Natural Flood Management Solutions

Willow & Poplar crops create a natural flood management solution, protecting your business and the local area.

Natural flood management solutions utilising willow and poplar crops are designed to store water in the landscape and reduce the speed at which water runs off into rivers. Natural Flood Management has four key components: decreasing water velocity, water retention, increasing soil infiltration, and intercepting rainfall.

Farm features can be utilized for natural flood management by implementing specific techniques. These methods rely on fundamental mechanisms, such as creating and maintaining capacity in bunds, ponds, ditches, swales or floodplains, intercepting rainfall through vegetation, improving soil structure, and increasing the resistance to water flow. Planting trees is also a crucial method in natural flood protection, as it can significantly increase soil infiltration and slow down water flow. Strategically planting trees in key locations such as run-off source areas and riparian zones can effectively interrupt, slow, and reduce flood water run-off.

Hydraulic roughness of different vegetation on floodplains

Pasture No. Brush	Min	Normal	Max
1. Short Grass	0.025	0.030	0.035
2. High Grass	0.030	0.035	0.050

Cultivated Areas	Min	Normal	Max
1. No Crop	0.020	0.030	0.040
2. Mature Row Crops	0.025	0.035	0.045
3. Mature Field Crops	0.030	0.040	0.050

Trees	Min	Normal	Max
1. Cleared land with tree stumps, no sprouts	0.030	0.040	0.050
2. Cleared land with tree stumps, heavy sprouts	0.040	0.060	0.080
3. Heavy stand of timber, few downed trees, little undergrowth, flow below branches	0.080	0.100	0.120
4. As above but with flow into branches	0.100	0.120	0.160
5. Dense Willows, Summer, Straight	0.110	0.150	0.200

These tables clearly shows Willow and other SRC/SRF crops’ dominance as flood water manipulators. The higher the value, the greater the surface resistance for slowing the flow of water. Pastures made up of grassland don’t offer much resistance, but a balanced mixture of trees, hedges and coppice can significantly slow the flow of water.

Willow plantations can enhance the resistance of land to flooding by augmenting infiltration and evaporation in order to decrease the volume of floodwater. Furthermore, such plantations can forestall damage to downstream infrastructure by retaining flood debris and sediment, limiting the hazard of destruction to farm bridges, fences, and other constructions situated downstream.

By increasing ‘hydraulic roughness’, willow plantations enhance evapotranspiration and decelerate the spread of water across a floodplain. These crops are resilient and expedite growth, providing flood protection even in their inaugural year. Additionally, they require less tillage and machinery, resulting in less soil compaction. As these crops diminish soil compaction, they enable improved water infiltration, further diminishing the rate at which rain water can reach streams and rivers. Adding energy crops in the appropriate locations to your grazed or arable land mix can mitigate runoff and erosion emanating from your land.

Eco Crops Ltd can assist you in effectively planning and designing Natural Flood Management (NFM) characteristics. NFM features such as energy crop types are not the only means by which to develop your land’s NFM qualities.

“When it comes to flood damage, prevention is better than cure. Government needs to do more to recognise the Natural Flood Management work farmers are already doing to help towns and villages reduce peak flood levels.”

Neil Watkins – Director, Eco Crops Ltd