8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-1
Interaction between fluid mud and salinity – Results of a field survey in the Ems River, Germany
Christian Maushake Federal Waterways Engineering and Research Institute – Coastal Department (BAW-DH) Hamburg, Germany
Contact
Address BAW-DH Wedeler Landstraße 157 D-22559 Hamburg Germany
Website www.baw.de Email [email protected]
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-2
Christian Maushake (BAW)
Interaction between fluid mud and salinity Results of a field survey in the Ems River, Germany
8th workshop ‚Seabed Acoustics‘
11/2017
outline
• Study area “Ems River” one of the muddiest rivers in Europe • Vertical gradients of salinity under Fluid Mud conditions CTD / OBS – data • Formation of Fluid Mud during a tidal cycle SES survey data • How are these two effects correlated ? Main message • conclusion
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-3
Den 50 km mark The Ems: A hyper turbid estuary Suspended Sediment Concentration from the North Sea to the inner estuary The North Sea
• strong tidal asymmetry 20 km
• flood - oriented transport of sediment The Nether- lands Germany • salinity intrusion reaches far upstream • formation of contiguous fluid mud layers Tidal curve today
level
water SSC mg/l Tidal curve 50 years ago Gandersum (barrier)
Dollart Development of velocity
Suspended Solids Concentration (SSC) Leer from the North Sea to the Current inner estuary in mg/l. Papenburg Values indicate the order of magnitude! Schematic diagram Herbrum (weir) Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Den 50 km mark The Ems: A hyper turbid estuary Suspended Sediment Concentration from the North Sea to the inner estuary The North Sea
Fluid Mud 20 km The Nether- lands Germany
SSC mg/l
Gandersum • cohesiv (adhesiv) (barrier) • thixotropic Dollart
• littly spezific gravity Leer (high percentage of organic) Papenburg • minor trend to consolditate Herbrum (weir) Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-4
Motivation
Improvement of the ecological state (European Commission / Masterplan Ems2050)
Enhancement as an economic factor Waterway, Ship Yards, Harbours
Maintenance (dredging)
Knowledge gaps of fundamental processes
Interaction between Fluid Mud and salinity intrusion into the estuary
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
EMDEN CTD – Longitudinals: - salinity measurements in fluid mud Vertical profiles of Salinity / Turbidity JEMGUM ”typical” “inverse” estuarine Ems (Elbe, Cuxhaven) LEER
WEENER
PAPENBURG
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-5
EMDEN CTD – Longitudinals: - salinity measurements in fluid mud Vertical profiles of Salinity / Turbidity JEMGUM ‘typical’ “inverse” estuarine Ems (Elbe, Cuxhaven) LEER
WEENER
PAPENBURG
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
EMDEN Tidal cycle measurements on cross sections GANDERSUM
POGUM
cont. JEMGUM
current (vxyz), backscatter
LEER
Minutes discharge 풒
13 h WEENER cont. depth / acoustic layers
PAPENBURG 1 / hr RHEDE CTD, Turbidity
1 / hr WEHR watersamples HERBRUM Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-6
EMDEN Formation of a fluid mud layer at Jemgum GANDERSUM
Highwater POGUM
JEMGUM 2,5 h
LEER
~ 2,5 h before WEENER Highwater
(vavg ~ 0.75 m/s)
PAPENBURG RHEDE
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
EMDEN Cross section Jemgum - salinity / tidal cycle GANDERSUM
1 2 3 4 5 POGUM 6
JEMGUM
LEER
6 7 5 8 4 3 9 2 10
11 WEENER 12 1
7 8 9 10 11 12 PAPENBURG RHEDE
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-7
EMDEN storing of (lower) salinity concentration in the fluid mud layer GANDERSUM
2,5 h POGUM
JEMGUM
Salinity [PSU] Δ SAL Velocity [m/s] LEER Waterlevel [mNHN]
WEENER
PAPENBURG RHEDE
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
EMDEN summary GANDERSUM
POGUM
• Fluid mud layers start to form at ~ 2,5 h before highwater JEMGUM vertical mixing is inhibited
LEER • Salinity was not full developed at this time (intruded into the estuary)
• Fluid mud layers are storing (lower) salinity concentration
WEENER
Δ t PAPENBURG RHEDE Δ SAL
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Download: www.innomar.com/seabed-acoustics-2017.php 8 th Workshop “Seabed Acoustics”, Rostock, November 9/10, 2017 P04-8
EMDEN conclusions GANDERSUM
• This is an important contribution to the understanding POGUM of estuarine physics under hyper turbid conditions JEMGUM
• The sediment induced stratification has to be taken into account to improve numerical transport modelling significantly LEER „Fluid Mud Model“
• Without consideration of these effects the implementation of „sediment management strategies“ will not be possible WEENER
Δ t PAPENBURG RHEDE Δ SAL
WEHR HERBRUM
Interaction between fluid mud and salinity - field campaign „Ems summer 2015“ – Christian Maushake www.baw.de
Download: www.innomar.com/seabed-acoustics-2017.php