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- 1. Densitometric probe basedon non-differential pressure the technique allowing to follow suspended matter loads at very high concentrations Department of Water Pollution Control D. Petrovic, A. Marescaux, J-P. Vanderborght & M. A. Verbanck IT4water project
- 2. Suspended sediment monitoring:no universal technique FIT LISST WTW ViSolid Advanced optical probes Gamma Alpha Nuclear probes UHCM aDcp Densitune Vibrating device Acoustic methods Remote Sensing Densitometry (760 - 900 nm) Manual Differential pressure
- 3. Rapid changes inwater depth and suspended sediment concentrations (10 to 30 g/L). Surveillance bridge in Caojiaquan, Lower Yellow River, Northern China. Rapid changes in water depth and SSC (10 - 30 g/l) Caojiaquan, Lower Yellow River, Northern China St Donat-sur-Herbasse, France, 6 Sep 2008 Which sensing method is available to monitor SSC at these high concentrations ?
- 4. T° p p0 H’ pressure sensor in air radar limnimeter H pressure sensor& thermometer Densitometric probe – based of absolute pressure measurements Proxy method based on combination of four sensors M. A. Verbanck, D. Petrovic & J-P. Vanderborght International patent application N° PCT/EP2012/054135
- 5. 5 rw (T) = rw (T0 ) 1+b(T -T0 ) Cv = rw (T) rs - rw (T) p- p0 rw (T)gH -1 æ è çç ö ø ÷÷ suspended sediment volumetric concentration Densitometric probe – basic principles p= rL gH rL = (1-Cv)rW (T)+Cvrs
- 6. Observed suspended sedimentvolumetric concentration versus known suspended sediment volumetric concentration (relative error less than 9%) Test in static conditions 2,5 m deep cylindrical tank water level at 2 m water temperature & atm pressure constant test of various sensors
- 7. Amazon river plumedata: - campaign to test DensiTune instrument (acoustic characterization of sediments) - Lab "Acoustics and environmental Hydroacoustics”, ULB , June 2012 , led by Prof. Hermand Cv = rw (T) rs - rw (T) p- p0 rw (T)gH -C vsalt rsalt - rw (T) rw (T) -1 æ è çç ö ø ÷÷ Test in environment with non negligible salt presence
- 8. Densitometric probe –validation in natural environment Ecuador – Jadan river (SSC up to 25g/l) Jan-Apr 2014 – expected rain season
- 9. Results application incomplex geometry use of sensors with regular sensitivity Difficulties: unexpected weather conditions influence of air bubbles & floatables water level measurement problems Ecuador – Jadan river (Jan-Apr 2014 ) Densitometric probe – validation in natural environment
- 10. Densitometric probe –(potential) new test site Laval, Draix – French Southern Alps Monitoring since 1984 water level: before 1997: bulle-à-bulle, US, ellan & pressure sensor presently: US & conductivity based method SSC – sampling + optical device
- 11. Hyperconcentrated black marlyslurry 800 g/l on Aug 13, 1997 Densitometric probe concept applied on historical data at Laval maximal SSC in g/l
- 12. 0 50 100 150 200 250 300 350 400 450 500 31/07/1990 12:00 1/08/199000:00 1/08/1990 12:00 2/08/1990 00:00 SSC(g/l) SSC by filtration densitometric probe Densitometric probe concept applied on historical data at Laval
- 13. 13 question & issueswe would like to discuss reliability of water level measurements by pressure sensor (air bubbles, sediment presence) when to turn to another methods? best protection from dynamic effects search for a new test location – any suggestion? high concentrations & fine sediment particles
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- 15. advantages: monitoringhigh SSC continuous real-time monitoring dynamical alluvial rivers short time scales: local resuspension cost reduction additional water parameters info disadvantages: limited sensitivity: not appropriate for low suspended sediment concentrations 15 Densitometric probe – based of absolute pressure measurements
- 17. Gray, J. R.,and J. W. Gartner (2009), Technological advances in suspended-sediment surrogate monitoring, Water Resour.Res., 45, W00D29.