CS3: Environmental Risk Management

CS3: Environmental Risk Management

Development that, on its own or cumulatively, would result in air, water or other environmental pollution or harm to amenity, health or safety will only be permitted if the potential adverse effects could be mitigated to an acceptable level by other control regimes, or by measures included in the proposals, by the imposition of planning conditions or through a planning obligation.

Development in zones 2 and 3 of the Environment Agency Flood Map will only be permitted where the PPS25 Sequential Test and, where applicable, the Exception Test are passed, unless it is:

  • development of a category for which PPS25 or its Practice Guide makes specific alternative provision; or
  • development of the same or a similar character and scale as that for which the site is allocated in this or another Local Development Document, subject to demonstrating that it will be safe from flooding, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall.

For the purposes of the Sequential Test:

1.The area of search for alternative sites will be North Somerset unless:

  • It can be demonstrated with evidence that there is a specific need within a specific area.
  • The site is located at Weston-super-Mare, either within the settlement boundary of the town or within the urban extension.  In these cases, the area of search will be the combined area of the settlement and the urban extension.
  • The site is located within the settlement boundaries of Clevedon, Nailsea or Portishead.  In these cases, the area of search will be limited to the town within which the site is located.

Other Local Development Documents may define more specific requirements.

2. A site is considered to be 'reasonably available' if all of the following criteria are met:

  • The site is within the agreed area of search.
  • The site can accommodate the requirements of the proposed development.
  • The site is either:

a)  owned by the applicant;

b)  for sale at a fair market value; or

c)  is council-owned land and could be purchased subject to negotiation.

Sites are excluded where they have a valid planning permission for development of a similar character and scale and which is likely to be implemented.

This policy contributes towards achieving the objectives of Planning Policy Statement 25: Development and Flood Risk and Planning Policy Guidance 24: Planning and Noise.


The Core Strategy seeks to raise the quality of development in North Somerset. It therefore sets out aspirations for the environmental standards to be met, including those relating to flood risk management and environmental protection. This will become increasingly important in response to climate change and the level of development proposed throughout the district.

The Core Strategy approach

The first part of the policy applies where any of the following problems exists or a risk of it occurring is identified, whether or not it arises as a consequence of a development proposal:

a) Coastal / riverbank erosion;

b) Contamination (including risk from migrating contaminants);

c) Electromagnetic fields;

d) Explosion;

e) Fire;

f) Flooding;

g) Ground instability;

h) Harmful emissions (including dust and wind-blown litter);

i) Heat;

j) Interference with radio transmission;

k) Light;

l) Noise;

m) Radiation;

n) Smell;

o) Vibration;

p) Visual distraction from moving machinery (including shadow flicker from wind turbines).

The policy approach is precautionary and the aim will always be to resolve issues constructively through agreed proposals for mitigation or compensation wherever appropriate. However, there will be circumstances where this is not possible and the adverse effects predicted, even allowing for all practical mitigation measures, are such as to justify refusal. Developers can assist a speedy decision by early discussion of likely requirements for supporting technical information and by ensuring that all relevant documentation accompanies the planning application.

Water Pollution

The main sources of water pollution include industrial processes, disturbance of contaminated land, run-off from roads and other impermeable surfaces, agricultural activity and foul sewage discharge to watercourses and to ground. In certain circumstances, development can increase the risk of foul sewage discharge into open watercourses.

The disposal of surface water run-off from development both during construction and after completion requires careful consideration in order to minimise harm to the environment. Development that, in the opinion of the council after consultation with the Environment Agency, poses an unacceptable risk of pollution of or damage to the water environment either directly or via the surface water sewerage system, or which does not dispose of surface water run-off in an acceptable manner, will only be permitted if these concerns can be overcome.

Sustainable drainage systems (SuDS) are the preferred approach to dealing with surface water run-off. Planning for major developments should explore possibilities for SuDS, especially as part of multi-functional green infrastructure.

Light Pollution

While light pollution is outside the scope of any legislation enforced by the council, planning policies must ensure that artificial lighting does not result in unacceptable intrusion.


PPG24: Planning and Noise indicates that the impact of noise can be a material consideration in the determination of planning applications and that the planning system has the task of guiding development to the most appropriate locations. Noise-sensitive development is categorised as housing, hospitals and schools (PPG24, para. 6). The council considers that other uses such as libraries and some other community facilities may also be sensitive to an unacceptable degree of noise disturbance. In applying this policy the council will have regard to the scale, nature and type of existing land uses in the surrounding area.

Proposals for noise-sensitive development that would be exposed to an existing noise source will be determined by reference to expected as well as current noise levels, e.g. if plant or roads are currently not operating at full capacity, their likely noise generation at full capacity will be taken into account. Additionally, permission will not be granted on unsubstantiated grounds that excessive noise is likely to be reduced at some indeterminate future date.

Flood Risk

Because much of North Somerset is low-lying, flood risk is a very important matter. PPS25: Development and Flood Risk provides the national framework for planning policy towards flood risk.

PPS25 identifies four flood zone categories with the risk of flooding associated with each flood zone set out at table D.1 of PPS25. These flood zones refer to the natural probability of sea and river flooding only, ignoring the presence of flood defences. If development were considered to be inappropriate for the flood zone within which the site is located then permission would normally be refused.

New development will need to be mindful of the increased risks of flooding as a result of climate change. The North Somerset Strategic Flood Risk Assessment (SFRA) (Level 1) maps 'climate change additional extents' shows how zone 3 will expand up to 2108. For long-term planning purposes, these areas - and any intervening zone 2 areas - will be treated as the equivalent of flood zone 3a unless there is evidence to the contrary. For development control purposes, the EA Flood Map extents will continue to apply, with the technical breakdown of the current zone 3 into 3a and 3b provided by the SFRA.

PPS25 categorises different types of development according to their vulnerability to the effects of flooding events. The vulnerability of a proposal can be established by referring to table D.2 of PPS25.

The principal way to manage flood risk is to avoid locating development within areas of flood risk. To encourage new development to avoid these areas, the Sequential Test and the Exception Test are used.

The Sequential Test is a tool to direct new development first to sites at the lowest probability of flooding (flood zone 1). Most development proposals within flood risk areas (flood zones 2, 3a and 3b) must have gone through a Sequential Test process. The circumstances where this rule does not apply are listed in the council's Advice Note, Development and Flood Risk Issues, based upon PPS25 and its Practice Guide.

If the Sequential Test is passed, an Exception Test is required for some vulnerable types of development which should not normally be allowed in flood zones 2 and 3 unless there are exceptional circumstances (see table D.3 of PPS25).

Flood risk assessments (FRA) are used to reduce flood risk at the site level. Planning applications for development proposals of one hectare or greater in flood zone 1 and all proposals for new development located in flood zones 2 and 3 should be accompanied by a FRA. The council must be satisfied that development proposals within flood risk areas incorporate appropriate mitigation measures which are themselves environmentally acceptable, e.g. Sustainable Drainage Systems (SuDS). The council will consult with the Environment Agency and Internal Drainage Boards as appropriate. Developers should have regard to PPS25, its accompanying Practice Guide and the Environment Agency's Policy and Practice for the Protection of Flood Plains.

How and where the policy will be delivered

The protection of new and existing residents from potential harmful environmental effects will be applied throughout the district although mitigation measures will be concentrated on areas where large scale development is anticipated.

The council will liaise closely with agencies such as the Environment Agency to ensure that the potential environmental effects of or on development are appropriately assessed and the necessary mitigation measures secured

The council will liaise closely with environmental protection agencies as well as using its own resources and staff.

Alternative options and contingency planning

The options considered were:

To have no policy on these matters. This was rejected because it would limit the ability to control matters affecting amenity, health and safety.

To continue to rely on the Replacement Local Plan until a Development Control Policies Development Plan Document is produced. This was rejected because it would divide policies on environmental risk management between the Core Strategy and the Local Plan (or its successor DPDs). The overall approach will be more readily grasped if this material is available in one place.

To have specific policies for sub-areas of North Somerset. This was rejected because any geographically distinct issues arise from the application of the policy rather than from its wording.

Monitoring and review

Monitoring will assess the number of planning applications approved against the advice of environmental protection agencies.