This study is based on the hypothesis that catenary soil development occurs in many landscapes response to way water moves through and over landscape. Furthermore, terrain attributes can characterize these flow paths and, therefore, attributes. Significant correlations between quantified measured were found a 5.4-ha toposequence Colorado. Slope wetness index most highly correlated with surface at 231 locations 15.24-m grid. Individually, they accounted for about one-half of variability A...

Abstract The length‐slope factor in the universal soil loss equation (USLE) is a purely empirical relationship that was derived from an extensive data base. A physically based independently this paper by using unit stream power theory to describe erosion processes associated with sheet and rill flow on hill‐slopes. It shown two factors are equivalent. Therefore, USLE measure of sediment transport capacity runoff landscape, but fails fully account for hydrological affect erosion. strength...

Abstract Explicit and quantitative models for the spatial prediction of soil landscape attributes are required environmental modelling management. In this study, advances in representation hydrological geomorphological processes using terrain analysis techniques integrated with development a field sampling soil-landscape model building strategy. Statistical developed relationships between (plan curvature, compound topographic index, upslope mean plan curvature) (A horizon depth, Solum E...

Future directions for physically based, distributed‐parameter models intended use as hydrologic components of sediment and nutrient transport are discussed. The attraction these is their potential to provide information about the flow characteristics at points within catchments, but current representations in process‐based often too crude enable accurate, a priori application predictive problems. difficulties relate both perception model capabilities fundamental assumptions algorithms used...

ABSTRACT THE relationship between topographic attributes and the distribution of surface soil water content in a small bare-fallow cultivated catchment was examined. The most statistically significant regression equations describing this contained independent variable aspect compound ln(A,), where A,=Ab/S A^ is local upslope contributing area per unit width contour line S slope. index measure saturation, product (A^.S), erosive power concentrated runoff, were both capable predicting location...

Theoretical equations for calculating the unit stream power of both sheet and rill flow were developed used to predict sediment transport capacity such flows. Independent data sets from three sources representing finely aggregated clay soils coarse textured nonaggregated soils, sheet, rill, composite systems, a range slopes test utility method. The results very good demonstrated simplicity robustness For shallow overland best obtained when critical at incipient motion was treated as constant...

THALES, a simple distributed parameter hydrologic model is presented and applied to two catchments in Australia the United States, each with different dominant responses. The simulates Hortonian overland flow runoff from saturated source areas used identify some of barriers modeling hydrology small catchments. At Wagga New South Wales, Australia, produced areas, whereas on Lucky Hills at Walnut Gulch Arizona, processes dominate. Simulations are based published parameters field data measured...

An automated method of partitioning catchments into interconnected elements using a “stream tube” approach and vector or contour‐based digital elevation models is briefly described. With this form partitioning, hydrologic can be structured based on the hydraulics flow within catchment effects topography runoff producing mechanisms spatially distributed characteristics (such as depth velocity) directly, realistically, accounted for in models. The allows complex three‐dimensional problems to...

A quasi‐dynamic wetness index that accounts for variable drainage times since a prior rainfall event is derived from simple subsurface flow theory. The method tested through series of field observations and numerical experiments using spatially distributed, dynamic hydrologic model. shown to be useful extension previously developed static indices predicting the location zones soil saturation distribution water (i.e., content overlying shallow impermeable or semiimpermeable layer). new not...

Five mathematical models for predicting subsurface flow were compared to discharge measurements made by Hewlett and Hibbert (1963) on a uniform sloping soil trough at the Coweeta Hydrologic Laboratory. The included one‐ two‐dimensional finite element based Richards equation, kinematic wave model, two simple storage‐discharge Boussinesq assumptions. simulated response water table positions as well more complex equation much economical use from point of view computational costs. Such have...

A digital model for discretizing three-dimensional terrain into small irregularly shaped polygons or elements based on contour lines and their orthogonals is described. From this subdivision the estimates a number of topographic attributes each element including total upslope contributing area, slope, aspect. This form discretization catchment produces natural units problems involving water flow as either surface subsurface phenomenon. The therefore has wide potential application...

Abstract After dry summers or drought, eucalypt forest soils at two sites in southeastern Australia developed hydrophobic non‐wetting surface characteristics that reduced infiltration, measured using a sprinkling infiltrometer. At one site the development of conditions caused rainfall to runoff conversion efficiency forested catchment increase from 5 per cent 15 cent. Under non‐hydrophobic this site, grassland always generated more than forest. However, major rainfall‐runoff was recorded...

Surface-related multiple elimination (SRME) is an algorithm that predicts all surface multiples by a convolutional process applied to seismic field data. Only minimal preprocessing required. Once predicted, the are removed from data adaptive subtraction. Unlike other methods of attenuation, SRME does not rely on assumptions or knowledge about subsurface, nor it use event properties discriminate between and primaries. In exchange for this “freedom subsurface,” requires acquisition wavelet...

We describe a new algorithm that uses known firing times to separate data from two or more impulsive, simultaneous seismic sources. Synthetic and field tests show the works well, especially when are not spatially aliased. Aliasing effects can be reduced if assumptions, such as in some sense sparse, made.

Three-component measurements of particle motion would bring significant benefits to towed-marine seismic data if processed in conjunction with the pressure data. We show that velocity can increase effective Nyquist wavenumber by a factor two or three, depending on how they are used. A true multicomponent streamer enable accurate reconstruction crossline direction cable separations for which pressure-only be irrecoverably aliased. also conventional workflows aimed at reducing these aliasing...

Seismic faulting is extremely detrimental to buried pipelines owing bending moments and axial forces generated by the soil–pipe interaction. Pipe responses ground rupture are usually evaluated beam-on-spring analysis. However, empirical data used define spring response were obtained for steel pipes with high flexural stiffness effectiveness of resulting values flexible questionable. This paper presents full-scale tests undertaken using a new split-box apparatus which permits testing in dry...

Relative ground movement represents a severe seismic hazard to pipelines crossing faults, and the maximum expected pipeline strains are primary design concern. Past research has documented how stiff steel respond permanent deformation produced calibrated empirical models of response strike-slip normal faulting. However, what little data exist on flexible illustrate ‘stiff pipeline’ soil reaction significantly overestimate peak for pipelines. Results four centrifuge tests conducted model...

Abstract Based on the experimental data presented in Part I, two uniaxial constitutive models are constructed. The first, a nonlinear viscoelastic (NVE) model, is formulated using mechanical analogy consisting of one independent spring and six Kelvin elements series. Creep used to determine model parameters. second viscoplastic (VP) formulation, developed theory proposed by Bodner characterize behavior metals. Inelastic strain rate introduced into state variable addition inelastic work...

Abstract Cross sections of a 203‐mm diam. soil core taken from site under Kentucky bluegrass ( Poa pratensis L. ) were scanned using x‐ray computed tomography (CT) to determine if macropores such as cracks, earthworm holes and root channels could be distinguished characterized. The was physically sectioned at the same locations CT scans verify size location pores seen on images. Macropores 1 mm larger easily quickly by method. By manipulation scanner images, air‐filled pores, roots stones...