them more flood-resistant. “These projects have to
be economically viable.”
Sometimes that comes down to simple attrition.
“Between now and 2080, practically all infrastruc-
ture will need to be replaced,” he explains. “When
something wears out, we can relocate it or make it
more flood-resistant at a marginal extra cost.”
In high-risk areas, all construction project
plans should incorporate efforts such as moving
electrical wiring to the ceiling or putting mechanical
backflow systems on drains and sewer lines to pre-
vent water from backing up inside a house.
“These are simple solutions that can reduce losses
should a flood occur and don’t cost a lot of money,
but they do require planning,” Mr. Thorne says.
NE W WAVE
The best way to encourage long-term planning is to
establish regulations and policies that force developers
to make better project decisions, says Mr. Holmes.
He points to Kane County, Illinois, USA, where
flood policy requires any urbanization of open land
to mimic the preconstruction rainfall runoff conditions of the land by including water-retention ponds.
“Kane County is a perfect example of how to do
the right thing,” he says.
Similarly, the U.K. government responded to the
Foresight report by crafting a flood-risk policy across
the region. The Environment Agency of England
and Wales alone annually spends £400 million on
flood-defense schemes and is currently developing a
plan to determine the level of flood protection
needed over the next century for London and the
The region is considered at risk due to higher
mean sea levels, increased rainfall and tide ranges,
as well as a greater number and intensity of storm
events. The Thames must also contend with the
gradual “sinking” of the southeastern tip of the
British Isles. The agency predicts that a large-scale
flood event in the area would cause millions of
pounds’ worth of damage to businesses, homes
and infrastructure, and potentially kill thousands
To minimize those risks, part of the planning calls
for a project to build a new flood barrier across the
river that can be closed during high-water events.
“These kinds of projects take years to build and
decades to get permitting,” Mr. Thorne says. “By
starting to plan now, London is giving itself the time
to be prepared.”
Such long-term planning is one of the biggest
challenges for municipalities, says Danka
Thalmeinerova, knowledge manager at Global Water
Partnership, an intergovernmental water resources
management advocacy group in Stockholm, Sweden.
Politicians typically hold office for “four years, so
they are often reluctant to commit to a project that
may take 20 years to build and 30 years to see the
benefit,” she says.
Sometimes it’s a matter of timing—people need
to see the aftermath to be spurred to action.
“The only way to mobilize stakeholders is
right after a catastrophe,” Ms. Thalmeinerova says.
“Otherwise people don’t pay attention.”
Without that stakeholder support and the
research and policies to make their case, many
cities around the world are at serious flood risk,
Mr. Thorne warns.
He cites the lack of progress in Sacramento,
California, USA, built on a sinking delta at the confluence of the San Joaquin and Sacramento rivers on
the edge of San Francisco Bay. “It’s vulnerable to sea
level rise, storm surges and river floods,” he explains.
Yet the city has done little to mitigate the risks.
“It has no clear flood policy, and the U.S.
Army Corps of Engineers has locked horns with
environmentalists over efforts to reduce flood
risks through removing trees and other vegetation
from river banks and levees,” he says.
Those kinds of arguments aren’t uncommon as
endangered species policies and clean-water requirements may conflict with flood-management efforts.
It all has to start with a holistic strategy that
everyone can buy into.
“The biggest driver of success is stakeholder
behavior. Environmental agencies, policy outfits,
local council people, and business and home
owners all need to take responsibility for flood
risks and come to agreement on how those risks
can be managed and act together to turn policy
into sustainable practice,” Mr. Thorne says. “If
everyone is working on their own, nothing can be
accomplished.” —Sarah Fister Gale