for high-profile reservoirs in a number of countries. Examples of inunda-
tion mapping experience in the UK, where circumstances are such that
quite modest dams may represent a significant potentialhazard by virtue
of their location relative to centres of population, are described by
Tarrant, Hopkins and Bartlett (1994) and Claydon, Walker and Bulmer
(1994).
7.5.3 Contingency and emergency planning
The logical corollary to inundation mapping for reservoirs in high-hazard
locations, e.g. sited in close proximity to sizeable communities, schools,
major industrial units etc., is the preparation of a contingency or emer-
gency response plan. Two principal elements are required within the
overall plan:
- the organisational action plan, for implementation by the owner
and/or operator of the dam in the event of a major emergency;
- the response plan, prepared in consultation with the civil authorities,
for action in conjunction with the emergency services.
The organizational or internal action plan is designed to document operat-
ing procedures etc., appropriate to all foreseeable emergency scenarios for
the site under review. For dams in vulnerable locations it may be appropri-
ate to give consideration to identifiable ‘external’ threats to safety such as
accidental aircraft collision, or the action of subversive organizations, in
generating project-specific ‘Standard Response Procedures’ (Moffat,
1998).
Operating staff at all levels must be made familiar with the response
plan, which should be subject to periodic reappraisal. The scope of the
plan should range from defining levels of incident and internal responsibil-
ities to procedures for alerting the emergency services, civil authorities
and the population at risk. The plan should state the appropriate on-site
response to likely incidents, e.g. the activation of bottom outlets etc., and
should provide documented instruction and guidance for staff in key posi-
tions.
The second element, the emergency response plan, must be prepared
in close collaboration with the appropriate civil authorities including, in
the UK, the county Emergency Planning Officer. The response plan
should embrace the ‘worst case’ scenario, i.e. rapid and catastrophic
breaching of the dam. The content of the plan is determined by, inter alia,
the inundation map, the nature of the flood plain, and the numbers, loca-
tions and accessibility of persons under threat. The response plan is
314 DAM SAFETY: INSTRUMENTATION AND SURVEILLANCE
