نتایج جستجو برای: sediment concentration
تعداد نتایج: 413988 فیلتر نتایج به سال:
There were similar distribution characteristics for acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in surface sediments, and the concentrations of AVS and SEM decreased from the deposition area to the center of the bay (lake). The ratio of AVS to SEM was <1 in the surface sediments, indicating that heavy metals in surface sediments may be bioavailable. The concentration ...
Computation of accurate sediment loads in rivers where the transport of suspended sediment is at least partially regulated by changes in the upstream sediment supply requires high-resolution measurements of suspended-sediment concentration that are collected independently of waterdischarge data. To meet this objective, a multi-frequency acoustic system has been developed and tested on the Color...
A three-dimensional water quality model was developed for simulating temporal and spatial variations of phytoplankton, nutrients, and dissolved oxygen in freshwater bodies. Effects of suspended and bed sediment on the water quality processes were simulated. A formula was generated from field measurements to calculate the light attenuation coefficient by considering the effects of suspended sedi...
A three-dimensional mixture theory model (SedMix3D) was used to simulate the flow and sediment transport over vortex ripples for scaled laboratory conditions. SedMix3D treats the fluid-sediment mixture as a continuum of varying density and viscosity with the concentration of sediment and velocity of the mixture calculated using a sediment flux equation coupled to the Navier-Stokes equations for...
So far, many attempts have been made to identify the relation between discharge and suspended sediment load.Empirical relations such as sediment rating curves are often applied to determine the average relationship between discharge and suspended sediment load. This type of models generally underestimates or overestimateswhen sediment load are estimated from water discharge using least squares ...
Sediment loss and nutrient cpncentrations in runoff were evaluated to determine the effects of site preparation burning on a recently harvested loblolly pine (Pinur taeda L.) site in east Texas. Sediment and nutrient losses prior to treatment were approximately the same from control plots and pretreatment burn plots. Nutrient analysis of runoff samples indicated that the prescribed burn caused ...
Soil is very important for the production of crops and foodstuffs. One of the most important environmental crisesin the relationship with soil is the phenomenon of soil loss and therefore the soil conservation is very important. In conditions that, there is not the possibility of establishing vegetation, the use of soil conditioners can be useful in controlling soil loss. The present study wa...
Variations of suspended sediment concentration over ripples in regular waves were described using an existing numerical model system. Nielsen’s (1992) empirical formula for sediment entrainment rate from the bed surface was used with an additional scale factor in the model system. The model system was applied to two typical laboratory experimental conditions selected for description of the vari...
Transport of suspended sediment between the two reservoirs of a pumped-storage plant in Switzerland was monitored over an 8-month period. A turbidity probe was installed on the upstream end of the pressure shaft, in which real-time monitoring was ensured by automatic data acquisition and remote control. The suspended sediment concentration in the reservoirs varies considerably over the course o...
Hysteresis patterns of different sediment particle sizes were studied via a detailed laboratory study and modelling. Seven continuous rainfall events with stepwisevarying rainfall intensities (15, 30, 45, 60, 45, 30 and 15 mmh-1, each 20 min duration) were conducted using a 5-m× 2-m erosion flume. Flow rates and sediment concentration data were measured using flume discharge samples, and interp...
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