Management of turbidity current venting in reservoirs under different bed slopes

Chamoun, Sabine; Cesare, Giovanni De; Schleiss, Anton

doi:10.1016/j.jenvman.2017.09.030

Cited by 13 publications

(8 citation statements)

References 30 publications

(37 reference statements)

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“…In the following, the LVE obtained with the early venting with Φ ¼ 115% is compared with that of the in-time venting with Φ ¼ 100%, Φ ¼ 115%, and Φ ¼ 135%. Note that the venting degree Φ ¼ 100% was previously found to be the optimal venting degree when in-time venting is performed on a horizontal bed (Chamoun et al 2017a), and Φ ¼ 135% the optimal venting degree for in-time venting on 2.4% and 5.0% slopes (Chamoun et al 2017b). Figs.…”

Section: Local Venting Efficiency: Early Venting Versus In-time Ventingmentioning

confidence: 73%

“…In previous research, the typical behavior of outflow concentrations was experimentally evaluated when venting was performed with continuously fed turbidity currents (e.g., Chamoun et al 2017b;Lee et al 2014). It is characterized by a first phase of increasing concentration followed by a quasi-steady state.…”

Section: Required Venting Duration After the End Of The Floodmentioning

confidence: 99%

“…These parameters include the outlet's discharge during venting (Chamoun et al 2017a;Lee and Yu 1997;Morris and Fan 1997); the geometric characteristics of the reservoir, notably the bed slope affecting the dynamics of the approaching current in the vicinity of the dam; the duration of venting (Basson and Rooseboom 1997); the number, dimensions, and position of the low-level outlets; as well as the timing of the opening of the outlet (Chen and Zhao 1992). In previous publications, the authors have investigated the systematic effect of the outlet's discharge (Chamoun et al 2017a) and the influence of different bed slopes (Chamoun et al 2017b) on the sediment release efficiency of venting. Based on these investigations, favorable conditions were drawn on the outlet's opening and topographic conditions close to the outlet.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Operational Timing on the Efficiency of Venting Turbidity Currents

2018

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Reservoir sedimentation is gaining growing attention as dams are aging, due to economic and environmental consequences. Venting of turbidity currents is one of many sediment management techniques, highly recommended when water is in shortage. The venting operation is experimentally investigated using two reservoir bed slopes. The main research questions concern the opening timing of bottom outlets and the duration of venting. The timings tested are relative to the arrival of the current at the outlet. The results showed that in-time venting, synchronized with the arrival of the turbidity current at the outlet, is more efficient than early or late venting. It is recommended to start opening the gates when the turbidity current is around 300 m upstream of the outlet, so that the evacuation is synchronized with the arrival of the current at the dam. Additionally, venting should not be stopped immediately after the end of the turbidity current flow but should instead last for a certain time in order to evacuate the muddy lake depending on the outflow discharge.

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Section: Local Venting Efficiency: Early Venting Versus In-time Ventingmentioning

confidence: 73%

Section: Required Venting Duration After the End Of The Floodmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Operational Timing on the Efficiency of Venting Turbidity Currents

2018

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“…Danau atau waduk merupakan salah satu ekosistem air tawar yang menyediakan berbagai jasa ekosistem mulai habitat biota perairan, rekreasi dan irigasi (Stoddard et al, 2016). Pengoperasian dan pemanfaatan waduk harus memenuhi beberapa persyaratan sehingga fungsi waduk dapat dimanfaatkan dalam jangka panjang (Chamoun et al, 2017).…”

Section: Pendahuluanunclassified

Prediksi Tingkat Kekeruhan (Turbiditas) Menggunakan Citra Satelit Sentinel-2a Di Waduk Jatiluhur, Jawa Barat

Rahman

Astuti

Warsa

et al. 2021

JSDA

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Turbidity is one of the remote sensing indicators on the reservoir physical characteristics that can reduce its brightness level. Measuring reservoir physical characteristics traditionally are expensive and time consuming as well. Therefore, remote sensing is used as an alternative for turbidity measurement because it can provide data and products spatially, temporally as well as synoptically with low cost. This study aims to obtain an algorithm using a combination of in-situ turbidity data measurement and Sentinel-2A satellite imagery data. The resulting algorithm can be used to predict and map turbidity in Jatiluhur Reservoir. Based on the multiregression between B3 (green band) and B4 (red band) with in-situ turbidity data measurement, it is obtainted that the regression coefficients are a = 76.77, b = 63.22 and c = -34.31 respectively, with the equation of Y = 76, 77+63.22 X1-34.31X2 (Y=predicted turbidity, X1=lnB3, X2=lnB4). The correlation value between in situ and turbidity prediction is quite strong with a coefficient of determination (R2) of 0.60, and Root Mean Square Error (RMSE) of 1.95 NTU. Based on Mean Absolute Percentage Error (MAPE) analysis, the deviation is 31.1%. High levels of turbidity can reduce the main productivity of water and its organisms, especially in respiratory and visual problems. Sedimentation caused by high turbidity levels can make siltation which results in reservoir capacity loss.Keywords: Turbidity, remote sensing, Sentinel-2A satellite imagery data, Jatiluhur Reservoir, siltation

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“…Density currents are divided into sediment density currents, salinity density currents, and temperature density currents [25]. Sediment density currents and temperature density currents are common in source water reservoirs, with the former carrying serious exogenous pollution [26,27].…”

Section: Introductionmentioning

confidence: 99%

Correlation Analysis of Rainstorm Runoff and Density Current in a Canyon-Shaped Source Water Reservoir: Implications for Reservoir Optimal Operation

Wei-xing

2018

Water

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Extreme weather has recently become frequent. Heavy rainfall forms storm runoff, which is usually very turbid and contains a high concentration of organic matter, therefore affecting water quality when it enters reservoirs. The large canyon-shaped Heihe Reservoir is the most important raw water source for the city of Xi'an. During the flood season, storm runoff flows into the reservoir as a density current. We determined the relationship among inflow peak discharge (Q), suspended sediment concentration, inflow water temperature, and undercurrent water density. The relationships between (Q) and inflow suspended sediment concentration (C S0 ) could be described by the equation C S0 = 0.3899 × e 0.0025Q , that between C S0 and suspended sediment concentration at the entrance of the main reservoir area S1 (C S1 ) was determined using C S1 = 0.0346 × e 0.2335CS0 , and air temperature (T a ) and inflow water temperature (T w ) based on the meteorological data were related as follows: T w = 0.7718 × T a + 1.0979. Then, we calculated the density of the undercurrent layer. Compared to the vertical water density distribution at S1 before rainfall, the undercurrent elevation was determined based on the principle of equivalent density inflow. Based on our results, we proposed schemes for optimizing water intake selection and flood discharge during the flood season.

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Management of turbidity current venting in reservoirs under different bed slopes

Cited by 13 publications

References 30 publications

Influence of Operational Timing on the Efficiency of Venting Turbidity Currents

Influence of Operational Timing on the Efficiency of Venting Turbidity Currents

Prediksi Tingkat Kekeruhan (Turbiditas) Menggunakan Citra Satelit Sentinel-2a Di Waduk Jatiluhur, Jawa Barat

Correlation Analysis of Rainstorm Runoff and Density Current in a Canyon-Shaped Source Water Reservoir: Implications for Reservoir Optimal Operation

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