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Nikolaus J Kuhn - One of the best experts on this subject based on the ideXlab platform.
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does the invasive plant impatiens glandulifera promote soil erosion along the Riparian Zone an investigation on a small watercourse in northwest switzerland
Journal of Soils and Sediments, 2014Co-Authors: Philip Greenwood, Nikolaus J KuhnAbstract:Purpose The invasive plant, Impatiens glandulifera (common English name: Himalayan Balsam), is now found in many river catchments in most European countries. Its preference for damp, nutrient-rich soils, along with its intolerance to cold weather and rapid dieback, has implicated it in promoting soil erosion along the Riparian Zone. Despite the implication, its influence on the sediment dynamics of river systems remains unconfirmed. This communication reports the preliminary findings of ongoing work to investigate a possible link between I. glandulifera and accelerated erosion rates in inland river systems.
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does the invasive plant impatiens glandulifera promote soil erosion along the Riparian Zone an investigation on a small watercourse in northwest switzerland
Journal of Soils and Sediments, 2014Co-Authors: Philip Greenwood, Nikolaus J KuhnAbstract:The invasive plant, Impatiens glandulifera (common English name: Himalayan Balsam), is now found in many river catchments in most European countries. Its preference for damp, nutrient-rich soils, along with its intolerance to cold weather and rapid dieback, has implicated it in promoting soil erosion along the Riparian Zone. Despite the implication, its influence on the sediment dynamics of river systems remains unconfirmed. This communication reports the preliminary findings of ongoing work to investigate a possible link between I. glandulifera and accelerated erosion rates in inland river systems. Erosion pins, a micro-profile bridge, and a digital caliper were employed to measure changes in the soil surface profile (SSP) at six separate locations, each contaminated with I. glandulifera, along the Riparian Zone of a small watercourse in northwest Switzerland. Changes in SSP were also measured at an identical number of nearby locations supporting natural vegetation, in order to establish baseline erosion conditions. Soil surface profiles at all 12 locations were re-measured on seven separate occasions, from October 2012 to May 2013. This covers the time before dieback occurred to the germination and seasonal regrowth of new plants. A total of 720 individual SSP measurements were recorded during the above monitoring period. Increasingly negative values relative to initial values were documented at most transects, indicating a net reduction in soil surface elevations. This is interpreted as evidence of the removal (i.e., erosion) of surface material. Paired samples statistical analysis of the data indicate that erosion from contaminated sites was significantly greater than erosion from topographically comparable reference sites (t =−5.758; P < 0.05; N = 359) supporting natural vegetation. The results provide tentative yet compelling evidence that I. glandulifera promotes soil erosion along the Riparian Zone of the watercourse investigated. Given the unrelenting spread of this notoriously invasive plant throughout inland river systems in many countries, the likelihood of greater quantities of nutrient-rich sediment entering into aquatic environments may steadily reduce water quality in all affected catchments. An absence of effective control measures capable of halting or even slowing its rate of invasion may make it increasingly difficult for affected European Union member states to meet and then maintain key water quality standards set by the Water Framework Directive (WFD) when fully implemented in 2015.
Jan Seibert - One of the best experts on this subject based on the ideXlab platform.
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Riparian Zone hydrology and soil water total organic carbon toc implications for spatial variability and upscaling of lateral Riparian toc exports
Biogeosciences, 2012Co-Authors: Steve W Lyon, Thomas Grabs, Hjalmar Laudon, Kevin Bishop, Jan SeibertAbstract:Groundwater flowing from hillslopes through ri- parian (near-stream) soils often undergoes chemical transfor- mations that can substantially influence stream water chem- istry. We used landscape analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the Riparian Zone (RZ) of a 67 km 2 catchment in Sweden. TOC exported laterally from 13 Riparian soil profiles was then estimated based on the Riparian flow-concentration integration model (RIM). Much of the observed spatial vari- ability of Riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI). Organic Riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow condi- tions and changing soil water TOC concentrations. Mineral Riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and min- eral soils in RZs constitute a heterogeneous landscape mo- saic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable Riparian TOC concentration profiles for RZs underlain by glacial till.
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variability of groundwater levels and total organic carbon in the Riparian Zone of a boreal catchment
Journal of Geophysical Research, 2011Co-Authors: Steve W Lyon, Thomas Grabs, Hjalmar Laudon, Kevin Bishop, Jan SeibertAbstract:The Riparian Zone is a narrow corridor where hillslopes (and their associated hydrobiogeochemical processes) interface with the river system. As such, the Riparian Zone serves as the last piece of landscape with which water interacts as it transitions from being water flowing primarily through the landscape (i.e., shallow groundwater) to water flowing primarily on the landscape (i.e., stream water). This study investigates the spatiotemporal variability in Riparian-Zone soil water total organic carbon (TOC) and its relation to the shallow groundwater table using observations from the recently instrumented Riparian observatory in the Krycklan catchment study area located in boreal northern Sweden. In general, there is a decrease in TOC concentration with depth down through the soil profile. The rate of this decrease was variable among the six monthly samplings used in this study. The spatial variability of soil water TOC in the Riparian Zone was connected to the spatial variability of the shallow groundwater levels. This demonstrated the importance of the temporal variation of flow pathways and the mixing of waters from different sources of TOC moving into and through the Riparian Zone. The coupled variation of the hydrologic and biogeochemical systems raised questions about the ability of simple lumped approaches to accurately predict how in-stream TOC concentrations will change with climate and/or land use. The integrated sampling approach in the Riparian observatory covers both hydrologic and biogeochemical aspects of soil water TOC and provides a basis for development and testing of distributed, physically based transport models.
Philip Greenwood - One of the best experts on this subject based on the ideXlab platform.
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does the invasive plant impatiens glandulifera promote soil erosion along the Riparian Zone an investigation on a small watercourse in northwest switzerland
Journal of Soils and Sediments, 2014Co-Authors: Philip Greenwood, Nikolaus J KuhnAbstract:Purpose The invasive plant, Impatiens glandulifera (common English name: Himalayan Balsam), is now found in many river catchments in most European countries. Its preference for damp, nutrient-rich soils, along with its intolerance to cold weather and rapid dieback, has implicated it in promoting soil erosion along the Riparian Zone. Despite the implication, its influence on the sediment dynamics of river systems remains unconfirmed. This communication reports the preliminary findings of ongoing work to investigate a possible link between I. glandulifera and accelerated erosion rates in inland river systems.
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does the invasive plant impatiens glandulifera promote soil erosion along the Riparian Zone an investigation on a small watercourse in northwest switzerland
Journal of Soils and Sediments, 2014Co-Authors: Philip Greenwood, Nikolaus J KuhnAbstract:The invasive plant, Impatiens glandulifera (common English name: Himalayan Balsam), is now found in many river catchments in most European countries. Its preference for damp, nutrient-rich soils, along with its intolerance to cold weather and rapid dieback, has implicated it in promoting soil erosion along the Riparian Zone. Despite the implication, its influence on the sediment dynamics of river systems remains unconfirmed. This communication reports the preliminary findings of ongoing work to investigate a possible link between I. glandulifera and accelerated erosion rates in inland river systems. Erosion pins, a micro-profile bridge, and a digital caliper were employed to measure changes in the soil surface profile (SSP) at six separate locations, each contaminated with I. glandulifera, along the Riparian Zone of a small watercourse in northwest Switzerland. Changes in SSP were also measured at an identical number of nearby locations supporting natural vegetation, in order to establish baseline erosion conditions. Soil surface profiles at all 12 locations were re-measured on seven separate occasions, from October 2012 to May 2013. This covers the time before dieback occurred to the germination and seasonal regrowth of new plants. A total of 720 individual SSP measurements were recorded during the above monitoring period. Increasingly negative values relative to initial values were documented at most transects, indicating a net reduction in soil surface elevations. This is interpreted as evidence of the removal (i.e., erosion) of surface material. Paired samples statistical analysis of the data indicate that erosion from contaminated sites was significantly greater than erosion from topographically comparable reference sites (t =−5.758; P < 0.05; N = 359) supporting natural vegetation. The results provide tentative yet compelling evidence that I. glandulifera promotes soil erosion along the Riparian Zone of the watercourse investigated. Given the unrelenting spread of this notoriously invasive plant throughout inland river systems in many countries, the likelihood of greater quantities of nutrient-rich sediment entering into aquatic environments may steadily reduce water quality in all affected catchments. An absence of effective control measures capable of halting or even slowing its rate of invasion may make it increasingly difficult for affected European Union member states to meet and then maintain key water quality standards set by the Water Framework Directive (WFD) when fully implemented in 2015.
Alan R Hill - One of the best experts on this subject based on the ideXlab platform.
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beaver dams along an agricultural stream in southern ontario canada their impact on Riparian Zone hydrology and nitrogen chemistry
Hydrological Processes, 2009Co-Authors: Alan R Hill, Tim P DuvalAbstract:The hydrology and nitrogen biogeochemistry of a Riparian Zone were compared before and after the construction of beaver dams along an agricultural stream in southern Ontario, Canada. The beaver dams increased surface flooding and raised the Riparian water table by up to 1·0 m. Increased hydraulic gradients inland from the stream limited the entry of oxic nitrate-rich subsurface water from adjacent cropland. Permeable Riparian sediments overlying dense till remained saturated during the summer and autumn months, whereas before dam construction a large area of the Riparian Zone was unsaturated in these seasons each year. Beaver dam construction produced significant changes in Riparian groundwater chemistry. Median dissolved oxygen concentrations were lower in Riparian groundwater after dam construction (0·9–2·1 mg L−1) than in the pre-dam period (2·3–3·9 mg L−1). Median NO3-N concentrations in autumn and spring were also lower in the post-dam (0·03–0·07 mg L−1) versus the pre-dam period (0·1–0·3 mg L−1). In contrast, median NH4-N concentrations in autumn and spring months were higher after dam construction (0·3–0·4 mg L−1) than before construction (0·13–0·14 mg L−1). Results suggest that beaver dams can increase stream inflow to Riparian areas that limit water table declines and increase depths of saturated Riparian soils which become more anaerobic. These changes in subsurface hydrology and chemistry have the potential to affect the transport and transformation of nitrate fluxes from adjacent cropland in agricultural landscapes. Copyright © 2009 John Wiley & Sons, Ltd.
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groundwater phosphate dynamics in a river Riparian Zone effects of hydrologic flowpaths lithology and redox chemistry
Journal of Hydrology, 2001Co-Authors: G C Carlyle, Alan R HillAbstract:This study examines the influence of Riparian Zone hydrology, lithology and redox chemistry on groundwater phosphate dynamics. Patterns of soluble reactive phosphorus (SRP), dissolved oxygen (DO) and ferrous iron (Fe2+) in combination with hydrologic data and sediment characteristics were studied in a forested floodplain connected to a large upland sand aquifer in an agricultural region of southern Ontario, Canada. Groundwater discharge from the upland aquifer flowed laterally beneath peat in a 2–4 m thick Zone of permeable sands across the floodplain to the river. Within the sands, low SRP concentrations ( 3 mg L−1 and Fe2+ concentrations <0.2 mg L−1 which extended for a horizontal distance of 100–140 m across the Riparian Zone. High SRP concentrations (50–950 μg L−1) were associated with low DO and high Fe2+ concentrations which exceeded 1 mg L−1 in buried channel sediments near the river bank. Sediment P fractionation indicated that the buried channel sediments contained a much higher pool of total P and Fe+Al–P than the sands. Groundwater SRP concentrations at the river bank were 25–80 μg L−1 compared to <10 μg L−1 in river water indicating that the floodplain was a source of SRP to the river. Areas of elevated SRP and Fe2+ within the floodplain expanded in August when DO concentrations in groundwater were lower than in late spring or autumn. These data suggest that the microbial reduction of Fe3+ to soluble Fe2+ in anaerobic conditions influences groundwater SRP concentrations in the Riparian Zone. This study shows that well-organized patterns of groundwater SRP concentrations occur in Riparian Zones which reflect the interaction of hydrologic flowpaths and environments of different redox state. Internal sources of P associated with buried channel sediments can also influence subsurface SRP transport and release to streams.
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groundwater phosphate dynamics in a river Riparian Zone effects of hydrologic flowpaths lithology and redox chemistry
Journal of Hydrology, 2001Co-Authors: G C Carlyle, Alan R HillAbstract:Abstract This study examines the influence of Riparian Zone hydrology, lithology and redox chemistry on groundwater phosphate dynamics. Patterns of soluble reactive phosphorus (SRP), dissolved oxygen (DO) and ferrous iron (Fe2+) in combination with hydrologic data and sediment characteristics were studied in a forested floodplain connected to a large upland sand aquifer in an agricultural region of southern Ontario, Canada. Groundwater discharge from the upland aquifer flowed laterally beneath peat in a 2–4 m thick Zone of permeable sands across the floodplain to the river. Within the sands, low SRP concentrations ( 3 mg L−1 and Fe2+ concentrations
Michael M Douglas - One of the best experts on this subject based on the ideXlab platform.
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timing and causes of gully erosion in the Riparian Zone of the semi arid tropical victoria river australia management implications
Geomorphology, 2016Co-Authors: Gillian Mccloskey, R J Wasson, Guy S Boggs, Michael M DouglasAbstract:Abstract Gully erosion in the seasonally wet tropics of Australia is a major source of sediment in rivers. Stabilization of gullies to reduce impacts on aquatic ecosystems and water storages is a focus for management. However, the cause of the gully erosion is poorly understood and so a critical context for soil conservation is missing. It is uncertain if they are the result of post-European cattle grazing or are they much older and related to non-human factors. The causes of Riparian gully erosion along a reach of the Victoria River in the semi-arid tropics of Australia were investigated using several methods. Gully complexes were described and characterised by two major components: a Flood Drainage Channel (FDC) and upslope of this an Outer Erosion Feature (OEF) characterised by badlands set within an amphitheatre. The OEF is likely to be a major source of sediment that appears to be of recent origin. A review of historical records, combined with Optically Stimulated Luminescence (OSL) dating, showed that the FDCs were well established prior to the introduction of domestic stock. It also showed that the badlands began to develop about 90 years ago; that is, about 40 years after the arrival of domestic stock. In addition, an analysis of aerial photos coupled with an on-ground survey and analysis of fallout radionuclides revealed that erosion processes are still active within the gully complexes. While the FDCs are natural drainage channels, cattle grazing probably triggered the badland formation, with the expansion aided by increased rainfall in the past 40 years. Therefore, the OEFs are of human origin and protection from grazing of the Riparian Zone should slow badland erosion and reduce sediment input to the river.
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comparison of image and rapid field assessments of Riparian Zone condition in australian tropical savannas
Forest Ecology and Management, 2007Co-Authors: Kasper Johansen, Michael M Douglas, Stuart R Phinn, Ian H Dixon, John LowryAbstract:Suitable methods for measuring and monitoring the condition of Riparian environments are being investigated by government agencies responsible for maintaining these environments in Australia. The objective of this work was to compare two Riparian condition assessment approaches, the Tropical Rapid Appraisal of Riparian Condition (TRARC) method developed for rapid on-ground assessment of the environmental condition of savanna Riparian Zones and an image based Riparian condition monitoring scheme. Measurements derived from these two approaches were compared and correlated. The sample representativeness of the TRARC method was evaluated and the cost-effectiveness and suitability for multi-temporal analysis of the two approaches were assessed. Two high spatial resolution multi-spectral QuickBird satellite images captured in 2004 and 2005 and coincident field data covering sections of the Daly River in the Northern Territory, Australia were used in this work. Both field and image data were processed to map indicators of Riparian Zone condition including percentage canopy cover, organic litter on the ground, canopy continuity, tree clearing, bank stability, and flood damage. Spectral vegetation indices, image segmentation, and supervised classification were used to produce Riparian health indicator maps. QuickBird image data were used to examine if the spatial distribution of TRARC transects provided a representative sample of ground based estimates of Riparian health indicators. Covering approximately 3% of the study area, the sample mean of the TRARC estimates of individual indicators of Riparian Zone condition were in most cases within 20% of the global mean derived from the whole imaged Riparian area. The cost-effectiveness of the image based approach was compared to that of the ground based TRARC method. Results showed that the TRARC method was more cost-effective at spatial scales from 1 km to 200 km of river in relatively homogeneous Riparian Zones along rivers with only one channel, while image based assessment becomes more feasible at regional scales (200-2000 km of river). A change detection analysis demonstrated that image data can provide detailed information on gradual change, while the TRARC method is less suited for multi-temporal analysis due to the ranked data format, which inhibits precise detection of change. However, results from both methods were considered to complement each other for single date assessment of Riparian Zones if used at appropriate spatial scales.
