PPS 15: Planning and Flood Risk
Annex B: Health Implications of Flooding

B4 Insurers have, for some time, been concerned about the potential frequency and cost of environmental risks, including flooding. Recent floods, particularly since 2000, have caused insurers to review the provision of flood cover to UK property owners. Insurers have stated that it is their intention to continue to provide flood cover to as many property owners and occupiers as possible. However they have also pointed out that new development in areas at risk of flooding which lack the appropriate standard of protection will face difficulties with the cost and/or availability of insurance. This is confirmed in the Association of British Insurers (ABI) statement of principles on the provision of flood insurance issued in November 2005¹⁵. In the opinion of ABI and the Council of Mortgage Lenders developing in areas at risk from flooding could thus create difficulties in the mortgaging of new development which could make it impracticable. This in turn could undermine the basis of regeneration or other development strategies. Developers will therefore wish to consider the availability of insurance for subsequent purchasers or tenants at the earliest stage of the site evaluation process. For its own part, the insurance industry may wish to make appropriate representations about proposals for the location of new development during the preparations of development plans.

B5 Many of the adverse consequences associated with flooding derive primarily from its physical impacts on buildings and the environment. The scale of damage to buildings is often dependent on the depth and duration of the flood event, while the primary significant environmental effects generally relate to water quality and polluted floodwaters. Table 2 (overleaf) illustrates flood damage to a typical residential property.

B6 Traditionally, the threat of flooding in Northern Ireland has been met by the construction of hard-engineered defences and drainage schemes to protect land and development in areas exposed to frequent or extensive flooding. However, this sort of protectionist approach to flood risk is expensive in terms of construction and long-term maintenance costs, and while it can reduce the risk of flooding it cannot eliminate it. Flood banks or walls will be overtopped when a flood event is of greater severity than the defence was designed for. In addition flood risk may increase over time where the changing frequency or severity of weather events effectively acts to erode the standard of protection that defences were originally designed to provide for.

B7 Hard-engineering solutions can create a cycle of vulnerability when the construction of a defence encourages further development that in turn leads to the need for further protection. Higher flood defences will lead to increased maintenance costs and may also result in more damaging floods when defences are breached by a severe weather event.

B8 To continue the construction of new hard-engineered flood defences required as a consequence of the development on land with a propensity to flood is inconsistent with a commitment to sustainable development and the adoption of a precautionary approach to flood risk.