The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Anthony J Parsons - One of the best experts on this subject based on the ideXlab platform.
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impact of connectivity on the modeling of Overland Flow within semiarid shrubland environments
Water Resources Research, 2007Co-Authors: Eva Nora Mueller, John Wainwright, Anthony J ParsonsAbstract:[1] The objective of this study is the evaluation of the spatial variability and intrinsic connectivity features of model input parameters for the parameterization of process-based, spatially distributed Overland Flow models. Parameter scaling tools based on the statistical and geostatistical properties of an extensive field data set were developed. These allowed the reproduction of the spatial heterogeneity of model parameters associated with the soil- and vegetation-related properties of semiarid shrubland environments to a varying degree. The outcome of the study emphasizes that connectivity plays a fundamental role in the modeling of water fluxes within semiarid catchments. The larger the degree to which connected features are represented, the better the model performance. In contrast, the parameterization approaches that did not contain connected patterns of parameter values performed comparatively poorly. A spatially connected Overland Flow model therefore enabled the generation of realistic Overland Flow patterns that qualitatively resembles field surveys of Overland Flow generation not only at the outlet of the model domains but also within the catchments without the need of calibration.
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Overland Flow hydraulics and erosion mechanics
2007Co-Authors: Anthony J Parsons, Athol D AbrahamsAbstract:Field and laboratory studies of resistance to interrill Overland Flow on semi-arid hillslopes in southern Arizona, Athol D. Abrahams, Anthony J. Parsons, Paul J. Hirsch Darcy-Weisbach roughness coefficients for Overland Flow, John E. Gilley, Dennis C. Flanagan, Eugene R. Kottwitz, Mark A. Weltz The control of headwater area on channel runoff in a small arid watershed, Aaron Yair Model KININF for Overland Flow on pervious surfaces, J.L.M.P. de Lima Modelling Overland Flow hydrology
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Depth distribution of interrill Overland Flow and the formation of rills
Hydrological Processes, 2006Co-Authors: Anthony J Parsons, John WainwrightAbstract:A Gumbel distribution for maxima is proposed as a model for the depths of interrill Overland Flow. The model is tested against three sets of field measurements of interrill Overland Flow depths obtained on shrubland and grassland hillslopes at Walnut Gulch Experimental Watershed, southern Arizona. The model is found to be a satisfactory fit to 81 of the 90 measured distributions. The shape δ and location λ parameters of all fitted distributions are strongly correlated with discharge. However, whereas a common relationship exists between discharge and δ for all depth distributions, the relationships with λ vary systematically downslope. Using the Gumbel distribution as a model for the distribution of Overland Flow depths, a probabilistic model for the initiation of rills is developed, drawing upon the previous work of Nearing. As an illustration of this approach, we apply this model to the shrubland and grassland hillslopes at Walnut Gulch. It is concluded that the presence of rills on the shrubland, but not on the grassland, is due to the greater runoff coefficient for the shrubland and/or the greater propensity of the shrubland for soil disturbance compared with the grassland. Finally, a generalized conceptual model for rill initiation is proposed. This model takes account of the depth distribution of Overland Flow, the probability of Flow shear stress in excess of local soil shear strength, the spatial variability in soil shear strength and the diffusive effect of soil detachment by raindrops. Copyright © 2005 John Wiley & Sons, Ltd.
F Darboux - One of the best experts on this subject based on the ideXlab platform.
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effects of surface water storage by soil roughness on Overland Flow generation
Earth Surface Processes and Landforms, 2002Co-Authors: F Darboux, Chantal Gascuelodoux, Philippe DavyAbstract:Overland-Flow generation is affected by surface roughness. This study analysed effects of surface roughness on Overland-Flow by means of a model simulating depression filling, Flow pathways and runoff generation. It examined the relevant characteristics of surface roughness using numerically generated surfaces. At first, horizontal surfaces with random roughness of different correlation distances were considered. This showed that Overland-Flow is sensitive to the random-roughness correlation only if the correlation distance is similar to the surface size. Because this correlation distance is limited in natural soil surfaces, correlation properties are unlikely to modify Overland-Flow triggering. This allowed simplification of the description of random roughness. Then a general slope was added and different amplitude ratios between general slope and random roughness were simulated. Slope modified the development of Overland-Flow. While runoff was only sensitive to steep slopes, water transfer by Overland-Flow inside the surface was affected by low slopes too. The ratio between general slope and random roughness is a major parameter that controls transfers both inside the surface and to the outlet. Copyright © 2002 John Wiley & Sons, Ltd.
Kenichirou Kosugi - One of the best experts on this subject based on the ideXlab platform.
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characteristics of Overland Flow generation on steep forested hillslopes of central japan
Journal of Hydrology, 2008Co-Authors: Takashi Gomi, Roy C Sidle, Masayasu Ueno, Shusuke Miyata, Kenichirou KosugiAbstract:Summary Overland Flow generation was monitored in large plots (8 × 25 m) on four hillslopes in a 4.9-ha catchment in Mie Prefecture, Japan. Three Japanese cypress (hinoki, Chamaecyparis obtusa) treatments (including three different understory conditions) and one deciduous forest treatment were studied. For all plots, including deciduous hillslopes, we observed Overland Flow even for small storm events ( 180 mm, runoff from Japanese cypress plots with dense fern understory exhibited a delayed and higher peak associated with return Flow. The dominance of hillslope-scale Flow contribution to catchment runoff was also affected by changes in the dominance of Overland Flow and return Flow. Understory vegetation cover and the availability of a litter layer altered the amount of Overland Flow, which was mediated by soil water repellency and soil moisture. Observations at the hillslope scale are essential for conceptualization of runoff mechanisms and pathways in forested headwaters.
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dynamic runoff connectivity of Overland Flow on steep forested hillslopes scale effects and runoff transfer
Water Resources Research, 2008Co-Authors: Takashi Gomi, Roy C Sidle, Shusuke Miyata, Kenichirou Kosugi, Yuichi OndaAbstract:[1] Both scaling effect and connectivity of Overland Flow were examined in steep hillslopes covered by (1) Japanese cypress (hinoki, Chamecyparis obtusa) plantations with sparse understory vegetation, (2) hinoki plantations with fern understory vegetation, and (3) deciduous forests. Two sizes of plots were installed for monitoring Overland Flow: small (0.5 × 2 m) and large hillslope scale (8 × 24–27 m). For all hillslopes, measurable amounts of Overland Flow occurred during storms. Runoff coefficients of large plots (0.1–3%) were consistently smaller than those of small plots (20–40%). Estimated runoff Flow lengths at the hillslope scale were based on runoff coefficients from small plots and were used to calculate runoff volume from large plots. Then we compared the differences between observed and estimated runoff volumes of large plots. Estimated runoff from large plots was smaller than observed runoff in hinoki slopes with sparse understory vegetation. Greater amounts of observed compared to estimated Overland Flow suggest that more runoff occurred from hillslopes with sparse understory. In contrast, estimated Overland Flow was larger than observed runoff from the deciduous forest, implying greater opportunities for infiltration compared to hinoki hillslopes. Comparison of estimated versus observed Overland Flow for successive 5 min intervals during storms indicates that runoff networks expand upslope during short and intense precipitation periods. Our examination and comparison of storm runoff from small and large plots facilitate better understanding of runoff mechanisms, scaling effects in hillslopes, and connectivity of the Overland Flow network.
Shusuke Miyata - One of the best experts on this subject based on the ideXlab platform.
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characteristics of Overland Flow generation on steep forested hillslopes of central japan
Journal of Hydrology, 2008Co-Authors: Takashi Gomi, Roy C Sidle, Masayasu Ueno, Shusuke Miyata, Kenichirou KosugiAbstract:Summary Overland Flow generation was monitored in large plots (8 × 25 m) on four hillslopes in a 4.9-ha catchment in Mie Prefecture, Japan. Three Japanese cypress (hinoki, Chamaecyparis obtusa) treatments (including three different understory conditions) and one deciduous forest treatment were studied. For all plots, including deciduous hillslopes, we observed Overland Flow even for small storm events ( 180 mm, runoff from Japanese cypress plots with dense fern understory exhibited a delayed and higher peak associated with return Flow. The dominance of hillslope-scale Flow contribution to catchment runoff was also affected by changes in the dominance of Overland Flow and return Flow. Understory vegetation cover and the availability of a litter layer altered the amount of Overland Flow, which was mediated by soil water repellency and soil moisture. Observations at the hillslope scale are essential for conceptualization of runoff mechanisms and pathways in forested headwaters.
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dynamic runoff connectivity of Overland Flow on steep forested hillslopes scale effects and runoff transfer
Water Resources Research, 2008Co-Authors: Takashi Gomi, Roy C Sidle, Shusuke Miyata, Kenichirou Kosugi, Yuichi OndaAbstract:[1] Both scaling effect and connectivity of Overland Flow were examined in steep hillslopes covered by (1) Japanese cypress (hinoki, Chamecyparis obtusa) plantations with sparse understory vegetation, (2) hinoki plantations with fern understory vegetation, and (3) deciduous forests. Two sizes of plots were installed for monitoring Overland Flow: small (0.5 × 2 m) and large hillslope scale (8 × 24–27 m). For all hillslopes, measurable amounts of Overland Flow occurred during storms. Runoff coefficients of large plots (0.1–3%) were consistently smaller than those of small plots (20–40%). Estimated runoff Flow lengths at the hillslope scale were based on runoff coefficients from small plots and were used to calculate runoff volume from large plots. Then we compared the differences between observed and estimated runoff volumes of large plots. Estimated runoff from large plots was smaller than observed runoff in hinoki slopes with sparse understory vegetation. Greater amounts of observed compared to estimated Overland Flow suggest that more runoff occurred from hillslopes with sparse understory. In contrast, estimated Overland Flow was larger than observed runoff from the deciduous forest, implying greater opportunities for infiltration compared to hinoki hillslopes. Comparison of estimated versus observed Overland Flow for successive 5 min intervals during storms indicates that runoff networks expand upslope during short and intense precipitation periods. Our examination and comparison of storm runoff from small and large plots facilitate better understanding of runoff mechanisms, scaling effects in hillslopes, and connectivity of the Overland Flow network.
Takashi Gomi - One of the best experts on this subject based on the ideXlab platform.
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characteristics of Overland Flow generation on steep forested hillslopes of central japan
Journal of Hydrology, 2008Co-Authors: Takashi Gomi, Roy C Sidle, Masayasu Ueno, Shusuke Miyata, Kenichirou KosugiAbstract:Summary Overland Flow generation was monitored in large plots (8 × 25 m) on four hillslopes in a 4.9-ha catchment in Mie Prefecture, Japan. Three Japanese cypress (hinoki, Chamaecyparis obtusa) treatments (including three different understory conditions) and one deciduous forest treatment were studied. For all plots, including deciduous hillslopes, we observed Overland Flow even for small storm events ( 180 mm, runoff from Japanese cypress plots with dense fern understory exhibited a delayed and higher peak associated with return Flow. The dominance of hillslope-scale Flow contribution to catchment runoff was also affected by changes in the dominance of Overland Flow and return Flow. Understory vegetation cover and the availability of a litter layer altered the amount of Overland Flow, which was mediated by soil water repellency and soil moisture. Observations at the hillslope scale are essential for conceptualization of runoff mechanisms and pathways in forested headwaters.
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dynamic runoff connectivity of Overland Flow on steep forested hillslopes scale effects and runoff transfer
Water Resources Research, 2008Co-Authors: Takashi Gomi, Roy C Sidle, Shusuke Miyata, Kenichirou Kosugi, Yuichi OndaAbstract:[1] Both scaling effect and connectivity of Overland Flow were examined in steep hillslopes covered by (1) Japanese cypress (hinoki, Chamecyparis obtusa) plantations with sparse understory vegetation, (2) hinoki plantations with fern understory vegetation, and (3) deciduous forests. Two sizes of plots were installed for monitoring Overland Flow: small (0.5 × 2 m) and large hillslope scale (8 × 24–27 m). For all hillslopes, measurable amounts of Overland Flow occurred during storms. Runoff coefficients of large plots (0.1–3%) were consistently smaller than those of small plots (20–40%). Estimated runoff Flow lengths at the hillslope scale were based on runoff coefficients from small plots and were used to calculate runoff volume from large plots. Then we compared the differences between observed and estimated runoff volumes of large plots. Estimated runoff from large plots was smaller than observed runoff in hinoki slopes with sparse understory vegetation. Greater amounts of observed compared to estimated Overland Flow suggest that more runoff occurred from hillslopes with sparse understory. In contrast, estimated Overland Flow was larger than observed runoff from the deciduous forest, implying greater opportunities for infiltration compared to hinoki hillslopes. Comparison of estimated versus observed Overland Flow for successive 5 min intervals during storms indicates that runoff networks expand upslope during short and intense precipitation periods. Our examination and comparison of storm runoff from small and large plots facilitate better understanding of runoff mechanisms, scaling effects in hillslopes, and connectivity of the Overland Flow network.
