Harbour developments and its. Increasing scientific efforts. effects on ecological functioning. parallel. and structures

Transcription

1 Harbour developments and its Increasing scientific efforts effects on ecological functioning parallel and structures increasing environmental deterioration in coastal and estuarine systems Victor N. de Jonge, Henk M. Schuttelaars, Justus E.E. van Beusekom, Stefan Talke & Huib E. de Swart

2 Question: what is going wrong? Answer: too narrow focus (own restricted network) not looking out of the box!

3 Expected port development Hamburg Wilhelmshaven Bremerhaven Planco Consulting GmbH Essen

4 Expected port development Antwerp Rotterdam Planco Consulting GmbH Essen Rotterdam says: 2.3% per year

5 What is our agenda for harbours and navigation routes or fair ways? The Marine Environment Protection Committee (MEPC) of the International Maritime Organization (IMO), has designated major parts of the Wadden Sea as Particularly Sensitive Sea Area (PSSA) in The Wadden Sea is the 5th designated PSSA worldwide Does this only hold for shipborn pollution or also mud? Wadden Sea Forum (5 October 2012) The shipping group elaborated further on shipping safety - Vessel Traffic Services (VTS) - Vessel Traffic Management (VTM) - Commitment among stakeholders with reference to the PSSA

6 Any benefit for the Wadden Sea system Most of these plans do not match the functioning and the status of the Wadden Sea as PSSA, UNESCO WHS, nature reserve.??? This is not a lake but a shallow coastal sea with all the related complex hydrodynamic processes!

7 Did we learn from our history? Not really - We too much believe in engineering - We too much believe model abstractions

8 Flyers: 2D/3D modelling systems to investigate hydrodynamics, sediment transport and morphology and water quality for fluvial, estuarine and coastal environments have not prevented that all the estuaries have only deteriorated. So far mainly environmentally unsustainable solutions were generated because the models in use were not fit for purpose

9 What are the envirionmental consequences? Test system Ems river & Ems estuary (both) 30 June 2011

10 River Ems downstream the weir is now Europe s own Yellow River mud, mud, mud

11 Borkum Eemshaven Knock Emden Delfzijl Leer Papenburg Herbrum

12 Ca 50 km North Sea Wadden Sea (ca 475 km 2 ) River Ems Randzel 110 m 3 s -1 a 5 km Wadden Sea (275 km 2 ) Outer reaches Main estuary Paap (90.5 km 2 ) Middle reaches Dollard (100 km 2 ) Heringsplaat Schanskerdiep River WWAa 10 m 3 s Emden: historical harbour 2. Delfzijl: historical harbour 3. Eemshaven: new 4. Shipyard Papenburg 50 km upstream Emden

13 Borkum Eemshaven Knock Emden Delfzijl Leer Papenburg Herbrum

14 Two main problems: 1. Ems estuary: - dredging 2. Ems tidal river: - deepenings

15 First part: The situation until 1983 Dredging mainly occurred in the Ems estuary

16 What does channel maintenance dredging do in the estuary: 1. Changes in morphology, flow current field & even internal tidal wave 2. Changes temporarily erosion sedimentation cycle temporarily resulting in higher SPM ~ 475 km 2 Middle Reaches 110 m 3 s -1 HGO Lower Reaches EH Emden Dollard Leer Papenburg

17 Second part: The situation between 1983 and 2005 Estuarine channel (maintenance) dredging plus Ems river deepenings

18 Impact of deepenings HGO EH + Emden Leer Papenburg Meyer shipyard Increased tidal range, increased asymmetry in vertical tide and tidal currents (dominating flood currents), fluid mud formation causing extremely low system resistance all contributing to SPM accumulation and related hypoxia / anoxia

19 Major dredging activities in estuaries are worldwide dictated by ship owners who, even today, continue to build bigger ships (+ for the Ems tidal river by 1 big shipyard) 1 since 1970, 2010: Netherlands 2 since 1970, 2011 Germany + 3 since 1984 Germany Meyer shipyard

20 Primary consequences estuarine dredging -in estuary (period ) (de Jonge, 1983)

21 SPM (mg l -1 ) 1200 data in next slide are annual means for the estuary between Emden and Borkum (tidal inlet-hgo) / weir River Ems Mean SPM of the ETM was constant Estuary Sea (Km) Emden HGO (de Jonge, 2000)

22 > 2-fold mean SPM variation Mean annual SPM over that area (Emden Inlet) correlated with the distance dredged Y= 36.9e 0.016x R 2 = 0.89 gradient Emden Eemshaven/Borkum ( distance = proxy represents aggregated information) de Jonge, V.N., Can. J. Fish. Aquat. Sci. 40 (Suppl. 1): Continental Shelf Research 20,

23 Primary consequences river improvements -in estuary (period ) - on the river Ems (1950s, 1970s, 1990s, 2000s) (Schuttelaars, de Jonge & Chernetsky (on line) de Jonge et al. (in prep)

24 mean suspended matter concentration in the Ems estuary weir Tidal Ems River Ems estuary mean SPM (g.m -3 ) / / distance from Herbrum (km) River P burg Leer Emden EH (Eemshaven) Borkum (HGO) Sea

25 SPM (gm -3 ) fit km Tidal Ems River Ems estuary y = e x R 2 = y = e x R 2 = y = 1181e x R 2 = y = 531.9e x R 2 = Km from weir Herbrum Emden Eemshaven Borkum 1954 reference situation provides effect of channel maintenance dredging (CMD) combines effect of CMD + Ems deepenings combines effect of CMD + Ems deepenings

26 SPM (gm -3 ) fit km y = e x R 2 = y = e x R 2 = y = 1181e x R 2 = y = 531.9e x R 2 = Km from weir Herbrum Eemshaven Borkum 1954 reference situation provides effect of channel maintenance dredging (CMD) combines effect of CMD + Ems deepenings combines effect of CMD + Ems deepenings

27 SPM (gm -3 ) fit km y = e x R 2 = y = e x R 2 = y = 1181e x R 2 = y = 531.9e x R 2 = Km from weir Herbrum This all happened despite application (in EIA) of the best state-of-the-art models

28 Ecological impact

29 River Ems not included in this figure Primary production (gc m -2 a -1 ) Dollard Middle reaches Lower reaches Predicted no dredging Measured Predicted Leer Km from weir Herbrum Emden EH HGO Circa 60% reduction of total primary production

30 What is the possible explanation for the developments on the tidal river Ems and the main estuary? Can system deepenings lead to these changes?

31 Use of simple analytical physical models to investigate causes and possible solutions Water level Simplified estuary shape (representing the Ems system) Weir in the river bottom Knock Weir at Herbrum Because of available data and model we focussed on the upper estuary (Knock weir at Herbrum)

32 Knock Weir Herbrum Realistic bottom schematisation

33 Parameter values for vertical mixing and partial slip parameter (related to bottom roughness) taken from 1965 Knock Weir at Herbrum Channel deepening results in SPM accumulation further upstream the tidal river Ems Bottom roughness and related parameters as in 1965

34 Parameter values for vertical mixing and partial slip parameter (related to bottom roughness) taken from the best fit in each year based on field data Knock Weir at Herbrum The combination of deepenings and changes in the vertical mixing and slip parameters over the years results for 2004 under specific conditions in a plateau-like solution in the tidal river Ems Based on best fit each year

35 Is there a solution? Schuttelaars, de Jonge, Chernetsky Weir Weir Present length!! OCMA, online Weir Knock

36 Lesson learned 1. Some recovery is possible 2. Do not focus on one technique 3. Use qualitative models (analytical physical, theoretical biological) models in combination with quantitative (complex state-of-the-art) models to find answers. Prevent disasters like that of the Ems estuary

37 Recommendations 1. The UNESCO WHS Wadden Sea should be increased by the veins of the Wadden Sea, the estuaries of Ems, Weser and Elbe 2. Harbour specialisation would be a goal for the Wadden Sea Board so that we can mitigate the present pressures

38 Thank you

39 Thank you

40 Influence of tidal river length on sediment trapping Varying length of the estuary Length: 60 km 70 km 90 km Moving weir Knock

41 Influence of tidal river length on sediment trapping Varying length of the estuary Length: 60 km 70 km 90 km

42 Influence of tidal river length on sediment trapping Varying length of the estuary Length: 60 km 70 km 90 km

43 Influence of tidal river length on sediment trapping Varying length of the estuary Length: 60 km 70 km 90 km

44 Curves valid for 1954 (?), (unchanged turbidity maximum, minimum mud disposal) SPM (gm -3 ) Fixed turbidity maximum during [35 km dredging] [0 km dredging] [50 km dredging] Natural situation no dredging Herbrum Maximum dredging distance was 51.4 km in 1972 & 51.3 km in 1978 Emden Distance (km) Eemshaven Borkum/HGO de Jonge, 2000 Curves calculated based on a statistical model and thus not predictive