Recent work on stream channels near Sydney, New South Wales, suggests that the dominant discharge model is inadequate in this climatic regime, as at least two sets of flow are responsible for major channel forms. Evidence of channel geometry
and meander changes for the Macquarie Rivulet near Wollongong agree in principle with this. The channel of the Macquarie Rivulet accomodates a 1.68 year flood and is modified by flows with 1-3 year recurrence intervals. In contrast, over the last 150 years
the meander pattern has changed during infrequent high magnitude flows and it seems that the size of these bends is an adjustment to events that are catastrophic by world standards, but which occur here at least once every 25 years.
by turbulence of the transporting flow, while for the bed load turbulence is not a determining factor. A scheme is suggested for the energy transformation in the near-bed area of the turbulence flow which is transporting saltation load. In conformity
with the above scheme, a part of energy of the averaged fluid stream may be transformed into energy of turbulent pulsations of its velocity by the mechanism of saltation motion of load. Results from experiments which support this consideration are given. (Ed.).
Micro-ripples (wavelength 0.5-2.0 cm, amplitude less than 0.2 cm) form on silt-dominated beds at the margins of ephemeral stream channels in reworked glacial lake sediments as a result of unidirectional currents, oscillatory flow or both. Pulsation
of flow and the presence of bed irregularities much larger than the dominant particle size result in local stress concentration, and micro-ripples may form even though the mean stress is below the theoretical threshold for the grain sizes involved. Grain
A field survey of thirty stream junctions from a small watershed, together with data collected by Miller (1958) allowed to investigate morphometric adjustments occurring at confluences. The model proposed by Roy and Woldenberg (1986) was slightly
modified and used as a tool for morphometric analysis. Total channel capacity tends to decline below most confluences. A reduction in cross-sectional area implies an increase in average flow velocity.
) of the hard rock basement. The anomalies are apparent reflections of the deep topography, they are manifest in changes in flow velocity and kinetic energy along the stream.
A study is made of temporal and spatial variations in material concentrations and transport in connection with spring and summer quick flow periods and episodes in a small drainage basin, Koiransuolenoja, of size 6.75 km2. More long-term variations
detectable in fluvial erosion and the development of the valleys of the streams are also examined. A total of 382 water samples for analysis were collected in 1984 and 1985, mostly using an automatic sampling device, in order to investigate variations within
different human activities on various water and soil phenomena, including groundwater, spring, and well levels, streamflow quantity timing and distribution| on-site erosion| sediment in streams| and nutrient out flow. Each chapter includes a short section
Failure and flow on a 35o slope : causes and three-dimensional observations
Three-dimensional characteristics of the active debris flow are reconstructed from mudlines on 58 trees still standing in the flow path. Mudline formation only on the up-flow side of trees indicates relatively high viscosity of the debris flow
. Mudline height is a function of the maximum thickness and velocity of the flow at any tree.
Violence in pyroclastic flow eruptions in Tephra studies.
Violence reflects the vigour with which a pyroclastic flow is emplaced. It is described quantitatively by the height of hills climbed by the flow (yielding flow-velocity estimates), the overall morphology of the deposit and by the proportion
of the flow which forms an ignimbrite veneer deposit. Using the Taupo ignimbrite (New Zealand) as an example of an extremely violent flow, we relate violence to the eruption intensity. The AA. consider that eruption magnitude and intensity control the gross
An hypothesis from which a general principle covering deformation of alluvial boundaries may be developed is proposed, namely flow of fluid past a deformable boundary will deform the boundary so as to increase the resistance to flow. Upon attainment
of a local maximum of resistance to flow the boundary shape will cease to change.
Debris flows involved in the development of Pleistocene stratified slope deposits in Periglacial processes and landforms.
Two approaches to this problem : 1) the analysis of recent debris flows within an Alpine environment, and 2) laboratory experiments, simulating debris flows under different conditions. Sedimentological characteristics of debris flow material
are discussed, as well as relationships between physical and sedimentological properties. Resulting criteria for the recognition of debris flow material are given and the role of temperature is treated briefly.
Size characteristics of sediment in interrill overland flow on a semiarid hillslope, southern Arizona
The aim of this study is to examine and consider the significance of the size characteristics of sediment removed in interrill overland flow in a semiarid environment on a plot covered by natural vegetation, undisturbed by agricultural practices
, and large enough to encompass the full range of interill overland flow.
Secondary flows and the pool-riffle unit : a case study of the processes of meander development
Major bed forms of bed-gravel rivers may be resolved into pool-riffle units. Their identification and observation demonstrate links between bedform, flow pattern and channel change. Each unit seems to be associated to a systematic pattern
of secondary flow, so that meanders tend to evolve by regular cycles of increasing curvature and complexity. - (CB)
The influence of debris flows on channels and valley floors in the Oregon Coast Range, U.S.A.
The A. presents a field study of the erosional and depositional characteristics of debris flows and their influence on alluvial channels and valley floors.
Incipient motion conditions for single rock fragments in simulated rill flow
This paper examines incipient motion conditions for single rock fragments in simulated rill channels : threshold conditions for rock fragments in rill flow will be compared with existing theory (Shields) for channels and rivers.