Changing Estuary – dynamic nature

Präsentation zum Thema: "Changing Estuary – dynamic nature"—  Präsentation transkript:

0 ELBE Restoration project: Spadenlander Busch / Kreetsand
Dr. Annedore Seifert, Hamburg Port Authority Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

1 Changing Estuary – dynamic nature
Elbe river mouth 1976 2002 Tidal Elbe highly dynamic: mouth is characterised by steadily moving multiple channel system; seabed dunes and ripples, intertidal areas, sand banks and islands are all constantly shifting within 30 years, loss of 100 million m³ of sediment  more tidal energy can enter the estuary Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority 1 1

2 Changing Estuary - uses
Past - Anthropogenic uses interfered with the natural development of the estuary: modification of river like construction of dikes and barriers, today roughly half of the entire river length is protected by embankments; also expansion of harbours and deepening of fairway (1843 depth 4.5m to 13.5 m today and 14.5 is currently planned - More than 90% of areas lost because of dykes Present Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

3 Changing Estuary: tidal range
Elbe Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

4 Nachteilige Veränderung: Verlandung
Changing Estuary: tidal pumping Nachteilige Veränderung: Verlandung silting up of anabranches and embankments More sedimentation in port and fairways Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

5 Restoration of the Estuary:
The Tidal Elbe Concept Three main Objectives for a Future Action Plan: Attenuation of the Tidal Energy through River Engineering in the Mouth of the Estuary, More Space for the River (Tidal Volume) in the upper Part Optimisation of the Sediment- management considering the whole System of the Elbe Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

6 Project: Spadenlander Busch / Kreetsand
Tidal Volume: New shallow water area Spadenlander Busch / Kreetsand Hamburg Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

7 Project: Spadenlander Busch / Kreetsand
former spoil area / dewatering field, partially dyke foreland with alluvial forest dyke realigned in 1999 planning area ~ 47 ha mean surface level +5,50 m NN Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

8 Tidal Volume: New shallow water area
Project: Spadenlander Busch / Kreetsand Tidal Volume: New shallow water area Operational Objectives increase of tidal volume reduction of tidal range (supporting MTLW) reduction of tidal pumping effects (less dredging efforts) Further Objectives Project integrating all needs of uses (nature and water conservation, tidal river development, recreation etc.) Maintaining and improving the diversity of biotopes Enhance public experience on interactions of tidal actions and nature Use the project for a new communciation scheme of the Tidal Elbe Concept Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

9 Design and evaluation of the preferential alternatives
Planning process / examinated criteria Design and evaluation of the preferential alternatives Hydrodynamics 2-D-modelling evaluation of the flow conditions evaluation of the sedimentation processes Nature conservation Inventory and assessment of the status quo Definition of required compensation Strategic environmental assessment Earth works planning Soil-mechanical and –chemical examination Removal: concept of re-use and disposal Geotechnical analysis Comparison, selection and technical planning of the final version Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

10 Selection of the preferential versions and modelling
Preselection of 8 different alternatives 8 versions due to expacted differences in current and sedimentation 3 versions selected: Selection of 3 preferential alternatives Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

11 Current modelling Alternative 1
Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

12 Modelling of the currents
Alternative 1 Alternative 3 Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

13 Modelling of sedimentation processes
Alternative 1 Alternative 3 Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

14 Evaluation matrix and criteria
Rating of the alternatives by using different evaluation criteria to the topics Target achievement Impact on nature conservation objectives Time line Costs Scoring to give more weight to extra important criteria Attenuation of the tidal range support of MTLW Sustainability  restriction of sedimentation Nature  alluvial forest, biotopes Sensitivity analyses to verify the results Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

15 Selection and detailed planning of the final version
Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

16 TIDE: Application of a new communication concept at Elbe estuary: „Deichbude (dyke shed)“
house on existing tide gate dyke shed is perfect location to inform public and to use it as a exhibition room, viewpoint and maybe also as a study room for workshops Feasibilty study: 2 different versions of a dyke shed will be developd including static anaylysis; furthermore concepts for both exhibitions and other uses will be elaborated Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

17 Time line Application for the planning approval: June 2010
Public hearing: October 2010 expected permission: end of 2011 anticipated start of construction: end of 2011 / beginning of 2012 The entire project will be finished end of 2014 / beginning of 2015 Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

18 Meeting TIDE - GIP Seine-Aval, 08. 06
Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

19 Meeting TIDE - GIP Seine-Aval, 08. 06
Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

20 Thank you! www.tide-project.eu www.hamburg-port-authority.de
| Hamburg Port Authority | Neuer Wandrahm 4, Hamburg, Germany

21 Meeting TIDE - GIP Seine-Aval, 08. 06
Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

22 Construction progress:
sounding and clearing of explosives Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

23 Construction progress:
Removal of 2 Mio. m³ in three phases of construction each with: Hot Spots other filled in soil unspoilt clay and sand Shaping Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

24 Meeting TIDE - GIP Seine-Aval, 08. 06
Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

25 Restoration of the Estuary:
The Tidal Elbe Concept Three main Objectives for a Future Action Plan: Attenuation of the Tidal Energy through River Engineering in the Mouth of the Estuary, More Space for the River (Tidal Volume) in the upper Part Optimisation of the Sediment- management considering the whole System of the Elbe Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

26 TIDE Pilot Projects: Elbe
1. Feasibility study: engineering measures (creation of sandbars) in the estuary mouth Modelling of expected behavior/effects 3. Evaluation of sediment trap as part of a sediment management scheme Functioning and effectiveness of the new approach Depth ~ 2m Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

27 Erlebbarkeit, über potentielle Weglänge Erzeugte Insellagen
In folgenden Kriterien weisen die Varianten bewertungsrelevante Unterschiede auf: Nachhaltigkeit, einschließlich der daraus resultierenden Betriebskosten Dämpfung Erlebbarkeit, über potentielle Weglänge Erzeugte Insellagen Rückgebaute Tidegehölze V1 dämpft signifikant besser als V2 und V3 V3 erzeugt deutlich weniger Sedimentationen als V1 und V2 V1 und V3 liegen in der Zielerreichung dicht beieinander V1 und V2 liegen in den Auswirkungen dicht beieinander Dauer und Kosten wirken sich nur unmaßgeblich auf die Auswertung aus V1 erhält vor V2 und vor V3 in der Summe die meisten Punkte Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

28 Weitere Zielsetzungen
ZIELFUNKTIONEN NATURSCHUTZ Minimierung des Eingriffes in schützenswerte Flächen bzw. Schaffung von Ersatz für rückzubauende Teilflächen des Auwaldes, der Röhrichtflächen und des Deichgrabens Förderung einer naturnahen Dynamik und biologischen Vielfalt Weitere Zielsetzungen ERLEBBARKEIT Wahrnehmbarkeit der Wasserflächen und -bewegung vom Deich aus !!! Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

29 Aufstellung Bewertungskriterien und Auswertungsmatrix
Einstufung der Varianten nach verschiedenen Kriterien Bildung von Bewertungsblöcken Zielerreichung Auswirkungen auf Schutzgüter Termine Kosten Vergabe von Wichtungspunkten zur Abwägung der Kriterien Herausarbeitung besonders wichtiger Kriterien Dämpfung Tidehub  Stützung Tideniedrigwasser Nachhaltigkeit  Beschränkung Sedimentation Schutzgut Natur  Auwald, Lebensräume Sensitivitätsanalyse zur Ergebniskontrolle Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

30 Installation of the rating criteria and - matrix
Rating of the alternatives using different criteria Creation of valuation units target achievement impact on subjects of protection time line costs Scoring to give extra important criteria more weight attenuation of the tidal hub subsidy of the tidal low water Sustainability  restriction of sedimentation nature  alluvial forest, biotopes Sensitivity analyis to verify the results Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority

31 Naturschutzfachliche Aspekte
BESTANDSAUFNAHME UND BEWERTUNG: Tide-Auwald (ca. 7,5 ha) Der Tide-Auwald stellt einen prioritären Lebensraumtyp dar Tideröhricht (ca. 6 ha) Die Tideröhrichtflächen sind nach § 28 HmbNatSchG geschützt Deichnaher Graben Der deichnahe Graben stellt einen wertvollen Biotyp dar (nicht nach § 28 HmbNatSchG geschützt) Meeting TIDE - GIP Seine-Aval, | Annedore Seifert | Hamburg Port Authority