Post on 12-Jul-2020
3 coastal landscapes in the Netherlands
Reconstruction c. 800 A.D.
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
1 Noordzee 2
5
eiland 3
getijdebekken 6 getijdebekken 4
To\from 1 2 3 4 5 6 1 + + + NVT NVT 2 + + NVT + NVT 3 ++ + ++ + ++ 4 ++ NVT + NVT + 5 NVT + ++ NVT + 6 NVT NVT + + ++
Model of a Wadden Sea island
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
Hypothetical balance in the mainland coast
A model of landscape processes along the
Delta coast
Van Haperen 2014
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)
Before closure After closure 7/25/2016 (Edwin Elias)
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)
From a natural to an engineered systeem
7/25/2016 (Edwin Elias)
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)
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)
Coastal management in the Nederlands
(Edwin Elias)
Volume changes in the coast 1990 – 2005 (million m3)
> 5
1 - 5
-1 - 1
-1 - -5
< -5
including nourishments: nourished: 102.9 coastal zone: -214.5 basins: 54.7 Total: -159.8
upper shoreface / beach / frontal dunes: natural -41.5 nourished 118.6 Total: 77.1
• Big losses along the Wadden Sea coast
• Sedimentation in the Waddenzee
• A stable, even expanding, mainland coast incl. Dutch mainland coast, incl. islands
• Sand redistribution
on the Voordelta (Zeeland)
(Edwin Elias)
Rijkswaterstaat 13 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2002
How sand nourishment works
Rijkswaterstaat 14 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2003
Rijkswaterstaat 15 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2004
Rijkswaterstaat 16 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2005
Rijkswaterstaat 17 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2006
Rijkswaterstaat 18 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2007
Rijkswaterstaat 19 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2008
Rijkswaterstaat 20 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2009
Rijkswaterstaat 21 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2010
Rijkswaterstaat 22 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2011
Rijkswaterstaat 23 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
2012
Rijkswaterstaat 24 Consultatie Kustlijnzorg – Meerjarenprogramma 2016-2019
In 4 years 0 to 150 m landward shift
In 4 years 300 to 500 m landward
shift
The Sand engine (Zandmotor)
Sep 5, 2011 March 20, 2012
July 2, 2012 Oct 31, 2012
(Edwin Elias)
Dynamic Preservation 26
The Sand engine : is it really a unique experiment?
May 16, 2013 Oct 31, 2012
This is Ameland!!!
(Edwin Elias)
Concepts for restoration and planning: focus on the “right” temporal and spatial scales
Examples from Schiermonnikoog and Terschelling
Schiermonnikoog
Schiermonnikoog situation 1959
stuivende duinen
onbegroeid strand
vergrast duin
zandige kopjes in kwelder
jonge kwelder
oude lage kwelder
vergraste kwelder
knopbiesvegetatie
Schiermonnikoog nowadays stuivende duinen
onbegroeid strand
vergrast duin
zandige kopjes in kwelder
jonge kwelder
oude lage kwelder
vergraste kwelder
knopbiesvegetatie
Restoration Washover complex
Schiermonnikoog with washover complex
stuivende duinen
onbegroeid strand
vergrast duin
zandige kopjes in kwelder
jonge kwelder
oude lage kwelder
vergraste kwelder
knopbiesvegetatie
Model results showing decrease in the fresh water body (A) as a consequence of a withdrawing coastline after sea level rise (1 meter).
Development of the fresh water body influenced by sea level rise and sand nourishment (example from south-Texel)
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
Paal 15-20
CLOSED DUNEBOW COMPLEX TERSCHELLING
Allowing natural erosion and sand blowing
Moving sand between 1997 en 2008 (analysis data by Bas Arens)
: erosie : sedimentatie
c. 1990
Habitats on model Schiermonnikoog
Is a natural landscape the best garantuee for coastal biodiversity ?
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.
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).
Natural and semi-natural management strategies on landscape and habitat level along the Dutch coastal areas
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) ?
– 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 ?
The End