Raising and advancing coastal land

Stakeholder participation is especially required if raising or advancing coastal land is part of larger coastal plans. Such plans that include defence structures might be the subject of Environmental Impact Assessment, depending on national laws and regulation. When this measure is implemented in protected sites such as Natura 2000 sites (under the EU Birds and Habitat Directives), claiming new natural land, an “appropriate assessment” that necessarily involve stakeholders in a structured public participation process, is usually required. Similarly, the EU Floods Directive calls for public participation processes for risk management plans. Moreover, proposals to raise urban land will most likely require public consultation under national and local laws. 

Conflicts can arise between stakeholders that can directly or indirectly benefit from coastal raising or advance. Tourism stakeholders and port authorities can benefit from beach extension and construction of new harbour areas respectively. Conversely, local communities can be worried about modification of the coastal landscape, habitat and biodiversity loss and environmental impacts in general. Such conflicts call for an active involvement of all interested actors, including local authorities, coastal communities, private companies, research institutions and/or NGOs. 

Like other grey measures for coastal defence, raising and advancing coastal land can provide predictable levels of safety. If the entire land area is raised above the highest projected sea level, only low residual risks still exist. Moreover, compared to other hard protection measures (such as seawalls and storm surge barriers), there is no risk of catastrophic failure. With projected increases in coastal zone populations, gaining new land can be a leverage for the advance or raising of coastal areas, providing new opportunities of coastal development.  

As other grey options, raising and advancing coastal land is poorly flexible and requires periodical maintenance or upgrade to ensure adequate protection level in the face of climate change and progressive sea level rise. Raising coastal land can be technically challenging, especially in urban and industrial areas hosting complex or highly vulnerable infrastructures. This is also the case for fragile historical areas, such as St. Mark’s Square and the whole city of Venice. In these cases, raising land is possible only till a certain level and technical constrains of different nature (e.g. the preservation of the artistic value of historical buildings) can prevail. 

Advancing coastal land can alter coastal ecosystems. It can also require other seaward physical preventive measures against flooding, with associated construction and maintenance costs, and impacts (e.g. alteration of coastal solid transport). This option is especially suited for small-scale interventions (e.g. to reduce the vulnerability of small ports or urban areas or of specific equipment to be put on safer areas). Raising or advancing large coastal areas can require disproportionate costs, be technically challenging and cause several environmental impacts. 

The main benefit associated to this option is the reduction of flooding, especially for areas or infrastructures affected by sea level rise and increasing frequency of storm surge events. It ensures full protection of the area at predictable safety levels without risks of failure sometimes associated to other grey protection measures. By creating new usable land, raising or advancing coastal areas can help preserving key economic activities (e.g. safe port areas), expanding land usability by citizens (elevation of urban pavements) and enhancing tourism and recreational activities (beach extension). 

The costs greatly depend on the specific location, the adaptation needs and the extension of the areas to be raised. Cost can also include the requirement for hard protection measures to defend reclaimed land from coastal flooding and erosion. Cost assessments should properly include both the construction phase and maintenance cost. The latter can progressively increase considering the increasing pressure from sea level rise and storminess. Synergies with other defence works already in place should be maximised to reduce the costs associated to this adaptation option, extend its effectiveness and increase the overall resilience of coastal areas. Synergies can also be created with dredging interventions: raising or advancing land can offer an opportunity for material disposal from ports, harbours and navigation channels (after proper assessment of contamination level). This could reduce the overall cost and eliminate the need to identify offshore disposal sites for dredged material. 

The construction of coastal works to mitigate erosion and hard sea defences ‘capable of altering the coast’ fall into Annex II of the Environmental Impact Directive (EIA): 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. 

Under the EU Habitats Directive, an appropriate assessment will be needed if works to raise or advance coastal land affect protected species or natural habitats.

Implementation time is highly variable, depending on the scale of the intervention. Small-scale interventions involving limited areas can require limited time (< 1 year), while large-scale interventions, raising wide coastal areas, as part of broader intervention plans, can require much more time. Technical constrains related to the complexity, fragility and value of the urban system (and buildings) usually increase the implementation time. 

A medium life time is expected for this option (more than 15 years). However, periodical maintenance and efficacy re-assessment must be ensured, especially to progressively adapt to the sea–level rise and the possible intensification of storms and storm surges.