Renewables-to-reefs? - Decommissioning options for the offshore wind power industry.

The offshore wind power industry is relatively new but increasing globally, hence it is important that the whole life-cycle is managed. The construction-operation-decommissioning cycle is likely to take 20-30 years and whilst decommissioning may not be undertaken for many years, its management needs to be addressed in both current and future marine management regimes. This can be defined within a Drivers-Activities-Pressures-State Changes-Impacts (on human Welfare)-Responses framework. This paper considers the main decommissioning options - partial or complete removal of all components. A SWOT analysis shows environmental and economic benefits in partial as opposed to complete removal, especially if habitat created on the structures has conservation or commercial value. Benefits (and repercussions) are defined in terms of losses and gains of ecosystem services and societal benefits. The legal precedents and repercussions of both options are considered in terms of the 10-tenets of sustainable marine management. Finally a 'renewables-to-reefs' programme is proposed.

Can the benefits of physical seabed restoration justify the costs? An assessment of a disused aggregate extraction site off the Thames Estuary, UK.

Physical and biological seabed impacts can persist long after the cessation of marine aggregate dredging. Whilst small-scale experimental studies have shown that it may be possible to mitigate such impacts, it is unclear whether the costs of restoration are justified on an industrial scale. Here we explore this question using a case study off the Thames Estuary, UK. By understanding the nature and scale of persistent impacts, we identify possible techniques to restore the physical properties of the seabed, and the costs and the likelihood of success. An analysis of the ecosystem services and goods/benefits produced by the site is used to determine whether intervention is justified. Whilst a comparison of costs and benefits at this site suggests restoration would not be warranted, the analysis is site-specific. We emphasise the need to better define what is, and is not, an acceptable seabed condition post-dredging.

Management of the marine environment: integrating ecosystem services and societal benefits with the DPSIR framework in a systems approach.

Ever increasing and diverse use of the marine environment is leading to human-induced changes in marine life, habitats and landscapes, making necessary the development of marine policy that considers all members of the user community and addresses current, multiple, interacting uses. Taking a systems approach incorporating an understanding of The Ecosystem Approach, we integrate the DPSIR framework with ecosystem services and societal benefits, and the focus this gives allows us to create a specific framework for supporting decision making in the marine environment. Based on a linking of these three concepts, we present a set of basic postulates for the management of the marine environment and emphasise that these postulates should hold for marine management to be achieved. We illustrate these concepts using two case studies: the management of marine aggregates extraction in UK waters and the management of marine biodiversity at Flamborough Head, UK.

An application of contingent valuation and decision tree analysis to water quality improvements.

This paper applies contingent valuation and decision tree analysis to investigate public preferences for water quality improvements, and in particular reduced eutrophication. Such preferences are important given that the development of EU water quality legislation is imposing significant costs on European economies. Results are reported of a survey undertaken of residents of Arhus County, Denmark for water quality improvements in the Randers Fjord. Results demonstrate strong public support for reduced eutrophication and identify key determinants of such support.

An initial economic evaluation of water quality improvements in the Randers Fjord, Denmark.

Eutrophication of estuarine and coastal waters has only been recognised as a potential problem since the early 1980s. This problem is being addressed by the European Union through the implementation of recent water quality legislation, which also calls for an economic analysis relating to its implementation. This paper examines the benefits and costs of reduced eutrophication of the Randers Fjord in Denmark, with a primary focus on assessing individual preferences for water quality improvements, using a contingent valuation survey approach. Initial findings of the survey are presented that offer support for funding an action plan to improve the ecological status of the Randers Fjord, as required by the Water Framework Directive. The paper highlights the considerable costs required to abate nutrient emissions into the Fjord, but identifies a need for greater cost evidence at the catchment level.