Mechanisms Of Overland Flow Generation And Sediment Production On Loamy And Sandy Soils With And Without Rock Fragments

Overland Flow ◽  
1992 ◽  
pp. 277-307
Keyword(s):  
Overland Flow ◽  
Sandy Soils ◽  
Rock Fragments ◽  
Sediment Production ◽  
Flow Generation

scholarly journals Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory

2014 ◽  
Vol 18 (5) ◽  
pp. 1873-1883 ◽  
Author(s):  
G.-Y. Niu ◽  
D. Pasetto ◽  
C. Scudeler ◽  
C. Paniconi ◽  
M. Putti ◽  
...  
Keyword(s):  
Null Hypothesis ◽  
Overland Flow ◽  
Landscape Evolution ◽  
Alternative Hypothesis ◽  
Biosphere 2 ◽  
Subsurface Heterogeneity ◽  
Flow Generation ◽  
Heterogeneous Soil ◽  
Seepage Face ◽  
Modeling Study

Abstract. Evolution of landscape heterogeneity is controlled by coupled Earth system dynamics, and the resulting process complexity is a major hurdle to cross towards a unified theory of catchment hydrology. The Biosphere 2 Landscape Evolution Observatory (LEO), a 334.5 m2 artificial hillslope built with homogeneous soil, may have evolved into heterogeneous soil during the first experiment driven by an intense rainfall event. The experiment produced predominantly seepage face water outflow, but also generated overland flow, causing superficial erosion and the formation of a small channel. In this paper, we explore the hypothesis of incipient heterogeneity development in LEO and its effect on overland flow generation by comparing the modeling results from a three-dimensional physically based hydrological model with measurements of total mass change and seepage face flow. Our null hypothesis is that the soil is hydraulically homogeneous, while the alternative hypothesis is that LEO developed downstream heterogeneity from transport of fine sediments driven by saturated subsurface flow. The heterogeneous case is modeled by assigning saturated hydraulic conductivity at the LEO seepage face (Ksat,sf) different from that of the rest (Ksat). A range of values for Ksat, Ksat,sf, soil porosity, and pore size distribution is used to account for uncertainties in estimating these parameters, resulting in more than 20 000 simulations. It is found that the best runs under the heterogeneous soil hypothesis produce smaller errors than those under the null hypothesis, and that the heterogeneous runs yield a higher probability of best model performance than the homogeneous runs. These results support the alternative hypothesis of localized incipient heterogeneity of the LEO soil, which facilitated generation of overland flow. This modeling study of the first LEO experiment suggests an important role of coupled water and sediment transport processes in the evolution of subsurface heterogeneity and on overland flow generation, highlighting the need of a coupled modeling system that integrates across disciplinary processes.

Quantification of Hortonian overland flow generation and soil erosion in a Central European low mountain range using rainfall experiments

CATENA ◽  
2014 ◽  
Vol 113 ◽  
pp. 202-212 ◽  
Author(s):  
V. Butzen ◽  
M. Seeger ◽  
S. Wirtz ◽  
M. Huemann ◽  
C. Mueller ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Overland Flow ◽  
Mountain Range ◽  
Central European ◽  
Flow Generation ◽  
Low Mountain Range

Effect of forest thinning on overland flow generation on hillslopes covered by Japanese cypress

Ecohydrology ◽  
2010 ◽  
Vol 4 (3) ◽  
pp. 367-378 ◽  
Author(s):  
Bui Xuan Dung ◽  
Shusuke Miyata ◽  
Takashi Gomi
Keyword(s):  
Overland Flow ◽  
Japanese Cypress ◽  
Forest Thinning ◽  
Flow Generation

Erosion and Sediment Control At Road-Stream Crossings

1983 ◽  
Vol 59 (2) ◽  
pp. 62-66 ◽  
Author(s):  
R. L. Rothwell
Keyword(s):  
Suspended Sediment ◽  
Overland Flow ◽  
Bare Soil ◽  
High Variability ◽  
Final Conclusion ◽  
Sediment Control ◽  
Sediment Production ◽  
Control Erosion

The effectiveness of a "brush mulch" to control erosion and sediment at road-stream crossings was evaluated by measurement and comparison of upstream and downstream suspended sediment. The brush mulch consisted of logging debris, such as branches, tree tops and logs 2-15 cm in diameter, laid on the ground to intercept and to slow overland flow and to trap sediment. Two treatments were defined and tested. Treatment no. 1 was a brush mulch and grass-fertilizer mixture applied by hydroseeding to three bare soil road-stream crossings. Treatment no. 2 was a grass-fertilizer mixture applied by hydroseeding to another three road-stream crossings.Total seasonal and storm sediment production for mulched and unmulched crossings averaged 31 and 37, and 566 and 2297 kg/day/ha, respectively. Tests showed significant differences between treatments for both seasonal and storm sediment production. The levels of significance were low because of high variability in sediment production among treatments and road crossings. Frequent onsite inspections during storm and nonstorm conditions, however, identified sources of variability and supported a final conclusion that the brush mulch was effective for erosion and sediment control at road-stream crossings.

Overland flow generation in two lithologically distinct rainforest catchments

2004 ◽  
Vol 295 (1-4) ◽  
pp. 276-290 ◽  
Author(s):  
S Godsey ◽  
H Elsenbeer ◽  
R Stallard
Keyword(s):  
Overland Flow ◽  
Flow Generation

Overland flow generation on hillslopes of complex topography: analytical solutions

2007 ◽  
Vol 21 (10) ◽  
pp. 1308-1317 ◽  
Author(s):  
Carmelo Agnese ◽  
Giorgio Baiamonte ◽  
Cecilia Corrao
Keyword(s):  
Analytical Solutions ◽  
Overland Flow ◽  
Complex Topography ◽  
Flow Generation

Diffused and localized sediment production processes in a distributed transport model

2020 ◽  
Author(s):  
Giulia Battista ◽  
Peter Molnar ◽  
Fritz Schlunegger ◽  
Paolo Burlando
Keyword(s):  
Surface Roughness ◽  
High Resolution ◽  
Overland Flow ◽  
Sediment Load ◽  
Transport Model ◽  
Sediment Sources ◽  
Local Surface ◽  
Sediment Production ◽  
Production Processes ◽  
Spatially Distributed

<p>The identification of preferential sediment production areas within a river basin is essential to improve predictions of sediment load and its sources, and to identify sources of potential water pollution. The role of these localized sediment sources is especially relevant in the sediment budget of alpine basins, where erosion in highly non-uniform and mass movements play a major role in the mobilization of sediments. While sediment tracers are useful to assess the origin of river-borne sediments, currently very few spatially distributed sediment transport models include the sediment production from a variety of sources and track sediment from source to outlet.</p><p>In this work, we present a new approach to include the production of sediment from localized sources, in addition to diffusive overland flow erosion, in a spatially distributed sediment production and transport model. This extension of the hydrological model Topkapi-ETH simulates the mobilization of sediments by (i) overland flow erosion, (ii) sediment pickup from landsliding areas by overland flow and (iii) river discharge, and (iv) sediment pickup from deeply incised valleys by channel flow. Landslides and incised valleys were identified from geological/geomorphological maps and a high resolution DEM of the study basin. To model the contribution of landslides, we introduce a parameter λ for gully competence, which describes the effectiveness of overland flow in mobilizing the sediments. Overall, λ affects the contributions of the different sediment production processes to the modelled sediment load at the basin outlet. To estimate a value of λ for the case study, we propose the local surface roughness to quantify the gully development onto the landslide surfaces. Additionally, we use available <sup>10</sup>Be measurements across the basin to assign a concentration to each sediment production process and select the end member value of λ that best reproduces the observed <sup>10</sup>Be concentrations at the outlet.</p><p>Our simulations indicate that including the production of sediments from localized sources with processes (ii) to (iv) is essential to capture the highest observed concentrations with the model. Moreover, the same observed suspended sediment concentrations at the outlet may be obtained with different combinations of sediment production processes in function of the gully competence. Finally, the local surface roughness analysis and the use of <sup>10</sup>Be concentration as a sediment tracer suggest that channel processes are dominant over hillslope sediment production in the study basin.</p><p>In conclusion, our work shows that combinations of physically-based sediment transport modelling with geomorphological mapping of localized sediment sources, high-resolution topographic information and point measurements of cosmogenic radionuclide concentrations allow to infer the dominant sediment production processes in river basins.</p>

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