THE PRECAUTIONARY PRINCIPLE AND THE
17. To manage these risks the draft PPG proposes
the use of the precautionary principle. This means erring on the
side of caution when deciding whether development, or what kinds
of development, should be permitted in areas at risk of flooding.
The emphasis of policy is to move away from flood defence and
the mitigation of the consequences of new development in flood
plains, towards a more emphatic avoidance of development in areas
at risk of flooding. However, the draft PPG does not go far enough
in this direction, and still gives the impression that flood plain
development is acceptable with suitable flood defences in place.
The scope for developers to build in areas at risk of flooding
provided certain conditions are met (e.g. it is 'safe' for the
occupants and will not cause adverse effects elsewhere)
should be curtailed. This is especially important on greenfield
sites where wholly new implications for flood waters arise.
18. The Environment Agency proposed ensuring that
development on the flood plain is a last resort by introducing
a "sequential search sequence for sites......preference going
to sites with no flood risk followed by those sites with low risk."
This approach has now been accepted by the Government. The Minister
"we want to ensure that
in cases of all new developments no development takes place that
puts people at risk and that is where the sequential approach
that I have suggested is absolutely fundamental to ensure that
we are always looking for the sites that provide the safest option".
"Our aim would be to
ensure that all developments that take place, either by the nature
of the site or by the defensive measures that are taken to protect
that site and that those should provide a more than adequate safeguard
against risks that can be reasonably foreseen".
The DETR memorandum stated that the PPG might:
"encourage the avoidance
of all but essential (water-related, utility and transport) development
in the functional flood plains deliberately used to hold excess
water in times of flood, unless there are wholly exceptional reasons".
19. To work effectively, a sequential approach will
require the Government to provide enough detail on the thresholds
between one step and the next. Advice must clarify what the normal
rules are, and where they will not apply. For instance, the Minister
suggested that while there should be a presumption against development
on the functional flood plain, there should be an exception for
boathouses. It will also be necessary to define concepts such
as the functional flood plain.
20. We welcome the proposed introduction of the
sequential approach as a progression from the precautionary approach.
We also strongly support the Minister's proposal that building
on the functional flood plain should be avoided. The final PPG
25 should indicate clearly the thresholds which will determine
the choice of one or another planning response. These should include
-No facilities for emergency
services should be permitted in the flood plain of even the most
extreme (1000 year) flood.
-Only very exceptional development should be allowed
in the functional flood plain.
-The Government should investigate whether the
functional flood plain should be defined as the one hundred year
flood or the two hundred year flood, which is used in coastal
regions and which might be more appropriate in view of climate
21. As well as boathouses, small extensions to existing
buildings might be another example of a suitable exceptional development.
The draft PPG suggests sports-related developments might be acceptable,
but, in view of the number of buildings and car-parking often
associated with them, they are probably not appropriate where
they would reduce flood water storage capacity. In a very few
areas where all the land forms part of the flood plain (the Environment
Agency suggested parts of East Anglia)
a sequential approach would necessarily indicate that the flood
plain was the only area where development could take place.