Large wood hydraulics - a fluvial process of growing interest

<p>In the last decade, the perception of large wood in rivers has shifted from a hazard perspective towards a valuable and required component of the river ecosystem. Consequently, there is a demand to quantify and predict the effects of large wood on flow, morphology and retention.</p><p>The research programme ‘Large Wood Hydraulics’ investigates the flow and turbulence characteristics of instream large wood. Within the programme, field measurements and lab experiments are conducted and cover different wood types (tree morphology, branching pattern), their position / orientation in the cross-section and single or multiple elements (wake interference). Field measurements were carried out in river Mulde, Germany within the BMBF-project ‘Wilde Mulde’ and flume experiments in the hydraulics lab of  TU Vienna.</p><p>The aim of the study is to predict the effects of different wood configurations to promote the use of wood in river restoration schemes.</p>

General opportunities and problems of point-bar to establish kilns

Point bar is a typical depositional landform of fluvial process. This physical feature is commonly found in the lower part of the Hooghly river. Point bars are very suitable location for brick kilns. There are many causes for choosing such a fragile landscape to set up this industry. Brick industry is an ancient industry in India. It is a distinctive type of enterprise of point bars and of inland vacant area as well, throughout the country. However, gradually the point-bar kilns are becoming a sick industry. The basic opportunities to set up the point-bar kilns have been highlighted in this article. Besides that, the article is also concerned about the problems coming out of the function of the point-bar kilns along with some probable remedies.

Susceptibilidade à Erosão Relacionada ao Escoamento Superficial na Sub-Bacia do Alto Mundaú, Ceará, Brasil (Susceptibility to Erosion Related to Surface Runoff in the Sub-Basin of the Upper Course of the Mundaú, Ceará, Brazil)

As propriedades morfométricas, climáticas e biológicas de uma bacia hidrográfica são fatores determinantes de seus processos morfogenéticos relacionados ao trabalho fluvial, como a erosão, o transporte e a deposição de sedimentos. Nessa perspectiva o escoamento superficial e suas modalidades constituem um dos principais agentes erosivos em bacias hidrográficas semiáridas. A erosão dos solos apesar de ter causas naturais como a morfometria do relevo, os aspectos físicos do solo e a intensidade e duração da precipitação, pode ainda ser intensificada pela ação antrópica através do uso do solo como recurso natural. No entanto, a elaboração de modelos capazes de simular esses fenômenos em bacias hidrográficas continua sendo um desafio. Os avanços na cartografia digital trouxeram uma nova perspectiva na criação de modelos geográficos assim como na sua representação através de mapas. No presente artigo propõe-se um modelo de representação espacial da susceptibilidade à erosão da Sub-bacia do Alto Mundaú, comparando seus resultados com variáveis morfométricas pertinentes às propriedades erosivas e ao escoamento superficial. A Sub-bacia hidrográfica do Alto Mundaú localiza-se à noroeste do estado do Ceará, a barlavento do maciço de Uruburetama pertencente ao município de mesmo nome. Com auxílio de ferramentas de geoprocessamento, foi possível a extração dos parâmetros morfométricos da sub-bacia. A criação do modelo de susceptibilidade à erosão obedeceu à técnica de sobreposição de camadas (layers) conhecida como álgebra de mapas, onde foram combinadas camadas matriciais com informações de declividade, intensidade pluviométrica, uso e cobertura do solo e tipos hidrológicos de solo. A B S T R A C T Morphometric, climatic and biological properties of a watershed are determining factors of their morphogenetic processes related to fluvial process, such as erosion, transport and deposition of sediments. From this perspective, surface runoff and its modalities are a major erosive agents in semi-arid watersheds. Despite natural causes such as morphometry relief, the physical aspects of soil and the intensity and duration of rainfall, Soil erosion can still be intensified by human action through the use of soil as a natural resource. However, the development of models able to simulate these phenomena in watershed remains a challenge. Advances in digital cartography brought a new perspective on creating geographic models as well as its representation through of the maps. In the present paper we propose a spatial representation model of susceptibility to erosion of the Sub-basin of the upper reaches Mundaú by comparing their results with morphometric variables relevant to the erosive properties and surface runoff. The Sub-basin of the Upper reaches Mundaú is located at the northwest of the state of Ceará, in the massive of the Uruburetama windward belonging to the municipality of the same name. With the help of geoprocessing tools, the extraction of morphometric parameters of the sub-basin was possible. The creation of the susceptibility to erosion model obeyed layers overlay technique known as map algebra, which were combined with matrix layers slope information, rainfall intensity, land use and land cover and hydrological soil types. Keywords: Morphometry; Surface Runoff; Map algebra.

Incipient Motion Experiment of Sediment in Silty-Sand Coast

Sediment issues, especially the channel siltation issues in silty-sand Coast are becoming more and more prominent as the development of harbor construction in silty-sand coasts. In order to learn the incipient motion characteristics under influence of wave, current and wave-current combination of sediment in silty-sand coasts, provide necessary parameters for engineering analysis of fluvial process and mathematical model analysis, and then provide science and technology fundamentals for harbor construction, experiments are carried out with samples from the under construction Haiyanghong port area in Dandong. Under the same condition, when the initial sediment density, which is of great influence on incipient motion, is larger, the incipient motion is harder to occur; and wave is the main hydrodynamic force to devote to sediment incipient motion. Generally, sediment in silty-sand coasts shows the characteristic of silt. However, fine sediment rises obviously in the experiment and the water gets muddy very easily as the existence of a certain amount of clay.

The Fluvial Process of Wandering Reach in the Lower Yellow River

There are three characteristics of river channel which are wandering, transitional, bending in the Lower Yellow River. The fluvial process is complicated and variable. The channel characteristics of wandering reach was analyzed, and then based on the measured data and model test data, the formation conditions, basic characteristics and influencing factor of the fluvial process law in wandering river were analyzed. All of this can provide technical guidance and theoretical support for river regulation of the Lower Yellow River.