Complex confining layers. A stochastic analysis of hydraulic properties at various scales
This volume presents a study of the problem of characterizing the hydraulic properties, i.e. hydraulic conductivity and effective porosity, and ground water flow of complex confining layers at various scales. The study has shown that it is possible
to derive representative hydraulic properties at the scale of model blocks, from hydraulic properties measured at the score scale. - (AGD)
A partial explanation of the dependency of hydraulic conductivity on positive pore water pressure in peat soils
Part of the relationship between positive pore water pressures and hydraulic conductivity in peat soils may be explained by accumulations of methane bubbles. The AA. show how compression and expansion of gas bubbles with changes in pore water
pressure could cause changes in hydraulic conductivity and thus help to explain some observations of dependency of hydraulic conductivity in peats on pore water pressure. Consideration is also given to the effect on hydraulic conductivities of methane gas
Hydraulics of interrill overland flow on rough, bare soil surfaces
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. 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
Hydraulics of sediment-laden sheetflow and the influence of simulated rainfall
This paper evaluates and compares hydraulic characteristics in flows with and without rainfall disturbance. The spatial uniformity of simulated rainfall properties, and its significance to flow hydraulics, are also discussed.
Sustained storage and transport of hydraulic gold mining sediment in the Bear River, California
This study examines the large deposits of hydraulic gold mining sediment and reevaluates Gilbert's (1917) classic model of sediment transport in a symmetrical wave that is based on hydraulic mining sediment primarily in the Yuba Basin. Sustained
storage and transport of hydraulic mining sediment in the Bear Basin are documented and a revised model of sediment transport is proposed.
Flow-separation berms downstream of a hydraulic jump in a bedrock channel
The purpose of this paper is to report the first direct observation of the phenomenon of gravel berm formation, downstream of a hydraulic jump. As the observations were fortuitous, detailed measurements of hydraulic conditions were not possible
but estimates were obtained. These observations are compared with laboratory experiments and theory. The deposits have significance in constraining flood palaeoflow reconstructions as the presence of berms determines the former location of hydraulic jumps.
Estimating unsaturated hydraulic conductivity from easily measured soil properties
The authors measured hydraulic conductivity (saturated and unsaturated) on 127 soil cores, which were taken in different horizons of a wide variety of Belgian soil series. The hot air method and the crust method were combined to obtain the complete
range of hydraulic conductivity from saturation to air-dry. Regression equations for estimating the Gardner parameters were established from simple soil properties, such as soil texture, carbon content, bulk density. Three parameters can reasonably well
be estimated from the textural composition and the saturated hydraulic conductivity.
Salt effect on hydraulic conductivity of a vertisol
The changes in saturated hydraulic conductivity, macroscopic swelling and clay dispersivity of a sodic black clay soil in relation to solution concentration and Na adsorption ratio of the percolating solution were measured. Based on the threshold
concentration curves, an empirical relationship relating saturated hydraulic conductivity and soil solution properties has been derived for vertisols and its field applicability established. For all practical purposes, swelling of clay seemed to be the major
factor responsible for loss of saturated hydraulic conductivity of a sodic vertisol.
Aquatic ecosystem ; Carrying capacity ; Ecosystem ; Environmental management ; Habitat ; Hydraulic works ; Longitudinal section ; North Carolina ; Spatial distribution ; Stream ; United States of America ; Woody debris
[b1] AEMGEO - CNRS UMR 5600 - Environnement Ville et Société, Ecole Normale Sup., Lyon, France
Discriminant function analysis of compositional data: an example from hydraulic geometry
Compositional discriminant function analysis of bank stability on the basis of hydraulic geometry had a success rate of 88%, making routinely archived measurements of stream width, cross-sectional area, mean velocity, and discharge a readily
Ungauged catchment modelling II. Utilization of hydraulic models for validation
This paper presents the second part of an exploration of the application of developments made in hydraulic floodplain modelling to ungauged flood forecasting. A two dimensional finite element model, RMA-2, is applied to a 25 km floodplain reach
Hydraulic conditions for rill incision under simulated rainfall : a laboratory experiment
A series of controlled laboratory experiments were conducted in order to obtain precise data on the hydraulic and sediment transport conditions during rill formation.
Logratio linear modelling of hydraulic geometry using indices of flow resistance as covariates
This study develops a statistical model for the relationship between channel friction and at-a-station hydraulic geometry, which presents potential difficulties with regard to both non-linearity and spurious correlation.
Establishing the role of pedogenesis in changing soil hydraulic properties
Chronosequences provide suitable sources for the study of changes in soil hydraulic behaviour as a result of long-term pedogenesis. For a podsol chronosequence in the Scottish Highlands, data are presented to indicate the changes that have occurred
over 13 000 years in the saturated hydraulic conductivity in each horizon. As the soil profile has evolved into a differentiated sequence of three horizons, the resulting hydrological changes can be both measured and quantified. The results
English to metric conversion of hydraulic geometry and its significance to basins software
The purpose of this technical note is threefold : 1) to provide a derivation for the conversion formula and to prove that the slopes (i.e., hydraulic exponents) are, in fact, independent of units; 2) to correct an erratum that appeared
in the conversion formula and a related error in the BASINS User's Manual, Version 2.0 (USEPA, 1998); and 3) to discuss the significance of different systems of units for describing hydraulic geometry.
Landscape position, surface hydraulic gradients and erosion processes
Different hydraulic gradients, especially due to seepage or drainage, at different locations on a hillslope profile may have a profound effect on the dominant erosion processes. A laboratory study was designed to simulate hillslope processes
and quantity effects of surface hydraulic gradients on erosion for a Glynwood clay loam soil. Results showed that, under drainage conditions, interrill processes dominated and rilling was limited.
Experimental field assessment of suspended sediment pathways for characterizing hydraulic habitat
This paper describes a field methodology for exploring the transfer of particulate matter at small scales within river channels, which may be used to aid hydraulic habitat characterization. The field protocol combines field measurement of high
frequency flow properties, to characterize hydraulic habitat units, and deployment of spatial arrays of turbidity probes, to detect the passage of artificially-induced sediment plumes through different biotope units. Relationships between the nature
of spatio-temporal hydraulic variations within glide, riffle and pool biotopes, and the character and mixing behaviour of sediment plumes within these habitat units are identified.