Flooding & Pollution
As urban and industrial areas throughout the country have continued to expand, the total area of impermeable surfaces such as roofs, roads, pavements and car parks has increased. This means that rainfall cannot infiltrate naturally into the ground and puts our already overloaded drainage systems to an even greater test.
Rainwater which could normally recharge groundwater or wetlands is now washed directly into water courses via convential drainage systems. With global warming leading to increased levels of rainfall, our ageing drainage systems are no longer able to cope with high volumes of storm water run off. This leads to flash flooding and increased pollution.
Pollution Risk
During periods of dry weather, heavy metals, hydrocarbons, oil, rubber and other pollutants are deposited on impermeable surfaces. When it rains these pollutants are washed into drainage systems and end up further downstream in rivers where they damage wildlife habitats.
Flooding Risk
The Environment Agency report on the Autumn 2000 floods in the UK, entitled "Lessons Learned - Autumn 2000 Floods" concluded that an estimated 1.85 million homes, 185,000 commercial properties and 5 million people in the UK are now at risk from flooding.
The Environment Agency's publication "Policy and practice for the protection of floodplains" stated that: Inappropriate development within floodplains should be resisted where such dvelopments would itself be at risk from flooding or may cause flooding elsewhere." To minimise any increased surface run-off, new developments must be carefully located and designed. Where appropriate, storm water source control measures, which also improve water quality, should be incorporated into the development proposal.