Experiments on the effect of inflow and outflow sequences on suspended sediment exchange rates
نویسندگان
چکیده
In laboratory experiments, the influence of inflow and outflow sequences on the behavior of fine sediment was investigated. The experimental set-up consisted of two interconnected rectangular basins, between which water was moved back and forth. Suspended sediment concentration in the main basin as well as the sediment exchange rates were derived from turbidity measurements.The suspended sediment ratio, SSR, and sediment exchange rates (influx sediment rate, ISR, and evacuated sediment rate, ESR) were measured. In twenty test runs, a parametric study on the magnitude and frequency of inflow and outflow cycles, the relative duration between inflow and outflow sequences, the initial sediment concentration, and the intake position was done. An initial test with stagnant water described the settling behavior of fine sediment and served as a reference scenario.The test results show that settling of fine particles near the intake/outlet structure can be considerably reduced by the nature of the inflow and outflow sequences. High cycle magnitude and frequency lead to maximum suspended sediment ratio in the system. For low discharges, the evolution of suspended sediment concentration cannot be directly correlated to the inflow and outflow cycles. However, compared to “no operation” conditions, the suspended sediment ratio could be increased by 10% to 40% locally. For high discharge, the evolution of suspended sediment concentration correlated with discharge cycles and suspended sediment ratios between 50% and 80% higher than for stagnant water could be achieved. Similar ratios could be obtained when the intake is located closer to the bottom or to the free water surface.Meanwhile, the overall sediment balance remained in equilibrium over the test period, indicating that the influx and evacuated sediment rates are not significantly influenced by the inflow and outflow cycles. & 2017 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved.
منابع مشابه
The Impact of Financial Sanctions on Capital Inflow and Outflow (case of Iran)
The paper aims to examine the impact of financial sanctions on capital inflow and outflow in Iran. The research question is about examining the effect of financial sanctions on FDI inflow and capital outflow in Iran. We used the intervention model as an econometric method to estimate the impact during 2005-2019. The paper discussed three periods. From 2005 to 2010, severe financial sanctions ne...
متن کاملSurvey of Integrated and Non-Integrated Formulae on Suspended Sediment Load; Case Study: Soolegan River, North Karoon Basin, Iran
Predictions of suspended sediment load for Soolegan River, Iran using selected empirical equ-ations were made based on 355 data sets. Data include flow discharges from 3.11 m3/s to 43.81 m3/s, flow velocities from 0.22 m/s to 1.03 m/s, and flow depths from 0.5 to 1.03 m. Equations of Einstein (1950), Bagnold (1966), Toufalleti (1968), Brooks (1963), Chang-Simons-Richardson(1965),Lane-Kalinske (...
متن کاملUnderstanding rill erosion rate in dry-wet condition
Rill erosion is considered to be the most important process affecting soils created by the concentrated flow of water. In this research to quantify sediment transport and runoff in natural rills, two rill experiments under dry and wet conditions were accomplished in November 2013 in the Golestan Dam. Filed experiments lead to a closer understanding of the dynamics and power of different soil er...
متن کاملSpatio-Temporal Variation of Suspended Sediment Concentration at Downstream of a Sand Mine
The growing population led to greater human need to use natural resources such as sand and gravel mines. Direct removal of sands from the bed river leads to increase suspended sediment concentrations in downstream of harvested area and creates other problems viz. filling reservoirs, change in hydraulic characteristics of the channel and environmental damages. However, the range of temporal and ...
متن کاملOne- and two-dimensional UVP velocity sampling in a cuboidal basin subject to in- and outflow sequences
In the framework of an experimental study on the influence of inand outflow sequences on flow patterns and suspended sediment behavior in reservoirs, flow fields and inflowing jet were sampled by Ultrasonic Velocity Profilers (UVP). The laboratory set-up consisted of two interconnected rectangular basins between which water was moved back and forth. A parametric study was performed on the magni...
متن کامل