Sunrise or Sunset. for the Ems estuary? The future Ems System: restored by the power of. nature. or engineers?

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1 The future Ems System: restored by the power of Sunrise or Sunset nature for the Ems estuary? or engineers? Prof. Dr. Victor N. de Jonge DSc 1 & Dr. Henk Schuttelaars 2 1 IECS, University of Hull, United Kingdom 2 TUD, Delft, The Netherlands Oct 2008

2 Starting point: The Ems estuary between the North Sea and the weir at Herbrum is one undividable system Challenge: How we can restore it

3 STRUCTURE OF TALK 1. What happened to the Ems estuary and its river? 2. What were the resultant environmental changes to the Ems river and Ems estuary? 3. Options on how to proceed

4 1.What happened to the estuary? Varying but large scale channel dredging result: times more suspended mud + Ems estuary River Ems 1.What happened to the river? Canalisations, deepenings & dredging result: 10 times more suspended mud

5 mean suspended matter concentration in the Ems estuary (near water surface) mean SPM (g.m -3 ) / 06 Zoom in 1975/ distance from Herbrum (km) River P burg Leer Emden EH HGO Sea

6 SPM (gm -3 ) Ems estuary 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 Emden Eemshaven Borkum 1954 reference situation provides effect of channel maintenance dredging (CMD) combines effect of CMD + Ems canalisation and deepening combines effect of CMD + Ems canalisation and deepening

7 SPM (gm -3 ) fit km y = e x R 2 = since y = e x R 2 = measurable y = 1181e x until R 2 = y = 531.9e x R 2 = Km from weir Herbrum : channel change 2. Steep slope 3. Effect Eemshaven to 3-fold increase Eemshaven Borkum Why important? This is the area where the food is produced for the rest of the system also the river!

8 2. The resultant environmental changes to the Ems river and Ems estuary

9 - extremely high SPM (organic material included) - extremely high BOD - extreme fluctuation in phosphorous levels - extremely low minimum oxygen in summer - extreme environment to organisms with gills Oxygen (mg l -1 ) Ems estuary Van Beusekom & de Jonge 1998 Minimum oxygen concentration in ETM as function of temperature y = x x x Phosphate, Fe, Al, dissolved organic C concentration salinity R 2 = sea Water temperature ( o C)

10 THE ULTIMATE PROBLEMS IN SUMMARY ALGAL GROWTH (tonnes organic C a -1 ) LOWER REACHES MIDDLE REACHES DOLLARD TOTAL ESTUARY Reference conditions (no dredging) Measured ( ) 35km estuarine dredging estuarine dredging + river improvements ( ) 75000

11 THE ULTIMATE PROBLEMS IN SUMMARY ALGAL GROWTH Primary production (%) LOWER REACHES MIDDLE REACHES DOLLARD TOTAL ESTUARY Reference conditions (no dredging) Measured ( ) 35km estuarine dredging (%) 62 Estuarine dredging + river improvements ( ) 38 Oxygen (mg l -1 ) Minimum oxygen concentration in ETM as function of temperature y = x x x R 2 = SPM (gm -3 ) fit km Water temperature ( o C) Km from weir Herbrum

12 3. How to proceed technically?

13 Emden Leer Herbrum km from Knock 1. Increasing the length of the freshwater tidal river 2. Creating a sill in the lower tidal river between Emden and Leer Knock The power of nature acting on the Ems has been amplified by the power of the engineers changing the morphology of the river.

14 Knock Natural depth profile and ETM natural depth profile Herbrum ETM for natural depth profile but longer tidal river part upstream Herbrum weir

15 Maximum near bottom concentrations of mud Leer Herbrum Knock Emden Leer

16 This is upstream Emden Another convergence/ mud accumulation area upstream the sill Sill option in river

17 3. How to proceed technically? - CHANGE EXTERNAL BOUNDARY CONDITIONS 1. Shipbuilding is partly done modulary. Hull construction and heavy engines could be completed upstream Completion (eg cabin mounting) above the engine-room could be done near deep water 2. The present location of the weir is, given the present boundary conditions, questionable. Upstream replacement is an option in combination with restoring river meanders (lengthening the fresh water tidal river. 3. The incoming tidal wave from the North Sea is very powerful. Seen the upstream consequences of it, shallows seaward from the tidal inlet could reduce the tidal energy there instead of upstream 4.. There are some more options

18 Thank you

19 1. Shipbuilding is partly done modulary. Hull construction and heavy engines could be completed in upstream while completion (eg cabins) above the engine-room could be done near deep water 2. The present location of the weir is, given the present boundary conditions, questionable. Upstream replacement is an option in combination with restoring river meanders (lengthening the fresh water tidal river. 3. The incoming tidal wave from the North Sea is very powerful. Seen the upstream consequences of it, shallows seaward from the tidal inlet could reduce the tidal energy there instead of upstream 4. Another option is a much longer new canal from circa Dörpen to Pogum connecting the Ems estuary to the Dortmund-Ems Kanal brings the water back where it was and provides big chances to industry, area, river, ecology landscape and economy. Active river undeepening may be necessary. 3. How to proceed? - TECHNICALLY: CHANGE BOUNDARY CONDITIONS

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21 28-95 km / / 06 Fluid mud pool act as a mud sink Papenburg Leer Emden Eemshaven Borkum Between 1980 and 1992 the system dynamics significantly and structurally changed Since then the system seems to be in another steady state

22 Curves calculated based on a statistical model and thus not predictive Findings published internationally by de Jonge in 1983 and 2000 Curves valid for 1954 (?), (unchanged turbidity maximum, minimum mud disposal) SPM (gm -3 ) (Fixed turbidity maximum) [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) Eemsh Borkum

23 Ongoing for already 30 years No anticipation to these negative environmental developments, which forms a general problem in both countries. Threshold for fish Figure copied from Restoration Plan Ems and Dollard (Waddenvereniging 1999) Publication in Dutch and German

24 4. How to proceed? - IN TERMS OF PROCEDURES: 1. Economic, ecological as well as social monitoring activities in the estuary, on the river, along the Ems system and in the drainage basin upstream should be carried out in co-operation between both countries because there is a joint interest 2. An international restoration plan for the entire drainage basin should be prepared and agreed upong at the highest possible level between both countries (see advice by Wadden Sea Council) 3. A geographical restructuring of industrial, rural and leisure activities required, in combination with other Belgian, Dutch, German regions 4. Giving space to the power of nature should be practiced from both an environmental and an economic perspective

25 Talking about the system values... Ecosystem Functions & Functioning this combination represents the total system value Ecosystem Services & Goods Ecosystem Structure & Processes Ecological values based on ecological sustainability Ecosystem Value Ecosystem Services & Goods Social-cultural values based on equity and cultural perceptions Total Value Decision making process Decision-making processes Ecosystem functions: Economic values Sustainable Management 1. Regulation 2. Habitat 3. Production based on efficiency and cost-effectiveness 4. Information After de Groot et al., 2002

26 THE ULTIMATE PROBLEMS IN SUMMARY ALGAL GROWTH ALGAL GROWTH Primary production (%) (tonnes organic C a -1 ) LOWER LOWER REACHES REACHES MIDDLE MIDDLE REACHES REACHES DOLLARD DOLLARD TOTAL TOTAL ESTUARY ESTUARY Reference conditions Reference (no dredging) conditions (no dredging) Measured (1975 Measured -1980) 35km (1975 estuarine ) dredging 35km estuarine dredging 82 (100%) 12 (100%) 6 (100%) 100 (100%) (60%) 8 (67%) 5 (83%) 62 (62%) Estuarine estuarine dredging + river improvements ( ) 28 (34%) 5 (42%) 5 (83%) 38 (38%) In terms of compensation measures the value of this algal growth to the functioning of the Ems system AND the UNESCO World Heritage Wadden Sea needs to be calculated and applied to come to future solutions in monetary units

27 3. How to proceed? - STARTING POINTS: 1. The Ems estuary is one undividable system 2. Do not exceed the limits of evidence (Ian Townend, Wallingford, UK) 3. Get everybody involved (also locals ) 4. Think out of the box, look over the fence, being flexible. 5. Create long term perspective.. (not only economically! Also ecologically, socially & culturally!)

28 Changes for the river in summary: increased tidal range, lower low tides, amplified flood currents, amplification of gravitational circulation, higher SPM (worsened light conditions) and related lower algal growth and low oxygen values