Why this could be a great place to build

The flooding disaster that followed Hurricane Katrina last year was a stark reminder of the destructive power of floodwater. Although the UK does not have the same extreme weather conditions, six years ago widespread flooding across Britain affected some 10,000 properties and cost the insurance industry £1bn in pay-outs to homeowners and businesses. Since the great floods of 1947, there has been an increased awareness and profile of flood risk and each incident of major flooding acts as another wake-up call.

Although estimates that 10% of existing homes in England are at risk of coastal or inland flooding may be rather alarmist, it is certainly a fact that many thousands of homes are at risk of flooding. Climate change may well increase the risk. The challenge is to ensure that housing growth can be achieved, particularly in the Thames Gateway, without further increasing the risk.

Under current policy, local planning authorities should consult the Environment Agency about development proposals. In practice, the Environment Agency has been criticised for its inconsistency in dealing with planning applications, different engineers making different judgments. However, the complexities of flooding issues are such that no two sites are the same so this criticism may be unfounded.

The policy framework

PPG 25, Development and Flood Risk, was issued in July 2001. Subsequent work, including the Institution of Civil Engineers' Learning to Live with Rivers and Defra's strategy consultation document Making Space for Water, have concentrated on the need for management of flood risk. Under PPG 25 and Making Space for Water, there are many opportunities for sustainable development in floodplain areas as long as an appropriate standard of flood defence is possible and, at the same time, significant improvements can be made to reduce flood risk elsewhere.

There is a risk that manmade climate change may result in an increase in flood levels. Developer-funded improvements may be the only way to mitigate such an effect. There is a strong public perception that floodplain development is bad and politicians will naturally play to this audience. But the truth is that much needed development can be appropriate in some floodplain areas. We need to address the legacies of past inappropriate development and the potential threat of climate change by putting forward robust and sustainable solutions. Such options may not always be practical or within the gift of small developments, but would be feasible for larger-scale developments.

There is a strong public perception that floodplain development is bad and politicians will naturally play to this

Regeneration

In areas of flood risk, securing adequate building insurance cover is becoming increasingly difficult. This raises the spectre of falling house prices resulting in owners having negative equity, business closures and the potential creation of ghettos in flood-risk areas. Wholesale urban regeneration could be an option, but that would require major investment or the implementation of a flood defence scheme, a faint hope for property owners. Demolition of a house and reconstruction with a raised floor level is unlikely to be economically viable without an uplift in its value to justify it. Such uplift might, however, be provided by an increase in the size of the accommodation or a change to multiple units on the same site. Environment Agency policies seem to object to any development that would increase the number of people living in the floodplain, increase the building footprint or that does not include means of access to a dry area outside of the floodplain.

Rigid application of policies often results in planning refusal and individual property owners are unlikely to have the skills or funds to go to appeal. In order to prevent progressive urban degeneration, local planning authorities need to work with the Environment Agency to seek solutions that are compatible with the overall aims of PPG 25 and Making Space for Water. These may involve, for example, providing dry access for the whole community and relaxation of certain flooding policy standards.

The Thames Gateway is London’s major growth area but, set in the Thames basin, is vulnerable to flooding. At the largest single development site – Barking Reach – houses will be built on land raised by covering contaminated land with soil. The Gateway development will take place on a “green grid”, open spaces that can be flooded to manage water flow

Emerging policy

In December 2005, the ODPM issued for consultation a draft PPS 25 - Development and Flood Risk, which will ultimately replace PPG 25. The consultation includes proposals to make the Environment Agency a statutory consultee for planning applications in flood-risk areas and allows for greater scrutiny of large developments. Where local planning authorities are minded to approve applications against sustained Environment Agency objection, a minister would have the power to intervene.

The draft builds on the guidance in PPG 25 and strives to clarify previous areas of difficulty in interpretation. PPG 25 has been interpreted as being predicated on the assumption that there is always residual risk, such that permissible land uses are taken as being based on the flood risk at the time of application rather than at the time of occupation (after some kind of defence may have been built as part of the project). However, more consideration should be given to the risks during the lifetime of the development.

Developers are challenged to design schemes that benefit local communities in a sustainable manner

Draft PPS 25 continues on a similar basis but includes a more explicit consideration of residual risks. As with PPG 25, it is likely that developers will focus on the prescriptive elements of the draft - in particular, the flood-risk zones, the flood-risk vulnerability classifications and the exception test.

Vulnerability classifications range from "essential infrastructure" (essential transport infrastructure, including mass evacuation routes, which has to cross the area at risk), at one end of the scale, through "highly", "more" and "less" vulnerable, down to "water compatible development" at the other end. Within flood zone 3a (land assessed as having a high probability of flooding), highly vulnerable land uses, such as police stations, hospitals and housing for the elderly are not permitted.

More vulnerable land uses such as residential, public houses and hotels are permitted subject to passing the exception test.

The exception test puts the issue of flood risk into context with other sustainability criteria and allows some tolerance to flood risk once the test is passed. The exception test is that:

• the development makes a positive contribution to sustainable communities
• the development is on brownfield land unless there are no alternative brownfield sites
• a flood risk assessment demonstrates that any residual risk is acceptable
• the development makes a positive contribution to reducing or managing flood risk.

Both PPG 25 and the draft PPS 25 promote the "sequential test" of allocating land for development in lower flood risk zones before considering higher flood risk zones. This is sensible but should only be considered in conjunction with other sustainability criteria. The sequential test should consider not merely existing flood risk, but the risk once the development is completed. Important as flood risk is to the planning process, it should not be treated in isolation.

Weighing up the risks

Effective policy against inappropriate development is welcome and both PPG 25 and draft PPS 25, with some clarification, provide this. However, we need to ensure flood risk is given the correct weighting within the planning process, and the planning authority has to make this judgment. We also need to ensure that appropriate floodplain development, which makes a significant contribution to both the reduction of flood risk and the creation of sustainable communities, is not dismissed through inappropriate application of overly prescriptive policies or sequential tests. We should develop in floodplains but only where appropriate and we should have confidence that the well-qualified professional sector will design sustainable schemes for flood protection.