The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Paolo Porto - One of the best experts on this subject based on the ideXlab platform.
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use of a 137cs re sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern italy
Journal of Environmental Radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly Cs-137, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the Cs-137 re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedur for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates. (C) 2014 Published by Elsevier Ltd.
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Use of a 137Cs re-sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern Italy
Journal of environmental radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly (137)Cs, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the (137)Cs re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedure for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates.
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Using caesium-137 and unsupported lead-210 measurements to explore the relationship between Sediment Mobilisation, Sediment delivery and Sediment yield for a Calabrian catchment
Marine and Freshwater Research, 2009Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, A. CapraAbstract:Recent concern about the many environmental problems associated with the transport of fine Sediment by rivers has generated a need to obtain spatially distributed evidence of the erosion rates operating within a catchment and to explore more explicitly the links between Sediment Mobilisation, transfer, storage and output. In the past few decades, the fallout radionuclides caesium-137 (137Cs) and unsupported lead-210 (210Pbex) have been successfully used as tracers to estimate soil erosion and deposition rates in many areas of the world. However, to date, most studies using this approach have focussed on relatively small areas, such as individual fields or small catchments. There is a need to explore the potential for upscaling the approach to larger areas or catchments. The present paper reports an attempt to use the fallout radionuclides 137Cs and 210Pbex to explore further the relationship between Sediment Mobilisation, Sediment transfer and storage, and Sediment yield for a medium-scale (31.61 km2) catchment located in Calabria, southern Italy. The results emphasise that the low value of specific Sediment yield derived for the study catchment from measurements of the suspended Sediment flux at the catchment outlet obscure the existence of appreciable erosion rates in many areas of the catchment. Much of this erosion is balanced by deposition and Sediment storage, resulting in a relatively low Sediment delivery ratio for the catchment.
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Investigating the effects of afforestation on soil erosion and Sediment Mobilisation in two small catchments in Southern Italy
CATENA, 2009Co-Authors: Paolo Porto, Des E Walling, Giovanni CallegariAbstract:Abstract Annual soil losses in southern Italy can exceed 100–150 t ha− 1 year− 1. Where erosion on agricultural land is particularly severe, land use change and afforestation are frequently seen as the most appropriate means of reducing erosion risk. However, the overall effectiveness of afforestation in reducing soil erosion remains uncertain, due to the poor development of the forest cover in some areas, leading to significant areas with sparse tree cover, and the erosional impact of forest harvesting, which commonly involves clearcutting. The study reported here addresses this uncertainty and focuses on two small catchments (W2 and W3) located in Calabria, southern Italy, for which measurements of suspended Sediment yield are available. Both the catchments originally supported a rangeland vegetation cover and they were planted with eucalyptus trees in 1968. Currently, only catchment W3 supports a continuous forest cover. In catchment W2 the forest cover is discontinuous and there is a significant area of the catchment (ca. 20%) where the tree cover is sparse and the vegetation cover is dominated by natural grasses. Two additional erosion plots were established within catchment W2 in 1991, in order to explore the effect of the density of the tree cover on soil erosion. Information on the Sediment yields from the two catchments and the plots for 10 storm events that occurred during the period December 2005–December 2006 and associated information on the 137Cs and excess 210Pb of the Sediment, have been used to investigate the effectiveness of afforestation in reducing Sediment Mobilisation and net soil loss from the catchments involved. The results demonstrate that the areas of greatest soil loss are associated with the slopes where the tree cover is discontinuous, and that forest harvesting by clearcutting causes significant short-term increases in Sediment Mobilisation and Sediment yield. These findings, which are consistent with previous work undertaken within the same area, emphasize the importance of vegetation cover density in influencing rates of soil loss in the study catchments. The study also provided a useful demonstration of the potential for using measurements of the 137Cs and 210Pbex content of Sediment, in combination with more traditional Sediment monitoring, to investigate Sediment sources and to compare the Sediment dynamics of catchments subjected to different land management practices.
Giovanni Callegari - One of the best experts on this subject based on the ideXlab platform.
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use of a 137cs re sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern italy
Journal of Environmental Radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly Cs-137, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the Cs-137 re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedur for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates. (C) 2014 Published by Elsevier Ltd.
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Use of a 137Cs re-sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern Italy
Journal of environmental radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly (137)Cs, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the (137)Cs re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedure for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates.
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Using caesium-137 and unsupported lead-210 measurements to explore the relationship between Sediment Mobilisation, Sediment delivery and Sediment yield for a Calabrian catchment
Marine and Freshwater Research, 2009Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, A. CapraAbstract:Recent concern about the many environmental problems associated with the transport of fine Sediment by rivers has generated a need to obtain spatially distributed evidence of the erosion rates operating within a catchment and to explore more explicitly the links between Sediment Mobilisation, transfer, storage and output. In the past few decades, the fallout radionuclides caesium-137 (137Cs) and unsupported lead-210 (210Pbex) have been successfully used as tracers to estimate soil erosion and deposition rates in many areas of the world. However, to date, most studies using this approach have focussed on relatively small areas, such as individual fields or small catchments. There is a need to explore the potential for upscaling the approach to larger areas or catchments. The present paper reports an attempt to use the fallout radionuclides 137Cs and 210Pbex to explore further the relationship between Sediment Mobilisation, Sediment transfer and storage, and Sediment yield for a medium-scale (31.61 km2) catchment located in Calabria, southern Italy. The results emphasise that the low value of specific Sediment yield derived for the study catchment from measurements of the suspended Sediment flux at the catchment outlet obscure the existence of appreciable erosion rates in many areas of the catchment. Much of this erosion is balanced by deposition and Sediment storage, resulting in a relatively low Sediment delivery ratio for the catchment.
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Investigating the effects of afforestation on soil erosion and Sediment Mobilisation in two small catchments in Southern Italy
CATENA, 2009Co-Authors: Paolo Porto, Des E Walling, Giovanni CallegariAbstract:Abstract Annual soil losses in southern Italy can exceed 100–150 t ha− 1 year− 1. Where erosion on agricultural land is particularly severe, land use change and afforestation are frequently seen as the most appropriate means of reducing erosion risk. However, the overall effectiveness of afforestation in reducing soil erosion remains uncertain, due to the poor development of the forest cover in some areas, leading to significant areas with sparse tree cover, and the erosional impact of forest harvesting, which commonly involves clearcutting. The study reported here addresses this uncertainty and focuses on two small catchments (W2 and W3) located in Calabria, southern Italy, for which measurements of suspended Sediment yield are available. Both the catchments originally supported a rangeland vegetation cover and they were planted with eucalyptus trees in 1968. Currently, only catchment W3 supports a continuous forest cover. In catchment W2 the forest cover is discontinuous and there is a significant area of the catchment (ca. 20%) where the tree cover is sparse and the vegetation cover is dominated by natural grasses. Two additional erosion plots were established within catchment W2 in 1991, in order to explore the effect of the density of the tree cover on soil erosion. Information on the Sediment yields from the two catchments and the plots for 10 storm events that occurred during the period December 2005–December 2006 and associated information on the 137Cs and excess 210Pb of the Sediment, have been used to investigate the effectiveness of afforestation in reducing Sediment Mobilisation and net soil loss from the catchments involved. The results demonstrate that the areas of greatest soil loss are associated with the slopes where the tree cover is discontinuous, and that forest harvesting by clearcutting causes significant short-term increases in Sediment Mobilisation and Sediment yield. These findings, which are consistent with previous work undertaken within the same area, emphasize the importance of vegetation cover density in influencing rates of soil loss in the study catchments. The study also provided a useful demonstration of the potential for using measurements of the 137Cs and 210Pbex content of Sediment, in combination with more traditional Sediment monitoring, to investigate Sediment sources and to compare the Sediment dynamics of catchments subjected to different land management practices.
Des E Walling - One of the best experts on this subject based on the ideXlab platform.
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use of a 137cs re sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern italy
Journal of Environmental Radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly Cs-137, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the Cs-137 re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedur for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates. (C) 2014 Published by Elsevier Ltd.
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Use of a 137Cs re-sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern Italy
Journal of environmental radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly (137)Cs, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the (137)Cs re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedure for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates.
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Investigating the effects of afforestation on soil erosion and Sediment Mobilisation in two small catchments in Southern Italy
CATENA, 2009Co-Authors: Paolo Porto, Des E Walling, Giovanni CallegariAbstract:Abstract Annual soil losses in southern Italy can exceed 100–150 t ha− 1 year− 1. Where erosion on agricultural land is particularly severe, land use change and afforestation are frequently seen as the most appropriate means of reducing erosion risk. However, the overall effectiveness of afforestation in reducing soil erosion remains uncertain, due to the poor development of the forest cover in some areas, leading to significant areas with sparse tree cover, and the erosional impact of forest harvesting, which commonly involves clearcutting. The study reported here addresses this uncertainty and focuses on two small catchments (W2 and W3) located in Calabria, southern Italy, for which measurements of suspended Sediment yield are available. Both the catchments originally supported a rangeland vegetation cover and they were planted with eucalyptus trees in 1968. Currently, only catchment W3 supports a continuous forest cover. In catchment W2 the forest cover is discontinuous and there is a significant area of the catchment (ca. 20%) where the tree cover is sparse and the vegetation cover is dominated by natural grasses. Two additional erosion plots were established within catchment W2 in 1991, in order to explore the effect of the density of the tree cover on soil erosion. Information on the Sediment yields from the two catchments and the plots for 10 storm events that occurred during the period December 2005–December 2006 and associated information on the 137Cs and excess 210Pb of the Sediment, have been used to investigate the effectiveness of afforestation in reducing Sediment Mobilisation and net soil loss from the catchments involved. The results demonstrate that the areas of greatest soil loss are associated with the slopes where the tree cover is discontinuous, and that forest harvesting by clearcutting causes significant short-term increases in Sediment Mobilisation and Sediment yield. These findings, which are consistent with previous work undertaken within the same area, emphasize the importance of vegetation cover density in influencing rates of soil loss in the study catchments. The study also provided a useful demonstration of the potential for using measurements of the 137Cs and 210Pbex content of Sediment, in combination with more traditional Sediment monitoring, to investigate Sediment sources and to compare the Sediment dynamics of catchments subjected to different land management practices.
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Using caesium-137 and unsupported lead-210 measurements to explore the relationship between Sediment Mobilisation, Sediment delivery and Sediment yield for a Calabrian catchment
Marine and Freshwater Research, 2009Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, A. CapraAbstract:Recent concern about the many environmental problems associated with the transport of fine Sediment by rivers has generated a need to obtain spatially distributed evidence of the erosion rates operating within a catchment and to explore more explicitly the links between Sediment Mobilisation, transfer, storage and output. In the past few decades, the fallout radionuclides caesium-137 (137Cs) and unsupported lead-210 (210Pbex) have been successfully used as tracers to estimate soil erosion and deposition rates in many areas of the world. However, to date, most studies using this approach have focussed on relatively small areas, such as individual fields or small catchments. There is a need to explore the potential for upscaling the approach to larger areas or catchments. The present paper reports an attempt to use the fallout radionuclides 137Cs and 210Pbex to explore further the relationship between Sediment Mobilisation, Sediment transfer and storage, and Sediment yield for a medium-scale (31.61 km2) catchment located in Calabria, southern Italy. The results emphasise that the low value of specific Sediment yield derived for the study catchment from measurements of the suspended Sediment flux at the catchment outlet obscure the existence of appreciable erosion rates in many areas of the catchment. Much of this erosion is balanced by deposition and Sediment storage, resulting in a relatively low Sediment delivery ratio for the catchment.
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using environmental radionuclides to trace Sediment Mobilisation and delivery in river basins as an aid to catchment management
2004Co-Authors: Des E WallingAbstract:Although Sediment problems have long been recognised in those areas of the world with high rates of soil loss and high specific Sediment yields, recent years have seen a growing recognition of the wider significance of fine Sediment as an environmental problem. This has resulted in a growing need to incorporate Sediment control strategies into catchment management programmes. The design of effective Sediment control strategies is, however, heavily dependent upon a sound understanding and knowledge of Sediment Mobilisation and delivery within the catchment system and thus the overall Sediment budget. Traditional monitoring techniques are generally unable to provide information on the internal functioning of the Sediment budget. Against this background, there is a need for new approaches to data collection and tracing techniques are being increasingly used. Environmental radionuclides provide a particularly useful tool for tracing Sediment Mobilisation and delivery and this paper provides further information on the basis for their use and on their potential applications. Selected examples of their application to documenting rates of soil loss and Sediment delivery from cultivated fields, Sediment source tracing, and documenting rates of floodplain Sedimentation and longer-term changes in suspended Sediment properties are provided.
Juan Albaladejo - One of the best experts on this subject based on the ideXlab platform.
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Relations between interrill erosion processes and Sediment particle size distribution in a semiarid Mediterranean area of SE of Spain
Geomorphology, 2002Co-Authors: M Martı́nez-mena, Victor Castillo, Juan AlbaladejoAbstract:Erosion and Sediment characteristics were measured using simulated rainfall on two cultivated soils of contrasting lithology (Quaternary calcareous colluvium and Tertiary marls) in a semiarid Mediterranean area of SE Spain. Two rainfall intensities, high (56.0±2.4 mm h−1) and medium (31.4±1.4 mm h−1), were used in order to know the mechanisms involved in each selected condition. For each simulated event, runoff and Sediment were sampled at 1-min intervals on a 1-m wide by 2-m long erosion plot. The erosion rate was calculated as the total amount of soil lost divided by the time period of the test. The duration of the test was that needed to reach steady state runoff, an average time of 24.5 min for Quaternary calcareous colluvium and 17.7 min for Tertiary marls. The size distribution of the transported Sediment in the field (effective size distribution) was compared with equivalent measurements of the same samples after chemical and mechanical dispersion (ultimate size distribution) to investigate the detachment and transport mechanisms involved in Sediment Mobilisation. The results showed that the soil type determined the hydrological response, regardless of the rainfall intensity. The erosional response was, however, determined by the rainfall and soil surface characteristics.\ud \ud In Quaternary calcareous colluvial soils, the predominant erosion process depended on the rainfall intensity, with a prevailing detachment-limited condition in high-intensity events and prevailing transport-limited conditions in those events of medium intensity. These differences in the main erosion processes were reflected in the size of the transported material and in the change in Sediment size within the storm. Thus, a time-dependent size distribution of the eroded material (decreasing coarse fractions and increasing fine fractions with runoff time) was observed for high-intensity events. In medium-intensity events, on the other hand, the time-independent size distribution of the eroded material indicated transport-limited erosion.\ud \ud Due to the rapid surface crusting on the Tertiary marl soil, no differences in the main erosion processes or in the Sediment size distribution occurred for the different rainfall intensities tested. The erosion of marl soils was determined mainly by the limited quantity of available Sediment.\ud \ud The effective size of material was a more sensitive parameter than the ultimate size of the Sediment to study the way in which the Sediment was transported.This research was supported by the EC Environment and Climate Research Programme (Contract no. ENV4-CT97-0687).Peer reviewe
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Relations between interrill erosion processes and Sediment particle size distribution in a semiarid Mediterranean area of SE of Spain
Geomorphology, 2001Co-Authors: María Martínez-mena, Victor Castillo, Juan AlbaladejoAbstract:Abstract Erosion and Sediment characteristics were measured using simulated rainfall on two cultivated soils of contrasting lithology (Quaternary calcareous colluvium and Tertiary marls) in a semiarid Mediterranean area of SE Spain. Two rainfall intensities, high (56.0±2.4 mm h −1 ) and medium (31.4±1.4 mm h −1 ), were used in order to know the mechanisms involved in each selected condition. For each simulated event, runoff and Sediment were sampled at 1-min intervals on a 1-m wide by 2-m long erosion plot. The erosion rate was calculated as the total amount of soil lost divided by the time period of the test. The duration of the test was that needed to reach steady state runoff, an average time of 24.5 min for Quaternary calcareous colluvium and 17.7 min for Tertiary marls. The size distribution of the transported Sediment in the field (effective size distribution) was compared with equivalent measurements of the same samples after chemical and mechanical dispersion (ultimate size distribution) to investigate the detachment and transport mechanisms involved in Sediment Mobilisation. The results showed that the soil type determined the hydrological response, regardless of the rainfall intensity. The erosional response was, however, determined by the rainfall and soil surface characteristics. In Quaternary calcareous colluvial soils, the predominant erosion process depended on the rainfall intensity, with a prevailing detachment-limited condition in high-intensity events and prevailing transport-limited conditions in those events of medium intensity. These differences in the main erosion processes were reflected in the size of the transported material and in the change in Sediment size within the storm. Thus, a time-dependent size distribution of the eroded material (decreasing coarse fractions and increasing fine fractions with runoff time) was observed for high-intensity events. In medium-intensity events, on the other hand, the time-independent size distribution of the eroded material indicated transport-limited erosion. Due to the rapid surface crusting on the Tertiary marl soil, no differences in the main erosion processes or in the Sediment size distribution occurred for the different rainfall intensities tested. The erosion of marl soils was determined mainly by the limited quantity of available Sediment. The effective size of material was a more sensitive parameter than the ultimate size of the Sediment to study the way in which the Sediment was transported.
Markus Zehringer - One of the best experts on this subject based on the ideXlab platform.
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use of a 137cs re sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern italy
Journal of Environmental Radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly Cs-137, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the Cs-137 re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedur for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates. (C) 2014 Published by Elsevier Ltd.
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Use of a 137Cs re-sampling technique to investigate temporal changes in soil erosion and Sediment Mobilisation for a small forested catchment in southern Italy
Journal of environmental radioactivity, 2014Co-Authors: Paolo Porto, Des E Walling, Giovanni Callegari, Christine Alewell, Lionel Mabit, Nicola Mallimo, Katrin Meusburger, Markus ZehringerAbstract:Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly (137)Cs, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954-1998 with that for the period 1999-2013. The availability of measurements of Sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the (137)Cs re-sampling study with the estimates of Sediment yield for the same periods. In order to compare the estimates of soil loss and Sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedure for such calculations, key factors influencing the uncertainty of the estimates were identified and a procedure developed. The results of the study demonstrated that there had been no significant change in mean annual soil loss in recent years and this was consistent with the information provided by the estimates of Sediment yield from the catchment for the same periods. The study demonstrates the potential for using a re-sampling technique to document recent changes in soil redistribution rates.