1. Deloffre J., Druine F., Verney, R., Lemoine, J.P., Lafite, R.
SPM Workshop, Brussels, Oct. 2016
Automated network in estuaries: Challenging issues associated with sensor and SPM variability
Deloffre J., Druine F., Verney, R., Lemoine, J.P., Lafite, R.

2. Long term monitoring on the Seine estuary
Plume (Balise A) ETM (Fatouville & Tancarville) Fluvial (Val des leux & Rouen)
5 Stations Along the Seine estuary:

3. Long term monitoring on the Seine estuary
Instrument: YSI 6600V2
1 measurement every 5mns
Sensors: NTU (fluvial part) or NTU (ETM & plume)
Turbidity sensor: NTU or NTU
Depth : 1m above the water surface using buoy (fluvial part)
and 1m over the seabed (ETM and plume)
Validated data : between 85 and 90%

4. Objective
Objective: Measuring sediment fluxes using SYNAPSES data (and associated standard deviation).
Topic: NTU vs SPM concentration
Sampling strategy
Measurements from piers (~ 50 days achieved):
Mainly under Spring tides (between 6.35 et 7,05m) conditions.
Vertical Profiles every 15’
› CTD Seabird 19plusV2 probe associated with an OBS3+ (2Hz)
› YSI 6600V2 multi-parameter probe (1Hz)
› LISST 100X-C (Laser In-Situ Scattering and Transmissometry) (1Hz)
Coupled with water samples (every hour): 1 meter depth and 1m above the bed
Assess current velocity from an ADCP (RDI Workhorse Sentinel 600kHz)

5. Pressure sensor (Niskin)
SSC and Turbidity measurement
Water Samples
Pier profiles
Pressure sensor (Niskin)

6. SSC and Turbidity measurementX2

7. Turbidity vs SSC: Instrument
Probe: between 1.7 and 2.6

8. Turbidity vs SSC: Site

9. Turbidity vs SSC: Site
Hach : 1.4 and 2.5
OBS3+ : 1.3 and 2.8
YSI: between 1.1 and 2.4

10. Hydrodynamics (temporal and spatial variability)
Spring tide
Neap tide
SPM concentration (mg/l)
Turbidity (NTU)
700m3/s (winter)
200m3/s (summer)

11. Turbidity vs SPM calibration coeff(mg/l)
Hydrodynamics (temporal and spatial variability)
Turbidity vs SPM calibration coeff(mg/l)
Turbidity vs SPM coeff
Turbidity vs SPM coeff
Turbidity vs SPM calibration coeff(mg/l)

12. Synthesis
Seasonnal (ETM)
Seasonnal (fluvial)

13. Work in progress/next step
Lessons learned
Acceptability vs time?
Each sensor need an accurate standardized calibration,
Seine estuary: slope ranging between « 1 and 5 » => need to take into account this variability to estimate sedimentary fluxes.
Turbidity vs SPM: Site specific and significant variations during the year (seasonal effect).
Work in progress/next step
Need to integrate SPM caracteristics: grain size (LISST) data and organic mater.
Statistical analysis to deeply decipher the influence of each parameter
Lab experiment (sensor response).

14. Thanks for your attention

15. Turbidity vs SSC: Site