Replacing an established plan is never straightforward. Accepted norms are challenged and disruption usually follows. This has certainly been the case for the Welsh Government as they have sought to update their TAN15 planning guidance.


The planning guidance that has been in use for many years can be found in the 2004 Technical Advisory Note 15: Development and Flood Risk (TAN15).

This document took a precautionary approach, outlining planning advice based on flood risk observed historically and at the time.


Everything changes with climate change. The outlook for areas at risk has altered dramatically, in ways that had not been accounted for.

As an example, NRW estimate that close to 250,000 existing houses are vulnerable to flooding already. According to Jeremy Parr from NRW, this is expected to rise by about a third in the coming years. Worryingly, these figures exclude houses that are yet to be built. The potential for huge-scale flooding disasters continues to escalate.

To avert crisis, the Welsh Government developed a new updated TAN15 with revised planning guidance.

The first iteration of the updated TAN15 was intended to come into effect on 1 December 2021. More information can be found in the previous WHS newsletter article: The future for TAN 15.

To prepare for climate change, a stricter set of rules was applied to proposed developments in updated flood zones that incorporated climate change impacts.

A new Flood Map for Planning (FMfP) was set out alongside the updated TAN15 guidance, displaying the updated flood zones. This was to replace the Development Advice Map, introducing new flood zones with significantly increased flood extents.

The Welsh government was the first in the world to declare a climate emergency and the updated TAN15 seemed in line with their determination to be at the forefront of climate preparedness. They had taken a strongly avoidance-based approach to flood risk management. Updated TAN15 now heavily restricted development in flood risk areas.

But when the new plan was presented to councils, it hit a major road block.

The enlargement of flood zone sizes to account for climate change left many important urban centres facing a potential embargo on all new development. This impact on key economic areas, many of which had plans for regeneration, was hugely problematic.

Many Welsh councils strongly opposed the updated planning guidance. The general view was that the balance for communities had tipped too far towards environmental security, and away from economic security, risking spiraling levels of deprivation within many towns and cities across the country.

In the face of such opposition, the updated TAN15 was pulled one week before its planned implementation date of 1 December 2021.

Initially delayed for just one month, it was then delayed to the 1 June 2023 to give councils time to prepare for the planned changes. It also gave time for the government to introduce conditions for flexibility that would allow appropriate redevelopment in economically important areas.


In January 2023, a new iteration of the updated TAN15 was released for consultation. The guidance now contained several positive points of change.

Notably, the Community Action and Resilience Plan (CARP) concept was introduced. This was a way in which local authorities could support developments that were part of a regeneration scheme within their area, by identifying measures to increase a region’s flood resilience as a whole.

Urban centres could now be economically protected in certain areas by taking the approach of living with flooding rather than trying to avoid it all together. As long as they had an active CARP in place, important town and city centre economic developments could be allowed.

However, although new flexibility within TAN15 has been largely welcomed, practical issues remain for implementation.

As highlighted within the WHS consultation response, the suggested approach requires Local Planning Authorities (LPAs) to take the lead role in developing CARPs. This would mean LPAs taking on the hugely resource-intensive task of overseeing

  • the development of strategic flood defences
  • climate change adaptation strategies
  • funding sources for these schemes.

Given that most, and perhaps all, LPAs do not have this capacity at present, it risks major delays in important regeneration developments. It is also not clear which flood risk areas will require CARP plans and who will approve them. Last but not least, questions remain over future funding for any proposed defences.

The road ahead

Following consultation responses, the latest iteration of the updated TAN15 has once again been delayed.

The government had stated categorically that there would be no further extension to the updated TAN15’s implementation, so further delay was a source of some embarrassment. It also drew criticism from opposition parties and environmental activists.

The situation has also led to significant uncertainty in the development sector. The new Flood Map for Planning co-exists with the Development Advice Map, and each shows different flood zones.

This has been a challenging episode for the Welsh government’s environmental policy.

Wider lessons can be drawn from this saga

  • The unfolding of the updated TAN15 highlights the vast array of complexities that have to be faced by governments as they plan for climate change. Wales took a lead and has been among the first to face these challenges head on.
  • It can be difficult to hard-engineer economic activity away from flood risk areas where there are established communities. Instead of complete flood risk area avoidance, it may be beneficial to allow instances of less vulnerable development with appropriate mitigations, whilst diverting developments such as housing elsewhere.
  • Clear communication and careful phasing of policy changes is essential when introducing big changes to established practices.

Despite the hard lessons, Wales may well be on course to have a purposeful new approach that meets the flood risk challenges posed by climate change.

The last word

The Fab Four get the last word this time!

The wild and windy night
That the rain washed away
Has left a pool of tears
Crying for the day.
Why leave me standing here?
Let me know the way.