Effect of Roughness Elements on Hydraulic Resistance for Overland Flow

Kowobari, T. S.; Rice, Charles E.; Garton, James E.

doi:10.13031/2013.38054

Cited by 23 publications

(8 citation statements)

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“…First, the estimated roughness for non‐aquatic vegetation that grows in ephemeral streams is very different from that of aquatic vegetation. Second, many studies have been performed using artificial vegetation implanted in artificial flume (Einstein and Banks, 1950; Robinson and Albertson, 1952; Sayer, 1961; Taylor and Brooks, 1962; Kowobari et al , 1972; Petryck and Bosmamajian, 1975; Kao and Barfield, 1982), whereas others were performed using natural conditions, with natural bed and vegetation types, but adapted to specific research topics (Emmet, 1970; Temple, 1980; Kao and Barfield, 1982; Temple, 1983; Rhee et al , 2008). The results show that Manning's roughness coefficients determined in these studies provide large discharge overestimates.…”

Section: Resultsmentioning

confidence: 99%

A soft hydrological monitoring approach for comparing runoff on a network of small poorly gauged catchments

Crabit

Colin

Moussa

2011

Hydrological Processes

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Abstract:Catchments in many parts of the world are either ungauged or poorly gauged, and the dominant processes governing their streamflow response are still poorly understood. The analysis of runoff coefficients provides essential insight into catchment response, particularly if both range of catchments and a range of events are compared. This paper investigates how well the hydrological runoff of 11 small, poorly gauged catchments with ephemeral streams (0Ð1-0Ð6 km 2 ) can be compared using estimated runoff with the associated uncertainty. Data of rainfall and water depth at a catchment's outlet were recorded using automatic logging equipment during [2008][2009]. The hydrological regime is intermittent and the annual precipitation ranged between 569 and 727 mm. Discharge was estimated using Manning's equation and channel cross-section measurements. Innovative work has been performed under controlled experimental conditions to estimate Manning's coefficient values for the different cover types observed in studied streams: non-aquatic vegetations (giant reed, bramble and thistle), grass and coarse granular deposits. The results show that estimates derived using roughness coefficients differ from those previously established for larger streams with aquatic vegetation. Catchment runoff was compared at both the event and the annual scale. The results indicate significant variability between the catchment's responses. This variability allows for classification in spite of all the uncertainty associated with runoff estimation. This study highlights the potential of using a network of poorly gauged catch ments. From almost no catchment understanding the proposed methodology allows to compare poorly gauged catchments and highlights similarity/dissimilarity between catchment responses.

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Section: Resultsmentioning

confidence: 99%

A soft hydrological monitoring approach for comparing runoff on a network of small poorly gauged catchments

Crabit

Colin

Moussa

2011

Hydrological Processes

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“…Also, Robinson and Albertson (1952) tested artificial standard roughness; similarly, Sayer (1961) determined the flow delay for various roughnesses. Kowobari et al (1972) not only analysed the roughness coefficients, but also developed a flow resistance model. Taylor and Brooks (1962) differentiated two kinds of roughness, one due to bare soil and another to vegetation, and Petryck and Bosmajian (1975) established a model through the differentiation of the dragging force on the bed and the resistance of vegetation on the flow.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Manning coefficient for small-depth flows on vegetated beds

Díaz

2005

Hydrol. Process.

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Abstract:The limitations of Manning's formula are analysed when it is in extreme conditions, and more specifically with smalldepth flows on natural-vegetation beds. A thorough analysis is made of research carried out on macro-rough beds, placing particular emphasis on vegetated beds. Research carried out to date on the roughness of vegetated beds and macro-roughness is commented on, including that carried out at the Laboratory of Hydraulics and Hydrology of the Forestry Engineering Faculty (Polytechnic University of Madrid). The work was done in two phases, the first in a laboratory channel with artificial vegetation and the second in natural beds. The results of the experimental research allow the development of a new approximate method of determining Manning coefficient according to the Froude number. This method may be applied in extreme conditions, both in small depths and steep slopes. It was proved that the Manning coefficient depends not only on roughness height, but also on depth and slope values; thus, it is advisable to choose the appropriate method for its calculation.

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“…Estimates of surface roughness n, values were ascertained from research results regarding shallow overland flow (Kowobari et al, 1972;Tollner et al, 1976;Ree et al, 1977;Hayes et al, 1978;Woolhiser et al, 1978;Hayes et al, 1979;and Kimes et al , 1979). The range of n values assigned to field cells varied from 0-07 for relatively smooth tilled land, to 0.10 for grass under converging flow conditions, to 0.20 for grass under diverging flow conditions, to 0.65 for woodland.…”

Section: The Modelling Approachmentioning

confidence: 99%

Identification of soil erosion and fluvial sediment problems

Dickinson

Rudra

Wall³

1986

Hydrological Processes

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A computer model has been used to estimate soil loss and sediment yield from irregular field-size units of small watersheds. Input to the model includes spring data (i.e. relating to February through May) for the independent variables of the Universal Soil Loss Equation, and for factors such as surface roughness, an index of overland runoff, and proximity to the stream. Output from the model includes maps of seasonal estimates of potential soil losses, field sediment delivery ratios, and expected sediment yields. On the basis of selected erosion and sediment yield tolerances, the output information has been analysed to identify watershed areas which (1) exhibit both erosion and sediment yield problems; (2) exhibit only erosion problems; (3) exhibit only sediment yield problems; and (4) exhibit neither erosion nor sediment yield problems. The percentage of the watershed area in each category and the percentage of the watershed soil loss and sediment loads contributed by each category are also identified. Application of the procedure for planning remedial control programs for five watersheds is discussed.

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Effect of Roughness Elements on Hydraulic Resistance for Overland Flow

Cited by 23 publications

References 0 publications

A soft hydrological monitoring approach for comparing runoff on a network of small poorly gauged catchments

A soft hydrological monitoring approach for comparing runoff on a network of small poorly gauged catchments

Analysis of Manning coefficient for small-depth flows on vegetated beds

Identification of soil erosion and fluvial sediment problems

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