1: The French National Institute for Agricultural Research Application of Delft3D to evaluate the spatio- temporal variability of Lake Geneva ecological status Delft3D User Meeting - 03 November 2016 Frédéric Soulignac 1 , P.-A. Danis 2,10 , D. Bouffard 3 , V. Chanudet 4 , E. Dambrine 5 , Y. Guenand 6 , B. Guillermin 1 , T. Harmel 7,10,2 , B. Ibelings 8 , I. Kiefer 3 , D. Trevisan 1 , R. Uittenbogaard 9 and O. Anneville 1 3 4 5 6 7 8 9 10 2: The French National Agency for Water and Aquatic Environments
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DSD-INT 2016 Application of Delft3D to evaluate the spatio-temporal variability of Lake Geneva ecological status - Soulignac
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1: The French National Institute for Agricultural Research
Application of Delft3D to evaluate the spatio-
temporal variability of Lake Geneva
ecological status
Delft3D User Meeting - 03 November 2016
Frédéric Soulignac1, P.-A. Danis2,10, D. Bouffard3,
V. Chanudet4, E. Dambrine5, Y. Guenand6, B. Guillermin1,
T. Harmel7,10,2, B. Ibelings8, I. Kiefer3, D. Trevisan1,
R. Uittenbogaard9 and O. Anneville1
3 4 5 6 7 8 9 10
2: The French National Agency for Water and Aquatic
Environments
Lake Geneva
Image from CIPEL, 2016
Lake catchment (7 419 km2)
Catchment of the Rhône river
after Lake Geneva
Rivers
Border France-Switzerland
Lake Geneva
2 Frédéric Soulignac, Delft3D User Days
2016
Surface area = 580 km2
Max depth = 309 m
Residence time = 11 years
Introduction – Material and methods – Results and discussion – Conclusions
I work here!
• European Water Framework Directive (EU, 2000)
• 3 types of indicators: biological, physico-chemical and hydro-morphological
• In France (French technical guide for evaluating ecological status of lakes
and reservoirs, 2016 ; De Bortoli and Argillier, 2008)
– Annual evaluation based on 4 samples taken over the year and at 1 sampling
station
– Parameters
• Chlorophyll a concentration (Chla)
• Ammonium concentration (NH4)
• Nitrate concentration (NO3)
• Total phosphorus concentration (TP)
• Secchi depth (Secchi)
• And others
• Lake Geneva
Evaluation of Lake ecological status
Frédéric Soulignac, Delft3D User Days
2016 3
Image from CIPEL, 2016
Monitoring station SHL2
Introduction – Material and methods – Results and discussion – Conclusions
Satellite observations
• Chla heterogeneities in Lake Geneva (Kiefer et al, 2015)
Frédéric Soulignac, Delft3D User Days
2016 4
Do spatio-temporal heterogeneities bias our estimation of lake ecological
status?
More generally, do these heterogeneities induce uncertainties in our
classification of lakes by ecological quality?
Introduction – Material and methods – Results and discussion – Conclusions
Objectives
• To simulate 5 parameters used for the estimation of lake ecological status
(Chla, NH4, NO3, TP and Secchi)
• To evaluate the variability of Lake Geneva ecological status linked to the
choice of the 4 sample dates
• To evaluate the spatial variability of Lake Geneva ecological status caused
by spatial heterogeneities
• To locate the most representative sampling station of Lake Geneva
5 Frédéric Soulignac, Delft3D User Days
2016
Introduction – Material and methods – Results and discussion – Conclusions
Numerical domain
Frédéric Soulignac, Delft3D User Days
2016 6
820 curvilinear grids (resolution 1 km2)
100 vertical Z-layers (resolution from 1 to 7 m)
Introduction – Material and methods – Results and discussion – Conclusions
Delft3D-FLOW model
Frédéric Soulignac, Delft3D User Days
2016 7
A
B
C D
A
B
C
D
Introduction – Material and methods – Results and discussion – Conclusions
Wind episode
Mixing regime explains Chla heterogeneity (Soulignac et al., 2016)
Delft3D-ECO processes configuration
• Reminder of the 1st objective: to simulate Chla, NH4, NO3, TP and Secchi
• Primary producers: BLOOM (Los, 2009) – Chla derived from 4 phytoplankton groups: diatoms, flagellates, green and blue green algae