Rivers &amp; estuaries

Coastal floods or storm surges

Estuarine floods

Erosion

Channel, Coastal and Floodplain Works

Hold the line

Grey infrastructure

Groynes are cross-shore structures designed to reduce longshore transport on open beaches or to deflect nearshore currents within an estuary. On an open beach they are normally built as a series to influence a long section of shoreline that has been nourished or is managed by recycling. In an estuary they may be single structures.

Based on kindly provided information by the Scottish Natural Heritage

Groynes reduce longshore transport by trapping beach material and causing the beach orientation to change relative to the dominant wave directions. They mainly influence bedload transport and are most effective on shingle or gravel beaches. Sand is carried in temporary suspension during higher energy wave or current conditions and will therefore tend to be carried over or around any cross-shore structures. Groynes can also be used successfully in estuaries to alter nearshore tidal flow patterns.

Technical feasibility

Groynes can be made from different material. Rock is often favoured as the construction material, but timber or gabions can be used for temporary structures of varying life expectancies (timber: 10-25 years, gabions: 1-5 years). Rock groynes have the advantages of simple construction, long-term durability and ability to absorb some wave energy due to their semi-permeable nature. Wooden groynes are less durable and tend to reflect, rather than absorb energy.

Groynes along a duned beach must have at least a short “T” section of revetment at their landward end to prevent outflanking during storm events. The revetment will be less obtrusive if it is normally buried by the foredunes. Beach recycling or nourishment is normally required to maximise the effectiveness of groynes. On their own, they will cause downdrift erosion as beach material is held within the groyne bays.

Groynes can have a significant impact on the shoreline, and schemes should always be undertaken under the supervision of a competent coastal consultant. As with all rock structures on the shoreline the rock size, face slopes, crest elevation and crest width must be designed with care. Rock size is dependent on incident wave height, period and direction, structure slope, acceptance of risk, cross-sectional design, and the availability/cost of armour rock from quarries. In general 1-3 tonne rock will suffice for the landward parts of the groynes, provided that it is placed as at least a double layer, with a 1:1.5 to 1:2.5 face slope, and there is an acceptance of some risk of failure. Larger rock, probably 3-6 tonne, may be needed for the more exposed body and seaward head of each structure.

The groyne berm should be built to the anticipated crest level of the beach. The groyne berm length should equal the intended crest width of the updrift beach. The groyne should extend down the beach at a level of about 1m above the anticipated updrift shingle beach, normally at a slope of about 1:5 to 1:10. The groyne head should extend down into the sand beach, allowing for some future erosion.

As a general rule, groynes should not be built on an open beach unless construction is accompanied by a commitment to regular recycling or nourishment. Without this commitment the groynes are likely to cause downdrift erosion as the upper beach becomes starved of sediment. Where there is a plentiful sediment supply, or where downdrift erosion is not considered to be a significant issue, then recycling may not be required.

Timber groynes must be built from hardwood to endure the harsh shoreline environment. Much hardwood comes from tropical sources, making it both costly and potentially environmentally unacceptable. Timber groynes tend to reflect, rather than absorb, wave energy making them significantly less effective than rock on exposed coasts. They are also more likely to structural failure due to formation of scour channels around their seaward ends.

Political & social feasibility

Rock structures on recreational beaches should be built with a view to minimising the potential for accidents involving beach users slipping between rocks

Cost of implementation & maintenance

The costs of groynes are considered as moderate

Ecological feasibility

Implementing groynes disrupts natural processes. The effects must be properly monitored and if possible compensated.

Key lessons learnt

Provided that groynes are used in appropriate locations, they reduce dependency on regular recycling or nourishment, and therefore reduce future disturbance of the shoreline environment. Localised accumulations of beach material will encourage new dune growth. Recycling, fencing and transplanting will help to keep the revetment sections buried, thereby enhancing habitat regeneration.

Measure category

Breakwaters

nst — Wed, 22 Mar 2017 08:49:13 +0000

Breakwaters nst Wed, 03/22/2017 - 09:49

Coastal floods or storm surges

Estuarine floods

Erosion

Channel, Coastal and Floodplain Works

Hold the line

Based on the information available on the ClimateAdapt Platform

Grey infrastructure

A breakwater is a coastal structure (usually a rock and rubble mound structure) projecting into the sea that shelters vessels from waves and currents, prevents siltation of a navigation channel, protects a shore area or prevents thermal mixing (e.g. cooling water intakes). A breakwater typically comprises various stone layers and is typically armoured with large armour stone or concrete armour units (an exception are e.g. vertical (caisson) breakwaters). A breakwater can be built at the shoreline or offshore (detached or reef breakwater). This measure is not directly addressed to protect the coast in flood events, but can indirectly stabilize the coast by preventing erosion.

To build breakwaters, rock size, face slopes, crest elevation and crest width and toe protections and aprons should be designed according to the natural characteristics of the sites as these factors have an important impact on the shoreline. Sand may build up behind breakwaters to form salients. Sand can accumulate enough to connect with the breakwater and form a tombolo (a stretch of sand developed by wave refraction, diffraction and longshore drift forming a ‘neck’ connecting the structure to the shore). Considering the significant impact these structures have on the coastal environment, they should only be considered as part of a global adaptive management policy, taking into account the characteristics of the specific site and the potential effects on the whole coast. The construction of breakwaters could also be linked to a beach nourishment programme, and breakwaters can be used in a protected beach nourishment approach.

Stakeholder participation

If an EIA is undertaken, the EU Directive provides for the right to access information and to participate in the environmental decision-making procedures to the public concerned by the project. If a project creates a significant impact on a Natura 2000 site, the ‘appropriate assessment’ of the infrastructure project could include a public participation process, but this is not mandatory. Similarly, the Floods Directive, the Water Framework Directive and the Maritime Spatial Planning Directive establish public participation processes that may include these projects.

A range of stakeholders could be affected by the construction of breakwaters: for local communities and landowners, hard defences could negatively impact their property. Hard defences can visually disrupt the landscape, affecting tourism interests, recreational users and other sectors. Waterborne activities can also be adversely affected if the installation of hard structures goes wrong.

Success and Limiting Factors

Artificial structures such as breakwaters tend to modify longshore drift, and have adverse effects on adjacent beaches by causing downdrift erosion. In general, to avoid these effects on the coastline, artificial nourishments and/or dune development are often preferable over hard structures unless there are other needs, such as the safe berthing of ships. However, the extent of the blocking of longshore drift, disturbance of adjacent beaches and degradation of landscape values depends very much on the design, orientation of the structure and the main wave/sediment transport direction at the specific site.

Breakwaters provide safe mooring and berthing procedures for vessels in ports. They enhance workability and provide thus higher efficiency in loading and unloading vessels.

Costs and Benefits

Construction costs depend significantly on structure dimensions. Costs can be highly influenced by availability of suitable rocks, transport costs to the construction sites and associated costs of beach nourishment.

In the Netherlands, breakwaters are estimated to cost about EUR 10,000 to 50,000 per running meter (Deltares, 2014).

According to Scottish Natural Heritage, in 2000 construction costs of breakwaters are high – GBP 40,000 to 100000 (50,000-125,000€) – but they require low maintenance; for these structures in particular, beach nourishment costs should be added.

Legal Aspects

The construction of coastal works to mitigate erosion and hard sea defences ‘capable of altering the coast’ fall into Annex II of the EIA Directive (codified as Directive 2011/92/EU): Member States decide whether projects in Annex II should undergo an EIA procedure, either on a case-by-case basis or in terms of thresholds and criteria. However, this requirement does not affect the maintenance and reconstruction of these works.

Any infrastructure project likely to have a significant impact on a Natura 2000 site must be subjected to an ‘appropriate assessment of its implications for the site’ to determine whether the project will adversely affect the integrity of the site.

The Water Framework Directive calls for the Good Environmental Status of Europe’s water bodies, including coastal waters. Coastal defences could alter the hydromorphological characteristics of coastal waters, for example in terms of water flow, sediment composition and movement, and thus to a deterioration of ecological status. Any projects that do so would need to meet criteria set out in Art. 4 of the Directive. The EU Floods Directive (2007/60/EC) provides a legal framework for flood actions and defence. The construction and restoration of dikes could be part of measures under flood risk management plans. The 2014 Maritime Spatial Planning Directive requires the consideration of the interactions between land and sea, along with maritime activities and adaptation to climate change. Breakwaters could affect these land/sea interactions.

Life Time

Breakwaters have a typical design lifetime of 30-50 years. This is the case for most rock structures.

Further Readings

Scottish Natural Heritage: A guide to managing coastal erosion in beach/dune sy…

VLAAMS INSTITUUT VOOR DE ZEE: Detached Breakwaters

Measure category

Public Awareness and Preparedness

Public Education Schemes

nst — Thu, 23 Feb 2017 10:25:51 +0000

Public Education Schemes nst Thu, 02/23/2017 - 11:25

Non-structural measure

Not all stakeholders are aware or informed about their vulnerability to a changing climate, or flood risk protection. Nor are they aware of the pro-active measures they can take to adapt or deal with climate change. Awareness raising and education programs are therefore important to manage the impacts of climate change, enhance peoples’ capacity to deal with the impacts, and reduce overall vulnerability.

Sharing knowledge in this way can help build safety and resilience, reduce future hazard impacts. Communities and individuals usually want to become partners in this, and the public can be empowered to deal with the impacts and reduce future problems related to flood risk and disaster risk response.

Based on the information available on ClimateAdapt Platform and the Ifrc-Guide on Public awareness and public education for disaster risk reduction.

Several types of approaches can be used such as campaigns, participatory learning, informal education, formal school based interventions.

Given that individuals and communities are in different positions, in terms of both capacity to act as well as vulnerability or being affected by, awareness raising schemes need to be tailored to their audience.

Large climate change awareness raising campaigns are often a mixture of mitigation, energy efficiency, and sustainability measures rather than adaptation measures.

Benefits

The benefits also mean that through knowledge transfer, the resilience of the community or individuals can be increased which is essentially transforming knowledge and information into potential for action, protection and mitigation of harmful effects. It stimulates self-mobilisation and makes excellent use of local knowledge and resources for improved overall capacity.

Awareness raising is continually relevant, and should be adapted as information and situation changes. Therefore, awareness raising is not only a first step but a step that can continually offer support to effectively managing flood risks.

It is also generally a measure that can accompany many others, explaining to a community the options available to for instance, prevent erosion at a local beach, thereby in theory, informing decision making and improving democratic participation in climate change adaptation and decision making.

Disadvantages

In itself, flood hazard mapping does not cause a reduction in flood risk nor does it directly lead to people adopting risk-reduction measures. Researchers have found that people take action only when

They know what specific actions can be taken to reduce their risks;
They are convinced these actions will be effective;
They people in their own ability to carry out the tasks.

Costs

Awareness raising and school education schemes are generally inexpensive in comparison to some other mitigation efforts, however, they also vary in scale, thoroughness, and continuation. For instance, in order to be effective, generally education and awareness raising should include consistent and standard messaging, legitimacy and credibility, and scalability. It may require adaptation to specific local circumstances, such as language translation, or continual evaluation as a situation changes or becomes different. It may also only be effective if it reaches the target stakeholders it was designed for, who may for instance, have low capacity to deal with flood disasters despite having increased their awareness about them. Thus finding, low cost solutions or area specific options is crucial.

Thus, awareness raising and education programs are most effective when developed through a participatory approach where needs, expectations, and capacity are measured and information is developed together. Moreover, the more tailored, maintained and thoughtful the approach the more likely it will be to be put into practice.

Measure category

Preparedness

Reconnecting rivers to floodplains

nst — Mon, 20 Feb 2017 09:27:15 +0000

Reconnecting rivers to floodplains nst Mon, 02/20/2017 - 10:27

Natural flood, runoff, catchment management

Water flow regulation

Based on kindly provided information by UNEP's "Green Infrastructure Guide for Water Management: Ecosystem-based Management Approaches to Water-related Infrastructure Projects " (UNEP, 2014)

River restoration contributes to flood risk management by supporting the natural capacity of rivers to retain water. As flood risk consists of damage times occurrence, flood risk management needs to reduce either the damage, or the likelihood of floods to occur, or both. River restoration reduces the likelihood of high water levels, and improves the natural functions of the river at same time.

In a natural river system a river spreads water beyond its banks and over extended areas of a floodplain during periods of high water. In order to protect property and contain waters, the classic flood risk management approach is to constrain watercourses with rivers being straightened and building dykes to increase discharge capacity, dredging to deepen channels, and building reservoirs and artificial retention areas to store excess waters.

While this generally reduces the likelihood of flooding, in the event of extremely high waters it increases the amount of damage if the engineered system is overwhelmed or fails. Without natural features such as wetlands and meanders, excess waters cannot be absorbed. Any breach will release an enormous amount of water, with potentially catastrophic consequences. Continuously reinforcing and building higher dykes cannot overcome this weakness, and is a very expensive option. Historically, engineering solutions upstream have created peak flows downstream, leading to more engineering. Moreover, climate change scenarios predict more extreme weather events and higher sea levels. A new approach is needed.

Advantages

By re-connecting brooks, streams and rivers to floodplains, former meanders and other natural storage areas, and enhancing the quality and capacity of wetlands, river restoration increases natural storage capacity and reduces flood risk. Excess water is stored in a timely and natural manner in areas where values such as attractive landscape and biodiversity are improved and opportunities for recreation can be enhanced. In these ways, river restoration directly contributes to climate change strategies aimed at mitigating the effects of increased and erratic peak flows and droughts.

River restoration is increasingly being delivered by flood risk managers to create space for flood water. Reconnecting floodplains to the river and managed realignment in estuaries is an important mechanism of water management.

Future climate change will potentially affect all aspects of the rainfall regime. The precise nature of these changes is uncertain, particularly for those extreme events, whether of short or long-duration, which tend to lead to flooding. Increases in rainfall at all scales will increase the risk of flooding to a greater or lesser extent, depending on how these increases manifest themselves in space and time and of the rainfall-runoff characteristics of the catchment in question.

Benefits

River restoration improves flood protection, but it also brings about co-benefits that are multifold. Firstly, river restoration can improve flood storage capacity of a river and reduce the volume and speed of water. Some of the co-benefitst can include cost reductions by removing the need to maintain hard infrastructure and also improving the quality of water, and thus in turn drinking water costs. Improved biodiversity and the creation of natural wetlands is another adjunct result of river restoration using green infrastructure. Finally it improves resilience to climate change by creating new floodplanes for increased water storage, green networks and more natural space for people and wildlife during higher temperatures.

Costs

There are different kinds and degrees of river restoration. A larger scale project can include an entire floodplane, removing past structures and restoring natural processes and channels of a water course. A smaller project may simply be removing structures in one place, and replacing them with more natural features.

Barriers to Implementation

Lack of funding is often cited as a key reason for failing to restore watercourses and rivers, as well as, consensus in agreement of users of a river. Given that restoration can take place on either a large or small scale, the associated barriers often also relate to how extensive the project is.

Measure category

EXAMPLE: Reconnecting lakes to the Yangtze River (CHN)

nst — Thu, 16 Feb 2017 11:16:41 +0000

EXAMPLE: Reconnecting lakes to the Yangtze River (CHN) nst Thu, 02/16/2017 - 12:16

Natural flood, runoff, catchment management

Ecosystem based approach

The 6,300 km long Yangtze River in China was facing a reduction of wetlands areas and flood retention capacity. In 2002, the World Wide Fund for Nature (WWF) initiated a programme to reconnect lakes in Hubei
Province to the Yangtze River through opening the sluice gates and facilitating sustainable lake
management. These wetlands can store floodwaters and therefore reducing vulnerability to flooding in the central Yangtze region.

Based on kindly provided information by UNEP's "Green Infrastructure Guide for Water Management: Ecosystem-based Management Approaches to Water-related Infrastructure Projects " (UNEP, 2014)

General description

The Yangtze River is 6,300 km long and home to more than 400 million people. The river basin drains a 1,800,000 km basin and has extensive lakes and floodplains of significant environmental and retention importance. In the summer, the basin experiences floods, especially in the central Yangtze. Extensive development in the last fifty years has converted 1,066 lakes 757 coverings along 2,150 km2 into polders, reducing wetland areas by 80% and flood retention capacity by 75%.

Since 1991 there have been several highly damaging flood events that have killed thousands of people and cost billions of dollars. The Lakes and basin have also become extremely polluted, in particular because of the application of fertilizer to aquaculture pens. The loss of connection to the Yangtze River prevents diluting flows and the migration of fish. Drought in recent years has increased water pollution, and climate change and increased temperatures are expected to worsen eutrophication

In 2002, the World Wide Fund for Nature (WWF) initiated a programme of sustainable lake management to reconnect the lakes in the Hubai Province to the Yangtze River through opening the sluice gates. The programme focused on three lakes: Zhangdu (40 km2), Hong (348 km2 and Tian’e Zhou (20 km2). Given the poverty of the populations in the region, finding alternative and sustainable livelihoods and sources of income was important. The average income of residents in the area was just USD 1.34 per day. WWF formed partnerships with government agencies and others to explore options for more sustainable river basin management.

Ecosystem-based aspects

Since 2004-2005 in Hubei Province, the sluice gates at lakes Zhengdu, Hong and Tien’e Zhou have been seasonally re-opened and illegal and uneconomic aquaculture facilities and other infrastructure removed or modified. Now these 448 km2 wetlands can store up to 285 Mm3 of floodwaters, reducing vulnerability to flooding in the central Yangtze region.

The forced ending or removal of illegal or unsustainable aquaculture have reduced pollution levels. In Lake Hong, pollution fell from national pollution level IV (fit for agricultural use only) to II (drinkable) on China’s five-point scale.

Of immediate benefit for the Yangtze River Basin was the increase in wild fisheries species diversity and populations. Within six months of reconnection of Zhangdu Lake, the catch increased by 17 per cent and nine fish species returned to the lake. Similarly the catch increased by 15 per cent in Baidang Lake. Development of certified eco-fish farming by 412 households increased income of fishers by 20 to 30 per cent on average. Similarly, the income from fisheries at the Yangcai Hu area of Hong Lake increased by 25 per cent after restoration. Bamboo farming has also been implemented as a measure to stabilize steeper lands near the lakes. Twelve migratory fish species have now returned to the lakes. At Zhangdu Lake, 60 km2 of lake and marshland were designated as a nature reserve by the Wuhan Municipal Government. To strengthen the effectiveness of wetland conservation efforts in the Yangtze River basin, a Nature Reserve Network was established to link 17 nature reserves (12 later designated) covering 4,500 km2. As a result of these benefits, in 2006 the Hubei Provincial Government adopted a wetlands conservation master plan and allocated resources to protect 4,500 km2 by 2010.

The success of these adaptations was replicated in other areas of the Yangtze and China.

Key lessons learnt

Combined using a green and grey approach. The implementation of sluice gates allowed for seasonal opening and reconnection of regional lakes to the Yangtze River. Reconnecting the water flows required the removal of some aquaculture businesses, but brought up overall levels of fisheries in the river basin with significantly more migratory species returning to the area, which in turn boosted incomes of local fishers. The environmental effects also significantly improved water quality which was extremely polluted prior to the facilitation of water flow via connecting the lakes to the tributaries.

Relevant case studies and examples

Flood storage systems

Measure category

EXAMPLE: Constructed wetlands to compensate for urbanization in souther Finland (FIN)

nst — Thu, 16 Feb 2017 09:00:50 +0000

EXAMPLE: Constructed wetlands to compensate for urbanization in souther Finland (FIN) nst Thu, 02/16/2017 - 10:00

Flash floods

Urban floods

Surface Water Management

Ecosystem based approach

In Finland urban wetlands are being implemented to help improve water quality, absorb storm water volume and flow control, and improve the land-water habitats for urban communities. The wetlands are designed to respond to the needs and negative impacts of urbanization and therefore, public acceptance and multifunctional benefits are central to the design and implementation of the wetlands. The acceptance and understanding of the importance of urban dwellers is important and thus the project sought to demonstrate several benefits of functional wetlands.

Based on Wahlroos et al. (2015): Urban wetland parks in Finland: improving water quality and creating endangered habitats. In: Urban wetland parks in Finland: improving water quality and creating endangered habitats. In: International Journal of Biodiversity Science, Ecosystem Services & Management Volume 11, Issue 1: Pages 46-60

General description

Urbanization is affecting water quality and there is increasing severity of flooding and drought periods in Southern Finland. This is expected to become worse because of climate change. During flooding events, run off from rain and melting snow are quickly carried over urban surfaces and overwhelm receiving streams. Habitat degradation is occurring as harmful water from urban areas is transferred into connected habitats. These urban streams in turn cause flooding and channel erosion. The creation of wetlands is an alternative ecosystem approach to conventional responses that have been to seal natural waterways into culverts or clearing, and stabilization for augmented conveyance and erosion control.

Two urban wetlands, the Nummela Gateway and the Nummela Niittu were designed and implemented. The wetlands are 6ha and 7ha respectively and are within 550 ha of the urbanized Kilsoi stream watershed in the catchment of Lake Enäjärvi, in the Nummela community, Municipality of Vihti, Southern Finland. The lake has poor water quality from algal blooms and fish kills that result from runoff from its catchments and phosphorus load from human activities. The Stream Kilsoi is an inland clay-soil stream that drains into the Baltic Sea. The habitat type and clay-stream is red listed in the Red list Assessment of Finnish habitat types as critically endangered.

Ecosystem-based aspects

The creation of wetlands is an ecosystem approach and replaced hard infrastructure and conventional responses that have previously been implemented in the area to control storm water volume. In the past, the convention has been to seal natural waterways into culverts or clearing, and stabilization for augmented conveyance and erosion control.

The two wetlands, Nummela Gateway and the Nummela Niittu, were established over five years and closely monitored. The ecosystem service that was deemed most important for the wetlands to provide was water quality management. Water treatment by wetlands depends on the plants and their associated microbes. Storm water and flooding events are the main carriers of potential pollutants from urban areas, and thus a high density and diversity of plans and microbes is necessary. In this case, the native origin of the plants was also found to be important to protect urban streams from the erosive effects of storms and snowmelts. Plant self-establishment occurred quickly and construction only required the monitoring of water levels, especially during winter. The existing shoreline and old drainage ditches acted as a seedbank and no maintenance of native plants was necessary.

In addition to improving biodiversity, water quality improvements were also achieved. There was an increase in phosphorus reduction after the third year. Despite that the Gateway wetland is just 0.1% of its 550 ha watershed area, it does achieve an annual 10% for total phosphorus reduction.

Key lessons learnt

The establishment of two wetlands near to an urbanized area was able to mitigate against various challenges stemming from urbanization. The Gateway and Niittu wetlands were successful in creating high biodiversity at the clay-stream habitats and relied on little human maintenance due to the naturally occurring habitat which was conducive to wetland creation and existence.

Some compromises were made in order to ensure the acceptance of the wetlands and their appreciation and support by the community. Both wetlands were designed to accommodate open water areas for recreational purposes and thus do not fulfill the most efficient capacity for pollution removal.

Despite the establishment of the wetlands, they do not address source control directly which remains an issue. If action is taken to reduce pollution at the source, then the wetlands will be more productive in response.

Continued monitoring during and after the establishment of the wetlands allowed for there to be definitive conclusions on the impact of the created wetlands on water pollution mitigation, self establishment of vegetation, and biodiversity development. Water quality improvements were demonstrated with continuous monitoring which would not have been deciphered via discrete water sampling.

Relevant case studies and examples

Wetland restoration

Literature sources

Main source: Outi Wahlroos, Pasi Valkama, Emmi Mäkinen, Anne Ojala, Harri Vasander, Veli-Matti Väänänen, Anna Halonen, Leena Lindén, Petri Nummi, Hannele Ahponen, Kirsti Lahti, Teuvo Vessman, Kari Rantakokko & Eero Nikinmaa (2015): Urban wetland parks in Finland: improving water quality and creating endangered habitats. In: International Journal of Biodiversity Science, Ecosystem Services & Management Volume 11, Issue 1: Pages 46-60

Measure category

Public Awareness and Preparedness

EXAMPLE: Developing an Attica Wetland Action Plan (GR)

nst — Thu, 16 Feb 2017 08:27:37 +0000

EXAMPLE: Developing an Attica Wetland Action Plan (GR) nst Thu, 02/16/2017 - 09:27

Non-structural measure

Attica, Greece is a region with extensive wetlands that include streams, estuaries and coastal marshes. The land area is also heavily in use for agriculture and experiences competition from various anthropocentric uses which have created a largely degraded environment. The wetlands that dot the region, are largely considered by communities as the remaining environmental hotspots and serve not only as ecologically important areas but peoples’ remaining contact with nature. They are for this reason, closely tied to community use and general well being. To protect these wetlands, an Attica Wetland Action Plan was developed.

Based on the information available on ClimateAdapt Platform

General description

Recognising the need for the sustainable and ecological management of these wetlands the Environmental Department of Attica Regional Authority with support from the Greek Biotope Wetland Centre (EKBY) developed an Attica Wetland Action Plan. The Action Plan is designed around seven axes under which measures with specific priority actions are identified. The strategy includes sustainable management and restoration of wetlands; their interconnection in a green arc; the evaluation of the services provided; awareness raising and environmental education in biodiversity and climate change and citizen participation.

The Action Plan is built on seven axes under which measures are listed and assigned priority. The development of the Action Plan sought to protect and preserve the biodiverse wetlands while simultaneously creating sustainable opportunities for use by the local community. In order to ensure acceptance and eventual implementation of the Action Plan, participation by the affected communities was central to its design and development. While there were no issues in developing the plan, ensuring its effective implementation faced several limiting factors including limited funds, operational capacity of involved services and bodies to take proposed action measure, regulation of land uses in relation to protection and restoration.

The region of Attica is a Metropolitan Region and the first in Greece to be mobilized towards a climate change adaptation strategy. It therefore was new in bringing a participatory process forward to propose management for natural ecosystems while dealing with sensitive issues of competitive land use between agricultural needs and environmental ones. The local authorities development of an Adaptation Plan brought together local authorities, social groups, environmental organisations and research institutes for the protection of wetlands in its jurisdiction.

Cost-effective and innovative aspects

The planned implementation of the Action Plan is meant to mitigate the effects of human interventions resulting from usage (i.e. agriculture) as well as pressures stemming from climate change. Implementing the suggested measures is expected to improve the protection of the coasts by reducing the effects of waves, storms and currents. It is also expected to improve water quality in the region by trapping sediments, nutrients and toxic substances. It is also expected to improve the possibility of economic returns of those using the wetlands.

During the development of the Adaptation Plan several awareness raising events were organized in the wetland in order to involve and educate local community members. For example, in 2014 a training seminar “Adaptation Strategy for Attica Wetlands” provided hands-on training for some 80 participants. In 2015, the Attica Region had a Green Week event called “Raising support to restore the wetland of Brexiza, in the Region of Attica Greece” which brought some 90 individuals to Brexiza to learn about the biodiversity of the area and its historical importance as an archaeological site of the Roman great temple of the Egyptian gods. Through public support, this event brought about a dialogue on Brexiza wetland restoration and biodiversity protection as well as on the implementation of the Action Plan.

Key lessons learnt

Prior to the development of the regional Adaptation Plan, knowledge and awareness about climate change adaptation and wetlands in particular was low and non-existent in the community. The partnership between the Regional Authority and a scientific environmental organisation, was an important partnership for mutual learning and the introduction of climate change planning for the first time. Moreover, the development of the Adptation Plan was participatory in its design, and thus generated wide support for the suggested measures despite previous issues related to competitive land use and widespread environmental degradation. The development of the Adaptation Plan had the effect of raising awareness of citizens and other actors, facilitating new collaborations between private, public and governmental actors, and generally brought into consideration a sustainable management plan for the wetlands.

In regions or situations where adaptation to climate change is being introduced for the first time, ensuring a participatory process whereby actors develop management plans through mutual learning and exchange

Relevant case studies and examples

Spatial Planning and Integrated Coastal Zone Management (ICZM)

Measure category

Prevention

Land claim

nst — Tue, 07 Feb 2017 13:09:59 +0000

Land claim nst Tue, 02/07/2017 - 14:09

Coastal floods or storm surges

Move seaward

EXAMPLE: Artificial Island - Amager Beach, Copenhagen (DK)

Grey infrastructure

The main objective of land claim is neither erosion nor storm reduction. The aim of land claim is to create new land from areas that were previously below high tide. These measures can be taken to reduce the exposure of these areas to coastal flooding. For example, in Singapore and Hong Kong, there are enforced minimum reclamation levels to account for future sea level rise

Based on information from ClimateTechWiki.

General Description

Land claim is likely to be accomplished by enclosing or filling shore or nearshore areas (Bird, 2005). Several alternative terms may be used when referring to land claim; these may include land reclamation, reclamation fill and advance the line. Typically this measure is undertaken to gain land (French, 1997), today especially around coastal cities (like Singapore and Hong Kong), where very high land values are justifying the costs.

In order to enclose areas for land claim, hard coastal defences must be constructed seaward of the existing shoreline. Dike and seawalls are typically constructed to protect the claimed land from flooding by the sea (Burgess et al., 2007). Two main methods of land claim are: (1) enclosing and defending shore or nearshore areas; and (2) filling shore or nearshore areas, often using the same techniques used in beach nourishment. When considering adaptation to climate change, land claim using fill methods is perhaps more appropriate as it does not carry such a great flood risk.

Advantages and disadvantages of the technology

The key advantage of land claim is the gain of additional coastal land for uses such as agriculture or development. Apart from the valuable land, this additional coastal land can function as a buffer and reducing the risks of flooding.

Land claim can also generate a number of negative impacts. The process of land claim requires either the enclosure of intertidal habitats by hard defences, or the raising of their elevation above that of sea level to prevent inundation. This causes the direct loss of intertidal habitats such as saltmarshes, intertidal flats and sand dunes (French, 1997). Another disadvantage is dewatering. By draining reclaimed land which has a high water content, land is caused to dry out, compact and shrink (French, 1997), thus reducing its elevation in relation to sea level. This causes a difference between land elevations inside the flood defences, where compaction and shrinkage has occurred and outside, where natural intertidal environments continue to naturally accrete sediments. This difference in elevation is also exacerbated by SLR and results in an ever increasing requirement for flood defences (Burgess et al., 2007). It also requires an ongoing commitment to defend these areas (French, 1997).

Any type of land claim will cause the displacement of water during a natural tidal cycle. Because of this displacement, incoming tides have a smaller area to inundate. This will cause water depths to increase and will mean intertidal areas are submerged for longer – this has the potential to cause negative biological consequences and can also increase the tidal range upstream (French, 1997).

Financial requirements and costs

The financial costs of land reclamation are dependent on a number of factors:

Chosen method of reclaim (enclosing previously intertidal areas using hard defences or raising the elevation of previously submerged land)
Availability and proximity of fill material from onshore or offshore sites
Number, type, size and availability of dredgers
Requirement for hard protection measures to defend reclaimed land from coastal flooding and erosion
Project size and resulting economies of scale
Estimated material losses

If land claim is conducted by enclosing previously intertidal areas, the additional costs of providing hard protective measures, such as seawalls or dikes, to prevent flooding and erosion of these areas is important. Ongoing maintenance costs for these structures must also be considered.

If land claim is achieved by raising the elevation of previously submerged land, the cost of fill material is likely to be the main determinant of project cost. In turn, this cost will be influenced by the availability of appropriate materials, their proximity to the construction site and the characteristics of the reclaim site – this influences the type of dredging equipment which can be used. Changes in the cost of fill material are likely to occur in future due to increased demand and greater restrictions on dredging.

Institutional and organisational aspects

The institutional and organisational requirements of land claim projects are likely to depend on the scale and ambition of the project. Small-scale land claim for agricultural uses is more likely to be achievable at the community level than large-scale island enlargement and creation as seen in Singapore or Dubai. These large-scale projects will require the involvement of large organisations and large amounts of funding.

Key lessons learnt

One barrier to the use of land claim is potential long-term costs. Land claim creates land which will require protection from coastal flooding and/or erosion. This requires construction of defences such as seawalls or dikes with associated construction and ongoing maintenance costs. Land claim through elevation raising may also be a cost-effective method of disposing of dredged material from ports, harbours and navigation channels. This could reduce the overall cost and eliminate the need to identify offshore disposal sites for dredge material. As with beach nourishment, pollutant levels in the dredge material should be carefully monitored.

Environmental concerns may provide another barrier to implementation. By reclaiming land in these areas, environmentally important intertidal habitats are lost, and knock-on impacts such as alterations to ebb/flood dominance may also occur. As a result, environmental opposition to land claim may mount. In the EU, compensation for lost habitats is required

Relevant case studies and examples

Further Readings

Wang et al (2014): Development and management of land reclamation in China

Literature sources

Bird, E. (2005) Appendix 5: Glossary of Coastal Geomorphology in Schwartz, M.L. (ed.). Encyclopedia of Coastal Science. The Netherlands: Springer, 1155-1192.

Burgess, K., Jay, H. and Nicholls, R.J. (2007) Drivers of coastal erosion in Thorne, C.R., Evans, E.P. and Penning-Rowsell, E.C. (eds.). Future Flooding and Coastal Erosion Risks. London: Thomas Telford, 267-279.

French, P.W. (1997) Coastal and Estuarine Management. London: Routledge.

Measure category

Prevention

EXAMPLE: Lowering the floodplain in Emilia–Romagna area (IT)

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EXAMPLE: Lowering the floodplain in Emilia–Romagna area (IT) nst Fri, 01/27/2017 - 13:48

Channel, Coastal and Floodplain Works

River bank relocation – floodplain lowering

Near to the RISC-KIT Case Study in Emilia – Romagna, a LIFE+ “LIFE RINASCE” project has been implemented in 2014 to improve some of Emilia - Romagna drainage channels in the Po floodplain. Project leader is the Emilia Centrale Land Reclamation Consortium, in collaboration with the Emilia -Romagna Region. The project was started in 2014 and will run the end of 2018 with a total budget of almost 2.1 million €.

Based on the project information from LIFE+

General description

The project aim is to reduce the risk of flooding and achieve good ecological status of the waters in the Po floodplain through ecological restoration of the channel network and vegetation management. It aims at demonstrating the feasibility and environmental and socio-economic benefits of such measures on a large floodplain area.

The project plans to develop an integrated restoration programme for floodplain channels using river restoration methods and protocols for sustainable management of aquatic and riparian vegetation. Planned interventions will aim to restore hydraulic functions of the floodplain, reduce the risk of flooding and improve the ecology.

One measure among others will include the lowering of the floodplain and thereby creating an arboreal strip of plants and shrubs. Other measures include the creation of a wetland, the enlargement of a natural channel. These measures are aimed to mitigate flood risks through water retention. Other benefits will be the improvement of drainage, purification of water, and improved ecological status.

It is foreseen that seven kilometer of canals will be restored by the end of the project by the creation and/or the lowering of three hectares of floodplain areas and vegetation. Additionally two hectare wetland should be created by then.

The Participatory process

The project used a participatory process to involve local actors, stakeholders and citizens in the strategic choices regarding the transformation of the territory and to collect ideas and proposals for the design of the rehabilitation interventions. Information, communication, consultation and listening to participants played an important role for the first steps in the project. The process was split into two main plenary sessions, six discussion meetings and a follow-up meeting for the technical and regulatory aspects hosted. These meetings involved a total of 189 participants coming from associations, organizations, companies and citizens. In parallel, the participatory process was supported by a dedicated web space.

Relevant case studies and examples

Further Readings

Website of the project (in Italian)

Measure category

Prevention

EXAMPLE: Restoring Riparian Forests (BG)

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EXAMPLE: Restoring Riparian Forests (BG) nst Fri, 01/27/2017 - 11:08

Natural flood, runoff, catchment management

Ecosystem based approach

Floodplain or riparian forests can be extremely important for the prevention of floods and landslides. Floodplain forests used to be widespread in Bulgaria, but today they are only partially preserved. WWF, in partnership with local Bulgarian partners began a project for restoration and conservation of natural riparian forests of native species along the rivers Danube and Maritsa.

Based on the project description of the WWF and LIFE+

General description

Riparian forests are rich in biodiversity, naturally purifying water, and can prevent floods and landslides. During heavy rain falls, riparian forests collect the water and then slowly return some in the riverbeds, therefore slowing down the water flow. Riparian forests create unique conditions that control and influence the transfer of energy, nutrients and sediments between the aquatic and terrestrial ecosystems.

These riparian forests have experienced frequent disturbance by human impact, resulting in a continuous decrease of the habitat area. In recent decades, they have suffered from a wide range of detrimental actions including: clear fellings; transformation into arable lands or hybrid plantations for intensive production of timber; cleaning/correction of riverbeds; and infrastructure projects or activities (such as the construction of small hydropower plants and the extraction of inert materials). Such long-term adverse human impacts lead to degradation of the priority habitat and negative changes in its structure, composition, stability and functionality.

The WWF together with local Bulgarian partners (National Forestry and regional forestry directorates "Ruse" and "Plovdiv") have applied for a LIFE+ project to restore 48.1 hectares of natural riparian forests. They will plant local tree species and remove exotic species. A guide will be developed for the recovery and management of riparian forests as well as an analysis of the relationship between the targeted areas and the other Natura 2000 sites. Additionally, volunteers will actively be engage in the project and in particular highschool students, who will help with the planting of trees.

The project is co-funded by the LIFE + instrument of the European Commission and will be implemented from September 2014 to 2019 with a total budget of around 500.000€.

Key lessons learnt

Restoring riparian forests can not only mitigate flooding problems to a certain extent, it also provides additional ecosystem services. While this concept could be difficult to implement in coastal urban areas due to the lack of space, it can be a valuable approach in rural areas. But also in rural the aspect of sufficient space is probably the most crucial factor in implementing the measure. If this initial obstacle is solved, the reforestation is a promising ecosystem-based approach.

Relevant case studies and examples

Reafforestation in upland areas and buffer zones

Further Readings

WWF project description

LIFE+ project description

Measure category