Natural Flood Management

Kentish Stour Volunteers planting a hedge to Slow The Flow

The climate has changed and our landscape has changed too.

Intense bouts of heavy rain have become a regular feature of our weather and have caused immense amounts of damage across the country through flooding. Nine of the wettest months since 1910 have occured in the last 20 years. (Out of 17 record-breaking rainfall months since 1910, 9 have occured since 2000) 1 in 6 properties in England are at risk of flooding.

KSCP have a partnership officer working with Kent County Council to return some of the natural processes to our landscape which slow the flow of water and hence reduce flooding.

Re-establishing natural processes can involve planting hedges across surface flow paths, building leaky dams in streams, river restoration, floodplain restoration, pond creation and Catchment Sensitive Farming.

It is important that we address this issue from all angles. Every household can do their part to help prevent flooding by installing water retention features on their property. The Charity Slow The Flow, based in the Calder Valley, has been doing lots of work on how to do this through such things as  rain gardens, leaky water butts and green roofs

Types of Flooding

There are different types of flooding

Fluvial – rivers , lakes and streams overflow because of rainfall and water draining off the land.

Coastal flooding – high tides and storms lead to the sea flooding the land.

Surface Water Flooding – occurs when rainwater cannot drain away.

Sewer flooding – caused by sewers becoming blocked or overwhelmed by the amount of water.

Groundwater flooding – occurs when the water table rises close to ground level.

Where water goes

Water falling as rain or snow flows downhill to the sea. Rivers and streams begin as small but fast flows of water at the steeper headwaters and tops of tributaries. Any rainwater which cannot be absorbed into the ground flows into watercourses.  At the Headwaters this water is slowed down by woodlands and rough grassland, where these still exist. As rivers  reach the lowlands they become wider and slower. Historically the riverbanks would have been lower and the rivers more meandering. Water would have been able to overtop the river banks and flow into the floodplain on either side where areas of woodland, grassland and wetlands would catch the water and slow it down.

The River Great Stour, Watercress Fields, Ashford. Wide fringes of vegetation, trees and grassland are part of a natural river system.

Housing and industrial development have occurred in our floodplains. We are building many more houses, gardens have been paved over, ponds filled in, rivers straightened. Intensive agriculture has removed more floodplain. Heavier machinery, loss of soil structure, over-grazing, hedgerow removal, pond removal, lack of wild margins in fields and straightened watercourses have all impacted. We cannot accommodate all the rain water because the natural mechanisms to do this have been removed or diminished and so flooding is getting worse.

90% of our floodplains no longer work properly so water flows much faster through the landscape.

There are many projects across the UK which utilise Natural Flood Management techniques to restore our floodplains and rivers.