3 coastal landscapes in the Netherlands. Reconstruction c. 800 A.D.

Transcription

1 3 coastal landscapes in the Netherlands Reconstruction c. 800 A.D.

2 Workshop 1: Challenges with rejuvenation and dynamics in inland and coastal dunes Introduction on the actual dynamic coastal management in the Netherlands and the ecological implications on landscape level Evert Jan Lammerts, Staatsbosbeheer/OBN Introduction of restoration of inland dunes Eva Remke, Stichting Bargerveen

3 1 Noordzee 2 5 eiland 3 getijdebekken 4 getijdebekken 6 To\from NVT NVT NVT + NVT NVT + NVT + 5 NVT + ++ NVT + 6 NVT NVT

4 Main components : 1. Island head (25-50) 2. Closed dune bow complex (50-400) 3. Washover complex (50-100) 4. Island tail (25-50) 5. Beach and foreshore Model of a Wadden Sea island

5 Hypothetical balance in the mainland coast

6 A model of landscape processes along the Delta coast Van Haperen 2014

7 From a natural to an engineered systeem Dominant events (measures) (1) Basin enlargement by peat cuttings and floodings (< 1900) (2) Basin reduction by impoldering and closing Zuiderzee (1932) and Lauwerszee (1969) (3) Stabilization of basin and Wadden Sea islands by the construction of dikes, (concrete and sandy) and coastal management (since 1990 mainly by sand nourishments) Lucas Jansz Waghenaer (1584) Spieghel der Zeevaerdt 7/25/2016 (Edwin Elias)

8 From a natural to an engineered systeem Dominant events (measures) (1) Basin enlargement by peat cuttings and floodings (< 1900) (2) Basin reduction by impoldering and closing Zuiderzee (1932) and Lauwerszee (1969) (3) Stabilization of basin and Wadden Sea islands by the construction of dikes, (concrete and sandy) and coastal management (since 1990 mainly by sand nourishments) Before closure After closure 7/25/2016 (Edwin Elias)

9 From a natural to an engineered systeem Dominant events (measures) (1) Basin enlargement by peat cuttings and floodings (< 1900) (2) Basin reduction by impoldering and closing Zuiderzee (1932) and Lauwerszee (1969) (3) Stabilization of basin and Wadden Sea islands by the construction of dikes, (concrete and sandy) and coastal management (since 1990 mainly by sand nourishments) 7/25/2016 (Edwin Elias)

10 From a natural to an engineered systeem Dominant events (measures) (1) Basin enlargement by peat cuttings and floodings (< 1900) (2) Basin reduction by impoldering and closing Zuiderzee (1932) and Lauwerszee (1969) (3) Stabilization of basin and Wadden Sea islands by the construction of dikes, (concrete and sandy) and coastal management (since 1990 mainly by sand nourishments) 7/25/2016 (Edwin Elias)

11 Coastal management in the Nederlands (Edwin Elias)

12 Volume changes in the coast (million m 3 ) > Big losses along the Wadden Sea coast Sedimentation in the Waddenzee including nourishments: nourished: coastal zone: basins: 54.7 Total: < -5 upper shoreface / beach / frontal dunes: natural nourished Total: 77.1 A stable, even expanding, mainland coast incl. Dutch mainland coast, incl. islands Sand redistribution on the Voordelta (Zeeland) (Edwin Elias)

13 2002 How sand nourishment works Rijkswaterstaat 13 Consultatie Kustlijnzorg Meerjarenprogramma

14 2003 Rijkswaterstaat 14 Consultatie Kustlijnzorg Meerjarenprogramma

15 2004 Rijkswaterstaat 15 Consultatie Kustlijnzorg Meerjarenprogramma

16 2005 Rijkswaterstaat 16 Consultatie Kustlijnzorg Meerjarenprogramma

17 2006 Rijkswaterstaat 17 Consultatie Kustlijnzorg Meerjarenprogramma

18 2007 Rijkswaterstaat 18 Consultatie Kustlijnzorg Meerjarenprogramma

19 2008 Rijkswaterstaat 19 Consultatie Kustlijnzorg Meerjarenprogramma

20 2009 Rijkswaterstaat 20 Consultatie Kustlijnzorg Meerjarenprogramma

21 2010 Rijkswaterstaat 21 Consultatie Kustlijnzorg Meerjarenprogramma

22 2011 Rijkswaterstaat 22 Consultatie Kustlijnzorg Meerjarenprogramma

23 2012 Rijkswaterstaat 23 Consultatie Kustlijnzorg Meerjarenprogramma

24 In 4 years 300 to 500 m landward shift In 4 years 0 to 150 m landward shift Rijkswaterstaat 24 Consultatie Kustlijnzorg Meerjarenprogramma

25 The Sand engine (Zandmotor) Sep 5, 2011 March 20, 2012 July 2, 2012 Oct 31, 2012 (Edwin Elias)

26 The Sand engine : is it really a unique experiment? This is Ameland!!! Oct 31, 2012 Dynamic Preservation May 16, (Edwin Elias)

27 Concepts for restoration and planning: focus on the right temporal and spatial scales Examples from Schiermonnikoog and Terschelling

28 Schiermonnikoog

29 Schiermonnikoog situation 1959 stuivende duinen onbegroeid strand vergrast duin zandige kopjes in kwelder jonge kwelder oude lage kwelder vergraste kwelder knopbiesvegetatie

30 Schiermonnikoog nowadays stuivende duinen onbegroeid strand vergrast duin zandige kopjes in kwelder jonge kwelder oude lage kwelder vergraste kwelder knopbiesvegetatie

31 Restoration Washover complex

32 Schiermonnikoog with washover complex stuivende duinen onbegroeid strand vergrast duin zandige kopjes in kwelder jonge kwelder oude lage kwelder vergraste kwelder knopbiesvegetatie

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34 Development of the fresh water body influenced by sea level rise and sand nourishment (example from south-texel) Model results showing decrease in the fresh water body (A) as a consequence of a withdrawing coastline after sea level rise (1 meter). Model results showing increase in the fresh water body (C) as a consequence of an expanding coastline after sea level rise (1 meter) combined with an expanding coastline by sand nourishment over a width of 800 meters on the adjacent beaches. Uit: Stuyfzand et al 2014

35 CLOSED DUNEBOW COMPLEX TERSCHELLING Paal Allowing natural erosion and sand blowing

36 Moving sand between 1997 en 2008 (analysis data by Bas Arens) : erosie : sedimentatie c. 1990

37 Is a natural landscape the best garantuee for coastal biodiversity? Habitats on model Schiermonnikoog

38 Key-factors for the future On the long term, maintaining many characteristic and threatened dune species is possible only when applying Nature management which is in phase and space with natural geomorphological and ecological processes. Dynamic coastal management probably increases coastal resilience and may increase safety while decreasing the need for sand nourishments.

39 Ecological strategies for coastal management 1. Dynamic coastlines with natural sedimentation and erosion : freely moving sand and salt/fresh water being in phase with the periodicity and spatial patterns of large scale natural sedimentation and erosion processes! 2. Within safety boundaries.. using natural sedimentation and erosion of sand as management tools, on partial landscape scale 3. Whén sand nourishments are needed to maintain the coastline, there are two options : 1. natural succession, 2. periodically active management (e.g. sod-cutting, mowing, grazing, artificially stimulating sand-blowing, water management).

40 Natural and semi-natural management strategies on landscape and habitat level along the Dutch coastal areas

41 Discussion items on management strategies along the European (or national?) coastlines : Do we know enough about the landscape settings and the corresponding natural processes? Is there an adequate picture of the main antropogenic influences (first of all coastal defense)?

42 Do we have the knowledge to choose the right spatial and temporal scales of nature management.. in other words : which criteria indicate when to act on landscape level and when on habitat level? which criteria indicate when to focus on influencing lifespans of individual species and when to act on successional change of ecosystem level? What can we do now on the habitat level?

43 The End