Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting

The technological model of operating area by the combined transport

The contribution deals with design technology service model using the combined transport. It assesses the performance indicators in relation to price and quality of services provided and on this basis decides on the type of the transport. This is the decision-making processes, which should answer the question, whether used directly in road freight transport, direct rail freight transport or combined transport. In this contribution is the combined transport meant as a system between the conventional modes, which are transhipped goods from road vehicles to the rail cars or river boats

Morphologische Entwicklung des Ucayali in Peru ohne menschliche Einflüsse

The Ucayali River originates in the high Andean Mountains near the city of Cusco in Peru. After about 1,600 km, it joins with the Marañón River. Both the Ucayali River and the Marañón River are sources of the Amazon. From 2001 to 2005, the Ministry of Transport and Communication of Peru funded a study to determine the navigability of the Ucayali River. In the process, an extensive data set was acquired including hydrological and sedimentological data as well as a comprehensive topographical survey of the riverbed. Since the Ucayali River has experienced no stream channel modification in the past, the available data provide information about the flow pattern for a natural stream and insight into a reference ecosystem. This paper offers the first analysis of the available data and a sediment transport calculation for the Ucayali River.Der Ucayali entspringt in den Anden nahe der Stadt Cusco in Peru. Er fließt über eine Strecke von rd. 1.600 km durch Peru bis zum Zusammenfluss mit dem Marañón. Beide Flüsse bilden die Quellflüsse für den Amazonas. Im Rahmen einer Studie über die Schiffbarkeit des Ucayali wurden vom peruanischen Ministerium für Verkehr und Kommunikation von 2001 bis 2005 umfangreiche Datenerhebungen durchgeführt. Die Datenerhebungen umfassen u. a. hydrologische und sedimentologische Daten sowie umfangreiche Vermessungen des Flusslaufs. Da der Ucayali bislang keinerlei Regulierungs- oder Ausbaumaßnahmen unterlegen ist, geben die Daten einen Einblick in die natürlichen Fließverhältnisse eines großen Flusses und damit einen Einblick in ein Referenz-Ökosystem. Erste Ergebnisse der Datensichtung und Sedimenttransportberechnungen zum Ucayali werden vorgestellt

Piracicaba river basin : mechanical and chemical erosion

It was carried out the characterization of the mechanical and chemical erosive processes in the Piracicaba River basin, for the period 1992-1996, in terms of the fluvial transport of dissolved and particulate materials. The mechanical erosion was calculated from the suspended sediment transport in the basin, considering the surface runoff discharge and the respective concentration calculated taking in account the statistical hydrogram separation method employed. The specific physical degradation calculated for the Piracicaba River basin was 90 t/km2.a, which correspond the velocity of the soil thickness reduction of about 64 m/Ma. The dissolved load of Piracicaba River was corrected due to the influence of the atmospheric inputs, mainly for SO4 2-, Ca2+ and Mg2+ (79.6; 63.8 and 41.8%, respectively). After the input corrections, it was estimated the total atmospheric/soil CO2 consumed during the silicate weathering (229 x 103 moles/km2.a) and the total chemical erosion (16.6 t/km2.a) expressed in terms of the total dissolved solids transported in the basin. The velocity of the silicate rock profile reduction (2.8 m/Ma) was calculated by the fluvial transport of dissolved silica knowing the mean silica concentrations in the parent rock and in the soil profile

Simulation of benzene transport and biodegradation during transient hydraulic conditions

Thesis (M.S.) University of Alaska Fairbanks, 2000MODFLOW and BIOMOC were used to simulate transport and biodegradation of benzene in the alluvial aquifer adjacent to the Chena River. MODFLOW was used to calculate ground water fluxes at the boundaries of the BIOMOC model, which was used to model transport and biodegradation of benzene. A benzene plume located 300 ft. southeast of the study site is superimposed onto the cross-sectional model of the study area. Only saturated zone processes were modeled. Anaerobic biodegradation was the only simulated biodegradation process. The simulation shows 0.003% of the theoretical benzene entering the saturated zone is biodegraded, 0.6% is adsorbed by solids, and 99.4% leaves the model boundaries. The simulation predicts theoretical concentrations of benzene are 2 to 8 ug/l when discharging into the river. Field data do not support this finding. Processes not simulated, such as aerobic degradation at the water table, may make significant contributions toward limiting benzene transport

Coordinated aircraft and ship surveys for determining impact of river inputs on great lakes waters. Remote sensing results

The remote sensing results of aircraft and ship surveys for determining the impact of river effluents on Great Lakes waters are presented. Aircraft multi-spectral scanner data were acquired throughout the spring and early summer of 1976 at five locations: the West Basin of Lake Erie, Genesee River - Lake Ontario, Menomonee River - Lake Michigan, Grand River - Lake Michigan, and Nemadji River - Lake Superior. Multispectral scanner data and ship surface sample data are correlated resulting in 40 contour plots showing large-scale distributions of parameters such as total suspended solids, turbidity, Secchi depth, nutrients, salts, and dissolved oxygen. The imagery and data analysis are used to determine the transport and dispersion of materials from the river discharges, especially during spring runoff events, and to evaluate the relative effects of river input, resuspension, and shore erosion. Twenty-five LANDSAT satellite images of the study sites are also included in the analysis. Examples of the use of remote sensing data in quantitatively estimating total particulate loading in determining water types, in assessing transport across international boundaries, and in supporting numerical current modeling are included. The importance of coordination of aircraft and ship lake surveys is discussed, including the use of telefacsimile for the transmission of imagery

Disorder-induced critical behavior in driven diffusive systems

Using dynamic renormalization group we study the transport in driven diffusive systems in the presence of quenched random drift velocity with long-range correlations along the transport direction. In dimensions $d\mathopen< 4$ we find fixed points representing novel universality classes of disorder-dominated self-organized criticality, and a continuous phase transition at a critical variance of disorder. Numerical values of the scaling exponents characterizing the distributions of relaxation clusters are in good agreement with the exponents measured in natural river networks

Transport on river networks: A dynamical approach

This study is motivated by problems related to environmental transport on river networks. We establish statistical properties of a flow along a directed branching network and suggest its compact parameterization. The downstream network transport is treated as a particular case of nearest-neighbor hierarchical aggregation with respect to the metric induced by the branching structure of the river network. We describe the static geometric structure of a drainage network by a tree, referred to as the static tree, and introduce an associated dynamic tree that describes the transport along the static tree. It is well known that the static branching structure of river networks can be described by self-similar trees (SSTs); we demonstrate that the corresponding dynamic trees are also self-similar. We report an unexpected phase transition in the dynamics of three river networks, one from California and two from Italy, demonstrate the universal features of this transition, and seek to interpret it in hydrological terms.Comment: 38 pages, 15 figure

Potensi Revitalisasi Transportasi Sungai Di Provinsi Lampung

The river provides a natural potential as a medium of movement for water vehicles such as boat or ship. Especially for the transport of goods, the revitalization of river transport can play an important role in load reduction in land transport by truck, so as to reduce the acceleration of road damage caused by truck traffic loads. To implement the river transport revitalization in the Province of Lampung, it is required the design and production of ships that have special characteristics that are suitable for a wide but shallow river