Flooding events occur at all scales, it can't be stopped but the impacts can be mitigated through natural flood management.
Flooding can be a devastating event for people, wildlife, homes and businesses -the economic costs can be huge and distressing, with impacts lasting for years. Flooding events occur at all scales, from a flashy tiny tributary stream catchment affecting a handful of houses and disrupting a local network of lanes to the colossal and relentless flows of the Severn in spate.
River flooding and surface water flooding are natural events
It happens when large volumes of water exceed the drainage networks.
For a river system, the rainfall across the catchment flows towards the channels and then out of the channel across the floodplain. Moving floodwater can physically harm the land, undermine and damage buildings, carry pollutants and threaten life.
Surface water floods or those arising from ground water sources can disrupt, pollute and harm too. Long term inundations such as those on the Severn and Vrynwy confluence can persist for weeks, endangering local communities, killing crops and impacting wildlife.
Flooding can not be stopped but the impacts can be mitigated
Traditional engineering responses such as embanking, dredging and attenuation pools, have a very limited but key role in addressing the reduction of flood impact. Property level protection can help, fitting flood proof doors or raising level of air bricks.
The deployment of temporary barriers has proved their worth repeatedly, bravely set up by the hardworking EA and their Local Government partners.
But rain falls over part or in many cases the whole of a catchment, it is not enough to focus purely on the drainage channel when the whole landscape can be brought to bear on the challenge.
Natural Flood Management
Natural flood management is a relatively new part of this multi-agency toolkit of flood management measures. It seeks to work with farmers, landowners, local Flood Action groups and local Parishes to improve the way a catchment functions.
Installing woody debris upstream reduces flood rates thereby lowering the peak wave of water ensuring traditional flood protections are less likely to be overwhelmed.
Other natural solutions that help slow the flow are to Increase the amount of permanent pasture land actively aerated which promotes infiltration.
Strengthening hedge and woodland network that lay across slopes can interrupt surface water flows.
Fencing watercourses, planting trees along the riparian corridor and increasing sinuosity all enhance channel roughness which slows flows and improves alert times.
The UK centre for Ecology and Hydrology has interactive live mapping which brings together rainfall, river flow, soil moisture and groundwater data, you can look at this here.