The Elbe Estuary Sediment Dynamic, Contamination and the Impact of High Water Discharges

Transcription

1 The Elbe Estuary Sediment Dynamic, Contamination and the Impact of High Water Discharges Susanne Heise, Judith Angelstorf, Maximilia Kottwitz, Pei-Chi Hsu

2 The Elbe Estuary Region divided among 3 Federal States 4,3 mio people (1.7 mio in HH) Distance Weir Geesthacht - N.S.a: 140 km

3 History of the Elbe Estuary till.. Reduction of flood plains : to 10 % Since 1950: to 2 % (Eichweber, 2007) Karte der Elbmündung 1721 von Samuel Gottlieb Zimmermann und Otto Hasenbanck

4 Adapting the Elbe to Human Interests Reduction of flood plains : to 10 % Since 1950: to 2 % (Eichweber, 2007)

5 Reasons for Changing the Morphology 1) Protection of Human Life 1962: 300 people killed in Hamburg Restriction of river to space beween dikes Less flood plains (2 % of original 2500 km 2 ) Consequences of channelizing the river: Increased suspended matter in the system Increased sedimentation in the remaining mud flats Changes in current velocity / storm surge water heights

6 Reasons for Changing the Morphology: 2) Shipping / The Harbour Industrial area in Hamburg Prognosis of container handling potential , in mio TEU Water sketch, nd largest port in Europe (Cont.) ca. 10 % of Hamburg area ca. 8 % of Hamburg water surface jobs in HH and metropol region HPA, 2010

7 Reasons for Changing the Morphology: 2) Shipping / The Harbour Wassertiefen in Meter und Schiffsgrößen in der Elbe von 1800 bis 1978 [Quelle: HPA]

8 Effect enhanced by deepenings: Tidal pumping Asymmetric tidal periods lead to a higher velocity of the flood tide. Sediment transport is exponentially proportional to the current velocity. Net-sediment transport upstream

9 Masses of Dredged Material Source: HPA Between 2000 and 2010: from 4 mio m 3 (2010) to 8 mio m 3 (2004) (BSU 2012)

10 BUT - the Estuary is not an Industrial Canal. Bernd Sterzel, Pixelio Erwin Knorr, Pixelio Bird protection areas FFH-areas Total Natura 2000: ha

11 Of Special ecological importance: Mudflats Brackish water mudflats at the North Sea Coast Relatively flat coastal wetland environment Varying salinity, influenced by freshwater Diversity of habitats Important feeding area for fish Breeding and wintering area for up to 12 Mio birds per year 66 % of the German Wadden Sea have been inscribed as UNESCO world heritage

12 Of Special Ecological Importance: Mudflats Freshwater mudflats in the Elbe Estuary Among the highest productive ecosystems Important for the assimilative capacity of rivers Important role in nutrient regeneration Important feeding areas for fish and birds Freshwater mudflats in the Elbe estuary upstream of Glückstadt e.g. Mühlenberger Loch, one of the largest freshwater wadden areas e.g. Heuckenlock one of the few tidal flood plain forests in Europe

13 Developments since 1900 Reduction of area 1896/05 vs. 1981/82 Changes in the tidal range Tidal Flats Brackish 21 % Freshwater: 51 % (WSS, Bakker et al. 1997) Increase of tidal range by 150 cm over 100 years due to natural processes, channelization and deepening of the river, (Source: Portal-Tideelbe) Water levels Hamburg (St. Pauli) since 1900

14 Gradients in the Elbe Estuary (IBP 2012)

15 What happens to SPM downstream? Many estuaries show an ETM an Estuary Turbidity Maximum Profiles of suspended matter concentration (Bergemann, 2004)

16 Mudflats exposed to contaminants Hg Coastal mudflats Fresh water mudflats Cu ARGE Elbe target value (class II) North Sea Hamburg

17 Areas of Risk of contaminants Historical sources: Mining Industrial emissions Recent sources: Contaminated soil and sediments Cd, Hg, Cu, Zn, Pb CR HCH, HCB, PCB, DDX TBT Details in Heise et al. 2008

18 Frachten in kg/d Particle-bound contaminant transport is flood dominated Hochwasser Feb/März 2000 Niedrigwasser September 2003 Hg-load in kg/day Quecksilberfrachten Schmilka Dommitzsch Schwarze Elster Mulde Saale Magdeburg Messstellen Downstream Schnackenburg Seemannshöft

19 Ölschlieren Schloss Pilnitz, (Foto: ARGE Elbe, 2003) Short repetition Sources of particle-bound contaminants are mostly upstream Transport of particle bound contaminants happens mostly with flood events In estuary: Rate of sedimentation in mud flats has increased over the years AND CC may lead to increased frequency of flood events (in winter) How do floods impact mudflats in the estuary?

20 Contamination of SPM during August-flood 2002 (ARGE-Elbe 2003) Concentration of contaminants in flood-spm at Seemannshöft (downstream HH) compared to concentrations in 2001 Concentration in many contaminants increased Reflected by sediment toxicity at mud flats or transported to the North Sea?

21 Case Site Hamburg Effects Sampling of the stations flood 2002 on brackish mudflats? Neufeld Elutriate and methanol extract Solid phase

22 E.g. Impact of the Elbe flood 2002 before the flood 23/ Positionen der GKSS-Proben 8 40' 8 45' 8 50' 8 55' 9 0' 9 5' 53 56' 53 56' 53 54' ' 53 52' ' 53 50' ' 8 40' 8 45' 8 50' 8 55' 9 0' 9 5' Scale: 1: at Latitude 0 öko toxikologie

23 E.g. Impact of the Elbe flood 2002 after the flood 30.9./ Positionen der GKSS-Proben 8 40' 8 45' 8 50' 8 55' 9 0' 9 5' 53 56' 53 56' 53 54' ' 53 52' ' 53 50' ' 8 40' 8 45' 8 50' 8 55' 9 0' 9 5' (Heise et al. 2003) Scale: 1: at Latitude 0 öko toxikologie

24 Other results? 53 56' 53 54' 53 52' Positionen der GKSS-Proben 8 40' 8 45' 8 50' 8 55' ' 9 5' ' 53 54' 53 52' Increased toxicity with algae (elutriate), bacteria and nematodes (sediment) 53 50' ' 8 40' 8 45' 8 50' 8 55' 9 0' 9 5' Scale: 1: at Latitude 0 öko toxikologie (Heise et al. 2003) Ötken et al. 2005: No effects of estuarine sediments after the flood on Chironomus riparius (insecta) and Potamopyrgus antipodarum (gastropoda) Einsporn et al. (2005): toxic effects in flatfish and mussels after the flood. Flatfish were most affected in the Elbe estuary and near Helgoland. High levels of organic contaminants in fish liver and mussels.

25 Further investigations into impact of HW-discharges on mud flats METHODS Event-based sampling of freshly deposited sediment (FDS) 6 average discharge situations 2 moderately high water events 1 HQ 20 ecotoxicological analysis of FDS chemical analysis of FDS

26 Case Site Hamburg Sampling stations Mühlenberger Loch Heuckenlock Neufeld

27 Case Site Hamburg Discharge Neu-Darchau H 1 H 2 HQ 20 H1 H2 H3 N

28 Chemical Analysis A) HCH, HCB, Hg, Cd and PAK show increased or highest concentrations in FDS during the HQ 20 at freshwater and coastal mud flats. B) PCB, As, Pb and Cu-concentrations are elevated during HQ 20, but are within the variation of data. C) pp-ddt, Ni, Zn and Cr do not show any increased concentrations during the high water event.. H1 H2 H3 N

29 Ecotoxicological Analyses Increased toxicity in contact test in Heuckenlock No effect of LBT, no effect of Algae Caution: Only few data available more data will be necessary

30 (Kappenberg et al. 2007, mod.) Estuarine Turbidity Maximum and High Water Discharge Salinity gradient Particles seem to remain in the ETM for some time.. High water discharge pushes the ETM downstream and moves SPM towards the North Sea In the area of our flood sampling, SPM Concentration could have doubled Deposition?? Neufelder Watt Discharge < 500 m 3 /s m 3 /s m 3 /s m 3 /s >2000 m 3 /s

31 Hypothesis on the impact of HW-Discharge on Mudflats Only extreme floods (e.g. HQ 20 ) increase contamination Effect most emphasized in Heuckenlock Effect still measurable at the brackish mudflats Sources of the substances (class A): Saale and the CR spring 2011: High discharges from Saale and CR Bacterial contact test: Inhibition in Heuckenlock adverse effect on organisms Freshwater mudflats are probably impacted by high water discharges! More sampling surveys would improve the certainty of these hypotheses

32 Thank you for your attention! and special thanks to GKSS for sampling sediments in 2002 to Frank Krüger (assistance during sampling surveys) to Sebastian Höss (Nematode testing) Susanne Heise