3 Planning

Planning an artificial reef includes different phases: pre?construction, construction and post? construction. The first two phases are time?limited, while the last phase will continue over the entire lifetime of the reef.

A crucial factor of success is effective cooperation between numerous maritime stakeholders, including national, regional and local government authorities, managers, planners, engineering offices, fishers (artisanal, recreational and commercial), divers and all stakeholders concerned with the coastal management of their marine estate. When all interested parties are involved and kept informed about activities connected to the construction, management and use of the artificial reef and their status, through stakeholders’ consultation and engagement, then these parties are more likely to offer guidance and assistance (see Chapter 9).
Therefore, it is important that a management plan clearly describing how the reef will be managed over its intended design life be developed by the proponent and adopted prior to the installation of the artificial reef.

This management plan should illustrate the proposal, its goal and objectives, its pre?installation planning (including stakeholders’ consultation and environmental assessment). Moreover, it should provide detailed information on the methods to be used to assess the effectiveness of the reef, the proposed mitigation measures to be implemented in the event of the reef causing a negative impact on the environment as well as the reef’s target users or non?target stakeholders.

3.1. Pre?construction phase

This phase involves all actions to be undertaken prior to the installation of an artificial reef; from the decision to construct the reef to the submission of its plan to the competent authorities.
The first step in planning an artificial reef consists in identifying the broader goal(s) for its construction (e.g. to enhance recreational fisheries or manage professional fisheries) as well as evaluating the ecosystem where the artificial reef should be deployed and how that environment will be affected by the immersion of new substrates, not only during the immediate installation process but also over the reef’s intended design life, which is likely to be around 30 years or more. Many questions relating to the “effect” of the artificial reef after its installation can be addressed thanks to the effective use of pre?installation environmental assessments which investigate the anticipated impacts (both positive and negative) of the installation of the reef and propose mitigation strategies for its ecological, physical and socio?economic impacts. These assessments can be used to formulate effective management plans for the reef’s post?installation operation in the longer term.
Therefore, the questions to be asked and answered before making any commitment in terms of planning and development are the following:
a) Is the concept of the reef realistic? This question is aimed at evaluating if the construction of an artificial reef is valid and feasible in a particular area.
b) How will the new reef and the natural ecosystem interact? It is essential that the influence of an artificial reef upon the seafloor is understood before its construction, in terms of how the natural habitat may be modified and how ecological processes may be affected by the new substrates. This is particularly important for the long?term operation of the reef. Concurrently, it is necessary to evaluate the local, social and economic situation and to involve potential users of the artificial reef in order to consider their opinions on the project.
Once the above questions have been addressed, more specific objectives should be defined (e.g. increasing the income of the local fisheries up to a certain level).
When the broader goals and specific objectives of the artificial reef have been defined, it is necessary to calculate the investments as well as expected ecological and socio?economic returns. With clearly defined goals and objectives, it will be then possible to verify the performance of the artificial reef over time.
c) What are the potential alternatives to reefs construction which may produce similar environmental, social and economic outcomes? What would be the likely situation if the reef were not built (e.g. continued degradation of natural habitats due to illegal fishing activities)? Answering this question also helps evaluate whether the choice of constructing an artificial reef is actually more effective than other solutions.
Once the specific objectives have been established and a preliminary cost analysis has been performed, the reef site can definitively be identified and the artificial reef designed.
In selecting the reef’s site, it is important to take into account: the physical features of the proposed site (water depth, sediment grain size and sediment cover, mean and extreme current, wave size and direction, etc.); the life history of the target species (i.e. distribution, reproduction, feeding, etc.), and the specific location of the site for the purposes of the reef (e.g. if an artificial reef is constructed to enhance local small?scale fisheries it should be located to provide cost?effective access from nearby mooring sites).
In addition, the choice of materials must comply with international and national legislations to avoid dumping and pollution in the marine environment. Moreover, the artificial reef should be designed by experts in the field, based on ecological and technical specifications relating to its purposes and setting. The structural integrity of the reef’s units and of the subsequent groups to be created should be given equal weighting to anticipate their ecological effectiveness, as a reef that is unstable will ultimately fail to meet its ecological objectives.
Finally, the operational long?term management plan has to be submitted to the competent national and/or local authorities which are responsible for the maintenance and monitoring of the artificial reef in order to obtain their authorization.

3.2. Construction phase

This phase comprises all activities related to the construction of the artificial reefs’ structures and their deployment at sea.
In general, attention should be paid in identifying the construction area and granting access to a suitable marine staging and load?out site where the reef material can be stored, moved and loaded onto the deployment infrastructure. This area should have easy access from both land and water to facilitate the transportation of the reef materials.
A safety perimeter should be established and signalled by buoys around the deployment site to avoid risks to leisure boats, divers, etc. during construction. The activity of transporting the reef material from the staging area to the deployment site may restrict manoeuvrability and thus represent a potential hazard to navigation. Consequently, it is prudent to notify the relevant marine authorities having jurisdictional authority over the reef installation site of the proposed operational timetable.
One of the main problems in the deployment of artificial reefs is to precisely place the structures in the pre?planned locations. It is therefore suggested to identify each site using a differential global positioning system (DGPS) and mark it with temporary marker buoys.
Once the deployment operations have been completed, the correct position and orientation of the reef structures (including minimum safe navigation depths on the lowest astrological tide [LAT]) should be verified through direct observation by scuba divers, surface deployed remote cameras or indirect surveys with side scan sonar or multibeam echosounder (MBES). The final location of the reef units (including the boundary of the reef complex) and the safe navigational depths (LAT) should be provided to national and regional hydrographers authorities so that they can be included in navigational map updates (e.g. notice to mariners).

3.3. Post?construction phase

After the artificial reef construction, the next question to be answered is: how can the reef be managed and used in a sustainable way? This question is aimed at identifying management options to optimize the reef’s benefits to all users and reduce conflicts among them. This aspect may not be particularly relevant when an artificial reef is constructed by private entities that have the ownership of the reef site. However, it is fundamental in the case of artificial reefs sponsored by national, regional or local authorities for the local communities (see Chapter 11).
Another important step is to determine the effectiveness of the artificial reef. A scientifically valid monitoring programme must be developed and “success criteria” established. Monitoring will enable the project sponsors to gain evidence concerning the ecological and socio?economic performance of the reef in relation to the expected objectives (see Chapter 9).