all experiments in this study were carried out in a flume which was located in the hydraulic laboratory of technical faculty in guilan university. the wave flume was 12 m long, 0.5 m wide, 0.5 m high and equipped with a wave-producing system and ultrasonic sensors. the objectives of current experimental study are to investigate sediment transport, bed formation and sustainability of sandy beach...

A thorough knowledge of sedimentary processes that cause the production, transportation and deposition in varied hydrodynamic conditions, is most important in environmental reconstruction. Size analysis of sediment is an essential requirement to understand their mechanism of transportion and deposition. Textural parameters are primarily related to made of transportation and energy condition of ...

This laboratory work examines the relationship between turbidity (NTU) and total suspended sediment concentration (TSS, mg/L) for a Cecil Ap soil, a common Southeastern Piedmont soil type. We show a 1:1 correlation between NTU and TSS for the silt and clay fractions, but a smaller ratio for clay and bulk-soil samples. These results suggest that NTU measurements can be used to estimate sediment ...

Capitellid polychaetes are generally considered opportunistic species, characteristic of organically enriched and disturbed habitats. The feeding behavior of capitellids dramatically affects physical properties of sediments by repackaging sediment particles into large fecal pellets that persist for years. Particle size selection by Capitella sp. I was quantified using two approaches. Organic-ri...

In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a commonly used assumption. However, not all natural gravel channels actually conform to this...

The Burdekin River catchment ( 130,400 km) is a seasonally dry tropical catchment located in north-east Queensland, Australia. It is the single largest source of suspended sediment to the Great Barrier Reef (GBR). Fine sediments are a threat to ecosystems on the GBR where they contribute to elevated turbidity (reduced light), sedimentation stress, and potential impacts from the associated nutri...

Sharks are apex-predators that play an important role in past and present aquatic food webs. However, their diet - especially extinct species is often not well constrained. Dental microwear texture analysis (DMTA) has been successfully applied to reconstruct feeding behaviours of different terrestrial vertebrates. unlike mammals, food-to-tooth contact sharks rather limited because only larger p...

The basic ecology of seagrass beds was investigated by comparing biomass, productivity and density of Thalassia testudinum (turtle grass) at three sites: Puerto Vargas, Punta Cahuita and Rio Perezoso, in Cahuita National Park, Limón, Costa Rica, over a two month period (March-April 1999). Above ground biomass, density, and productivity were highest in the Puerto Vargas site while Punta Cahuita ...

Lake Powell is a large reservoir in Utah and Arizona that has experienced large changes in water level during a recent drought. As a first step in assessing the connection between hydrologic and chemical changes at Lake Powell, we characterized the particle size and solid-phase bulk concentrations for 31 elements and 25 minerals in sediment from the inflow region and some shoreline locations by...

The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by the Water Resources Division for analysis of fluvial sediments to determine the concentration of suspendedsediment samples and the particle-size distribution of both suspended-sediment and bed...