Flow resistance in concentrated overland flow on rough slope surfaces

Roels, J. M.

doi:10.1002/esp.3290090608

Cited by 62 publications

(41 citation statements)

References 6 publications

(7 reference statements)

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“…Their further research demonstrated that f-Re relation was positive for grassland but negative for shrubland. Roels (1984) considered slope length as an important factor of f-Re relation thus the f-Re relation for long slope couldn't obtain by interpolating and extrapolating. These differences may be attributed to rainfall, underlying surface, vegetation type, slope feature, etc.…”

Section: Plant-plotsmentioning

confidence: 99%

“…Emmett (1978) stated that this relation applied only for plane beds where the resistance to flow was entirely grain resistance, with f ∝ Re −1.0 for laminar flow and f ∝ Re −2.0 for turbulent flow. Roels (1984) found the exponent ranged from −0.07 to −0.90 without taking into account flow regime factor. Abrahams et al (1992) reported that the f−Re relation for standard plane-bed was not ubiquitous, and either positive or negative relationships may fit in different conditions.…”

Section: Introductionmentioning

confidence: 99%

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Effects of patterned Artemisia capillaris on overland flow resistance under varied rainfall intensities in the Loess Plateau of China

Zhang

Liu

et al. 2014

Journal of Hydrology and Hydromechanics

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Abstract:In this paper simulated rainfall experiments in laboratory were conducted to quantify the effects of patchy distributed Artemisia capillaris on spatial and temporal variations of the Darcy-Weisbach friction coefficient (f). Different intensities of 60, 90, 120, and 150 mm h -1 were applied on a bare plot (CK) and four different patched patterns: a checkerboard pattern (CP), a banded pattern perpendicular to slope direction (BP), a single long strip parallel to slope direction (LP), and a pattern with small patches distributed like the letter 'X' (XP). Each plot underwent two sets of experiments, intact plant and root plots (the above-ground parts were removed). Results showed that mean f for A. capillaris patterned treatments was 1.25-13.0 times of that for CK. BP, CP, and XP performed more effectively than LP in increasing hydraulic roughness. The removal of grass shoots significantly reduced f. A negative relationship was found between mean f for the bare plot and rainfall intensity, whereas for grass patterned plots f r (mean f in patterned plots divided by that for CK) increased exponentially with rainfall intensity. The f -Re relation was best fitted by a power function. Soil erosion rate can be well described using f by a power-law relationship.

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Section: Plant-plotsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of patterned Artemisia capillaris on overland flow resistance under varied rainfall intensities in the Loess Plateau of China

Zhang

Liu

et al. 2014

Journal of Hydrology and Hydromechanics

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“…Data needed to calculate hydraulic roughness from empirical relationships (e.g. Roels, 1984;Gilley and Finkner, 1991) are either measured (e.g. Fig.…”

Section: Surface Roughness and Detention Storagementioning

confidence: 99%

Spatio-temporal patterns in land use and management affecting surface runoff response of agricultural catchments—A review

Fiener

Auerswald

Oost

2011

Earth-Science Reviews

122

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a b s t r a c t a r t i c l e i n f oSurface runoff and associated erosion processes adversely affect soil and surface water quality. There is increasing evidence that a sound understanding of spatial-temporal dynamics of land use and management are crucial to understanding surface runoff processes and underpinning mitigation strategies. In this review, we synthesise the effects of (1) temporal patterns of land management of individual fields, and (2) spatio-temporal interaction of several fields within catchments by applying semivariance analysis, which allows the extent and range of the different patterns to be compared. Consistent effects of management on the temporal dynamics of surface runoff of individual fields can be identified, some of which have been incorporated into small-scale hydrological models. In contrast, the effects of patchiness, the spatial organisation of patches with different soil hydrological properties, and the effects of linear landscape structures are less well understood and are rarely incorporated in models. The main challenge for quantifying these effects arises from temporal changes within individual patches, where the largest contrasts usually occur in mid-summer and cause a seasonally varying effect of patchiness on the overall catchment response. Some studies indicate that increasing agricultural patchiness, due to decreasing field sizes, reduces the catchment-scale response to rainfall, especially in cases of Hortonian runoff. Linear structures associated with patchiness of fields (e.g. field borders, ditches, and ephemeral gullies) may either increase or decrease the hydraulic connectivity within a catchment. The largest gap in research relates to the effects and temporal variation of patch interaction, the influence of the spatial organisation of patches and the interaction with linear structures. In view of the substantial changes in the structure of agricultural landscapes occurring throughout the world, it is necessary to improve our knowledge of the influence of patchiness and connectivity, and to implement this knowledge in new modelling tools.

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“…However, the f±Re relationship for overland flow deviates from the conventional resistance diagram developed for open channel flow (Savat 1977(Savat ,1980Dunne and Dietrich, 1980;Roels, 1984;Abrahams et al, 1986). Savat (1980) conducted a series of experiments using fixed beds with varying roughness.…”

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confidence: 95%

Hydraulics of interrill overland flow on rough, bare soil surfaces

Takken

Govers

2000

Earth Surf. Process. Landforms

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A set of laboratory experiments on bare, rough soil surfaces was carried out to study the relationship between soil surface roughness and its hydraulic resistance. Existing models relating roughness coefficients to a measure of surface roughness did not predict the hydraulic resistance well for these surfaces. Therefore, a new model is developed to predict the hydraulic resistance of the surface, based on detailed surface roughness data. Roughness profiles perpendicular to the flow are used to calculate the wet cross-sectional area and hydraulic radius given a certain water level. The algorithm of Savat is then applied to calculate the hydraulic resistance. The value for the equivalent roughness, which is used in the algorithm of Savat, could be predicted from the roughness profiles. Here, the tortuosity of the submerged part of the surface was used, which means that the calculated roughness depends on flow depth. The roughness increased with discharge, due to the fact that rougher parts of the surface became submerged at higher discharges. Therefore, a single measure of surface roughness (e.g. random roughness) is not sufficient to predict the hydraulic resistance. The proposed model allows the extension of the flow over the surface with increasing discharge to be taken into account, as well as the roughness within the submerged part of the surface. Therefore, the model is able to predict flow velocities reasonably well from discharge and roughness data only.

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Flow resistance in concentrated overland flow on rough slope surfaces

Cited by 62 publications

References 6 publications

Effects of patterned Artemisia capillaris on overland flow resistance under varied rainfall intensities in the Loess Plateau of China

Effects of patterned Artemisia capillaris on overland flow resistance under varied rainfall intensities in the Loess Plateau of China

Spatio-temporal patterns in land use and management affecting surface runoff response of agricultural catchments—A review

Hydraulics of interrill overland flow on rough, bare soil surfaces

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