Sediment Solutions Webinar 27.11.2020
Saltmarsh restoration by soil removal – Legal framework and examples
Anna Groeneveld & Jürn Bunje - Nationalparkverwaltung Niedersächsisches Wattenmeer
“Let nature be nature”
The Wadden Sea is a Place for natural dynamics
inland with villages etc.
summer polder with grazing cattle
foreland salt marsh
tidal flat
Before the establishment of the national park:
• Intense use of saltmarshes for grazing
• Installing and maintaining of drainage systems
• Drainage system still functions even after decades without maintenance .
• Ongoing steady & intense drainage as consequence.
Maßnahmenvorschläge des Masterplan Ems/ IBP
• Elymus sp. / higher saltmarsh become mono-dominant.
• Decrease of Lower salt marsh types including characteristic bird species
Maßnahmen aus dem Vorlandmanagementplan mit Bedeutung für die Renaturierung
How do we
achieve this?
Machbarkeitsstudie zur Verbesserung des Erhaltungszustands der nördlichen Krummhörn Salzwiesen-Renaturierungsmaßnahmen
„sowieso“?
Saltmarsh Restoration 1986 - 2020
Restoring NATURAL HYDROLOGY Deactivating artificial Drainage
Restoring SALTMARSH TERRAIN LEVELS Removal of Topsoil
Restoring TIDAL INFLUENCE De-Embankment of Summerpolders
Machbarkeitsstudie zur Verbesserung des Erhaltungszustands der nördlichen Krummhörn Salzwiesen-Renaturierungsmaßnahmen
„sowieso“?
Saltmarsh Restoration 1986 - 2020
Restoring NATURAL HYDROLOGY Deactivating artificial Drainage
Restoring SALTMARSH TERRAIN LEVELS Removal of Topsoil
Restoring TIDAL INFLUENCE
De-Embankment of Summerpolders 376 ha
271 ha 207 ha
Leybucht Mittelplate 2013
Norderney Ostheller 2008 u. 2015
Langwarder Groden 2014
Vorland Campen 2014-2018 Borkum Ronde Plate 2018
Dorum Neufeld 2008 Cappel Neufeld 2008
Wapeler Groden ab 2015 Langeoog Sommerpolder 2003
Elisabeth Außengroden 2013-2015 Juist Billheller 2017
Leybucht Hauener Hooge 1994
Lütetsburger Sommerpolder 1986
Dyksterkruger Heller 2020
Restoring TIDAL INFLUENCE
De-Embankment of Summerpolders
Langeoog Summerpolder
Pioneer zone
Salt marsh vegetation Meadow vegetation
2002 2005 2006 2013
2018
Restoring NATURAL HYDROLOGY Deactivating artificial Drainage
Norderney Ostheller
• Removal of topsoil to close drainagesystem
• Two phased project (2008 and 2016)
• No material is removed
Restoring SALTMARSH TERRAIN LEVELS Removal of Topsoil
• Last option in the range of restoration
• Rather strong impact
• Material leaves the system
Disadvantages
:• Loss of salt marsh habitat (10 to 30 years)
• Loss of habitat for halophilic insect species (10 to 30 years)
• Loss of breeding habitats of typical salt marsh bird species (15 to 40 years) (eg redshank)
• Loss of resting grounds
Restoring SALTMARSH TERRAIN LEVELS
Removal of Topsoil
Advantages:
• Development of habitats through natural dynamics
• Salt marsh habitats with all stages of development and in the medium term of good condition
• Natural tidal creek systems
• Medium-and long-term improvement of natural resting, breeding and feeding habitats for bird species
Langwarder Groden
Langwarder Groden
Advantages:
• Development of habitats through natural dynamics
• Salt marsh habitats with all stages of development and in the medium term of good condition
• Natural tidal creek systems
• Medium-and long-term improvement of natural resting, breeding and feeding habitats for bird species
ecoplan: Juni 2018
Requirements:
• Natural development potential based on height and frequency of flooding
• Extraction depth in relation to mean high tide
• quick saltmarsh development
Campen
Requirements:
• slopes and shallow shore
• no straight design of soil sampling
Campen
Requirements:
• slopes and shallow shore
• no straight design of soil sampling
Campen
Requirements:
• demolition of existing anthropogenic structures
• connection to existing tidal channels
• initiating of a natural tidal creek system
Neuwapeler Außengroden Pütte B
Campen (ecoplan): Feb 2018, Abschnitt B, Herrichtung 2016
Campen
Requirements:
• creation of predation poor areas and island locations
Campen (ecoplan): Feb 2018, Abschnitt B, Herrichtung 2016
Requirements:
• creation of predation poor areas and island locations
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
• Clay or sand mining → aims for material extraction
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
• Clay or sand mining → aims for material extraction
- the Nationalpark was established with the aim of protecting and preserving waddensea dynamics.
Prof. GASSNER (2007): Definition of legal options for clay extraction at the example of the the Elisabeth - Außengroden on behalf of the III. Oldenburgischen dyke band.
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
• Clay or sand mining → aims for material extraction
- the Nationalpark was established with the aim of protecting and preserving waddensea dynamics.
- Clay extractions for coastal protection only are not compatible with the law (NWattNPG)
Prof. GASSNER (2007): Definition of legal options for clay extraction at the example of the the Elisabeth - Außengroden on behalf of the III. Oldenburgischen dyke band.
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
• Clay or sand mining → aims for material extraction
- the Nationalpark was established with the aim of protecting and preserving waddensea dynamics.
- Clay extractions for coastal protection only are not compatible with the law (NWattNPG)
- But: Generating soil can be a by-product of nature improvement measures
Prof. GASSNER (2007): Definition of legal options for clay extraction at the example of the the Elisabeth - Außengroden on behalf of the III. Oldenburgischen dyke band.
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
• Clay or sand mining → aims for material extraction
- the Nationalpark was established with the aim of protecting and preserving waddensea dynamics.
- Clay extractions for coastal protection only are not compatible with the law (NWattNPG)
- Generating soil can be a by-product of nature improvement measures - Saltmarsh restoration accomplished through mining
in areas with acceptable clay for dyke improvement:
Prof. GASSNER (2007): Definition of legal options for clay extraction at the example of the the Elisabeth - Außengroden on behalf of the III. Oldenburgischen dyke band.
Prof. GASSNER (2007): Definition of legal options for clay extraction at the example of the the Elisabeth - Außengroden on behalf of the III. Oldenburgischen dyke band.
Legal framework for realization:
• Nature conservation project → aims for improvement of nature
• Compensation obligations → aims for improvement of nature
• Clay or sand mining → aims for material extraction
- the Nationalpark was established with the aim of protecting and preserving waddensea dynamics.
- Clay extractions for coastal protection only are not compatible with the law (NWattNPG)
- Generating soil can be a by-product of nature improvement measures - Saltmarsh restoration accomplished through mining
in areas with acceptable clay for dyke improvement:
→ WIN - WIN
Pre-planing of dyke authorities:
• No clay available in the inland in a 30 km strip along the coast
• Searching for suitable areas for clay extraction in the foreland
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Pre-planing of dyke authorities:
• No clay available in the inland in a 30 km strip along the coast
• Searching for suitable areas for clay extraction in the foreland
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Example: Neuwapeler Außengroden Example Neuwapeler Außengroden
Clay mining for dyke improvement
Existing anthropogenic influences
• rigid drainage system with regular purified ditches
• Complete lack of relief structure on the mowing areas
• Completely missing natural gully system
• traditional land use by mowing the entire areal
Habitat structure and habitat diversity Example: Neuwapeler Außengroden
Habitat structure and habitat diversity
• Dominance of Elymus
• complete lack of habitat diversity in a wide range
• Limited habitat diversity only in the silted clay pits
• Near-natural habitat diversity only in the natural sedimentation areas
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Elymus (couch gras)
Habitat structure and habitat diversity Example: Neuwapeler Außengroden
Habitat structure and habitat diversity
• Dominance of Elymus
• complete lack of habitat diversity in a wide range
• Limited habitat diversity only in the silted clay pits
• Near-natural habitat diversity only in the natural sedimentation areas
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Elymus (couch gras)
Elymus (couch gras)
highest salt marsh upper salt marsh
lower salt marsh
Elevation
• unnatural height
• lack of salt water influence
• Low natural development potential
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Assessment of the FFH conservation status
• In a bad state of preservation (C) in terms of FFH
Example Neuwapeler Außengroden
Clay mining for dyke improvement
1
2
3
Summary:
• improvement salt marsh habitats by soil extraction is possible
Example Neuwapeler Außengroden
Clay mining for dyke improvement
1
2
3
Summary:
• improvement salt marsh habitats by soil extraction is possible
Example Neuwapeler Außengroden
Clay mining for dyke improvement
1
2
3
Summary:
• improvement salt marsh habitats by soil extraction is possible
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Martin Sprötge (PGG): Sep 2016
Example Neuwapeler Außengroden
Clay mining for dyke improvement
Martin Sprötge (PGG): Sep 2016
Example Neuwapeler Außengroden
Clay mining for dyke improvement
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
Will it work? Cross-Check planning, e.g. by hydrological models simulating flooding. Use local (!) gauge data!
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
Will it work? Cross-Check planning, e.g. by hydrological models simulating flooding. Use local (!) gauge data!
↓
Find money / project sponsors (compensation measures from impact regulation)
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
Will it work? Cross-Check planning, e.g. by hydrological models simulating flooding. Use local (!) gauge data!
↓
Find money / project sponsors (compensation measures from impact regulation)
↓
Realize It!
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
Will it work? Cross-Check planning, e.g. by hydrological models simulating flooding. Use local (!) gauge data!
↓
Find money / project sponsors (compensation measures from impact regulation)
↓
Realize It!
↓
Make sure long-term Monitoring & Evaluation!
Ensure (deeper) scientific analysis!
↓
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
Will it work? Cross-Check planning, e.g. by hydrological models simulating flooding. Use local (!) gauge data!
↓
Find money / project sponsors (compensation measures from impact regulation)
↓
Realize It!
↓
Make sure long-term Monitoring & Evaluation!
Ensure (deeper) scientific analysis!
↓
Share Results!
(Our) lessons learned so far
Identify requirement for Salt marsh restoration (Conservation Status B or C: Vegetation/Birds)
↓
Management plan for Salt marsh restoration (incl. priorization)/
Feasibility study scale
↓
Detailed planning: Do consider terrain level heights (vs. mean high tide) at early stage!
↓
Choose suitable measures for the site (combination!):
• TIDAL INFLUENCE (De-Embankment)
• NATURAL HYDROLOGY
• SALTMARSH TERRAIN LEVELS (Removal of Topsoil ->
management for surplus soil!)
↓
Will it work? Cross-Check planning, e.g. by hydrological models simulating flooding. Use local (!) gauge data!
↓
Find money / project sponsors (compensation measures from impact regulation)
↓
Realize It!
↓
Make sure long-term Monitoring & Evaluation!
Ensure (deeper) scientific analysis!
↓
Share Results!
