection. In the case of annual soil erosion, they were measured as 1·0 Mg ha?1 yr?1 and 0·3 Mg ha?1 yr?1. Both are lower than the tolerance values evaluated in Andalusia (Spain). These results support the implementation of no‐tillage with spontaneous grass cover for sloping land, although the reduced infiltration conditions determined by Ks in the first horizon suggest grass should be allowed to grow not only in spring but also in autumn. In addition, specific measurements to control gullies, which have formed in the terraced area in the catchment, should be included since it is expected that they could be the main sources of sediments. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

15.
In semi‐arid environments, the characteristics of the land surface determine how rainfall is transformed into surface runoff and influences how this runoff moves from the hillslopes into river channels. Whether or not water reaches the river channel is determined by the hydrological connectivity. This paper uses a numerical experiment‐based approach to systematically assess the effects of slope length, gradient, flow path convergence, infiltration rates and vegetation patterns on the generation and connectivity of runoff. The experiments were performed with the Connectivity of Runoff Model, 2D version distributed, physically based, hydrological model. The experiments presented are set within a semi‐arid environment, characteristic of south‐eastern Spain, which is subject to low frequency high rainfall intensity storm events. As a result, the dominant hydrological processes are infiltration excess runoff generation and surface flow dynamics. The results from the modelling experiments demonstrate that three surface factors are important in determining the form of the discharge hydrograph: the slope length, the slope gradient and the infiltration characteristics at the hillslope‐channel connection. These factors are all related to the time required for generated runoff to reach an efficient flow channel, because once in this channel, the transmission losses significantly decrease. Because these factors are distributed across the landscape, they have a fundamental role in controlling the landscape hydrological response to storm events. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

16.
Understanding the impacts of land‐use changes on hydrology at the watershed scale can facilitate development of sustainable water resource strategies. This paper investigates the hydrological effects of land‐use change in Zanjanrood basin, Iran. The water balance was simulated using the Soil and Water Assessment Tool (AVSWAT2000). Model calibration and uncertainty analysis were performed with sequential uncertainty fitting (SUFI‐2). Simulation results from January 1998 to December 2002 were used for parameter calibration, and then the model was validated for the period of January 2003 to December 2004. The predicted monthly streamflow matched the observed values: during calibration the correlation coefficient was 0·86 and the Nash–Sutcliffe coefficient 0·79, compared with 0·80 and 0·79, respectively, during validation. The model was used to simulate the main components of the hydrological cycle, in order to study the effects of land‐use changes in 1967, 1994 and 2007. The study reveals that during 1967 a 34·5% decrease of grassland with concurrent increases of shrubland (13·9%), rain‐fed agriculture (12·1%), bare ground (5·5%) irrigated agriculture (2·2%), and urban area (0·7%) led to a 33% increase in the amount of surface runoff and a 22% decrease in the groundwater recharge. Furthermore, the area of sub‐basins that was influenced by high runoff (14–28 mm) increased. The results indicate that the hydrological response to overgrazing and the replacing of rangelands (grassland and shrubland) with rain‐fed agriculture and bare ground (badlands) is nonlinear and exhibits a threshold effect. The runoff rises dramatically when more than 60% of the rangeland is removed. For groundwater this threshold lies at an 80% decrease in rangeland. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

17.
The impacts of historical land cover changes witnessed between 1973 and 2000 on the hydrologic response of the Nyando River Basin were investigated. The land cover changes were obtained through consistent classifications of selected Landsat satellite images. Their effects on runoff peak discharges and volumes were subsequently assessed using selected hydrologic models for runoff generation and routing available within the HEC‐HMS. Physically based parameters of the models were estimated from the land cover change maps together with a digital elevation model and soil datasets of the basin. Observed storm events for the simulation were selected and their interpolated spatial distributions obtained using the univariate ordinary Kriging procedure. The simulated flows from the 14 sub‐catchments were routed downstream afterwards to obtain the accrued effects in the entire river basin. Model results obtained generally revealed significant and varying increases in the runoff peak discharges and volumes within the basin. In the upstream sub‐catchments with higher rates of deforestation, increases between 30 and 47% were observed in the peak discharge. In the entire basin, however, the flood peak discharges and volumes increased by at least 16 and 10% respectively during the entire study period. The study successfully outlined the hydrological consequences of the eminent land cover changes and hence the need for sustainable land use and catchment management strategies. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

18.
This study develops a novel approach for modelling and examining the impacts of time–space land‐use changes on hydrological components. The approach uses an empirical land‐use change allocation model (CLUE‐s) and a distributed hydrological model (DHSVM) to examine various land‐use change scenarios in the Wu‐Tu watershed in northern Taiwan. The study also uses a generalized likelihood uncertainty estimation approach to quantify the parameter uncertainty of the distributed hydrological model. The results indicate that various land‐use policies—such as no change, dynamic change and simultaneous change—have different levels of impact on simulating the spatial distributions of hydrological components in the watershed study. Peak flow rates under simultaneous and dynamic land‐use changes are 5·71% and 2·77%, respectively, greater than the rate under the no land‐use change scenario. Using dynamic land‐use changes to assess the effect of land‐use changes on hydrological components is more practical and feasible than using simultaneous land‐use change and no land‐use change scenarios. Furthermore, land‐use change is a spatial dynamic process that can lead to significant changes in the distributions of ground water and soil moisture. The spatial distributions of land‐use changes influence hydrological processes, such as the ground water level of whole areas, particularly in the downstream watershed. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

19.
The results of a hydrological analysis that was conducted as part of a larger, multifaceted, collaborative effort to quantify ecosystem functions in watersheds subjected to land‐use and land‐cover change are presented. The primary goal of the study was to determine whether a small watershed in the Appalachian region (USA) that was recently subjected to surface mining and reclamation practices produces stormflow responses to rain events that are different from those produced by a nearby reference watershed covered by young, second‐growth forest. Water balances indicated that runoff yields did not vary significantly between the two watersheds on an annual basis. Statistically significant differences (p?0·05) in runoff responses were observed on an event basis, however, with the mined/reclaimed watershed producing, on average (a) higher storm runoff coefficients (2·5×), (b) greater total storm runoff (3×), and (c) higher peak hourly runoff rates (2×) when compared with the reference watershed. Results of a unit hydrograph analysis also showed, unexpectedly, that the modelled unit responses of the two watersheds to effective rainfall pulses were similar, despite the noted differences in land cover. Differences in stormflow responses were thus largely explained by dramatic reductions in cumulative rates of rainfall abstraction (measured using infiltrometers) attributable to soil compaction during land reclamation. Additional field hydrological measurements on other mined watersheds will be needed to generalize our results, as well as to understand and predict the cumulative hydrological impacts of widespread surface mining in larger watersheds and river basins. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

20.
Wildfires change the infiltration properties of soil, reduce the amount of interception and result in increased runoff. A wildfire at Northeast Attica, Central Greece, in August 2009, destroyed approximately one third of a study area consisting of a mixture of shrublands, pastures and pines. The present study simultaneously models multiple semi‐arid, shrubland‐dominated Mediterranean catchments and assesses the hydrological response (mean annual and monthly runoff and runoff coefficients) during the first few years following wildfires. A physically based, hydrological model (MIKE SHE) was chosen. Calibration and validation results of mean monthly discharge presented very good agreement with the observed data for the pre‐wildfire and post‐wildfire period for two subcatchments (Nash–Sutcliffe Efficiency coefficient of 79.7%). The model was then used to assess the pre‐wildfire and post‐wildfire runoff responses for each of seven catchments in the study area. Mean annual surface runoff increased for the first year and after the second year following the wildfires increased by 112% and 166%, respectively. These values are within the range observed in similar cases of monitored sites. This modelling approach may provide a way of prioritizing catchment selection with respect to post‐fire remediation activities. Additionally, this modelling assessment methodology would be valuable to other semi‐arid areas because it provides an important means for comprehensively assessing post‐wildfire response over large regions and therefore attempts to address some of the scaled issues in the specific literature field of research. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

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