Environmental Engineering Reference
In-Depth Information
15
Towards the Next Generation of
Risk-Based Asset Management Tools
PAUL B. SAYERS, MIKE J. WALLIS, JONATHAN D. SIMM,
GREG BAXTER AND TONY ANDRYSZEWSKI
Introduction
.
System-based: Recognizing that the protection
afforded to a given person, property or other valued
feature in the floodplain (i.e. receptor) reflects the
performance of the asset system as a whole and
how it responds under a wide range of loads (and
not the performance of an individual asset during a
single design storm).
.
Evidence-based: Recognizing the need for trans-
parent and auditable/challengeable evidence,
whilst formally acknowledging that much of this
evidence is uncertain.
.
Hierarchical: Allowing for progressive refine-
ment of the data and analysis to reflect the de-
mands of the decision at hand (being just sufficient
to ensure a robust choice and one that further
refinement would not alter).
.
Wide ranging: Enabling fixed and operational
defence assets to be seen as only one, albeit im-
portant, component of a wider flood risk manage-
ment strategy (where structural and non-
structural measures act in concert tomanage flood
risk, allowing the advantages of one action to
compensate for disadvantages of another).
This chapter explores the state of the art in
assessing the performance of individual assets and
asset systems. It provides a discussion of reliabil-
ity analysis and system-based risk analysis tools.
It also provides a forward look towards the prac-
tical application of formal optimization tools that
support the development of robust management
strategies.
Ensuring the acceptable performance of flood de-
fence assets and the asset systems they compose is
a considerable challenge. Thewide variety in asset
types (from natural channels to engineered walls,
embankments, gates and pump systems) and the
interaction between them and their physical set-
ting further complicate the task. The concepts of
system analysis, reliability and structured option
searching all provide useful decision aids. These
advanced tools and techniques enable critical as-
sets and asset components to be identified and
investment options to be compared and prioritized
on a common footing (from data collection and
further analysis through to actions to repair, ren-
ovate, replace or indeed remove assets).
Over recent years the principles, methods and
tools to help support better asset management
have significantly advanced (Environment Agen-
cy 2002 & 2004, 2010; Sayers and Meadow-
croft 2005; Simm et al. 2006; USACE 1993
& 2008, HR Wallingford, 2008). All of these ap-
proaches recognize the need to prioritize limited
resources to best effect (maximizing risk reduction
and maximizing beneficial opportunities) whilst
taking account of present and futureuncertainties.
To provide meaningful evidential support the
underlying analysis must be:
