Environmental Engineering Reference
In-Depth Information
its own challenges, notably where this entails
intertidal working. Finally, having completed the
works, there is invariably a need to monitor how
the site performs and to evaluate how well the
scheme objectives have been met. As part of
the monitoring process it is important that the
findings are communicated widely. The process of
collating and disseminating the lessons learned
also helps to improve the process of implementing
future schemes. In this chapter, the main steps
involved in promoting a managed realignment
scheme and taking it to completion through
these stages are reviewed under the following
subheadings:
.
Setting scheme objectives
.
Selecting a site for realignment
.
Designing the scheme (including identifying
design constraints, characterizing the existing site
conditions and developing the design layout)
.
Obtaining planning approval and consents
.
Undertaking the construction work
.
Monitoring and evaluating scheme performance
It is hoped that this stepwise review of the
relevant issues at each key step in the lifetime of
such projects will, alongside the supporting liter-
ature, provide a useful and practical guide that
will help coastal managers to implement such
schemes more effectively, and perhaps, more im-
portantly, to improve the quality, quantity and,
where possible, the size of such schemes in order
to maximize the benefits for the environment, the
economy and society.
been significantly enhanced in recent years. This
has come froma combination of research into the
performance of completed schemes and new un-
derstandings about the valuation of ecosystems.
In the past, for instance, there was confusion
about which elements within an ecosystem to
value and how to cost for these, but this impasse
has been unlocked by recent assessment and
guidance documents, such as the UN Millenni-
um Ecosystem Assessment (MEW) reports and
the UK government's guide to valuing ecosystem
services (Defra 2007). The guidance sets out a
method to describe what an ecosystem does for
the 'human community' by recognizing that the
biological diversity contributes to 'wellbeing' but
framed in economic terminology (Watts and Kre-
mezi 2008). Therefore, whereas in the past the
economic value of managed realignments was
dictated by the flood defence costs, it is now
possible to quantify the wider economic gains
from habitat creation. Case example valuations
have been made using the research findings from
completed realignments such as Abbotts Hall on
the Blackwater Estuary (Salcott Creek) and both
Paull Holme Strays and Alkborough on the Hum-
ber Estuary (Kremezi 2007) and for the recently
consented (July 2009) Wallasea IslandWild Coast
Project on the Roach Estuary (Eftec 2008). These
studies considered the socioeconomic benefits
from fisheries, carbon storage, nutrient proces-
sing, pollutant sequestration and job creation to
indicate that managed realignment schemes can
be justified by the economic gains that they pro-
vide alongside their flood and coastal defence
benefits.
Whatever the objectives when developing a
scheme, what has become very clear is that these
need to be identified at the outset. This then
greatly facilitates the processes of site selection
and designing suitable site layouts and, crucially,
the consultation process. As with any develop-
ment, there are a number of requirements that
need to be met to promote the scheme through
the planning system and so obtain the necessary
consents and licences. Once obtained, construc-
tion can commence and this involves working in
or next to the marine environment, which brings
Setting Scheme Objectives
Of paramount importance in habitat creation or
restoration schemes is the setting of clear aims and
objectives that define what the scheme is princi-
pally trying to achieve. The schemes that have
been successfully promoted and consulted upon
have usually benefited from having this clarity of
purpose and, ideally, from a reliance on simple,
consistent and non-technical messages. These pri-
mary objectives might encompass the basic ratio-
nale and more specific delivery needs. Previous
schemes have been undertaken for various reasons
