In recent times we have seen an increase in the frequency and intensity of flood events. NFM techniques including tree planting and other changes in land management can help reduce the frequency and impact of these events on our daily lives.
Willow spiling is a traditional form of riverbank stabilisation; it can protect land from eroding and damaging water quality.
Live willow rods are woven around upright posts driven into the stream bank where erosion is occurring. The willow is back-filled with soil which encourages roots to grow, creating a woven wall of vegetation.
Willow Spiling is categorised as Green Engineering- creating a healthy living environment through the utilisation of natural resources wisely and conservatively.
Floodplain & Catchment
Woodland planted on floodplains reduces flooding further downstream. The roots of the trees open the soil structure allowing the land to absorb more water, so less run off enters the watercourse. Trees and woody debris on the floodplain act as barriers slowing the flow of run off and reducing flood risk.
When rain falls on an area of land, the water is absorbed by the soil and flows downhill collecting into a streams and rivers. This area of land including the hills, valleys, farmland, and settlements is known as a catchment. Well planned areas of woodland can significantly reduce flooding in these catchment areas.
Trees such as Alder, Poplar and Aspen are well adapted to growing along watercourses and in wet ground.
Where trees such as this are planted along stream and riverbanks, we call this riparian woodland.
The tree roots function like a sieve, filtering sediment and nutrients from run off before it enters waterways. The shade created by trees improves the river ecosystem by cooling the water improving conditions for species such as trout and salmon.
When streams and rivers flood, fallen trees and branches are often washed into the watercourse blocking the flow of water and slowing its release downstream. This natural process can be mimicked by strategic placement of secured logs across becks and streams known as leaky dams.
Leaky dams push water out of the drainage channel onto surrounding land and slow its release as it progresses downstream.
Flooding can cost the UK economy more than £1Billion annually. In recent times increased winter rainfall levels and development activity have reduced the ability of the land to hold water. The excess water has nowhere to go resulting in surges of flood water.
NFM techniques manage flood risk and restore the natural regulation of water flow by mimicking natural processes. This can take many different forms and can be applied in urban and rural areas.
Instream structures, riparian and catchment woodland can reduce flood risk, by slowing, storing and filtering water, complementing traditional engineering techniques.
We are commissioning a series of stories with our videographer to help demonstrate the success of Natural Flood Management ”