abstract in all river engineering projects, determination of flow resistance is essential. most commonly, the manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. over the past decades little or no study has been conducted to investigate the effects of particle shapes on manning roughness coefficient. therefore, it is the...

The origin of the microbial community in a coastal marine sediment was investigated by examining the physical, chemical, and microbial characteristics of the sedimenting particles in Halifax Harbor, Canada. Particles were collected using particle interceptor traps placed on the sediment surface. The measured rate of particle accumulation compared to the sediment accumulation rate indicates that...

importance of sediment storage has been expressed as being higher than that of water in floodwater spreading networks. to determine the contribution of each geological formation in sediment input of gachsaran floodwater spreading station after 12 years of flood spreading, sediment sampling was conducted in 16 points and 0-15 cm depth of the field. using dry sieve analysis, all samples were anal...

Salmonid embryos depend on the adequate flow of oxygenated water to survive and interstitial passageways to emerge from the gravel bed. Spawning gravels are initially cleaned by the spawning female, but sediment transported during subsequent high-runoff events can nfiltrate the porous substrate. In many gravel-bed channels used for spawning, most of the infiltrating sediment consists of sand an...

HIGHLIGHTS: Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H2S. Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended...

Phosphate interacts with inorganic sediment particles through sorption reactions in streams. Collectively, this phosphorus (P) buffering mechanism can be an important determinant of soluble reactive P (SRP) concentrations. If sorption reactions control SRP concentrations in a stream, then differences in sediment characteristics may cause spatial differences in SRP concentrations. This predictio...

In aquatic environment, microorganisms such as bacteria and microalgae usually secrete a matrix of mucilaginous extracellular polymeric substances (EPS) to form a “microbial biofilm” when they are associated with solid surfaces (e.g., sediment particles, plant surfaces). Biofilms and the associated mucilaginous secretions form a cohesive matrix surrounding sediment particles, modifying the sedi...

The interaction between pollutants and sediment particles often occurs on the particle surface, so surface properties directly affect surface reaction. The physical and chemical processes occurring on sediment particle surfaces are microscopic processes and as such need to be studied from a microscopic perspective. In this study, field emission scanning electron microscopy (SEM) and energy disp...

today's, adverse effects of off-site erosion, namely damages received from sediment, is a serious bioenvironmental problem. one of the methods for temporary soil stabilization before permanent rehabilitation of vegetation cover, especially on slopes, for mitigating of bioenvironmental contaminants, is using materials having property to cementate the dispersed particles on the soil surface....

The fall velocity of sediment particles plays a key role in sediment transport studies. Researchers have attempted to determine the terminal fall velocity, and most of the studies in this regard have been based on experimental, quasi-experimental, and in-situ measurements. The present study aimed to use a numerical model to estimate the fall velocity of a single sediment particle in distilled a...