Urban sprawl has been identified as the biggest future threat to flood control in a new study in the United States which says controlling it, followed by increased tree cover, are the most effective ways of controlling run-off and flooding.
The study, in Environmental Management by Purdue University scientists, modelled Mitchigan's Muskegon River from 1900 to 2040 with several future scenarios built in, including forest regrowth, urbanization and buffers between development and streams.
Some predictions suggest America's urban area, unchecked, could double in the next 20 years.
"Changes in the land's surface feed back to runoff, said associate professor of forestry and natural resources Bryan Pijanowski.
"Urban sprawl and impervious surfaces are the biggest culprits. If you're able to control development, it is the most effective way to save our river ecosystem."
He said excessive run-off can cause flooding, pollution of watercourses by agricultural and urban pollutants and damage to aquatic life, wetlands and groundwater.
The study found curbing urban sprawl would be the most effective way to control run-off, although reafforestation and buffer zones could also help.
Some good news that emerged from the study was the benefit from the extensive federal programme of reafforesting failed farms between the 1930s and 1960s; the state's forests had been extensively cut down following the great Chicago fire of 1871.
"The lesson here is that with time and care, these systems can be restored," said Prof Pijanowski.
His team is now working on the role landscape change plays in climate change and tipping points.
