The dynamics of river bed evolution are known to be notoriously complex affected by near-bed turbulence, the collective motion of clusters of particles of different sizes, and the formation of bedforms and other large-scale features. In this paper, we present the results of a study aiming to quantify the inherent nonlinearity and complexity in gravel bed dynamics. The data analyzed are bed elev...

Geomorphic and hydraulic processes, which form gravel bars in large lowland rivers, have distinctive characteristics that control the magnitude and spatial patterns of infiltration and exfiltration between rivers and their immediate subsurface environments. We present a bedform-infiltration relation together with a set of field measurements along two reaches of the San Joaquin River, CA to illu...

Open-framework gravel has permeability, k, above the measurement range of most laboratory constant-head permeameters because the head difference across the length of conventional permeameters is too small to be measured. Here we addressed the challenge of measuring the high k by using a 3 m long permeameter. The head difference over this length was of the order of 10(-2) to 10(-3) m, which we c...

rotavirus, a triple-layered non-enveloped member of the reoviridae family, obtained a transient membrane envelope when newly synthesized subviral particles bud into the endoplasmic reticulum (er). as rotavirus particles mature, they lose their transient membrane and obtain outer layer. it is mostly believed that only double layered particles bud into the er. the present study describes that the...

Septic systems can be a potential source of phosphorus (P) in groundwater and contribute to eutrophication in aquatic systems. Our objective was to investigate P transport from two conventional septic systems (drip dispersal and gravel trench) to shallow groundwater. Two new in-situ drainfields (6.1 m long by 0.61 m wide) with a 3.72 m2 infiltrative surface were constructed. The drip dispersal ...

Four seabed backscatter image classification methods that differ substantially in their approach are compared, using a dataset from Sydney Harbour. The first method is based on GeoAcoustic’s commercial GeoTexture software. GeoTexture relies on the user to extract features from the image to train the system to recognize textures based on a statistical method, before classifying the entire image....

How to make relevant decisions to preserve the quality of the hydrosystem and human wellbeing? This work assists in answering this question at a local level. A negotiation support simulator for a regional project is proposed which includes the numerous actors involved in water resource management projects. This simulator combines negotiation support tools and role-playing game for gravel extrac...

Bankfull discharge was identified in some 30 gravel-bed rivers representing in total c. 40 gauging stations. The catchment sizes vary from 4km2 to nearly 2700km2. Bankfull discharge value increases with basin size. In the case of gravel-bed rivers developed on an impermeable substratum, the following equation emerges: Qb=0·087 A 1·044. Bankfull discharge recurrence interval was determined by fi...

Granulometric, mineralogical and morphological investigation of the sea-bottom sediments in the Grgur Channel has revealed fi ve sediment types, the most frequent of which are muds containing some amount of coarse fractions (sand and gravel). The coarsest fractions are predominantly composed of recent shell fragments. Unexpected well rounded carbonate gravel was found SE of Prvić Island in 83 m...

Analysis of frozen cores of chum salmon egg pockets collected in the fall revealed that spawning activity purged about 75% of the fine sediments Corn the stream bed. The egg pocket was one of four distinct vertical strata detected in the cores. There was an undisturbed layer below the egg pocket and cover and bridge strata above the egg pocket, defined by their particle size distributions. Howe...