15.10 Risk Informed Decision Making and Roadmap
259
Table 15.13 Synthesis of the results of the portfolio analysis developed in this chapter
Evaluation
criteria
Dam
1B
2 on 3
3
4
Corporately
intolerable
(qualitative
Fig. 15.9)
Yes
Barely
Almost
Widely
Corporately
intolerable
(quantitative
Fig. 15.10)
(M$/year)
0.5
<0.1
Largest tolerable
80
Negligence test
min. mitigation
(M$/year)
1
0.2
10
100
Societally
unacceptable
(Fig. 15.14)
Yes
Widely
Mitigations
Operational
(Fig. 15.11)
Reinforce toe to
be evaluated
Buttress and/or
reduce
uncertainties or
other to evaluate
Tactical
(Fig. 15.12)
Reinforce Dam
2 or toe of Dam
3, or both to
evaluate
Strategic
(Fig. 15.13)
Move
population,
lower the dam to
evaluate
unacceptable. Moreover, the operational mitigation would “kill two birds with one
stone” as it would also mitigate the scenario of Dam 2 interdependent on Dam 3.
• Third priority, Dam 2 interdependent on Dam 3. This interdependent scenario is
barely corporately intolerable and has a low negligence test. Possible mitigation
must be seen in conjunction with interdependent Dam 3.
• Fourth priority, Dam 1B. Although this dam represents a strategic risk the low
probability of failure, its societal acceptability, low negligence test value and low
intolerable risk suggest the lowest priority in the portfolio.
After residual risk evaluations, i.e., the evaluation of the entire portfolio including
the selected mitigative measures it would be necessary to repeat the roadmap exercise.