Chapter 6
Avoiding Hazard
The plan should be read as a whole.
The general planning policies in Chapter 2
will be applied to all planning applications,
in addition to those in other relevant sections.
Avoiding Hazard
Avoiding Hazard
Our Strategic Approach
6.1
There are two types of hazard which are relevant to land use planning. These are:
 Natural hazards which may threaten existing or proposed development e.g.
flooding
 Man-made hazards e.g. mining, leading to land stability problems, previous
development which has resulted in contamination, or new developments which
cause pollution or noise nuisance etc.
6.2
The planning system must consider how these hazards may affect the current and
future uses of land. Often detailed advice and guidance must be sought from other
statutory bodies such as the Environment Agency or the Health and Safety Executive.
The role of the planning system is to take these natural and man-made hazards fully
into account in considering the location and design of new development, so that the
need for any future mitigatory measures can be avoided and any risks to existing
development, the community or the environment can be minimised.
6.3
In some cases the nature of risk from a hazard is unknown or poorly understood. In
such cases the precautionary principle, one of the key principles of sustainable
development, will be applied. This works on the basis that where there are significant
risks of damage to the environment, the local planning authority should seek to limit
risks, even where scientific knowledge is not conclusive, if the balance of costs and
benefits justifies it.
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Avoiding Hazard
Avoiding Hazard
Our Detailed Policies
Unstable Land
6.4
There is no register of unstable land in the Park and the NPA has does not have the
statutory responsibility to produce such a register. However there are areas where land
stability is likely to be an issue. The responsibility lies with the developer to ensure and
effectively prove that the proposed development will not be affected by instability or
trigger ground movements off-site. Where unstable land is suspected, the NPA will
require applications to be accompanied by a stability report prepared by a geo-technical
specialist, describing and analysing the issues relevant to ground instability and
indicating how they would be overcome. Such a report would be required to
demonstrate:
 whether the land is capable of supporting the loads imposed over the expected
lifetime of the development; and
 whether the development would threaten the continuing stability of the site and its
surrounds through the processes of excavation, changing drainage or groundwater
regimes, changes in land use etc.
Policy H1: Development on Unstable Land
Proposals for development on potentially unstable land will only be permitted where it
can be demonstrated that the site is stable or could be made stable and that
development is unlikely to trigger any form of instability within or beyond the
boundaries of the site. The applicant will be required to provide a stability report,
undertaken by a suitably qualified person and agreed with the NPA, on how the factors
relevant to ground instability would be overcome.
Development on Land Liable to Flooding
6.5
It is important to ensure that new development is safe and not exposed unnecessarily
to flooding. Development may also impair the effectiveness of the floodplain in
conveying and storing water, causing an increased risk of flooding elsewhere. Flood
plains should therefore be allowed to continue to function for their natural purposes and
be protected from inappropriate development.
The Welsh Assembly Government
advice note TAN15 ‘Development and Flood Risk’ provides advice as to the areas and
zones where development could be considered and where it should be resisted. TAN15
is supported by development advice maps showing the flood risk zones as follows:
- Zone C2 – areas of the floodplain without significant flood defence infrastructure;
- Zone C1 – areas of the floodplain that are developed and served by significant
infrastructure including flood defences;
- Zone B – areas known to have flooded in the past evidenced by sedimentary
deposits;
- Zone A considered to be at little or no risk of fluvial or tidal/coastal flooding.
6.6
Further detailed guidance on considering risks from flooding can be found in TAN15.
The terms used in Policy H2 below find detailed expression in TAN15. The
Environment Agency will be a key consultee in the NPA’s application of this policy.
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Avoiding Hazard
Policy H2: Development and the Risk of Flooding
Development, including the raising of land, will not be permitted where that
development would:
ia)
be on land at high risk of flooding
i)
result in an unacceptable risk of flooding either on or off site;
ii)
adversely affect flood management or maintenance schemes;
iii)
impede flood flows or result in changes in flow regime; or
iv)
result in a net loss of flood-plain storage.
Where, exceptionally, development is allowed on land at high risk of flooding, such
exceptional circumstances will be justified where it can be demonstrated that:
It needs to be located in a high risk area, or be part of a local strategy
sustaining the settlement; or

It is necessary to contribute to key employment objectives;

The proposal is on previously developed land; and

The potential consequences of flooding have been considered and found to
be acceptable.
and,
Highly vulnerable development will not be permitted on land at high risk of flooding
where that land is without significant flood risk infrastructure.
Reducing the Risk of Flooding
6.7
Attempts should be made in all development proposals to reduce to a minimum the rate
of run-off caused by new development. The NPA will encourage the development and
use of sustainable drainage systems and of rainwater recycling in general. Sustainable
drainage systems use techniques to control surface water run-off as close to its origin
as possible, before it enters a watercourse. Such systems include filter strips and
swales, filter drains and permeable and porous pavements, infiltration devices and
basins and ponds.
Policy H3: Reducing the Risk of Flooding
Development will only be permitted where:(i)
it can be demonstrated that there is no increased risk of flooding locally or
elsewhere due to additional surface run-off or changes in flow regime; or
(ii) where adequate mitigation works which are necessary to achieve such aims can
be provided.
Notifiable Installations
6.8
Under health and safety legislation, certain sites and pipelines are designated as
"notifiable installations" by virtue of the quantities and type of hazardous substances
stored or used. Consultation with the Health and Safety Executive, and other relevant
organisations such as the Environment Agency, is required if further installations are
proposed. The Executive has defined consultation zones around such installations,
mostly gas pipelines, and requires to be consulted if development is proposed within
them. It may be necessary to refuse permission for residential and some other types of
development within these zones.
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Avoiding Hazard
Policy H4: Notifiable Installations
Development proposals for notifiable installations or proposals affecting notifiable
sites will not be permitted unless the NPA is satisfied that there is no risk to public
health and safety, following consultation with the Health and Safety Executive and
other relevant bodies.
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