Best practice in water management: it’s a win/win

It’s fair to say that flooding is in the news quite regularly – from experts predicting rising sea levels due to climate change, to the storm events that have impacted on residents in places such as Hebden Bridge and Boscastle, as well as the more recent flash floods in London.

The UK has always experienced clusters of flooding events (though only the most severe would have been reported on the news in the past), but experts advise that flash flooding may become a more common occurrence as the climate crisis worsens.

In a recent article in The Guardian (26th July 2021), Dr Jess Neumann, a hydrologist at the University of Reading, urged action.

 She explained that no city, town or village is immune, and the article went on to outline that planning and development processes need to adapt accordingly, with better drainage systems, more green spaces, and innovative approaches such as porous pavements.

We couldn’t agree more. We’ve always been of the opinion that water management measures should never be a compromise, and more is more – we will always go above and beyond with our water management strategies, as this sort of best practice will ensure that our homes continue to serve the wellbeing of their residents even taking into account more extreme weather conditions anticipated in the future.

But what does our best practice in water management look like? Well, it’s a lot more rigorous and ecologically-sound than many developers in our industry might consider the norm.

Firstly, we will never build on a flood plain. There are developers out there who will do this, because they can – although the Government’s National Planning Policy Framework says “appropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk,” it also says that, where development is necessary, it can go ahead – but that the development “should be made safe for its lifetime without increasing flood risk elsewhere.” We don’t think it’s worth the risk – or the cost, since we want our retirement-suitable homes to be affordable to the average person – and choose our sites accordingly.

In addition, we always build in a landscape-led way, where our buildings are designed to suit the site rather than the site being forced to work with a pre designed development on it. This isn’t common in the construction industry, where usually designs are architect-led. Also unusually, we ask our flood consultants and landscape consultants to work together, to achieve the best possible solution (we’re quite different to many construction companies, in that we prioritise the health and wellbeing of our future residents, and not profits).

Unlike some within our industry, who leave the detailed plans for water management until a fairly late stage in the development, we prefer to tackle this important element early on in the process – after all, the groundworks quite literally underpin the homes that we’re building, so they need to be fit for purpose. We’re rigorous about it, too.

We’ve come across others using flawed calculations – for example, allowing for surface water on site without factoring in the effect of the buildings; or not taking into account the surrounding infrastructure and its limitations, such as any pipes which block easily, or surrounding ditches that are not well maintained. This can obviously mean that a seemingly adequate water management strategy simply doesn’t work in reality.

In contrast, we always make detailed plans, with accurate figures and modelling, and conduct investigations into the surrounding areas as well as the site itself – in fact it’s not unheard of for our measures to be designed in such a way as to benefit neighbouring properties too.

One of the ways we do this is to slow the flow of surface water into the mains drainage system, to avoid the pipework downstream being overwhelmed. What’s more, some of the ways we achieve this have other benefits both for the future residents, and also for the site’s biodiversity and ecological value.

Detention basins are one of our preferred ways to control the flow of water into the mains drainage system, and we tend to overspecify for good reason – making them deeper than strictly necessary (often by using plantable Gabion baskets), so that there’s always water in them, which means they also function as a lake that is not only a pleasant, wellbeing-enhancing feature for residents (being close to water has been proven to enhance happiness) but a pleasing aesthetic feature for the site, too.

Despite the significant capacity that the depth affords, we also design in wildflower meadows around these lake features, to act as a flood plain in case of heavy rain – and we specify native species of plant which thrive in this type of environment, to ensure no storm event can impact on biodiversity, let alone impact on residents. In addition, on some sites we use crates underneath the roads to capture rainwater, to slow it down on its route into the detention basin and beyond.

We use simple – yet effective, and also eco-friendly – measures in our homes’ communal and private garden areas too. ‘Rainwater gardens’ are areas where rainwater is directed, either into the soil (planted with moisture-loving plant varieties), or into open containers that are planted up with pond-dwelling plants. This water then slowly filters through the ground (which also cleanses it), and drains into the detention basin, before being released – slowly – into the mains sewer.

We strongly believe that water management strategies can not only be more effective than they might be when designed in the ‘normal’ way, but also that they can ensure more positive benefits than just managing the flow of surface water – both for residents, and for the ecological value of new housing development sites. We hope that our way can become the new normal, one day, too, for the benefit of all.