Roofing

Rainwater
From Rain to Drain:
Taking Water Management Seriously
Steve Durdant-Hollamby, Managing Director of Alumasc Water Management Solutions, says rainfall,
climate change and the increase in urbanisation are testing our built environment so that water
management now needs to be a top priority.
The Thames Barrier is being closed more frequently than ever
before. Not due to North Sea surges, which it was originally
designed to protect against, but because prolonged and
heavy rainfall in the London catchment area has regularly
overwhelmed drainage systems. Built in 1982 and designed to
deal with 2-3 closures a year, the Thames Barrier shut 8
times in the 1980s, 31 times in 1990s, 80 times in the 2000s,
and 55 times up to mid-2014.
In July, London saw a month’s worth of rain fall in a single
day. The Environmental Agency reports that parts of the
south coast of England have already received over twice as
much rainfall this year as the national average.
But this isn’t just a UK problem – it’s worldwide. In
September, violent storms and flooding hit south-eastern
France, killing more than 20 people. The city of Nice received
10% of its average yearly rainfall in 2 days.
Our roofs weren’t built to cope with such excessive,
concentrated rainfall and the drainage systems they’re
connected to can’t cope.
Insurers are concerned about climate change. Heavy rainfall
and flooding in the built environment has a dramatic effect on
our homes and businesses. In the past year more than 165,000
flood insurance claims in the UK have amounted to an
estimated £3bn. Climate change is increasing the intensity
and frequency of extreme rainfall events, making flash
flooding an ever increasing problem.
Recently, the Governor of the Bank of England, Mark Carney,
said that climate change is the biggest threat to the UK
economy and businesses. His comments were based on the
Financial Services report into the insurance sector’s exposure
to climate risk. By 2080, Government estimates the cost of
flooding to UK economy and businesses will reach up to
£12bn. If the Bank of England is starting to worry, so should
we!
On average the UK gets 133 days of precipitation every year,
totalling almost 34 inches of rain. It may not seem a lot but in
heavy storms when we’re dealing with intense rainfall in
roofs, gutters, downpipes and drains can be overwhelmed.
In 2014, Government introduced a £2.5bn investment in flood
defence. The scheme aims to provide funding to over 1,400
projects in a 6 year plan to protect over 300,000 homes.
Recently, The Institute of Civil Engineers (ICE) called for
Government to protect this flood defence scheme from cuts,
saying that a ‘prevention is better than cure’ approach was
needed. Nick Baveystock, ICE Director General, argued that
robust, effective infrastructure benefits society and the
economy.
Green Infrastructure alternatives, such as Green Roofs and SuDS are seen as a
highly effective way of reducing the risk associated with severe rainfall and
flooding, protecting buildings in urban developments, and minimising the
impact of climate change.
The 2010 Flood and Water Management Act, which set out to make SuDS
mandatory on all developments, was never implemented and is now only a
guideline rather than an essential measure. SuDs need only be considered on
large developments with policy and decisions on their use devolved to local
authorities.
Government estimates that just 40% of new developments and redevelopments
are drained by SuDS. So 60% are being built for yesterday.
Capturing, Containing, Channelling
More storms and heavy rainfall is just the beginning. Increased urbanisation in
towns and cities, and more paved over landscape has reduced natural drainage
where rain can drain in a controlled and sustainable way. But we need to be
thinking about water as soon as it hits the building, starting at the roof, and
capturing, containing and channelling rainfall all the way from water source to
water course.
How we deal with more intense rainfall is important. And if climate change is
becoming one of the biggest risks to the economic and financial stability of
the UK, action is needed; now. We need to take water management seriously.
Rethinking what, where and how we build, and more importantly, how we
look after buildings.
Joined up thinking: From rain to drain
We can protect our buildings, people and environment by incorporating
practical joined up thinking across all levels of the supply chain; suppliers,
contractors, architects, merchants and builders. As an industry, investing in
risk reduction now will bring effective, tangible and immediate benefits.
Think coherent, fully integrated water management systems, for every stage,
from roof to ground. Absorbing rain, slowing up the process and ensuring that
the whole system copes better with water flow.
AWMS provides engineered products that help capture, contain and channel water in a
controlled and sustainable way. To find out more visit www.alumascwms.co.uk. Follow
us @AlumascWMS.
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