Ad hoc new land use at Sieperda-schor (NL-B)

Transcription

‘Flood Risk Management in Estuaries: Sustainable New Land Use in Flood Control Areas’
‘Flood Risk Management in Estuaries: Sustainable New Land Use in Flood Control Areas’
FRaME
FRaME
Reviewand
andEvaluation
Evaluationofof
Review
AlternativeLand
LandUse
Use
Alternative
Estuaries
StrategiesininEstuaries
Strategies
FRaME – Review and Evaluation of Alternative Land Use Strategies in Estuaries
Name
Lead Partner
Contractant
Authors
Release
Date
Number of pages
Copyright
2
FRaME – Review and Evaluation of Alternative Land Use
Strategies in Estuaries
DLG - Government Service for Land and Water Management
Soresma nv,
Halcrow Group Ltd.
Kristof Van Stichelen, Marc Leysen, Richard Ashby-Crane
Jan Parys
6th of February 2004
75
© All rights reserved. No part of this publication may be
reproduced, stored or transmitted in any form, or by any
means, electronic, mechanical, photocopying, recording or
otherwise, without the prior permission of the lead partner of
this project.
Content
Glossary and abbreviations ............................................................................ 5
Summary in English ........................................................................................ 7
Samenvatting / Summary in Dutch ................................................................. 8
1. Previous activities ........................................................................................... 9
2. General information main review .................................................................. 11
3. Case: Recreative development at Aakvlaai area (NL) ................................. 14
3.1 General case description 3,7,20 ................................................................. 14
3.2. Objective aspects................................................................................... 16
3.3. Legal and governance aspects.............................................................. 17
3.4. Organisational, technical and management aspects ............................ 18
3.5. Communication aspects......................................................................... 20
3.6. Societal, economic and ecological consequences................................ 20
3.7. Intervention aspects ............................................................................... 21
3.8. Were the objectives achieved ? 1,2,3,4,7,9,16,20 .......................................... 22
3.9. Summary and lessons learned .............................................................. 22
3.10. Contacts and information: .................................................................... 24
4. Case: Ad hoc new land use at Sieperda-schor (NL-B) ................................ 26
4.1. General case description 2, 4 .................................................................. 26
4.6. Societal, economic and ecological aspects........................................... 30
4.8. Were the objectives achieved ? 2,4,5,6,7,9,10,14 .......................................... 32
4.10. Contacts and information ..................................................................... 34
5. Case: Baie des Veys..................................................................................... 36
5.1. General case description ....................................................................... 36
5.6. Societal, economic and ecological consequences................................ 42
5.8. Were the objectives achieved ?............................................................. 44
6. Case: Flood bank setback of Norfolk Broads (UK) ...................................... 47
3
7. Case: Paull Holme Strays in Humber Estuary (UK) ..................................... 58
8. Main review conclusions ............................................................................... 68
8.1 Introduction.............................................................................................. 68
General overall observations ........................................................................ 68
8.2 Individual lessons learned....................................................................... 69
8.3 Overall lessons learned .......................................................................... 73
4
Glossary and abbreviations
Abbreviation Meaning in Dutch
AMINAL
Administratie Milieu, Natuur,
Land- en Waterbeheer
AROHM
AWZ
B
B.Vl.R.
COM
DTM
F
FCA
GEIS
Administratie Ruimtelijke
Ordening, Huisvesting en
Monumenten en landschappen
Administratie Waterwegen en
Zeewezen
België
Besluit van de Vlaamse
Regering
communicatie
Digitaal terreinmodel
Frankrijk
Gecontroleerd
overstromingsgebied (GOG)
Meaning in English
Environment, nature, landand water management
administration
Environmental planning,
housing, monuments and
landscape administration
Waterways and marine affairs
administration
Belgium
Implementing order of the
Flemish Government
Communication
Digital terrain model
France
Flood control area
KPI
General environmental
impact study
FCA with reduced tidal
influence
Regional developmental
company
Institute for nature
conservation
Essentiële performantieindicator Key performance indicator
KUL
LTV
MCA
NAP
Katholieke Universiteit Leuven
Lange termijn visie
multicriteriaanalyse
Nieuw Amsterdams Peil
NL
NLU
OMES
Nederland
Alternatief landgebruik
Onderzoek naar de
milieueffecten van het
Sigmaplan
Potentiële
overstromingsgebieden
Projectdirectie
Ontwikkelingsschets
Scheldeëstuarium
maatschappelijke kosten-baten
GGG
GOM
IN
PFCAs
ProSes
SCBA
Algemene Milieu Impact Studie
(AMIS)
Gecontroleerd gereduceerd
getijdengebied
Gewestelijke
ontwikkelingsmaatschappij
Instituut voor Natuurbehoud
Catholic University of Leuven
Long term vision
multi criteria analysis
New Amsterdams level
(reference level for height
determination in the
Netherlands)
The Netherlands
New land use
Investigation of the
environmental effects of the
Sigmaplan
Potential Flood Control
Area’s
Project Management
Developmental plan Scheldt
Estuary
Societal Cost-Benefit
5
SSB
TAW
analyse
plan-milieueffectrapportering
(plan-MER)
Maatschappelijke impact studie
(MaIS)
stormvloedkering (SVK)
Tweede algemene waterpassing
UK
Verenigd Koninkrijk
SEIA
SIA
6
Analysis
strategic environmental
impact assessment
Societal impact assessment
storm surge barrier
Second General Level
(reference level for height
determination in Belgium)
United Kingdom
Summary in English
The FRaME project aims to implement flood control areas as means to reduce
floodrisk in estuaries.
To allow for optimal learning and knowledge
development in the FRaME setting and to realise fruitful demonstration
projects in the future, (review) studies have been commissioned to collect
relevant international experience.
Each of the review studies – on Flood Control, New Land Use and
Communication – performs a broad initial quick scan, more or less restricted in
scope to estuarine areas. The purpose of the quick scan was to obtain a
comprehensive overview of relevant experience with flood control areas, land
use and communication issues in the EU and in North America. Therefore an
initial longlist of potential sites has been drafted, that subsequently and after
investigation has been reduced to a medium list, to end after interviewing the
site contact persons with a shortlist of sites. Some of those shortlist sites were
carried forward to a main review.
By mutual agreement 5 shortlist sites were analysed on their suitability and
relevancy for New Land Use (or NLU) learning and knowledge. The following
5 spots were considered:
- Recreative development at the Aakvlaai area (NL)
- Ad hoc new land use at the Sieperdaschor (NL-B)
- Baie des Veys (F)
- Flood bank setback of the Norfolk Broads (UK)
- Paull Holme Strays in the Humber Estuary (UK)
To evaluate the success of those NLU area a number of Key Performance
Indicators (KPIs) were studied. 18 KPIs were brought together in 7 successive
Key Areas:
- Objective aspects
- Legal and governance aspects,
- Organisational, technical and management aspects,
- Communication aspects,
- Societal, economic and ecological aspects,
- Intervention aspects,
- Evaluation of the whole NLU project.
Once all these elements have been made clear for the 5 sites, the success
factors of NLU were evaluated. Based on that information suggestions on NLU
were formulated. The most important recommendations or lessons were:
- Plan the strategy
- Contact the key parties
- Fathom the different sensitivities
- Give consideration to multiple land use types
- Design carefully: A detailed designing plan is essential. It has to
consider all conceptual ideas and especially the final ideas. One must
be able to trace how the final ideas were chosen. Therefore study work
must ‘go’ along an inventory part, a guiding part, a binding part and a
monitoring part.
- Make use of the existing guidances to NLU
7
Samenvatting / Summary in Dutch
Het FraME-project tracht gecontroleerde overstromingsgebieden (GOG’s) op
terrein te realiseren als een middel om overstromingsrisico’s in estuariene
gebieden te verkleinen. Om terzake kennis en expertise bij elkaar te brengen,
en om op termijn zinvolle FRaME-demonstratiesites te kunnen realiseren,
werden een aantal (recensie)studies uitgeschreven waarmee men probeerde
relevante internationale expertise te vergaren.
Elk van de recensies – in totaal 3, nl. gecontroleerde overstroming, nieuw
landgebruik en communicatie – startte met een globale screening van diverse
estuariene gebieden in Europa en Noord-Amerika. Het doel van deze
screening was het verwerven van een totaalbeeld van de relevante expertise
in de EU, inzake gecontroleerde overstroming, alternatief landgebruik en
communicatie. Om die reden werd gestart met het opmaken van een
overzichtlijst van potentiële overstromingssites. Vervolgens werd die lijst na
een korte analyse van de betrokken overloopgebieden ingekort tot een 30-tal
sites (mediumlijst), om uiteindelijk uit te komen bij een tiental zones na
contactname met de verschillende verantwoordelijken van ieder afzonderlijk
overstromingsgebied (korte lijst).
Met instemming van de verschillende partners betrokken bij deze studie,
werden 5 kortelijstsites geanalyseerd op vlak van geschiktheid en
toepasbaarheid bij kennisoverdracht inzake Nieuw Landgebruik (NLG). Het
gaat om de volgende 5 zones:
- Recreatieve ontwikkeling in de Aakvlaai (NL)
- Onvoorzien nieuw landgebruik in het Sieperdaschor (NL-B)
- De Baai van Veys (F)
- Verbreding van de riveriene slijkplaten bij de Norfolk Broads (VK)
- Paull Holme Strays in het estuarium van de Humber (VK)
Om het succes van deze zones met nieuw landgebruik te kunnen evalueren
werden een aantal sleutelcriteria onderzocht. 18 sleutelcriteria werden
gebundeld in een 7-tal criteriumgroepen, zijnde:
- Objectieve aspecten
- Juridische en beleidsmatige aspecten
- Organisatorische, technische en beheersaspecten
- Communicatieaspecten
- Maatschappelijke, economische en ecologische aspecten
- Interventieaspecten
- Evaluatie van het volledige NLG-project.
In een volgende stap werden de succesfactoren van het NLG geëvalueerd, en
op basis daarvan werden suggesties gedaan. De belangrijkste lessen en
aanbevelingen waren de volgende:
- Plan de te volgen strategie
- Contacteer tijdig de belangrijkste partners
- Achterhaal de diverse gevoeligheden
- Analyseer diverse landgebruiksmogelijkheden
- Ontwerp zeer nauwgezet, en integreer een informatief luik, een
richtinggevend gedeelte, een bindend deel, en een monitoringstuk.
- Maak gebruik van bestaande richtlijnen inzake NLG
8
1. Previous activities
The FRaME project aims to implement flood control areas as means to reduce
floodrisk in estuaries. A total of five demonstration sites has been selected for
the implementation of these solutions:
- Zuiderklip – Biesbosch (NL)
- The Northern Fringe of Goeree Overvlakkee – Haringvliet (NL)
- Alkborough flats – Humber estuary (UK)
- Kruibeke-Basel-Rupelmonde – Scheldt estuary (B)
- IJzer – IJzer estuary (B)
To allow for optimal learning and knowledge development in the FRaME
setting and to realise fruitful demonstration projects, studies have been
commissioned to collect relevant international experience. The studies focus
on a review of:
- flood control areas;
- new land uses;
- communication aspects.
Each of the review studies performs a broad initial quick scan (definitive report
Hallcrow, Soresma, Black & Veatch, WL Delft, 9 Sept. 2003). The quick scan
describes the results of the quickscan phase of the FRaME projects ‘review of
flood control areas’ and ‘new and innovative land uses’. These two reviews are
more or less restricted in scope to estuarine areas. The communication review
was able to cover a wider search area.
The purpose of the quickscan was to obtain a comprehensive overview of
relevant experience with flood control areas, land use and communication
issues in the EU and in North America. To promote a co-operative approach
between the three parallel review efforts, the consortia were invited to present
suggestions at the kick off meeting in Voorburg, the Netherlands. The
approach, discussed and agreed upon at that meeting, consisted of the
following actions.
- To achieve a comprehensive overview of experiences, an initial
longlist of potential sites has been drafted, based on maps. The
resulting longlist contained a relatively large number of potential
estuaries (order 100 – 110).
- Based on expert judgement by the consultants, this longlist was then
reduced to a medium list of approximately 30 sites, for more detailed
investigation through interviews with the key contacts for each site.
These sites were then distributed among the consultants according to
indicated preferences and the nature of the available contacts. A
standard questionnaire has been drafted to ensure the production of
comparable results. After a period of interviewing contacts the results
were merged again into a single database. WL|Delft Hydraulics & Black
and Veatch agreed to draft a long list and an initial questionnaire. The
drafts were then sent to Soresma & Halcrow and TNO respectively for
emendation. The process resulted in a detailled questionnaire.
9
-
After interviewing the contacts for each site on the medium list,
evaluation of the gathered information per site facilitated drafting a
shortlist of sites to be carried forward to the main review.
After short listing, the combined consortia of ‘Soresma & Halcrow’ and ‘Black
and Veatch & WL|Delft Hydraulics’ selected (on suitability and on interest as a
FRaME component) the sites to be addressed during the Main Review.
In the text below the Main Review elements on the New Land Use areas can
be found. After describing the Key Performance Indicators (KPI’s) (already
mentioned in de final quick scan report), 5 sites are analysed on their suitability
and relevancy for New Land Use learning and knowledge. The following 5
spots were considered:
- Recreative development at the Aakvlaai area (NL)
- Ad hoc new land use at the Sieperdaschor (NL-B)
- Baie des Veys (F)
- Flood bank setback of the Norfolk Broads (UK)
- Paull Holme Strays in the Humber Estuary (UK)
Note: the consortium ‘Black and Veatch & WL|Delft Hydraulics’ considers the
same sites were studied on Flood Control. ‘Sieperdaschor’ however was
replaced by ’Tielrodebroek’ along the Scheldt river (B).
10
2. General information main review
The NLU review analyses its cases, according to the frame of reference
methodology. In the event that an integrated analysis is not supported, this
means that only alternative land use objectives will be addressed, but the
principle remains the same: evaluation of the success of any given NLU area
involves an investigation of a number of Key Performance Indicators (KPIs).
The KPI’s were already formulated in the Quick Scan; the elaboration of the
assessment frame did not change during the execution of the main review
study.
So, we consider 7 successive issues or Key Areas with 18 KPI’s in total. The
analysis consists of the following steps:
1) Key Area: Objective aspects
We start with an inventory of the strategic and operational objectives that were
formulated for the NLU. Clearly establishing the possible land use aims is
crucial, in order to enable a useful evaluation of its success. As key
performance indicators (KPIs) we identify whether or not objectives have been
formulated.
- Has a clear strategic objective been developed?
- Has a clear operational objective been developed?
2) Key Area: Legal and governance aspects
It is also valuable to analyse in a second step the national and international
legislation, towards the creation of NLU.
Based on that information,
suggestions towards required adjustments of governance are also possible.
- To what effect has national legislation been an impediment or
opportunity for alternative land use strategies?
- To what effect has European legislation (e.g. Natura 2000) been an
impediment or opportunity for alternative land use strategies?
- To what extent has a co-operation between governmental bodies or
lack thereof affected the implementation of alternative land use
strategies?
3) Key Area: Organisational, technical and management aspects
It’s important not only to fix on the legal or governance aspects, but also to
look at their actual implications. To look into that, as a third step we investigate
how the land use was ‘framed’ and how it developed in a particular area. To
enable a rational design in function of NLU, general information about
methodology, organization, procedures, etc. is needed. As key performance
indicators (KPIs) we identify whether or not such elements are gathered:
- Who was the initiator and who were the actors of the process, and to
what extent did they improve or facilitate the implementation of the
NLU?
- Has there been functional instruments to implement the strategy?
- Has there been a methodology on which the planning was based?
- Has there been flexibility of the organisation structure and process
towards practical and operational needs?
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-
Has there been a clear decision procedure (e.g. social cost benefit
analysis, …) to judge which was the desired aspectstate of a NLU
area?
Has there been different technical and management approaches in
implementing and maintaining land use changes considered, tested
or studied?
4) Key Area: Communication aspects
To find support for the realisation of a certain plan or project, it can be useful to
ask for cooperation and to consult the inhabitants or other people directly
involved.
- Has there been any societal participation or opposition, and was
this addressed successfully, or has there been a functional
communication plan?
5) Key Area: Societal, economic and ecological aspects
It is clear that these KPI’s support an overview of the presence of some
essential elements of the project. Not only the aspects mentioned above are
important but also an analysis of the actual and potential ecological (incl.
functionality), economic and societal (incl. accessibility) elements is important
in judging and assessing NLU areas. As a fifth step we analyse these aspects.
- Are the observed ecological effects positive, are they lasting, and
can negative effects be reversed?
- Are there economic consequences and was there any kind of
financial compensation?
- Are there any social consequences towards the planned NLU
activities?
6) Key Area: Intervention aspects
Once it is clear that, based on the elements mentioned above, a piece of land
needs to be flooded to reach the earlier defined objectives, an intervention will
take place. The intervention may be active or passive in nature but should
have an effect on the present state in either case. Furthermore, the successful
operation of a NLU area requires a clear timing and definition of
responsibilities. As key performance indicators (KPI’s) we identify whether or
not an intervention procedure is present and whether or not timing and
responsibilities are sufficiently clear.
- Has there been developed a clear intervention procedure based on
the decision procedure?
- Has there been developed an intervention scheme containing a
description of the timing and responsibilities during the operations
(and also afterwards) towards ecology, economy and society, and
were those elements monitored?
7) Key Area: Evaluation of the whole NLU project
Once all these elements have been made clear, we can evaluate the success
factors. This success is closely related to the measure by which it has been
successful in achieving its objectives. As a seventh and final step we therefore
assess the extent to which a given NLU area has been successful in
12
achieving its strategic and operational objectives. The evaluation will be
gathered and visualised into one conveniently arranged table, as stated below,
and the ‘lessons learned’ will be mentioned.
The overview of the KPI’s described above, facilitates assessment of a NLU
area success or failure. The background information for each KPI helps to
identify which factors contributed to or impeded successful operation of a given
NLU area. At a level of sites we aim to determine whether or not the strategic
objectives are effectively reached. Based on that information we can formulate
suggestions as required for the FRaME project.
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3. Case: Recreative development at Aakvlaai
area (NL)
3.1 General case description 3,7,20
The Aakvlaai project is located southeast of the national park the Biesbosch,
which itself is located approximately 30 km southeast of Rotterdam. The
Biesbosch is divided into various parts. Several polders, used for agriculture,
are found dispersed in the area, resulting in a scattering of the reserve area.
Planners aim to reintroduce natural conditions into these polders in order to
create one large natural area. A larger area offers greater opportunities for
species of plants and animals, to recover or return (for those that have
disappeared).
For six polders, together covering an area of 2500 hectares, nature
development plans have been prepared in this context. Landowners were
bought out after which the area was to be restored to the wet type of
landscape that was common there in earlier days, consisting of a multi channel
system with sloping banks and islands in between. The Aakvlaai area, which
mainly consisted of farmland that had been reclaimed relatively recently, is
actually located just outside of the Biesbosch.
It is not so much the Aakvlaai area itself as it is the semi surrounding
Biesbosch area that triggered the shift in its land use. With the finalisation in
the early 1970’s of the nearby Haringvliet sluices, that were built in the context
of the Delta project (this project incudes the creation of dams on all the
estuaries between the Westerscheldt and Rotterdam, and the raising of the
dikes along all tidal rivers), the difference between ebb and flood in the
Biesbosch area was strongly reduced (from 1.8 m to 0.4 m). With the milder
tidal regime, the area remained navigable throughout the tidal cycle and water
recreation started to flourish. The recreation activities had a negative impact on
the environment and a decision was made in 1975 to close some of the most
valuable creeks for water recreation. The active recreation lobby did not accept
this closure of the hart of the Biesbosch area. The pressure resulted in a
promise of compensation through the creation of the so called ‘Miniature
Biesbosch’, with an area of 150 hectares, in the polders located in the south
east corner of the Biesbosch. The project was given the name of the local
creek: the Aakvlaai.
14
Location Aakvlaai (Source: RIKZ, Haren)
Triggered by the high water events of 1995 and 1996 along the Meuse, a
project was started to create more ‘room for the river’. The high water events
had shown that in case of peak discharges, flood risk is high along significant
stretches of the Dutch rivers. Due to climate change and the anticipated
resulting sea level rise and soil subsidence, such high water events are in fact
expected to occur ever more frequently in the future. The resulting flood risks
are augmented by river narrows, caused by villages and towns colonizing the
river’s floodplains. To be prepared for the expected increase in unfavourable
hydraulic and hydrologic conditions, a national project was started to create
more ‘room for the rivers’. The additional room would lower the peak water
levels on the river itself, reducing the pressure on dikes and thus to reduce
flood risk. The room for the river approach has been adopted in addition to the
other potential solution, viz. raising the dikes. Throughout the 1990’s it was felt
that, with an expected increase in peak water levels in the order of tens of
centimetres, the latter approach alone could not be sustained.
The Biesbosch area lies in the Dutch delta area where the largest rivers of the
Netherlands find their way to the sea. Although, as a result of the Delta works,
the tidal range in the Biesbosch area had been significantly reduced, flooding
is still a real issue. The main threat is now not so much the sea as it is the
fresh water from the rivers that flow through the area. From this perspective,
Rijkswaterstaat wanted to participate in the Aakvlaai project because they saw
the opportunity to use the area as an additional floodplain. This initiative was
embraced by the initiative to turn the Aakvlaai into a recreation area under the
precondition that the original plans would not be changed significantly. Study
showed that the initiatives could be integrated with almost no modifications to
the original plans and in 1999 the work began.
15
Situation after designing (source: Oranjewoud bv, Oosterhout)
From 1800 till 1998 the Aakvlaai area was an agricultural polder, with cropping
of potatoes and wheat, and in places also mangel-wurzel. Before the
recreational designing, no inventory or vegetation mapping took place, but one
can suppose that because of the presence of intensive mechanized agriculture
the nature values were rather low.
3.2. Objective aspects
Has a clear strategic objective been developed ? 3,7,16
Yes. The Aakvlaai project started because of two major problems:
1) When the Dutch Deltaworks were finished in the early 70’s, the tidal
amplitude in the Brabantsche Biesbosch decreased significantly.
This resulted in an explosive increase of the local water recreation.
Next nature values decreased. The “Nationaal Park De Biesbosch
in development” decided to zone and limit the water recreation.
Around 1978 it was settled with local water sport organisations to
expand the Biesbosch with a water recreation area of ±150ha.
2) In different studies it was proved that the indicative river discharge
and the water levels will increase in the future, as a result of climate
changes, sea level rise and soil subsidence. To counter these
threats, dikes need to be raised or the storage capacity of the rivers
needs to be increased.
Now, the project Aakvlaai falls into the cluster “lower region projects”, as
part of the ‘room for the river’-project to implement flood-prevention policy
in the heavily inhabited lower regions of the Rhine and Meuse.
16
The project focused specifically at the agricultural Allardspolder where
land had been acquired to set up a ‘miniature Biesbosch’. The objectives
of the project were integral so that flood-prevention and nature
development go hand in hand. The major objective of the polder
reconversion of the Aakvlaai area was the zoning of recreation, but also
to a lesser degree to strengthen the ecological structure. The Aakvlaai
polder will thereby be developed into a (nature) recreation area in order
to compensate for creeks that have been closed for recreation in the
past.
Has a clear operational objective been developed ? 3,7,16
Yes. In a design plan it was concretely defined where anglers, sailors,
and other (‘water people’) recreational activities belonged, and in what
extent and where nature values need to be created in relation to the
water recreation.
Water storage in and flow rate through the Aakvlaai area (and how this
can be linked to recreation) were also main issues in this plan.
3.3. Legal and governance aspects
To what effect has national legislation been an impediment or
opportunity for alternative land use strategies ? 3,4
In a lot of Dutch wetlands large-scale nature development is or has been
planned. The Aakvlaai area perfectly matches in that Dutch policy. This
policy was an important opportunity for the creation of this water
recreation area.
To what effect has European legislation (e.g. Natura 2000) been an
impediment or opportunity for alternative land use strategies ? 22
The European legislation was a good opportunity to implement the
‘nature part’ of the alternative land use at Aakvlaai:
- Aakvlaai is part of a Special Area of Protection (Habitats directive),
named NL 1000015 Haringvliet. The most important habitat type
protected by this directive is ‘Fringe forming, eutrophic tall herbs of
the lowland, and of the mountainous and alpine areas’.
- Aakvlaai is also part of a Special Protection Area for Birds (Birds
directive), named NL 67 Haringvliet.
Due to that element of the EU nature policy, the ‘reorganisation’ of the
Aakvlaai landscape needs to carry evidence of relevant nature
development and nature quality in the area has been lifted up.
To what extent has a co-operation between government bodies or lack
thereof affected the implementation of alternative land use strategies ?
1,2,3,4,7
Because of juridical tussling between 1978 (promise of the government
to create a mini-Biesbosch) and 2001 (finalisation in situ), it took quite a
long time before the plans took their definitive shape. In 1998, when al
juridical problems were solved, Rijkswaterstaat (RWS) decided to
participate in the project. RWS was aware of the ‘room for the river’
possibility and the water storage capacity of the Aakvlaai project. The
17
area could play an important role to relieve the dikes from extreme water
pressure in the Bergsche Maas. For that reason the Bergsche Maas
dikes along the Aakvlaai area were lowered to decrease the maximum
river discharge. From that moment on the original recreation plan in fact
became a nature recreation plan. The nature elements got more
chances; recreation elements have to adapt.
Two government agencies were the main co-operators in managing this
new marsh area:
- Rijkswaterstaat / Department of Waterways and Public Works:
manager of the main waterways and rivers, and responsible for dikes
and quays.
- The Ministry of Agriculture, Nature management and Fishery,
including Staatsbosbeheer / Dutch Forestry Commission and Dienst
Landelijk Gebied / Rural Area Service: monitoring and developing the
site, and also owner.
Two other main co-operators were:
- The local authority
- The feedback group of water sport fans
The plan preparation was done by:
- Oranjewoud bv
The plans were executed in situ by two firms:
- Boskalis bv
- A.H. Breijs & zonen bv
3.4. Organisational, technical and management
aspects
Who was the initiator and who were the actors of the process, and to
NLU?7,16
The “Nationaal Park De Biesbosch” (a public body closely linked to
Staatsbosbeheer) was the initiator of the Aakvlaai recreation idea. Since
nature and water storage ideas got involved (and after solving the
juridical problems), RWS can be seen as a co-initiator.
Has there been functional instruments to implement the strategy ? 7
Not specifically.
Has there been a methodology on which the planning was based ? 1,3,4,16
The potential of the Aakvlaai project as a recreation, nature and water
storage area, is investigated in the study “Integrale Verkenning
Benedenrivieren” (IVB, Integral Investigation of the Lower Rivers). As a
result different targets with respect to recreation (water and ecology)
were identified and a specific design plan was made up.
When the plan became definitive, schemes and specifications were
made in relation to water and excavation works. To realize the water
recreation area, one started in may 1999 (after changing the local
destination plan, purchasing the parcels, and receiving the different
permissions needed) with reconverting the arable land. This started with
18
the creation of a dike of 3,5km. The spoil for creation of the new dike
(sand and clay) originated from the digging of water recreation creeks.
When the digging was finished, planting, road building and bank
protection was undertaken.
This new dike now is 2,00 m + NAP (the former dike was 3,40 + NAP,
and was cut through on the 7th of June 2001), by which it is now possible
that the Aakvlaai becomes part of the river when bank discharge is high.
In periods of extreme discharges (e.g. in spring and autumn), there are
no tourists in the area, so that Aakvlaai can fulfil its second function of
‘streaming water storage’.
Has there been flexibility of the organisation structure and process
towards practical and operational needs ? 4,7,16
The steering committee was established quite flexibly. The integration of
new committee members, partners and a management budget went very
easily.
Especially when the juridical problems were solved there was a lot of
space to include new partners during the planning process. Also other
people and agencies were consulted; people who were not involved at
the beginning of the process. Because of the intensive but careful
consideration moments and the frequent interactions between the
partners, new drawings were often necessary.
Has there been a clear decision procedure to judge which is the desired
state of a NLU area ? 16
The action plan ‘Inrichting Aakvlaai’ was made in dialogue with the
different partners. With respect to this (ideal) target state it is possible to
assess whether the original targets were achieved.
Have there been different technical and management approaches in
implementing and maintaining land use changes considered, tested or
studied ? 9,16
Yes. For this can be referred to other reports and analyses (e.g.
Integrale Verkenning Benedenrivieren, Inventory of the ecological
restoration of the Meuse, …). In these studies different suggestions
were made towards the Meuse and her onshore zones. This basic
information formed a relevant input to become the final Aakvlaai
development plan, and considered 4 basic aspects:
- Topography: it was considered that this should change significantly
(artificial changes). Especially the eventual sedimentation problems
after creation of the new NLU area were considered.
- Breach size and location: in combination with topography the
location(s) of dike breaches in the present river dike was considered,
which in turn drives the habitat type and recreation possibilities.
Breach design was modelled to ensure an appropriate flooding
regime for the site.
- Creek creation: drainage of the site was largely and rigourously
marked out on forehand, natural creek development was limited;
19
-
different ponds and landing places
were also planned and
constructed within the NLU area.
Monitoring and Management: the development of habitats on the site
is largely being left to ‘men’; some monitoring helps decide what to do
if any intervention may be needed in the future.
3.5. Communication aspects
Has there been any societal participation or opposition, and was this
addressed successfully, or has there been a functional communication
plan ? 3,7,9,16
When the Biesbosch was to become a national park in 1987, a lot of
commotion had preceded since 1984. As part of the Aakvlaai project the
function of the area had to be changed from agricultural to recreational.
The local inhabitants and municipality strongly opposed this - in their
eyes - pointless creation of a new recreational area on their lands.
Between 1984 and 1998, a number of four exhaustive participation
procedures ran. Practically each time up to the highest level of appeal.
Since 1998, especially during the final planning process, there was some
constructive information input of the inhabitants and other persons
involved.
3.6. Societal, economic and ecological
consequences
Are the observed ecological effects positive, are they lasting, and can
negative effects be reversed ? 1,2,3,4,7,9,16,22
To facilitate the creation of the desired nature recreation environment, a
system of creeks has been dug inside the Aakvlaai. The creeks create a
system of channels, islands and quays for the benefit of water recreation.
The fact that the Aakvlaai was to be used as a ‘nature recreation area’
implied the need for a relatively detailed design. Elements like quays and
miniature beaches would not have been introduced if the area only had a
‘nature’ function. In fact other nature development projects in the
Biesbosch, like Noorderwaard and Zuiderklip, have been designed in a
much coarser manner. There, only the basic system of creeks will be dug
out, after which nature is free to take its course. Because the Aakvlaai
has a specific recreational function the design had to meet more strict
requirements, e.g. the creeks needed to be kept open and at sufficient
depth, etc. A key element of this interior design of Aakvlaai is the open
connection with the surrounding waters. The open connection allows
boats to enter the area and introduces a tidal range into the area that
helps to create and maintain certain natural values.
Although the planned actions were not designed specifically for birds,
there are currently a lot of birds in the Aakvlaai area. The first year there
were avocets, common tern, greylags, and a lot of ducks. During the
second year the area was already roughly grown, by which warblers
entered the wetlands. In creeks the number of waterweed increases,
and in the swamps a lot of sea rushes grow. For the moment it seems
20
that the developed nature values are permanent, but a further increase of
waterweed can cause a lot of recreation damage.
For the moment there is no specific monitoring program to assess and
examine the activities. The ecological evolution is checked regularly by
global observation Staatsbosbeheer on the field. In 2002 the province of
Noord-Brabant made a detailed inventory of the breeding birds in the
Aakvlaai area. Based on this and previous inventories one is able to
steer the original plan in a new direction.
In the eastern part of the area there is almost no water circulation. As a
result it is possible that water quality problems will appear in short-term,
which will have consequences towards water recreation. The
cyanobacteria in the eastern part are an indication of poor water quality.
Are there economic consequences and was there any kind of financial
compensation ? 7,9
The employment linked to recreation increased. Persisting the different
recreational provisions turned out to be more expensive than expected.
Are there any social consequences towards planned NLU activities ? 7,9
The local farmers were bought out and stopped their activities or
replaced them. In any case, all areas with an added recreational value
are having a huge impact on the societal structure in the vicinity.
3.7. Intervention aspects
Has there been developed a clear intervention procedure based on the
decision procedure ? 2,7,9,16,20
For recreation and ecology, it is of great importance that negative
evolutions (smell discomfort, cyanobacteria, waterweed, …) are
monitored and countered if necessary. However a clear intervention
procedure for that is not present for the moment. The planned process
is to reduce intervention to a minimum and to make decisions to do so
based on the results of monitoring.
Aerial view of the Aakvlaai area at start and finish of implementation
21
Has there been developed an intervention scheme containing a
description of the timing and responsibilities during the operations (and
also afterwards) towards ecology, economy and society, and were those
elements monitored ? 3
Not for the moment
3.8. Were the objectives achieved ? 1,2,3,4,7,9,16,20
Recreational objectives
The Aakvlaai project has met its primary recreation objective well. The area is
used intensively for recreation. The quays attract a lot of boats, the grass
attracts campers and the miniature beaches are used intensively for
swimming. The channel system was intentionally designed to let the river water
run in and out of the area. The activity of the flow was to keep the navigational
channels at a minimal depth. Furthermore the connection with the surrounding
water was intentionally located at the western part of the area rather than the
southeast. The reason for this was to prevent excessive settling of silt from the
river water. So far the accessibility of the Aakvlaai has been up to standards.
Despite the western entrance, silt does enter the Aakvlaai however. In
particular the miniature beaches suffer from the silting up and maintenance of
these beaches turns out to be fairly costly.
Environmental objectives
With respect to the environmental objectives, the project also seems to be
successful. After the construction of the channel system, nature basically has
taken control of the area. Vegetation has taken hold and the area has taken on
its green appearance. The entrance and the connecting channels were
designed in such a manner that the tidal influence would be felt in the entire
area. Although part of the water in the creeks flows in and out, computer
models had shown that the water in the southeast part of Aakvlaai would not
be refreshed. There was some initial worry that during warm weather
conditions this could result in toxic algal blooms. The summer of 2003 has
been exceptionally warm. So far, however, no insuperable problems of this
nature have occurred.
3.9. Summary and lessons learned
Recreative development at Aakvlaai area, NL
Key Area
Key Area result
Reducing the recreational
Objective
pressure on the Biesbosch area
aspects
Legal and
governance
aspects
22
Lesson
It can be important to make
clear the elements you want
by creating a mini Biesbosch, and to realize on the field, and the
create quays, creeks and nature aspects you want implement
elements on specific places in de (recreation, nature).
Aakvlaai area.
Creating at the same time
relevant nature values and ‘room
for the river’.
The legal and governance
It is advisable to have a clear
opportunities to create the NLU
view on the local policy and
area are present.
legislation, and the
Organisational,
technical and
management
aspects
Communication
aspects
Societal,
economic and
ecological
aspects
In the Netherlands a positive
attitude towards nature recreation
is present
A serious amount of basic and
other useful information was
present (abiotic inventory, soil
plan, water modelling, …),
although some information lacked
(water refreshment plan)
opportunities that it brings.
It can be important to have a
soil flow plan. This plan
identifies the soil types that
are to be excavated and
where the material is best
reapplied.
It is recommended to
determine abiotic parameters.
A soil plan can identify the soil
types that are present, and by
that abiotic prediction of the
future biotic c.q. botanical
situation is feasible (also on
the field), and immediate and
specific management
measures can be taken.
It can be useful to work with a
neutral soil balance in order to
prevent delays with permit
procedures. Make sure to
know where soil pollution can
be present, in order to limit
extreme increase of the costs.
Non-refreshment of water can
be prevented by making a
detailed DTM, a river sand
and river mud input analysis
in situ and in vitro, and a
surface water flow model.
The provision of a flexible and
After decennia of opposition of
broad deliberation platform or
the inhabitants, there was a
consultative body is essential;
certain constructive contribution
during the final planning process. the lack of detailed
A flexible and extendable steering information to the public at the
project start, can be very
committee supervised
invaluable for the progress of
the process.
Those aspects where intensively It is useful to design the
interior of the FCA’s carefully
studied, and the societal
to suit the needs that can be
(recreants), ecological (nature
values) and economical (income derived from the land use
objectives. The Aakvlaai
and receipts) states of the
Aakvlaai area are more or less as nature aspects could do with
a coarser design than a
predicted
nature recreation area.
It can be a useful addition to
the landscape to create small
elevated areas, used for e.g.
grazing cattle, in between
channels and islands. The
enlargement of spatial and
23
Intervention
aspects
For the moment, there is no clear
intervention procedure in case
something goes wrong (f.i. the
unwanted algal growth)
Are the
objectives
achieved ?
The original recreative, natural
and ‘river space’ objectives are
more or less achieved
biological diversity in that way,
can increase the recreational
appreciation.
It is advisable to determine in
advance the desired species
and vegetation types and
implement an accurate
monitoring program (for al
types of animals and plants);
in that way it is possible to
intervene quite quickly when
some unwanted land use
evolution occurs.
/
3.10. Contacts and information:
The following persons provided relevant information:
1. Henk Jagt (RWS, directie Zuid-Holland),Boompjes 200, NL – 3011 XD
Rotterdam, 0031 (0)10 402 62 00, www.rijkswaterstaat.nl
2. Romke van Willenswaard (DLG, Tilburg), Prof. Cobbenhagenlaan 47,
NL – 5037 DB Tilburg, 0031 (0)30 275 66 00
3. René Bol (RWS, directie Zuid-Holland), Van Oldenbarneveltplaats 442,
NL – 3012 AP Rotterdam, 0031 (0)10 217 09 12,
www.rijkswaterstaat.nl
4. Jos Prinsen (Ingenieursbureau Oranjewoud bv), Beneluxweg 7, NL 4900 AA Oosterhout, 0031 (0)162 48 70 00, www.oranjewoud.nl
5. Luc Koks (Ingenieursbureau Oranjewoud bv), Beneluxweg 7, NL - 4900
AA Oosterhout, 0031 (0)162 48 70 00, www.oranjewoud.nl
The following literature contained information mentioned above:
6. Bisseling, C. M., Draaijer, L. J., Klein, M., and Nijkamp, H., … Ecosysteemvisie Delta. Wageningen, Informatie- en KennisCentrum
Natuur, Bos, Landschap en Fauna.
7. Bouma S., Veen S.M. & Bonhof G.H., 2002. – Proefgebieden herstel
zoet-zout overgangen in het Deltagebied. RIKZ, Middelburg.
8. De Leeuw C.C. & Backx J.J.G.M., 2001. - Naar een herstel van
estuariene gradiënten in Nederland. Een literatuurstudie naar de
algemene ecologische principes van estuariene gradiënten, ten
behoeve van herstelmaatregelen langs de Nederlandse kust. RIKZ,
RIZA.
9. Dienst Landelijk Gebied, 2000. - Brochure "Van landbouwgrond naar
natuurrecreatiegebied". Dienst Landelijk Gebied.
10. Eertman, R. H. M., 1997 - Veranderingen in de estuariene ecotopen in
de delta. RIKZ.
11. Gotjé, W., 1999 - Soortsbeschrijving Brakke Ecotopen. Het
benedenrivierengebied. Amsterdam, AquaSense.
12. Jansen, S. and Wardenaar, K., 1997. - Doelsoorten en doeltypen MERHaringvlietsluizen. De betekenis van Hollands Diep, Haringvliet,
24
Biesbosch en Voordelta voor doelsoorten en doeltypen bij verschillende
vormen van sluisbeheer. Amsterdam, VISTA.
13. Lenselink G. & Gerits R., 2000. - Kansen voor herstel van zout-zoet
overgangen in Nederland.
14. Louman, E. G. M, 1991. - Inventarisatienota waterkwaliteit en ekologie.
Integraal beleidsplan Haringvliet, Hollandsch Diep, Biesbosch, Nieuwe
Merwede, Amer. Leiden, Bureau Duin + Kust.
15. Ministerie van Verkeer en Waterstaat, Directie Zuid-Holland, … - MER
Beheer Haringvlietsluizen. Over de grens van zout naar zoet.
“Haringvliet in het kort”, een brochure over de studie naar een ander
beheer van de Haringvlietsluizen.
16. Oranjewoud, 1984 – 2000. - Aakvlaai-onderzoek allerlei (luchtfoto’s,
doelplannen, inrichtingsplannen, bestekken, begeleidingsnota’s, …)
17. Vanhemelrijk, J. A. M. and de Hoog, J. E. W., 1996. - Amoebe's
Benedenrivierengebied.
Studie
naar
ecologische
ontwikkelingsrichtingen. RIZA.
18. Veen, S.M., Boudewijn T.J. & van de Haterd R.J.W., 2002. - Natte As
Biesbosch- Deltagebied. Quickscan. I.o.v. Provincie Zeeland Bureau
Waardenburg, Culemborg.
19. Veen, S.M., Boudewijn T.J. & van Horssen P.W., 2002. - Natte As
Biesbosch – Deltagebied. Verkenning van knelpunten en
mogelijkheden voor moerasnatuur in het Deltagebied. Bureau
Waardenburg, Culemborg.
20. www.ruimtevoorderivier.nl
21. www.cipm-icbm.be/files/pubs/4/inventdefn.pdf
22. http://www.minlnv.nl/thema/groen/natuur/natura2000
25
4. Case: Ad hoc new land use at Sieperdaschor (NL-B)
4.1. General case description 2, 4
The Sieperdaschor, situated near the eastern part of the Westerscheldt, is the
youngest marsh of the Zeeland province (The Netherlands). Till 1966 it was a
part of the Verdronken Land van Saeftinghe.
Relation Sieperdaschor <->Verdronken Land van Saeftinghe (Source: http://www.scheldenet.nl)
Because of a quay construction (actually a small dike from west to east for
bundling some electric wires) and a small, illegal (!) dike (from north to south,
on the most eastern side) a long, narrow piece of land was cut off from the
Verdronken Land. The result was an outer dike polder, the so called
Selenapolder (total area ±100ha). The owner of the entire Selenapolder was
the Belgian dredging firm De Cloedt who leased the polder parcels to some
local farmers. Initially the polder was used for cattle grazing, lateron (>1970)
crop growing was also possible (a maximum of 40% of the area was used for
potatoes, beet, rapes, flax, maize, …; the rest was used in extensive cattle
breeding).
In winter the Westerscheldt water level raised so that water could enter the
Selenapolder. In spite of two dike breaches in 1976 and 1985 (in both cases it
was restored to its original state) the general use of the polder stayed quite
stable till 1990.
On the 26th of February 1990 the dike breached for the third time. It was the
result of a so called ‘three level storm’ (resulting in 3 times high tide, without an
ebb interval). De Cloedt considered the costs to repair the dike too high, and
accepted the new situation. After 24 years the polder was restored to his
original state: a tidal, brackish marsh. The Stichting Zeeuws Landschap
started managing the area, few years later they obtained the ownership of the
Selenapolder.
26
After the dike breach the agricultural use of the Selena polder partly changed.
As a result of the intake of salt and brackish water the former parcels were not
suitable for farming anymore; the most western part of the polder was still
grazed by cattle.
In 1993 the former polder got his present name: the Sieperdaschor.
The Sieperdaschor (Source: www.rikz.nl)
Dutch-Belgian border
Has a clear strategic objective been developed ? 1,2,3
No. After empoldering in 1966, the following two dike breaches were
repaired, but the costs for the third breach were considered too high. It
was decided to restore the polder as a tidal area. That decision matched
perfectly in the Dutch style of governing of the late eighties. At that time,
there was a lot of public support towards nature management,
conservation and development. The creation of this FCA was also useful
– although very limited – to preserve Antwerp and the villages and cities
downstream from flooding.
Has a clear operational objective been developed ? 2, 3
No. Before the last dike breaching it was not quantified nor qualified
what kind of new land use would be chosen for this regularly flooded
area.
opportunity for alternative land use strategies ? 2
In a lot of Dutch wetlands large-scale nature development is or has been
planned. The tidal zone of the Sieperdaschor perfectly matches in that
27
Dutch policy. This policy was an important opportunity for the creation of
this marsh area.
impediment or opportunity for alternative land use strategies ? 16
The European legislation was a good opportunity.
Sieperdaschor is part of a Special Area of Protection (Habitats directive),
named NL 9803061 Westerscheldegebied. The most important habitat
types protected by this directive are:
- Estuaries (and the corresponding vegetation types)
- Atlantic marshes with Sea poa (Glauco-Puccinellietalia maritimae)
Sieperdaschor is part of a Special Protection Area for Birds (Birds
directive), named NL 25 Verdronken Land van Saeftinghe.
thereof affected the implementation of alternative land use strategies ? 2,3
Immediately after the last dike breaching the RIKZ started some internal,
off-the-record research on the flooded Selenapolder and wrote some
small development plans. Also other agencies and departments started
some research (the Dutch nature conservation organisation De
Steltkluut, the Flemish Institute for Nature Conservation, the Utrecht
University, the measurement information service of the Rijkswaterstaat,
…).
In 1990 the Rijkswaterstaat together with Bureau Liefense and the
Waterschap ‘De 4 Ambachten’ developed a specific plan for the flooded
Selenapolder. That was necessary because spontaneously a channel
was developing (too) close to the lower, northern Selena dike c.q. quay.
The channel was relocated to the middle of the polder and the
spontaneous one was filled up.
In 1993 the Selenapolder got his new name.
In 1994 a concrete monitoring scheme was developed.
In 1995 the monitoring activities started.
The monitoring was finished in 2000.
In 2001 some aspects already mentioned in the specific plan of 1990,
were realised on the terrain (e.g. extending the gullies, …).
Three government agencies were the main co-operators in managing this
new marsh area:
- RIKZ (Rijksinstituut voor Kust en Zee / Royal Institute for Coast and
Sea): monitoring and developing the site
- SZL (Stichting Zeeuws Landschap / the Zeeland landscape
foundation): since the mid 90’s the owner of the Sieperdaschor
- RWS (Rijkswaterstaat / Department of Waterways and Public Works):
manager of the Westerscheldt and responsible for dikes and quays.
28
aspects
NLU? 1,2
Initially the implementation of this NLU area was a pure economical
measure. A well-considered cost-benefit analysis – although ad hoc –
made the owner decide that repairing the dike breach could in no way be
justified.
Although the RIKZ started sampling and unofficial monitoring, it can be
stated that the Rijkswaterstaat is the initiator of the Sieperda project.
Has there been functional instruments to implement the strategy ? 2
No. Circumstances beyond one’s control. No clear strategy towards one
or other steered action.
Has there been a methodology on which the planning was based ? 2
None. Ad hoc ‘management’ afterwards.
towards practical and operational needs ? 1,2,3
The ad hoc steering committee was established quite flexibly. The
integration of new committee members, partners and a management
budget went very easily.
state of a NLU area ? 2
Not in this case. Before the last dike breach no plans were made for the
ecological ‘re-designing’ of the Selenapolder. Neither was there a prior
permission to develop a new marshland in relation to the Verdronken
Land van Saeftinghe. Also in this case the decision procedures were ad
hoc again.
studied ? 4,5
No. Concerning the ecological development of this area, several
discussions took place and some working papers were made up,
especially after the last dike breach. The technical and management
approach is compiled in the document "Together with the tide. About the
development of the Sieperdaschor" 4. In this document it was estimated
how the Sieperdaschor would evolve without a change of management:
"The grazed western part will keep his outlook: open, short vegetations of
Sea poa and ruderal or pioneer species with swamps in the lowest parts.
The pools and ditches will silt up and grow over with vegetation. The
eastern part with higher vegetations will evolve to an unbroken reed
marsh, in which different plant species will be pushed back. An eldorado
for water birds, but the total bird numbers and species will decrease. In
29
the most eastern part the same thing will happen for grazed resp. not
grazed sites. In short, the Sieperda area will get more uniform, and will
lose some of its biodiversity".
To ensure Sieperdaschor will evolve towards a marsh, several
management actions were planned: levelling parts of the Sieperda soil,
extending the central channel, cattle grazing management and better
retaining the water input. As far as we know only the channel extending
has been realised. By tide restoration in the former Selena polder
approximately 100ha of marsh is added to the total Westerscheldt marsh
area. This marsh extending is considered to be positive, because a lot of
marshes were destroyed by empoldering. On a European scale, brackish
marshes are threatened and very rare biotopes. That is mainly the
reason why they are an important element in the European Habitat
directive.
plan ? 2
No. Communication in advance was not possible because of the sudden
occurrence of the dike breach.
The former Selenapolder is part of an area that only has an important
agricultural function. The recreational, societal, economical, …value of
the Sieperdaschor is rather limited. Furthermore the area is surrounded
by one of the most important Dutch nature reserves (the Verdronken
Land van Saeftinghe) and the Belgian border, in other words in an
‘administratively hardly accessible corner of the Netherlands’. A specific
structure to manage this area has never been developed before.
4.6. Societal, economic and ecological aspects
negative effects be reversed ? 6,7,8,9,10,11,12,13
When the central channel was repositioned in 1993, this enhanced the
creek development in the eastern Sieperda zone. During the first two
years after repositioning, the creeks deepened autonomously, and the
draining of the Sieperdaschor improved. A shallow clay layer partly
stopped the creek development. From then on the vegetation extended
explosively. Since 1999 the mud flats that developed during the period
1990-1995, are replaced by a mosaic of reed swamps and other high
growing marsh vegetations. Most of the organisms are typical for
brackish marshes. Grazing led towards low marsh vegetation types
dominated by Sea poa. Bird species changed because of the changed
environmental conditions. The most eastern part of Sieperda always
remained a bare mud flat without much vegetation and did not change
significantly after reconverting.
30
1
2
3
4
5
6
7
8
Some photos of Sieperdaschor (from the left to the right, and top-down): 1) name-board; 2) photo
taken in the bird observation hut with western pond, quay and Verdronken land van Saeftinghe in the
back; 3) from west to east; 4) a view on the Westerscheldt; 5) the southern Delta-dike; 6) the
Sieperda ‘creek’ between Westerscheldt and inlet; 7) the Sieperda ‘creek’ from inlet to the west; 8)
one of the natural ‘creeks’ scattered all over the Sieperdaschor (Source: Soresma, 2003)
31
The last years a lot of water birds are replaced by other bird species that
now started breeding in the Sieperdaschor, because of the changing
vegetation. Although there is a clear impact of the salt of the
Westerscheldt water on the vegetation in the Sieperdaschor, there were
no significant morphological processes. The most important reason for
that is the long-drawn-out shape of the Sieperdaschor and the limitation
of the tidal water volumes as a result of the narrow opening under the
bridge in the most eastern part of the Sieperdaschor. A wider ‘gap’
would create a greater impact on the morphological situation.
compensation ? 2
Within this considered area different parcels could not be used anymore.
The arable area shrunk. The farmers were partially compensated for the
loss. Cattle breeding is still possible, although very extensively. The
budget necessary for the nature management in the Sieperdaschor is
negligible.
Are there any societal consequences towards planned NLU activities ? 1,2
Some Belgian and Dutch farmers of the villages of Doel, Emmadorp,
Nieuw-Namen and Kieldrecht lost a part of their used parcels.
decision procedure ? 2
No. The Sieperda area spontaneously developed as some sort of test
case. A considerable amount of halophytes and brackish plants settled
and maintained, together with a huge amount of birds using the
Sieperdaschor as stop or as forage zone southerly of the Verdronken
Land van Saeftinghe.
Has there been an intervention scheme containing a description of the
timing and responsibilities during the operations towards ecology,
economy and society, and were those elements monitored ? 2
None.
4.8. Were the objectives achieved ? 2,4,5,6,7,9,10,14
The development of the Sieperda area 10 years after the breaching of the dike
showed that a former marshland can regain the character of a marshland.
This in particular is the case for the eastern part of the Sieperdaschor with its
quite well developed and natural creek system. The monitoring resulted in
specific knowledge, in general and in particular. Now more than 10 years later,
the fast evolution in vegetation and species diversity has stopped, but in a
decreased tempo changes are still going on.
It is clear that ‘pure chance’ is a major factor in nature development. Without
any previous analysing an ecologically relevant marshland has been created.
A study in which the Sieperdaschor was examined in relation to polder re-
32
conversion elsewhere revealed that some essential soil features like redox
potential, pH, nutrients and organic matter were not measured. These
parameters are of great importance for nature restoration speed. Also the salt
content of water and soil are not examined, though this is a decisive factor in
vegetation evolution. Since 1999, only vegetation and birds are still monitored
as part of the national monitoring program (MWTL).
Ad hoc new land use at Sieperdaschor, NL - B
Key Area
Key Area result
Lesson
None
None
Objective
aspects
Legal and
opportunities to create the
governance
NLU
area
are
present.
legislation, and the opportunities
aspects
Organisational,
technical and
management
aspects
Communication
aspects
Societal,
economic and
ecological
aspects
In the Netherlands a positive
attitude towards large-scale
nature development is
present. Dealing with this
dike breach problem was only
possible due to a creative
analysis of local legislation
After the breaching of the dike
specific management and
monitoring took / take place.
No specific new land use was
planned in advance.
that it brings.
None
It is important to realise that not
all new land use needs planning.
Daring to realise a concrete dike
breaching on a well located and
safe place, with only a negligible
societal and economic relevance,
can result in some interesting
information on natural
development (without human
interfering) and practical (and not
only theoretical) information
based on terrain experience.
Nevertheless, it can be
recommended to determine
abiotic parameters in similar
(future) projects and in project
monitoring. A soil plan should
identify the soil types that are
present, and by that abiotic
prediction of the future biotic c.q.
botanical situation is feasible, and
immediate management
None
Those aspects where studied,
after dike breaching, not in
advance. Societal
(accessibility of the parcels),
economic (the aggrieved
It is important to realise that a
nature area, can do with a very
coarse ‘design’. The addition of
small elevated areas in the new
nature area can ease goal-
33
Intervention
aspects
Are the
objectives
achieved ?
parties), and ecologic (the
possible vegetation types and
bird populations)
For the moment, there is no
clear intervention procedure in
case something goes wrong.
Although no specific
objectives were defined, an
interesting new land use type
is achieved
oriented (ecological) measures
(e.g. terps for cattle grazing,
education spots, …)
The writing and implementation of
a concrete and accurate
management and monitoring
program can trace eventual
changes in the area, so that
undesired effects can be
countered immediately.
/
Airial view (source: Bofoto luchtfotografie, Heinkenszand)
4.10. Contacts and information
The following persons provided relevant information
1. Ir. S. Nollet (AWZ, Afd. Zeeschelde), Copernicuslaan 1, bus 13, B –
2000 Antwerpen www.awz.be
2. E. Stikvoort (RIKZ), Grenadierweg 31, NL – 4338 PG Middelburg,
0031–(0)118–672200, www.rikz.nl
3. Stichting
Het
Zeeuwse
Landschap
(Gert-Jan
Buth
[email protected]
and
Jos
Neve
[email protected] of visitors centre ‘Verdronken Land
van Saeftinghe’ (Emmadorp))
4. Stikvoort E.C., 2000. - Met het tij mee. Over de ontwikkelingen in het
Sieperdaschor. RIKZ-2000.046. RIKZ, Middelburg.
5. Van Oevelen D., Van den Bergh E., Ysebaert T. & Meire P., 2000. –
Literatuuronderzoek naar ontpolderingen. IN – UIA, Brussel/Wilrijk.
6. Bouma S., Veen S.M. & Bonhof G.H., 2002. – Proefgebieden herstel
zoet-zout overgangen in het Deltagebied. RIKZ, Middelburg.
7. Castelijns H., van Kerkhoven W., Wieland A. & Maebe J., 2000. - Tien
jaar Sieperdaschor. Een evaluatie van het voorkomen van vogels in
een in 1990 uit cultuurland ontstaan schor. Vogelwerkgroep De
Steltkluut, Terneuzen.
34
8. Holland A., 2000. - Veranderingen in de fysische en chemische
parameters in de bodem van de Selenapolder. Werkdocument
RIKZ/AB/2000.826x. RIKZ, Middelburg.
9. Kornman B.A., 2000. - Het Sieperdaschor. Tien jaar morfologische
ontwikkeling in vogelvlucht, lessen voor de toekomst. Werkdocument
RIKZ/OS/2000.850x. RIKZ, Middelburg.
10. Reitsma J.M., 1995. - Vegetatiekartering Sieperdaschor 1995.
Rapportnummer 95.34. Bureau Waardenburg, Culemborg.
11. Rijkswaterstaat, 1999. - Waterstandsmetingen Selenapolder Land
van Saeftinge 1992 t/m 1999. Rijkswaterstaat Meetdienst Zeeland.
12. Stikvoort E.C., 2000. - 5e en laatste voortgangsrapportage
Monitoringsplan Sieperdaschor. Werkdocument RIKZ/AB/2000.829x.
RIKZ, Middelburg.
13. Stikvoort E.C., 2000. - Vijf jaren bodemdieren bemonsteren in hert
Sieperdaschor: 1995-1999. Werkdocument RIKZ/AB/2000.829.002.
RIKZ, Middelburg.
14. Van der Pluijm A.M. & de Jong D.J., 2000. - Vegetatieontwikkeling
Sieperdaschor 1990-1999. Werkdocument RIKZ OS/2000.831x.
RIKZ, Middelburg.
15. Van Oevelen D., Van den Bergh E., Ysebaert T. & Meire P., 2000. –
Literatuuronderzoek naar estuariene herstelmaatregelen. IN – UIA,
Brussel/Wilrijk.
16. http://www.minlnv.nl/thema/groen/natuur/natura2000
35
5. Case: Baie des Veys
5.1. General case description
Situation
The inclusion of the “Baie des Veys” case in the FraME-NLU main review was
motivated by elements from different angles. The site does not comprise FCA
projects in the strict sense, it does however fulfil an important estuarine flood
control function which is being maintained, and its land use is being managed
and adapted in that respect. This makes the site functionally strongly
comparable to the FRaME demonstration site in the IJzer valley (B) where a
similar system of water management and land use solutions is being
implemented (be it at a significantly different scale).
A peculiar functional and spatial differentiation is observed: a large estuarine
area is subject to fresh water flooding under indirect tidal influence, while a few
small coastal NLU projects downstream of the tide locks are being developed.
The latter are not being considered in detail in this review since they are rather
considered with giving land back to the sea than to the river. By consequence,
they have no impact on the estuarine flood control issue.
The Baie des Veys itself hosts an important cultivation area of mussels and
oysters in the off-shore waters. In the past decades, this important economic
activity has suffered some set back due to silting up of the banks and pollutant
contamination of the water. Measures to reduce the silting up of the cultivation
banks are currently being studied and in a future phase, different scenarios will
be evaluated in order to formulate adequate management measures in the
total bay area. These may have an impact on the desired management
scheme of the sluices on the rivers feeding the bay, and therefore on the total
hydrological and ecological situation in the estuary. This issue is being studied
in detail and the outcome will have to be incorporated with the needs and
possibilities of all other conservation and development issues in the site.
Baie des Veys
Situation map Baie des Veys (Bron: http://natura2000.environnement.gouv.fr)
Ecology
The marshland area of the “Marais du Cotentin et du Bessin” is situated 250
km west of Paris in the Manche (Cotentin peninsula) and Calvados
departments, in the Basse-Normandie region. The two departments meet in
the Baie des Veys. The marshes of the Marais du Cotentin et du Bessin cover
36
the four river valleys of the Taute, Douve, Aure and Vire. This uninterrupted
stretch of marsh opens out into the sea at the Baie des Veys. The site is
subject to a very marked oceanic climate with typically slight temperature
differences, prevailing westerly winds and frequent rainfall. The marshes are
subject to regular winter flooding. The Cotentin peat bogs cover 15 – 16.000
ha, making them the largest peat reserve in France.
The Marais represent an exceptional wetland in terms of size and ecological
diversity, hosting a mosaic of biotopes. It is the largest flatland area of peat in
France. It hosts a good representative example of a western European coastal
wetland, with its wet meadows along the coast. The site is a particularly
favourable wetland for waterfowl because the bay and marsh complement
each other: birds can feed in the marshes by day and roost in the bay at night.
These wetlands are well suited for breeding bird species because of the lack of
disturbance during the breeding season and the mosaic of biotopes. For
migratory birds, the Marais du Cotentin play a prime role due to their position
on the migration routes.
Hydrology& Soil
Due to their small gradient, the rivers have low evacuation capacity with
respect to the amount of water captured in the catchment. A system of sluice
gates downstream prevents salt water from flowing upwards to the marshes.
This does not imply the exclusion of tidal impact since the outflow is blocked as
well. The result is a regime of fresh water flooding under (indirect) tidal
influence. This hydrological regime inherited from two centuries of
management and water control has led to alternating flooding in winter and
drying out in spring and summer. Peat is still the major soil component,
although it can be concealed under surface mineral strata. Peat strata play a
decisive role in the changes in height of ground water tables.
Land Use
Nearly the entire domain of wetland prairies is used for extensive cattle stock
raising (1,4 Large Cattle Equivalents per ha), either by direct grazing or by
cultivating grass for hay. In the sixties, several projects for land reclamation or
drainage have been studied, in order to upgrade the area for more intensive
agricultural activities. Due to the anticipated high costs and the problems the
presence of peat would raise, they were abandoned. In the eighties the
discussion between agricultural production and environmental protection rises
again, to be strongly moderated by the appearance of the European issue of
reduction of milk product reduction. This supports the maintenance and
promotion of extensive livestock farming activities.
The latter observation would then combine with the insight that maintaining
and promoting the traditional livestock farming practice is the best way to
guarantee the preservation of the so valuable ecological system. Abandoning
the extensive grazing or haying would cause the marshes to be in danger of
becoming completely abandoned, leading to progressive overgrowth by rank
vegetation, scrub and, ultimately, woodland. This would in turn lead to the
disappearance of the flora and fauna that are presently of great conservation
significance.
37
These insights led to the integration of the formerly opposed objectives of
agriculture and environmental protection. Debate is still sometimes vivid, but
the overall agreement reigning currently is that sustainable development will
have to be based upon the integration of both values.
In 1990, proposals for commercial exploitation of peat were subject to an
environmental impact study. Finally, there is very little tourism in the area, but
a lot of fishery and hunting.
Environmental Protection
Several parts of the site are in some way protected. There are six hunting
reserves, one nature reserve, one public riverine reserve and one protected
biotope reserve. All of the Cotentin and Aure marshes are classified as Natural
Zone of Ecological, Floristic and Faunistic Interest (ZNIEFF), and a large part
of the site is included in a Special Protection Area under EU regulations.
The most important regional initiative however was developed in the late
eighties, consisting of the creation of the Regional Natural Park “Marais du
Cotentin et du Bessin”. The parc covers a total of 145.000 ha of which 25.000
ha wetland prairies and 16.000 ha peat bogs. It stretches over the territories of
144 municipalities hosting 65.400 inhabitants.
The principal aim of the Regional Natural Park is to maintain extensive
agricultural practices, but without the use of fertilisers or additional drainage,
that could in turn also cause problems to the site. This type of management is
considered to be the only way of assuring that the marshes have a lasting
future. The purpose of the Regional Natural Park would also be to improve
water quality, to manage watercourses and to develop fish stocks.
Has a clear strategic objective been developed ?
Yes. The Charter regulating the creation of the Regional Natural Park
“Marais du Cotentin et du Bessin” (14 May 1991) was accepted by all
144 involved municipalities. It was elaborated in consultation amongst all
involved; policy makers, local authorities and associations. The Charter
formalises the project envisaging “the preservation and valorisation of the
natural and cultural patrimony, while promoting the economical, cultural
and social development in connection with its inhabitants”.
A clear strategic objective is set and it has been officially installed in a
legal document laying out the basis, setting the wider scope and drawing
the strategic limitations for concrete action.
Has a clear operational objective been developed ?
Yes. The broadly scoped strategic objective is translated into operational
objectives along the following fields of action:
• to manage and preserve the environment
• to contribute to the economical development
• to contribute to the country planning
• to mobilise the population
• to develop the knowledge on the state and evolution of the territory
38
In particular the activity field concerning the objective of “managing and
preserving the environment” is further specified in a number of concrete
operational targets:
• to maintain and restore biodiversity
• to restore the “bocage” landscape
• to guarantee the preservation of the areas with major ecological
importance
• to stimulate improvements of the waste management
The operational objectives are being elaborated at the level of individual
projects or measures, ensuring that their impact serves the balance of
the strategic objective for the entire park.
The actual implementation of the Charter plan is conducted under
supervision by two dedicated bodies:
• the Mixed Syndicate regrouping all stakeholders and steering the
implementation process through analysis, evaluation and
deliberation
• a multidisciplinary technical team supporting municipalities in the
conception and execution of actual projects
opportunity for alternative land use strategies ?
The construction of a Regional Natural Park is in France the most suited
official procedure to develop an action programme integrating “nature
and landscape protection” and “economical development”. This
legislative instrument has been exploited in all respects in the installation
of the Regional Natural Park of the “Marais du Cotentin et du Bessin”.
National legislation has therefore provided with the necessary frame
deploy an integrated initiative at such a regional scale.
impediment or opportunity for alternative land use strategies ?
The Regional Natural Park contains some conservation sites recognised
as such in the European networks. European legislation therefore
provides for additional support to the conservation issues in the land use
strategy planning.
o the « Marais du Cotentin et du Bessin, Baie des Veys » site was
designated a Ramsar wetland in 1991, code France 7FR004 (surface
32.500 ha)
o two Natura 2000 sites intersect in the area:
o FR2510046 Basses Vallées du Cotentin et Baie des Veys,
1990 (15.465 ha)
o FR2500088 Marais du Cotentin et du Bessin – Baie des Veys,
1999 (29.270 ha)
An important impulse to the discussion between the agricultural and
conservational concerns has been the issue of the surplus production of
39
milk products in the EU and the legislative reaction to that situation by
providing support to initiative reducing milk production. This brought in a
strong support to the option of maintaining and promoting the traditional
extensive livestock farming practice.
In addition to the legislative support, European programmes have been
instrumental in studying, evaluating, instigating the establishment and
supporting the operations of the Regional Natural Park (ACE 1983-’89,
LIFE 1995-’98, agri-environmental support)
The installed Regional Natural Park and especially its Charter base
document is the result of a consultation process between local and
regional authorities. It was accepted by all 144 municipalities involved,
and can as such be seen as an indisputable instrument for balanced
implementation of a land use strategy affecting a large area covering the
jurisdiction of many independent authorities.
aspects
what extent did they improve or facilitate the implementation of the NLU?
The start to the project was given in 1980-’81 when departmental and
regional authorities (Directions Départementales de l’Agriculture et des
Forêts (DDAF) resp. Délégation Régionale à l'Architecture et à
l'Environnement (DRAE)) installed a working group to formulate solutions
to the problems presented at that time.
From 1983 to 1989 studies were conducted in the fields of pedology,
agronomy, fauna and flora, in order to elaborate the “wetlands charter”.
With the formulation of this document, and its acceptance by the
participating municipalities, the actors and their mutual relationships are
established.
Has there been functional instruments to implement the strategy ?
The functional instruments to translate strategic options and decision into
operational objectives consist of the deliberation processes between the
stakeholders as they are regulated in the Park Charter. Important bodies
in this process are the Mixed Syndicate and the Technical Support team.
Has there been a methodology on which the planning was based ?
Not specified.
towards practical and operational needs ?
The way of working through a Charter clearly stating the broad scope of
the Park and the means and procedures to bring this scope into
operational and practical existence (including supervising and supporting
40
bodies) in se provides for flexibility and the need for deliberation between
stakeholders and project partners.
The impact of individual projects and activities needs to be considered
with respect to the envisaged balance over the entire park en region. It is
however inevitable that in specific local situations, conflicts may rise
between individual stakeholder interests. This is where the strategic
umbrella and the supervising bodies play their major role in maintaining a
balanced regional project.
state of a NLU area ?
Yes and no. Deliberation amongst all stakeholders throughout the
conception and planning phase of the Regional National Park is a central
theme in the Park operational way of working. The decision procedure
consists of searching a common understanding between stakeholders,
not of a predefined scheme under which a unique solution is imposed to
a certain situation.
studied ?
Yes. From 1983 to 1989 studies were conducted in the fields of
pedology, agronomy, fauna and flora, in preparation of the “wetlands
charter”. These studies were supported through regional, national and
European funding (ACE programme). Several modelling studies were
executed in order to evaluate the impact of modified sluice operation.
Result of one of the modelling studies (red are the areas with strong silting-up)
The impact of possible controlled summer flooding of a part of the Park
was studied with respect to land use and ecological development. The
41
opposition to the loss of agricultural land however prevents its
implementation.
plan ?
The central process of deliberation at each of the strategic, operational
and practical levels can as such be seen as societal participation.
Opposition is a nearly constant factor in this regional scale programme,
drastically affecting both agricultural and environmental issues. Hence
the importance of an integrated approach where stakeholders from all
sectors are involved in the consultation, conception, planning and
implementation.
One of the five core strategic objectives of the Park Charter is “to raise
public awareness”. Public awareness campaigns are permanently
running.
5.6. Societal, economic and ecological
consequences
negative effect be reversed ?
The evaluation of the overall scheme is positive, as can be derived from
the extension of the charter for 10 more years in 1997.
From the preparatory studies performed, it can be derived that without
the initiatives developed by the Park authorities, the existence of the
marsh and wetlands was under serious threat. By consequence, the Park
has offered significant operational support to safeguarding this important
natural value.
Several other initiatives, ideas and options that might have brought
further improved functionality with respect to the environmental value of
the area have not been realised due to opposition to giving up
agricultural land. It is clear that the balancing between both fields of
interest limits the possibilities of each individual activity field.
42
Pictures taken in winter (Source: http://www.normandia.com)
compensation?
The economic consequences are mostly focused on the agricultural
practice conducted in the Park area. While some two decades ago, this
extensive cattle breeding activity was bound to be abandoned, the
installation of the Park and the support possibilities linked to it have
helped to promote and maintain this agricultural practice. The outcome is
clearly beneficial for the agricultural sector.
Are there any social consequences towards planned NLU activities ?
There are no significant consequences to be noted since the Park activity
basically comes to safeguarding a traditional agricultural land use
practice.
Has a clear intervention procedure been developed based on the
decision procedure ?
The intervention procedure adopted is fairly straightforward. Once a
project is determined to have suitable operational objectives serving the
regional strategic objective, the actual implementation measures will be
supervised by the technical team. This team will assist the project initiator
and executor (municipality, land owner, association) in the
implementation.
Has there been developed an intervention scheme containing a
description of the timing and responsibilities during the operations (and
also afterwards) towards ecology, economy and society, and were those
elements monitored ?
Yes. All interventions are planned and executed under responsibility of
the Park Mixed Syndicat. The actual implementation of the projects is
being supported and supervised by a dedicated technical support team.
In addition, an evaluation and revision procedure is explicitly foreseen in
the Regional National Park implementation scheme. The RNP « Marais
du Cotentin et du Bessin » was installed in 1991and the original Charter
was revised, adapted and extended for another 10 years in 1997. At the
same occasion, a number of additional municipalities subscribed to the
Charter and thus joined the Park and its strategic land use planning.
43
5.8. Were the objectives achieved ?
The Regional Natural Park “Marais du Cotentin et du Bessin” appears to meet
its core strategic objectives fairly well.
o The anticipated loss of the traditional landscape and ecological
values of the marsh and wetland area has been countered to large
extend.
o This was realised according to the original strategic objectives set,
by maintaining and promoting the traditional land use practice of
extensive livestock agriculture.
o European level impulses were successfully integrated in both the
deliberation process and the support to the actual measures.
Nevertheless, the “Marais du Cotentin et du Bessin” cover an exceptionally
large consistent area, with extremely high and internationally important
ecological value. The carrying capacity in particular with respect to migratory
and nesting waterfowl could still be improved through specific measures.
Opposition to the linked loss of agricultural land however is at this time
blocking such initiatives.
Baie des Veys, F
Key Area
Objective aspects
Legal and
governance
aspects
Organisational,
technical and
management
aspects
44
Key Area result
Lesson
Clearly specify strategic goals,
centred on five lines of action,
captured in a Charter
subscribed to by 144
participating municipalities,
specifically for agriculture
nature area. Translate the
strategic goals into operational
goals and practical measures
on a project basis
The construction of a Regional
Natural Park is the appropriate
official procedure to develop an
action programme integrating
“nature and landscape
protection” and “economical
development”.
It can be important to specify
the actions and the elements
you want to realize on the
field, and the aspects you
want implement (economical
development, landscape
conservation), in the very
beginning of the project.
The implementation of the
Regional National Park Charter
was under supervision by two
dedicated bodies:
o the Mixed Syndicate
regrouping all stakeholders
The construction of a Park
area can be useful to
integrate the needs of
different public sectors (e.g.
social/industry,
nature/agriculture, water
control/cattle breeding, …).
It can be helpful to provide for
sound conceptual and
strategic planning, translating
in a stepwise manner into
operational level objectives
(local as well as thematic)
Communication
aspects
and steering the
implementation process
o a multidisciplinary technical
support team which
coordinated the different
study aspects
Deliberation is a core process in
the implementation of actions
linked to the Park
Public awareness development
is a strategic goal
and further on into practical
measures.
It is important to provide for
broadly accessible and
lasting deliberation platforms.
Interests change over time,
and so will the balance
between them.
It is advisable to take
Societal, economic Preservation of the traditional
land
use
leads
to
environmental
advantages of economical
and ecological
protection
evolutions and the impulse
aspects
Permanent conflict between
they can provide to the
conservation and agriculture
integration of apparently
interests remains
opposed interests (e.g. milk
quota).
The writing and
Intervention procedures are
Intervention
implementation of a concrete
foreseen in the Charter
aspects
procedure. Evaluation, revision and accurate management
and monitoring program can
and extension of the Charter
trace eventual changes in the
proves overall satisfaction
area and sensitivities at the
public and partners.
The objectives are fairly well
/
Were the
achieved
objectives
achieved ?
The following persons and organisations were contacted; not all of them
supplied us with information yet:
- l’Agence de l’eau Seine-Normandie, Direction des Bocages
Normands, Rue de la Pompe 1, 14200 Hérouville-Saint-Clair, tel:
0033 – 02 - 3146.20.20, fax: 0033 – 02 - 3146.20.29,
[email protected]
- DDAF de la Manche, Cité administrative, Bâtiment B, 50009 Saint-Lo
Cédex, tel : 0033 – 02 - 3377.51.00, fax : 0033 – 02 - 3356.09.57,
[email protected]
- le conservatoire de l’espace littoral et des rivages lacustres, Jean
Philippe Deslandes, rue Pémagnie 5-7, 14037 Caen Cedex
- Forum des marais atlantiques, Quai aux vivres, 17300 Rochefort,
0033 – 05 -4687.06.00, fax: 0033 – 05 - 4687.69.90, [email protected]
- Parc naturel régional des Marais du Cotentin et du Bessin, Valérie
Paquereau Maison du Parc, Rue de Cantepie 17, 50500 Les Veys,
tel: 0033 – 02 - 3371.61.90, fax: 0033 – 02 - 3371.61.91
- direction régional de l’environnement (DIREN) Basse Normandie,
Cite Le Pentacle, Avenue de Tsukuba, 14209 Herouville-Saint-Clair
45
-
-
cédex, tel: 0033 – 02 - 3146.70.00, fax: 0033 – 02 -3144.7281,
[email protected]
Direction de la nature et des paysages; direction d’ études
économiques et de l'évaluation environnementale, Avenue de Ségur
20, 75302 Paris Cedex 07, tel: 0033 – 01 - 4219.19.00
Délégation à l’aménagement du territoire et à l’action régionale
(DATAR), Avenue Charles Floquet 1, 75343, Paris Cedex 07, tel:
0033 – 01 - 4065.12.34
Institut francais de l’environnement (IFEN), Boulevard Alexandre
Martin 61, 45058 Orléans Cédex 1, tel: 0033 – 02 - 3879.78.78, fax:
0033 – 02 - 3879.78.70, [email protected]
IFREMER, direction de l’environnement littoral (DEL), DEL Haute et
Basse Normandie, Avenue du Général de Gaulle, 14520 Port-enBessin, tel: 0033 – 02 - 3151.13.00, fax: 0033 - 02 - 3151.13.01,
[email protected]
chambre d’agriculture Normandie, Rue des Rocquemonts 6, 14053
Caen Cedex, tel: 0033 - 02 - 3147.22.47, fax: 0033 – 02 3147.22.60; [email protected]
Université de Caen, Anne-Marie Fixot, UFR de géographie, tel: 0033
– 02 -3156.58.07, [email protected]
l’association Terre et Mer environnement, Cour Saint Martin, Rue
Emile Demagny, 14230 Isigny-sur-Mer, tel: 0033 – 02 - 3121.89.78,
fax: 0033 – 02 - 3121.34.41, [email protected]
- /
46
6. Case: Flood bank setback of Norfolk
Broads (UK)
The project overall
The Broadland Flood Alleviation Project is a long-term project to provide a
range of flood defence improvements, maintenance and emergency response
services within the tidal areas of the Rivers Yare, Bure, Waveney and their
tributaries. The project is based in the eastern part of the County of Norfolk,
and also the northernmost part of Suffolk, both English counties. The project is
based on an area called The Broads (or Broadland). In May 2001 BESL
(Broadland Environmental Services Limited) was appointed by the
Environment Agency to deliver these services in a 20-year programme of
sustainable and cost-effective flood defences for Broadland. This is the first
such project of its kind in Broadland – and in the country – to provide a longterm commitment to the continuing maintenance of riverine flood defences.
Location of Norfolk broads in UK context, and key fluvial features of the Norfolk Broads
This publicly-funded project is being delivered by BESL under the Public
Private Partnership Programme on behalf of the Environment Agency. BESL is
a consortium of two private companies, Edmund Nuttall Ltd and Halcrow
Group Ltd. For the first two years of the project BESL worked with CSERGE
(Centre for Social and Economic Research on the Global Environment) part of
the University of East Anglia. CSERGE assisted and advised on consultation
and public participation aspects of the BFAP (Broadland Flood Alleviation
Project).
The Broadland grazing marshes, wetlands and fens all lie below current high
tides. The riverside settlements face a future of higher sea levels with, as yet,
47
no flood defences. Economic activity in the Broads, whether it be through
agriculture, local commerce, recreational boating, fishing or rambling is heavily
dependent upon reliable flood defences.
The Broadland project meets rigorous environmental standards in a way that is
technically feasible, cost effective, environmentally sound and acceptable to
communities – this underpins BESL’s approach to the provision of sustainable
flood defences. It is also a project that is subject to extensive public
participation in a manner that identifies, and wherever possible and
appropriate, incorporates the views and opinions of its stakeholders. Overall,
the progressive implementation of the project will maintain and improve the
Broadland environment for the benefit of local communities both now and into
the future. The Project will implement flood defence improvements in
Broadland whilst also aiming to ensure that navigation, recreational and wildlife
interests are all fully protected. However it cannot do this entirely on its own.
BESL must also consult widely with a range of stakeholders to ensure that the
programme as a whole is sustainable both economically and environmentally
and has continuing public support.
The project represents a unique opportunity to integrate flood defence work
with other public interest initiatives of benefits to the Broads. The Environment
Agency is actively engaged in developing partnerships with stakeholders. The
delivery of partnership benefits in conjunction with improved flood defences for
Broadland forms an important element of the overall vision for the Project.
The case study
Managed retreat is one of the flood alleviation solutions being promoted in
Broadland. In the project area, this is called ‘setback’ and involves constructing
a new flood bank up to 50 metres inland from the existing in one (i.e. setting
back a flood bank). This is usually planned where the erosion protection
provided by either a reed rond, or sheet steel piling in insufficient. Stable
ground conditions, sufficient local sources of clay for construction and
landowner agreement are factors that contribute to the feasibility of setback.
Where setback is carried out, this involves the existing flood bank being
removed once the new bank is stable. Once this is done, the rond can become
flooded at most normal high tides and drain as tides recede. This acts to allow
the river to act more naturally while still being an embanked watercourse – it
also increases flood storage capacity during peak flood events.
Re-profiling the existing flood bank allows a substantial area of new rond to be
established, enhancing the local presence of this wetland habitat type. Reeded
ronds in the study area have alternative uses that include nature conservation,
recreation (such as angling and wildfowling) and growing and managing ronds
for a crop of reed.
Among the first setback schemes in Broadland will be carried out at
Halvergate. Of the 6km of flood banks in the study area, setback is the solution
for 2.5km.
48
Has a clear strategic objective been developed ?
Yes. The Broadland Flood Alleviation Project is implementing the
Environment Agency’s Flood Alleviation Strategy for Broadland, 1995.
The Broadland Project has an environmental vision and three overarching aims that set out and encapsulate a high-level approach to
delivering sustainable flood defences. They are:
1. To improve flood defences and to increase flood banks’
resistance to breach with an allowance for future bank settlement
and sea level rise;
2. To provide flood defences to undefended riverside communities;
and
3. To provide sustainable flood defences that are technically
feasible, cost effective, environmentally sound and acceptable to
communities.
opportunity for alternative land use strategies ?
Though a publicly-funded, public infrastructure project of the Environment
Agency, sponsored by Defra (Government’s Department of Environment,
Food and Rural Affairs), The Broadland Project must still comply with a
full range of national legislation. This especially relates to planning and
environmental protection legislation, having regard to the duties of the
Broads National Park duties that include a remit for navigation,
conservation and public access/enjoyment. Each presents additional
duties and responsibilities to this project. Because of the potential cost
uplift over core flood defence objectives it has been necessary to develop
a shared vision between key organisations. Strategic partnerships have
therefore been developed to add value to aims and objectives of different
organisations.
impediment or opportunity for alternative land use strategies ?
Broadland is considered one of Europe’s finest wetlands supporting a
wide range of habitats and species. The nature conservation value of the
study area is recognised through various international, national and local
designations:
International
• Breydon Water SPA (Special Protection Area) (including Breydon
Water Marine Site);
• Breydon Water Ramsar Site;
• Broadland SPA;
• Broadland Ramsar Site; and
• The Broads cSAC (Special Area of Conservation);
49
Breydon Water SPA
The SPA comprises Breydon Water SSSI (Sites of Special Scientific
Interest) and part of Halvergate Marshes SSSI. The site provides habitat
for a large assemblage of wintering and migratory waterfowl including the
Annex 1 species (of the Birds directive) Bewick’s swan (Cygnus
columbianus bewickii), Avocet (Recurvirostra avosetta), Golden plover
(Pluvialis apricaria) and Ruff (Philomachus pugnax). In summer a further
Annex 1 species, Common tern (Sterna hirundo), is present in nationally
important numbers. In addition, the site regularly supports over 20.000
waterfowl. Both the Halvergate and Breydon component SSSI’s are
utilised by most of the species, though Golden plover and Ruff tend to
favour the grazing marshes while Avocet remain on the mudflats in the
winter. The Halvergate SSSI includes the RSPB’s Berney Marshes
Reserve (RSPB = Royal Society for the Protection of Birds). Large
numbers of birds are attracted to Berney, where water level management
and sanctuary from shooting provide ideal conditions. An area of arable
conversion, currently outside the designated site, is particularly attractive
for both wintering and breeding birds.
The Breydon Water Marine Site comprises those areas of the Breydon
Water SPA that are covered continuously or intermittently by tidal waters
(i.e. Breydon Water SSSI and the ronds within Halvergate Marshes
SSSI). The qualifying interest is the same as that of the SPA, and the
important habitats are those listed for Breydon Water SSSI.
Breydon Water Ramsar Site
The boundaries of this site are co-incident with those of Breydon Water
SPA. The qualifying interests are Bewick’s swan, Lapwing (Vanellus
vanellus) and the large assemblage of wintering waterfowl.
Broadland SPA
The SPA comprises 27 SSSI’s throughout Broadland. Component sites
within compartment 11 are Decoy Carr SSSI and part of Halvergate
Marshes SSSI. Upstream of compartment 11 two further component
SSSI’s, Cantley Marshes and Yare Broads and Marshes, adjoin the river.
Halvergate Marshes supports the following Annex 1 species: Bewick’s
swan, Bittern (Botaurus stellaris), Whooper swan (Cygnus Cygnus),
Marsh harrier (Circus aeruginosus), Hen harrier (Circus cyaneus) and
Ruff. Lapwing, a non-Annex 1 species, also occurs internationally
important numbers. The site also qualifies because it regularly supports
at least 20,000 waterfowl, including populations of Gadwall (Anas
querquedula), Pink-footed goose (Anser branchyrhynchus) and Shoveler
(Anas clypeata) that are of European importance.
Broadland Ramsar Site
The Ramsar site comprises 28 SSSI’s throughout Broadland i.e. the
same ones as the Broadland SPA with the addition of Damgate Marshes.
Component sites within compartment 11 are Damgate Marshes SSSI,
Decoy Carr SSSI and part of Halvergate Marshes SSSI. Cantley
50
Marshes SSSI and the Yare Broads and Marshes SSSI are also included
within this site.
The citation refers to:
1. Regular usage >1% of the biogeographic populations of waterfowl
species;
2. Supports an appreciable assemblage of rare, vulnerable or
endangered species or subspecies of plant or animal, or an
appreciable number of individuals of any one or more of these
species; and
3. It comprises many good and representative examples of wetland
habitat characteristic of the biogeographical region.
Broads cSAC
The Broads cSAC comprises 27 SSSI’s throughout Broadland.
Component sites within compartment 11 are Damgate Marshes SSSI,
Decoy Carr SSSI and part of Halvergate Marshes SSSI. Cantley
Marshes SSSI and the Yare Broads and Marshes SSSI are also included
within this site. The site is designated because it contains habitat types
or species that are rare or threatened in a European context. Part of
Halvergate Marshes SSSI form part of the cSAC designation due to the
presence of alder carr woodland on the floodplains and naturally nutrient
rich lakes (dykes) that are often dominated by Pondweed (Potamogeton
lucens).
Extensive discussions and negotiations have taken place with English
Nature and Defra on the principle of retreating the line of riverine flood
defence (setback) into the European site. In the case of Halvergate,
English Nature was able to advise that the flood defence works were
‘necessary for the conservation management of the European site’ on the
grounds that failure to protect the site from the damaging effects of a
breach would cause long-term, damaging saline inundation of the
protected freshwater features. The standard of flood defence was
suitable to allow some saline overtopping, but at a frequency (10 to 1
chance) that allowed habitats and species to recover.
Habitat Change for Halvergate
Habitat
Area (ha) within
European site
Rond
+9.7
Floodbank
+3.6
Folding
-0.2
Soke Dyke
+3.9
Grazing Marsh Dyke -0.6
Grazing Marsh
-16.1
Scrub
-0.03
Arable
0
Area (ha) outside
European site
-0.1
+0.5
-0.1
+1.1
-0.03
0
0
-1.4
Total
+9.6
+4.1
-0.3
+5.0
-0.63
-16.1
-0.03
-1.4
While setback has created 9.5 ha of reed rond (a priority habitat) setback
has also necessarily resulted in a loss of 16.1 ha of lowland wet
grassland, in this case grazing marsh (also a priority habitat). The
statutory advice on this proposal is that the benefits for the conservation
51
of the freshwater ecological interest outweighed the loss of grazing
marsh habitat. BESL have re-provided this on a voluntary basis through
habitat creation and reversion of former arable land adjacent to the
designated site.
The key organisation is the Broads Authority who are the National Park
Authority as well as the local planning authority. They thus have a wider
stakeholder role and a statutory function to operate the local planning
decision-making process. The statutory plan for the area is the ‘Broads
Local Plan’, a statutory development framework adopted in 1997. It
contains a positive policy framework to help the Environment Agency
deliver its programme of flood defence improvements. The Authority’s
management plan, the ‘Broads Plan’, adopted in 1997, also provides a
positive context for the Authority’s wider work to help deliver the flood
defence work. Another key statutory body is English Nature who have
examined specific aspects of BESL’s supporting technical work
concerning hydraulic modelling and the contribution of BESL’s work to
medium term targets to bring designated sites into favourable condition.
aspects
The initiator is the Environment Agency and the work is being carried out
on their behalf by BESL. The key decision making agencies were the
Broads Authority and English Nature. The RSPB is an NGO who have a
direct interest in the area being an owner of the Berney Nature Reserve
in Halvergate. They were a key actor in the decision-making process.
Have there been functional instruments to implement the strategy ?
Yes. BESL’s work for the Environment Agency is based on stringent
financial controls that are verified to ensure best value of public
expenditure. All expenditure is in accordance with prevailing Government
policy for flood defence.
Has there been a methodology on which the planning was based ?
Yes, there is a clear set of decision-rules by which setback is proposed
as a valid technical solution. The planning, design and implementation of
all of BESL’s work for the Environment Agency is based on a rigorous set
of environmental standards that have been subject to public scrutiny and
endorsement. The proposals for Halvergate were assessed by the
Broads Authority in accordance with the policies of the statutory Broads
Local Plan.
52
towards practical and operational needs ?
The organisational structure of the Environment Agency and BESL is
solely geared towards delivery of flood defence improvement in
consultation with key local stakeholders and, crucially, landowners whose
agreement is required.
state of a NLU area ?
Yes. There are clear objectives for the creation of new setback flood
banks, and the rond in front of it that provides the erosion protection.
Post construction monitoring is an essential component of planning and
will take place for at least two years to verify predicted impacts, and to
ensure the enhancements have been delivered. BESL has convened a
panel of local experts in the field of rond establishment and usage. They
will advise on alternative models for habitat creation and management.
Being among the first of the new setback areas, monitoring in Halvergate
will continue over several years before drawing conclusions on its
outcome.
Have there been different technical and management approaches in
studied ?
Yes. Setback provides the opportunity for significant ecological
enhancement to the existing habitats by creating a mosaic of brackish
communities including new large areas of reed rond and saltmarsh
communities.
Vegetation communities on the existing ronds at Halvergate are a
mixture of reed swamp and mid to upper saltmarsh. The extent of the
different communities is summarised in table1. The rond edge next to the
river and drainage channels tends to be dominated by sea couch grass
(Elytrigia atherica) i.e. ‘high saltmarsh’ whilst the relatively lower ground
behind has a mixture of species typical of mid-upper saltmarsh. Stands of
reed tend to be confined to the band of rond next to the flood bank
following the line of the former backfilled soke dyke. Further upstream,
above Seven Mile House, there is some saltmarsh on the first section of
rond but the remainder are dominated by reed. Photographs in Appendix
1 give examples of the existing rond vegetation communities.
The objective of ecological management on the new rond at Halvergate
will be to establish similar vegetation communities to those that already
exist, although the extent of these habitats will significantly increase.
To establish successful reed bed, a series of lateral drains (‘grips’) will be
dug to link the old soke dyke with the new water/rond interface. These
will allow the rond to be flooded adequately at high water. The grips will
allow water on and off the rond as the water levels fluctuate. These grips
will be subject to some erosion where they connect into the main river
due to normal tidal flows into and out of the rond. BESL will assess the
need for soft erosion protection in these locations. BESL’s approach to
erosion and erosion protection is set out later in this report.
53
The new rond will form an integral part of the new setback flood
defences. BESL will design and initially manage the rond to ensure its
long-term effectiveness for flood defence purposes and also to accrue
the ecological and landscape benefits associated with this solution.
Following the establishment of the vegetated rond and removal of piling,
BESL will review the need for further work to the flood defence as part of
its annual maintenance programme for the remainder of the overall
Broadland contract.
Aerial photo of setback works underway in Halvergate. July 2003.
The creation of a reed rond will provide natural erosion protection; this is
an integral part of the proposals. Reeds are technically suitable for
channels in soft silty clays and muds such as those in Broadland. They
dissipate boatwash by absorbing up to 60% of wave energy. They are
able to tolerate tidal waters and seasonal fluctuations in water levels.
The amount of rond being generated by the proposed setback provides
considerable protection against moderate rates of erosion. However the
line of existing piling will be retained in place to allow the reed rond to
establish.
The vegetation communities that develop on the new rond will be
monitored by a combination of fixed point photographs and recording
species composition and cover within quadrats across the rond.
plan ?
Yes. There was substantial public consultation before progressing to the
formal planning stage. As this is a new approach to flood defence on
inland waterways, a number of significant policy decisions needed to take
place. Although few objections were recorded there was concern about
the likely success of previously untried methods. This public consultation
for Halvergate is part of a wider consultation strategy by BESL to
communicate effectively at the appropriate level on all aspects of its
work.
54
negative effect be reversed ?
At the time of writing (Autumn 2003) the first year of a three-year work
programme had been completed. It is too early to measure actual
environmental responses, or to audit consistency with predicted
environmental effects. An EIA for the Halvergate scheme was
undertaken and reported no significant adverse environmental impacts
(after mitigation or management systems are put in place).
Photographs of some rond habitat types that will be created or recreated as part of the setback
works (source: J. Halls, 2002)
compensation ?
Landowners are compensated for direct losses during construction and
for permanent changes in land usage afterwards. These can include loss
of marshland available for cattle grazing, loss of income from agrienvironment schemes (particularly the Environmentally Sensitive Areas
Scheme) and other incidental costs. However, in practice, many potential
claims are mitigated by a positive and pro-active relationship between the
BESL contractor and landowners.
Are there any social consequences towards planned NLU activities ?
There are no long-term social consequences, expect for the long-term
positive benefits of protection from the damaging effects of saline
flooding. At a detailed level, there are recreational uses that may be
affected in the short-term, notably public rights of way, navigation,
birdwatching angling and wildfowling. The EIA for the project has
concluded that any residual significant impacts after mitigation measures
are in place are short-term, during construction only.
decision procedure ?
Yes. There is a clear methodology and procedure in place for physically
effecting the change in land use (and removing the existing floodbank).
55
economy and society, and were those elements monitored ?
Yes. There is a monitoring scheme in place as part of the Environmental
Action Plan.
Specific objectives were defined and were achieved.
Flood bank setback of Norfolk Broads, UK
Key Area
Key Area result
Objective aspects Improving and providing
Legal and
governance
aspects
Organisational,
technical and
management
aspects
Communication
aspects
Societal, economic
and ecological
aspects
Intervention
aspects
56
Lesson
It can be important to make
(sustainable) flood defences along clear the elements you want
to realize on the field, and to
the tidal rivers.
give a firm basis to the
reason why implementation
is necessary (flood
problems).
The statutory advice and policy is It is advisable to have a clear
in place to deliver this type of
flood defence solution.
Its eventual success also depends opportunities that it brings.
on agreement with landowners.
Flexibility in policy or acting
to the intention of an order is
important.
It is advisable to design the
An innovative and sustainable
interior of the FCA’s carefully
flood defence solution that relies
on monitoring to test and confirm to suit the needs that can be
derived from the land use
the validity of environmental
predictions and of the suitability of objectives.
the solution.
Positive public consultation set in The provision of a flexible
and broad deliberation
the context of a wider on-going
platform or consultative body
inclusive, participatory process.
is essential. If already a
platform is available it is
advisable to fit the new
participatory process in the
existing platform.
A full EIA was carried out as part It is useful to assess the
of the statutory planning and
planned activities and the
consenting process. The
way in which they will affect
significant effects are likely to be
the environmental conditions,
during construction only, with no
and to remedy or re-evaluate
long-term residual effects.
(second opinion) the planned
activities.
There is a clear methodology and It is advisable to determine in
procedure for construction. There advance the desired species
is a monitoring programme to
and vegetation types and
verify the predictions, and may
highlight further remedial work if
monitoring program (for al
unexpected effects are also
detected.
Were the
objectives
achieved ?
At this stage, all high-level
objectives for the project overall
and the Halvergate scheme are
met.
types of animals and plants;
monitoring the field situation
to test the validity of
vegetation predictions).
/
There has been very significant lessons learnt amongst organisations involved
in decision-making for these works in Halvergate, being located in a National
Park, and in European sites. These are mainly concerned with establishing
new structures for decision-making in ways that support common objectives for
the management, protection and implementation of vital work to promote flood
alleviation work in the public interest. It is too early to tell at this stage what
lessons can be learnt about implementation.
The following persons provided relevant information:
- Paul Rao, Environmental Manager, Broadland Environmental
Services Limited, 103 Prince of Wales Road, Norwich NR1 1DW,
United Kingdom, Tel +44 (0)1603 226161, [email protected],
www.halcrow.com
- Several Halcrow c.q. BESL studies on the Norfolk Broads
57
7. Case: Paull Holme Strays in Humber
Estuary (UK)
The Humber Estuary is one of the North Sea’s major estuaries, draining more
than one fifth of England’s land area. It also has the largest tidal range on the
east coast of the British Isles. The estuarine/intertidal habitats and species
supported by the estuary, especially the large numbers of wetland birds, give it
international importance in this respect recognised by the majority of the area
being designated as a Special Protection Area (SPA) and possible Special
Area of Conservation (pSAC) under the EU Birds and Habitats Directives
respectively.
Land around the estuary is protected by 235km of flood defences largely
comprising grassed, earth embankments, or heavier rock/stone protected
banks where the wave climate makes this necessary. Land use in the estuarial
flood plain comprises agriculture (with significant reclamation for agricultural
use having taken place historically), nationally important port facilities at Goole,
Hull and Immingham/Grimsby, and large areas of industry.
The Paull Holme Strays area (previously known as Thorngumbald) lies on the
north bank of the Humber some 10km to the south east of Hull. In 1995 a
2,5km length of sea defence (embankment) fronting this area, and ultimately
providing protection to Hull itself, was identified as being in need of urgent
improvement to ensure the appropriate standard of flood/tidal protection was
maintained. After considering many options for the provision of new defences
in the area a strategy of ‘managed realignment’ was selected. The proposals
received planning consent in 2001 and construction was completed in 2003.
The consultation, design and consenting period took many years due to the
complexities of application of the EU Habitats Directive, links to ongoing
development of longer term plans for the estuary e.g. The Humber Estuary
Shoreline Management Plan (HESMP) and the Humber Estuary Coastal
Habitat Management Plan (CHaMP).
In summary the proposed defence realignment scheme and creation of the
NLU involved:
• Construction of a new embankment between 500 and 250m landward of
the existing defence line;
• Construction of new ‘drainage’ ditches to landward of the new
embankment;
• Creation of two breaches (one of 150m and one of 50m) in the ‘old’
embankment to allow tidal waters into and out of the site.
• Considerable modelling of the breach scenarios was undertaken to
optimise the filling and emptying of the site and minimise risks of scour /
creek formation in unwanted areas.
• Provision of some new protection to parts of the new and old defence in
areas where erosion might be problematic.
• The strategy for the majority of the old bank was to let it gradually decay
with wave action etc, over time.
58
The realignment (or NLU) area included the following features, prior to
implementation, many of which had to be considered carefully in the design of
the scheme.
• Two lighthouses of navigation and historic importance – access to the long
term security from flooding/erosion had to be provided;
• The majority of the NLU had been previously reclaimed earlier in the 20th
century by empoldering;
• Existing internationally protected intertidal habitats;
• A gas distribution compound, which had to be excluded from the NLU and
two high pressure gas pipelines running under the NLU, which had to be
provided with protection from future scour.
• A gravity-fed freshwater drainage outfall, which required installation of a
pumping station to ensure continued operation.
The project was promoted by the Environment Agency (who are responsible
for the provision of appropriate flood and coastal defences in the UK), funded
through the flood defence budget of the Government’s Department of
Environment, Food and Rural Affairs (DEFRA) and supported by a number of
other organisations who formed an Environmental Steering Group, including
English Nature, Royal Society for the Protection of Birds (RSPB), Yorkshire
Wildlife Trust, East Riding of Yorkshire Council and Paull Parish Council.
Humber Estuary
Existing mudflat
Approximate
boundary of
NLU area
Has a clear strategic objective been developed?
Yes. The original strategic objective at the area was to provide improved
tidal defences. It was decided that the most economic and most
59
environmentally desirable way to achieve this was to ‘set-back’ the
defence and create a NLU. The strategic objective for the site in terms of
an NLU became the creation of intertidal habitat to provide
‘compensation’, under the Habitats Directive, for the adverse impacts of
other tidal defence works in the estuary and for the intertidal habitat
losses being caused by ‘coastal squeeze’
Note: ‘coastal squeeze’ is a term used to describe the process by which
sea level rise causes loss of habitat where this is adjacent to hard
defences i.e. where habitats cannot migrate in land.
Yes. A number of clear objectives for the NLU were developed by an
Environmental Steering Group. These included the provision of
approximately 75ha of intertidal habitat of suitable quality (over time) to
qualify for inclusion within the SPA/pSAC boundary and provide
appropriate ‘compensation’ for losses/changes elsewhere in this part of
the estuary.
More specifically a scheme of monitoring was put in place to measure the
development of the site against a number of targets:
• Quantitative habitat creation targets based on levels of habitat losses
elsewhere – the NLU is anticipated to absorb these easily.
• Provision of the following habitat types, based on topography and
anticipated tidal inundation regime:
-
60
3ha upper saltmarsh
25ha middle saltmarsh
15ha lower saltmarsh
32ha of mudflat (including 15ha of potential temporary muddy
pools where borrow pits existed).
Qualitative targets comprising lists of characteristic species /
communities for the above habitat types and for birds using the area.
• A number of other ‘soft’ objectives were set for the site including the
provision of footpaths around the perimeter, car parking,
interpretation boards and bird hides for ornithologists.
opportunity for alternative land use strategies?
In this case there has been some impediment in terms of the long time
taken to achieve the NLU area, but this has more to do with the national
interpretation of European legislation and the lack of familiarity of the
relevant authorities in dealing with this legislation (see below).
impediment or opportunity for alternative land use strategies?
European legislation in the form of the Habitats Directive has been both
an impediment to and driver of the development of the NLU area. The
requirement placed on the UK Government, by the Directive, in respect
of ensuring the maintenance of SPA/SAC integrity and the compensating
for ‘coastal squeeze’ losses has been a significant driver for the project.
The priority habitats and species, listed within the Directive, have also
been a significant driver for the design of the NLU area.
However it is also true that the lack of familiarity, of the relevant
authorities and organisations, with the UK Habitats Regulations caused
significant delays in the consenting process. The definition of ‘significant
adverse effect on integrity’ of the site was a key factor in this.
thereof affected the implementation of alternative land use strategies?
Cooperation between government (and other) bodies was generally good
in striving to implement the NLU area. Key Government parties were:
• Environment Agency (lead authority with regard to promotion)
• Defra (provision of main funding)
• English Nature (advisor with regard to the Habitats Directive)
• East Riding of Yorkshire Council (planning authority and ‘competent
authority’ with regard to ‘appropriate assessment’ under the Habitats
Regulations)
aspects
• The project was promoted by the Environment Agency as the
most economic and environmentally sustainable option for
improving tidal defences in the area.
61
•
•
•
Funding was secured through the flood defence budget of the
Government’s Department of Environment, Food and Rural
Affairs (DEFRA).
Planning permissions was consented by East Riding of Yorkshire
Council.
The project was facilitated by a number of other organisations
who with individuals from the above formed an Environmental
Steering Group (ESG) including:
- English Nature
- Royal Society for the Protection of Birds (RSPB)
- Yorkshire Wildlife Trust, and
- Paull Parish Council.
A significant factor in the implementation of the project was early
negotiations with the two landowners. The purchase of the land from
these was done in parallel with securing planning consent for the work.
Have there been functional instruments to implement the strategy?
The project was implemented through the existing framework of
functional instruments available for the implementation of flood/coastal
defences in the UK. A Section 105 agreement (a legal agreement
produced as part of the planning consent) was set up to ‘guarantee’ the
subsequent land use and management of the site for the purposes of
securing planning consent for the project.
Has there been a methodology on which the planning was based?
The planning and design of the project was based on the following:
• Environment Agency & Defra guidance and procedures for the
planning and implementation of flood/coastal defence capital
works.
• Experiences and results of monitoring of other ‘managed
realignment’ schemes in the UK e.g. at Wash Banks and
Tollesbury.
• Consultation with interested parties representing nature
conservation and local community interest.
• The qualifying features of the adjacent SPA/SAC formed a basis
for design of the land use in the area.
• The production of an Environmental Action (or Management) Plan
under the auspices of the Environmental Steering Group. This
plan was initiated at the planning consent stage and developed
through the detailed design and construction phases. It also
dictates the likely management and the monitoring of the site for
the first 5 years of operation/development.
towards practical and operational needs?
Yes. The Environmental Steering Group was set up to guide and review
the detailed design process and deal with any variations from the original
62
planning consent that were found to be necessary due to constraints
arising during the construction process.
state of the NLU area?
Yes. The design was based on meeting the requirements for
‘compensatory habitat’ under the UK Habitats Regulations. Obviously
designs were constrained also by the topography and inundation regime
for the area.
studied?
Yes. The critical drivers for the development of the desired land uses (or
in this case habitat types) in the NLU area are as follows:
• Topography – it was considered that this should remain largely as
existing (no significant artificial changes), but that sedimentation
in the NLU area would lead to raising of the lower mudflat areas
over time.
• Breach size and location – in combination with topography the
size and locations of breaches in the old (seaward) embankment
are the main driver for the inundation regime, which in turn drives
the habitat type. Breach design was extensively modelled to
ensure an appropriate flooding regime for the site.
• Creek creation – drainage of the site was largely left to develop
naturally once the breaches were constructed but some artificial
channel/creek construction was carried out to constrain
movement of water and development of natural creeks in
• areas where this might threaten the embankments. Some shallow
ponds/scrapes were also constructed within the NLU area.
• Monitoring and Management – the development of habitats on the
site is largely being left to ‘nature’ but this is being monitored
closely to help decide what if any intervention may be needed in
the future.
Humber Estuary
Old Flood
Embankment
Agricultural land
(previously reclaimed)
63
plan?
Yes. Community involvement and consultation hase been as follows:
• The outline design of the project was subject to the normal
consultation process for planning consent in the UK
• The Environmental Steering Group for the project included a
representative from Paull Parish Council, the local community
representative body.
• Public meetings were held locally to discuss designs and identify
other community enhancements such are car parking, footpaths
and access for disabled persons.
There was no significant opposition and minor conflicts were resolved in
public or specific stakeholder meetings.
A communication plan was not produced at the beginning of the process,
but this is now standard practice for the Environment Agency on such
schemes. In this case the EIA and later the Environmental Action Plan
laid out the plans for communications with statutory and other
stakeholders through the design, implementation and operational
phases. These aspects of the project were very successful
negative effect be reversed?
The area has only been subject to flooding since 10 September 2003 and
the development of the desired habitats will take some time. Habitats,
flora, fauna and morphological development of the site is being
monitored. Early signs are that the predictions as regards inundation
regime were very good and that therefore habitat development and the
subsequent ecological benefits should be realised. Already the area is
being used by large numbers of wetland birds. The positive effects
should increase and be lasting. Any negative effects will be identified
through the monitoring scheme and addressed through intervention if
necessary.
compensation?
The land was previously in agricultural use and the project was clearly
going to prevent this in the future. There were two landowners at the site
and agreements were reached for the purchase of the land. The
purchase was made economically viable by the improved flood defences
realised by the scheme.
64
Are there any social consequences towards planned NLU activities?
It is planned that the NLU area will bring a number of social benefits
including:
• Better and more interesting recreational footpaths with some
access for disabled persons;
• Improved flood defences for persons living within the flood risk
area;
• Bird watching facilities and opportunities
• Local car park to aid access and interpretation boards for the
purposes of ecological education.
decision procedure?
The planned process is to reduce intervention to a minimum and makes
decisions to do so based on the results of monitoring. Possible
interventions might include:
• Increased protection may need to be supplied to the high
pressure gas pipes that go under the site, if erosion causes a
problem;
• Increased protection may need to be provided to the new and old
embankments in specific locations, if erosion causes a problem;
• Further re-profiling or construction of scrapes/ponds or artificial
creeks may be implemented, if habitats do not develop as
anticipated.
View from the lighthouse (Source: http://myweb.tiscali.co.uk/hullvalley/hv05010.htm)
economy and society, and were those elements monitored?
There is extensive monitoring of the ecology planned and any required
interventions will be highlighted by this. Monitoring of any economic and
societal aspects are less likely. Perhaps use of the site by different
groups (cars, walkers, birdwatchers, disabled persons etc) should be
implemented to better understand the economic benefits arising in this
area.
65
Specific objectives were defined and were achieved.
Example: Paull Holme Strays in Humber Estuary, UK
Key Area
Key Area result
Lesson
Objective aspects Clear strategic and operational It is essential to specify the
objectives were set
actions and the elements you
want to realize on the field
It is important to have a good
Legal and
opportunities
to
create
the
NLU
knowledge of local legislation.
governance
area
were
present,
but
Lack of familiarity with the
aspects
procedures associated with
requirements of the
Habitats Regulations
regulations, directives,
consenting process were
conventions, laws, policies, …
unfamiliar to the parties
can cause delays to the
involved (this will be better in
planning and consenting
the future) and this created long process.
time delays
Extensive monitoring was put in It is important to model the
Organisational,
place for pre, during and post
inundation regimes; that can
technical and
construction
phases.
The
allow good prediction of the
management
specific
NLU
was
well
planned.
habitat types and that may
aspects
reassure the project could
deliver its objectives.
Communications were
Extensive consultation and the
Communication
extensive
and
successfully
involvement of key parties in
aspects
planned and executed
the design team ensured
ownership of decisions and
outcomes. Although this
project proved extensive
communication is important,
the setting up of a steering
group to guide detailed design
of the area and make quick
decisions regarding
environmental aspects during
the construction phase has
proved invaluable.
The production of an
Those aspects were more or
Societal,
environmental plan can
less studied before the dike
economic and
ecological aspects breaching, but will probably be provide all parties with
assurances regarding the
studied intensively later on.
environment.
Intervention procedures,
The production of a detailed
Intervention
dictated by monitoring are
scheme of monitoring can
aspects
reasonably clear.
provide all parties with
assurances regarding
protection of the environment
both during and post
construction.
66
Were the
objectives
achieved ?
Excellent NLU appears to be in
development. This was well
planned and executed,
although the time to achieve
design and consents was
considerable.
/
The following persons provided relevant information
- Keith Slaney (Project Manager), Environment Agency North East
Region, Phoenix House, Global Avenue, Leeds, LS11 8PG,
[email protected]
- Helen Richardson (Humber Ecologist), Environment Agency North
East Region, 1 Viking Close, Great Gutter Lane East, Willerby Hull
HU10 6DE, United Kingdom, [email protected], www.environment-agency.gov.uk
- # Halcrow studies on Thorngumbald c.q. Paull Holme Strays
67
8. Main review conclusions
8.1 Introduction
General overall observations
In this final chapter we summarize the findings after reviewing and evaluating
of five case studies. The analysed cases show a diversity of findings and
lessons in implementing New Land Use on the field. These are summarised in
brief:
• Aakvlaai is designed for recreational and ecological purpose all year
round ànd to cope with long lasting high water waves. The main threat
comes from river discharges, the tide plays only a minor role in this
area.
Operational since 2001; original objectives more or less
achieved.
• Sieperdaschor is designed to work permanently taking the normal and
critical peak of the high water wave during high tides. The main flood
risk comes from storm surges at sea. The ecological purpose is the
most important one.
Sieperdaschor developed more or less
spontaneously out of a former polder landscape. Operational since the
early 1990’s; although no objectives were formulated, an interesting
New Land Use type is achieved.
• For Baie des Veys the management challenge is selecting a water
level management strategy that optimally satisfies all the interests
present in the system. This case provides an illustration of controlled
flooding, in which not the reduction of flood damage, but the
maintenance of an historically relevant landscape in relation to the
economical needs of the area is important. Management operational
since 2002; objectives are fairly well achieved.
• The Norfolk Broads provide interesting illustrations of the construction
of floodplains by managed realignment. As such, this site is innovative
on an organisational rather than a technical level. Not yet fully
operational, but at this stage all high-level objectives are achieved.
• The Paull Holme Strays site was constructed as a cost-effective
replacement of existing defences that also provided compensation for
nature losses due to flood defence strengthening elsewhere in the
system. Operational since September 2003; excellent NLU appears to
be in development.
Site-specific lessons are discussed in the relevant chapters and are not
repeated here.
68
8.2 Individual lessons learned
Intercomparison of the lessons of different NLU-cases, and drawing specific
characteristics of each case studied
The italic parts in the table on the following page can be seen as very specific ideas; not italic table cells give general lessons towards
NLU implementation.
LEGISLATION
OBJECTIVE
Key
Area
Aakvlaai
Sieperdaschor
Baie des Veys
Norfolk Broads
Paull Holme Strays
It can be important to
make clear the
elements you want to
realize on the field, and
the aspects you want
implement (recreation,
nature).
None
specify the actions and
the elements you want to
realize on the field, and
the aspects you want
implement (economical
development, landscape
conservation), in the very
beginning of the project.
make clear the elements
field, and to give a firm
basis to the reason why
implementation is necessary
(flood problems).
It is essential to specify the
actions and the elements
field
It is advisable to have a
clear view on the local
policy and legislation,
and the opportunities that
it brings.
The construction of a Park
area can be useful to
integrate the needs of
different public sectors
(e.g. social/industry,
nature/agriculture, water
control/cattle breeding, …).
policy and legislation,
and the opportunities that it
brings.
policy and legislation, and
the opportunities that it
brings. Flexibility in policy or
acting to the intention of an
order is important.
It is important to have a good
knowledge of local
legislation.
Lack of familiarity with the
requirements of the
regulations, directives,
conventions, laws, policies, …
can cause delays to the
planning and consenting
process.
TECHNICAL
Key
Area
70
Aakvlaai
Sieperdaschor
Baie des Veys
Norfolk Broads
Paull Holme Strays
have a soil flow plan.
This plan identifies the
soil types that are to be
excavated and where the
material is best reapplied.
It is recommended to
determine abiotic
parameters. A soil plan
can identify the soil types
that are present, and by
that abiotic prediction of
the future biotic c.q.
botanical situation is
feasible (also on the
field), and immediate and
specific management
It can be useful to work
with a neutral soil
balance in order to
prevent delays with
permit procedures. Make
sure to know where soil
pollution can be present,
in order to limit extreme
increase of the costs.
Non-refreshment of water
can be prevented by
making a detailed DTM, a
river sand and river mud
input analysis in situ and
in vitro, and a surface
water flow model.
It is important to realise that
not all new land use needs
planning. Daring to realise a
concrete and controlled dike
breaching on a well located
and safe place, with only a
negligible societal and
economic relevance, can
result in some interesting
information on natural
development (without human
interfering) and practical (and
not only theoretical)
information based on terrain
experience.
Nevertheless, it can be
recommended to determine
abiotic parameters in similar
(future) projects and in project
monitoring. A soil plan
should identify the soil types
that are present, and by that
abiotic prediction of the future
biotic c.q. botanical situation
is feasible (also on terrain),
and immediate and specific
management measures can
be taken. By that
It can be helpful to
provide for sound
conceptual and strategic
planning, translating in a
stepwise manner into
operational level objectives
(local as well as thematic)
and further on into practical
measures.
It is advisable to design
the interior of the FCA’s
carefully to suit the needs
that can be derived from the
land use objectives
It is important to model the
inundation regimes; that can
allow good prediction of the
habitat types and that may
reassure the project could
deliver its objectives.
SOCIETAL, ECONOMICAL, ECOLOGICAL
COMMUNICATION
Key
Area
Aakvlaai
Sieperdaschor
Baie des Veys
Norfolk Broads
Paull Holme Strays
The provision of a
flexible and broad
deliberation platform or
consultative body is
essential; the lack of
detailed information to
the public at the project
start, can be very
invaluable for the
progress of the process.
None
It is important to provide for
broadly accessible and
lasting deliberation
platforms. Interests
change over time, and so
will the balance between
them.
The provision of a flexible
and broad deliberation
platform or consultative
body is essential. If already
a platform is available it is
advisable to fit the new
participatory process in the
existing platform.
Extensive consultation and
the involvement of key
parties in the design team
ensured ownership of
decisions and outcomes.
Although this project proved
extensive communication is
important, the setting up of a
steering group to guide
detailed design of the area and
make quick decisions
regarding environmental
aspects during the construction
phase has proved invaluable.
It is useful to design the
interior of the FCA’s
carefully to suit the
needs that can be
derived from the land use
objectives. The Aakvlaai
nature aspects could
do with a coarser
design than a nature
recreation area.
It can be a useful
addition to the
landscape to create
small elevated areas,
used for e.g. grazing
cattle, in between
channels and islands.
The enlargement of
spatial and biological
diversity in that way, can
increase the recreational
appreciation.
It is important to realise that a
nature area, can do with a
very coarse ‘design’. The
addition of small elevated
areas in the new nature area
can ease goal-oriented
(ecological) measures (e.g.
terps for cattle grazing,
education spots, …)
It is advisable to take
advantages of economical
evolutions and the impulse
they can provide to the
integration of apparently
opposed interests (e.g.
milk quota).
It is useful to assess the
planned activities and the
way in which they will affect
the environmental
conditions, and to remedy or
re-evaluate (second opinion)
the planned activities.
The production of an
environmental plan can
assurances regarding the
environment.
71
INTERVENTION
Key
Area
72
Aakvlaai
Sieperdaschor
Baie des Veys
Norfolk Broads
Paull Holme Strays
It is advisable to
determine in advance
the desired species and
vegetation types and
monitoring program (for
al types of animals and
plants); in that way it is
possible to intervene
quite quickly when some
unwanted land use
evolution occurs.
The writing and
implementation of a
concrete and accurate
management and
monitoring program can
trace eventual changes in
the area, so that undesired
effects can be countered
immediately.
The writing and
implementation of a
concrete and accurate
management and
monitoring program can
trace eventual changes
in the area and
sensitivities at the public
and partners.
It is advisable to determine
in advance the desired
species and vegetation
types and implement an
accurate monitoring
program (for al types of
animals and plants;
monitoring the field situation
to test the validity of
vegetation predictions).
The production of a detailed
scheme of monitoring can
assurances regarding
protection of the environment
both during and post
construction.
8.3 Overall lessons learned
Recommendations drawn from the KPI analysis
on implementing New Land Uses in flood risk
areas
After analysing the individual lessons of the different case studies mentioned
in this main review and after analysing the Key Area results, we can draw
some conclusions. Those conclusions concern elements that seem to be
essential in having a smooth course of the whole procedure starting from the
first brainstorm to the finalisation of the field activities. Some aspects are –
off course – quite obvious, but nevertheless important.
The recommendations arising from this study have been subdivided to ensure
that they are readily accessible for use in the FRaME demonstration projects.
The subdivision is based on the three main phases of project implementation,
i.e. Planning, Design, Implementation, but these phases are not mentioned as
such. Though the succession of those three phases has been respected.
We can mention the following aspects furthermore, information on detailed
technical issues can be found within the FRaME literature review report):
Lesson: Plan the strategy !!
The project best starts with a strategic planning. In this strategic
planning one can determine which administration, authorities and
private persons can be addressed, what is the objective of the study,
which elements need to be assessed and analysed in the study, what
will be the procedure of intervening, interviewing and communicating
(see FRaME; strategy analysis, 2004). Some studies obviously go
without previous strategy, though the risk of problems during
maintenance and management is higher.
The strategic objectives relate to long-term fundamental issues across
an entire estuary, while the operational objectives refer to the goals of
individual measures or projects and thereby enable the attainment of
the strategic objectives. The establishment of clear objectives at the
beginning of the project is essential in order to develop relevant New
Land Use. Once the objectives are established, it must easily be
possible to formulate and integrate alternative measures.
Lesson: Contact the key parties !!
The provision of a flexible and broad deliberation platform or
consultative body is essential. A step-by-step part in which the different
communication steps and practical measures that are necessary are
lined out, can be advised. The provision of a ‘quick decision’ or ‘ad hoc’
steering group often proved to be invaluable.
Anticipating on
economical evolutions can create new options, and is easier when a
deliberation platform is present.
Communication issues are mostly critical and generally will need to
have been dealt with at the planning stage, but ongoing consultation will
almost certainly be required. The implementation of New Land Use
may be seriously delayed when stakeholders oppose. Using the Main
Review, it can not made not clear what can be an appropriate strategy
to deal with this problem, but the earlier the opposition is addressed in
the planning phase the better (see FRaME Communication Main
Review, and Best Practice Manual, 2004).
Lesson: Fathom the different sensitivities !!
Familiarity with local policy, legislation, authorities and all other kinds of
‘sensitivities’, as well as a detailed knowledge of the studied site is
essential to be credible, to make your study convincing in the end, and
to avoid delays. The range of solutions will also be determined by the
regulations and policies at a local, national and European level. Options
should be screened against these policy and legislation as early as
possible in order that non-compliant options can be quickly eliminated.
Lesson: Give consideration to multiple land use types !!
Flood control often provides the economic justification for implementing
an FCA, but measures to improve recreation, economical aspects or
natural values are also useful to ensure successful progression of the
project.
Lesson: Design carefully !!
A detailed designing plan is essential. It has to consider all conceptual
ideas and especially the final ideas. One must be able to trace how the
final ideas were chosen. Therefore study work must ‘go’ along essential
lines, f.i.:
o an inventory part by which it is possible to have insight in the
spatial, ecological, recreational, … relationships, potencies,
bottlenecks and values. Given the nature of flood risk and the
implementation of new land use in an area, designing of the NLUarea can rarely be considered in isolation from other tidal aspects
(recreational, economical, nature values, etc.) around. It is
therefore vital to take a broad approach (f.i. small project area, but
very large study area). This will help ensure that the NLU is
appropriate and its influence on flood risk is optimal. The
visualisation of the present situation is also very important.
o a guiding part in which inventory elements are converted with
regard to the definitive plan formation (drawing of aims or pursuits,
target systems, eco-scope, …). It is common practice in the
implementation of NLU areas to first consider a wide range of
possible solutions, and then gradually reduce this range of options.
It is recommended that a pragmatic ‘expert judgement’ is / can be
used, in order to eliminate without excessive time or cost.
o a binding part in which one find a set of concrete measures.
Usually the construction of NLU areas involves a number of
measures that need to be carried out. Careful planning can save
considerable time and money. Reusing soil1 that is dug out in the
area itself for the construction of new dikes, for instance, may
1
A ‘soil plan’ can also be very useful. The qualitative and the quantitative aspects of the soil
can be checked. In that way it is possible to reduce soil transportation (reduce cost, reduce
contamination elsewhere), and it become possible to better determine spatial and ecological
possibilities in the area concerned
74
o
significantly reduce construction costs. Whether or not a certain
scheme will work and to what extent, is usually not something that
is easily established based on expert judgement. To deal with that,
models2 can be used. Computer models are also often critical to
gaining approvals, but in order to produce accurate computer
results it is important to provide appropriate input information.
a monitoring part increases flexibility, because new elements can
more easily be integrated in the plan and realised on the field.
Even adopting the best available technology and expertise during
the planning and design phases is unlikely to remove altogether the
uncertainty over the success of the scheme. In recognition of this, a
useful approach is to accept a degree of uncertainty during the
planning and design phases, but make sufficient provision for
monitoring during operation such that remedial measures can be
taken when necessary.
Some studies obviously go without previous designing and planning,
though the risk of problems during implementation is higher.
Lesson: Make use of the existing guidances to NLU !!
Considerable effort has been spent in recent years on the
implementation and monitoring of demonstration sites, and the
development of guidance documents that have at least some bearing on
the implementation of NLU areas. These are summarised in the FRaME
Literature, Strategy and Communication Reports.
2
A ‘water plan’ can be very useful in New Land Use areas (used in Flood Control) with a
significant sea and river water input and water level fluctuation. By that the areas with soil
deposition and silting up can be indicated on forehand, so that specific actions can be
undertaken and ad hoc intervening after implementation is not needed. Water refreshment
reduces oxygen and overfertilization problems, so it can be useful to model how the water will
flow, in which amount and where stagnation can result in anaerobic, unwanted situations. A
clear modelling of inundation regimes has also an important, ecological and communicative
relevancy
75
For more information on the FRaME project contact the Project Manager
Frank van Holst +31 70 3371 219 or Henkjan Faber +31 70 3371 242
or visit the FRaME website at http://www.frameproject.org
Partner:
LeadLead
Partner:
FRaME – Review and Evaluation of Alternative
Land Use
Strategies in Estuaries
FRaME
is co-financed by the
FRaME is co-financed by the
European
Community
European
UnionUnion
Community
Government
Service
DLG DLG
Government
Service
for for
Initiative
Programme
Interreg
Initiative Programme Interreg
IIIB IIIB
Land
and
Water
Management
Land and Water Management
Sea Region
North North
Sea Region
Burgemeester
Feithplein
2
Burgemeester
Feithplein
2
P.O.
Box
3010
P.O. Box 3010
JB Voorburg
22702270
JB Voorburg
The Netherlands
The Netherlands
For more information on the FRaME project contact the Project Manager
Frank van Holst +31 70 3371 219 or Henkjan Faber +31 70 3371 242
or visit the FRaME website at http://www.frameproject.org
76

Ad hoc new land use at Sieperda-schor (NL-B)

Transcription

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