Ask the Expert: Don’t Let Flood Risk Stop Your Development

Ask the Expert: Don’t Let Flood Risk Stop Your Development

Matt Travis, Director at Enzygo, shares some of his experiences in unlocking complex flood-related development problems and how to avoid development pitfalls.

What do you do at Enzygo?

Enzygo is a multi-disciplinary environmental consultancy specialising in providing technical services to the built environment sector ( We work all over the UK, unlocking land for residential, commercial, industrial, waste, mineral and energy developments. We are a director-led business providing technical expertise to solve complex problems.

We pride ourselves in delivering complex schemes through our multidisciplinary model, we have worked on projects ranging from rocket testing facilities, Muslim burial grounds, energy from waste sites, holiday park expansions and a range of commercial and residential developments.

Why are we still building in floodplains

There is still a pressure on development around brownfield land, much of which is on floodplains due to their historical industrial setting. There is also a desire to maximise value and density on development sites. Importantly, in the UK we aren’t making any more land so there will always be pressure on a scarce resource.

Some types of development can be safely built on floodplains if the flood risk can be mitigated. New sustainable drainage schemes also provide the opportunity to reduce flood risk downstream by controlling runoff.

Recent changes in government policy are moving thoughts towards improving resilience to flooding as opposed to flood defences. There is a realisation that we are going to have to become resilient and respond to events as opposed to the King Canute strategy of trying to stop the sea.

At what point in the development process should you consider flooding and drainage

Too many times development doesn’t consider flood risk at the outset. The drainage is often an afterthought with insufficient space left for it within the development. This results in disappointment as the initial layout and density can’t be achieved because constraints haven’t been properly considered.

Correctly, master planning by building in the constraints from an early stage, not only ensures you can build what you have designed but it also gives an opportunity for blue/green landscape features adding extra value to the development, making it more desirable for future residents.

We recommend early consultation to avoid such pitfalls, it is also important at the point of sale because if you can’t drain the site it will have a material impact on the value which can be achieved.

All too many times we have had clients wanting help to resolve site drainage issues at the reserved matters stage which can have negative impacts on delivering the development which they have been planning for.

How has the impact of recent flooding changed the way development is brought forwards

Since 2007, flood risk has become a significant material aspect of development. It has moved up the local and national political agendas and is often the source of public objection to the development.

More recently since 2014, there has been a realisation of the importance of all forms of flooding, pluvial – I.e. runoff from rainfall onto the ground, and groundwater flooding. This has led to new improved flood risk and drainage assessments for development sites and consideration outside the previous focus on tidal and fluvial (river) flooding mechanisms.

What advice would you give to developers considering developing in flood-prone areas?

Don’t always rely upon the Environment Agency flood maps, they can be challenged and aren’t always fully accurate

  • Sequentially plan your site making use of flood-prone areas for public open space
  • Provide enough green space for drainage of the site, thinking about the topography
  • Consider pluvial flooding, as noted in the 2007 Pitt report. Flooding isn’t just from rivers and the sea.
  • Always make sure you can drain your site, don’t ransom yourself


Matt Travis BSc (Hons) MSc MCIWEM C.WEM CEnv CSci, Director

Matt Travis has become one of the UK’s leading authorities on hydrology and flood risk with over a decade’s worth of experience in providing hydrological advice in the areas of water supply, flood modelling, water quality, drainage, business continuity planning and environmental permitting, and is frequently called upon to act as an expert witness.

Matt has substantial experience in the modelling of hydrological events, from 1D and 2D modelling of tidal and fluvial flooding through to the simulation of drainage systems and reservoir operation. His work has more recently centred around providing flood risk advice and modelling for a wide range of applications including energy infrastructure, LNG terminals, oil pipelines, golf courses, wind farms, renewable energy plants, housing developments and holiday parks.

Matt leads Enzygo’s Hydrology team and is based in the company’s Sheffield office.

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