CCRI’s Chris Short gave a public lecture at the University of Gloucestershire Oxstalls Campus on the subject of natural flood management on Thursday, 25th February.
Flooding has become an increasing concern in recent years and the threat of rising waters is never far from the minds of many people. The winter of 2015/16 has been recorded as the wettest and warmest on record and the impact of climate change may mean these events will become more frequent. From sand bags to flood barriers, attempts to hold back the water have met with varying levels of success. Chris demonstrated in his lecture that as well as these defences, there is a need to consider the simple, low-cost, actions that can work in combination to provide effective solutions.
As well as using concrete and steel to stop flooding, Chris explained the benefits of using natural features to help reduce the flow of water downstream. He talked about a pioneering scheme that he has been working on with Stroud District Council in the Stroud Valleys, which is using natural features, such as leaky dams, to reduce the risk of flooding.
He explained how leaky dams help to slow down the momentum of water flowing down the hills into the valleys and increase the infiltration into the soil, thus reducing the risk of flooding. The dams are made by laying loose logs and wooden debris across the river, which, as well as slowing the flow of water, also provide habitats for wildlife.
As part of the Rural Sustainable Drainage System project, over 100 individual natural flood defences have been constructed so far, with an overall target of 1000 in the Stroud Valleys alone. The cost of the work is much lower than engineered and hard flood defences and the structures fit well within the landscape and can be constructed through community groups, such as local flood action groups, helping them to contribute to the solution.
Chris also talked about how farmers are changing their farming practices to become more resilient to changing weather patterns by looking to the soil. Many are adopting a practice of less cultivation, letting the soil take on a more natural profile by allowing earth worms to turn the soil, rather than the plough. ‘Roots not iron’ is a philosophy being increasing adopted by some farmers and discussed by many, who by a careful choice of deep rooted crops change the soil profile and release nutrients much deeper in the soil for crops to benefit. This also lets rain water penetrate more quickly and deeply.
Finally, there were some tips for homeowners to help prevent flooding by creating a ‘rain garden’, a new trend for water management using water from roofs and hard surfaces. Chris explained that some floods are caused by a large volume of water generated by water from hard sufaces, like roofs and roads, meaning that the water infrastructure can’t cope. He described how water runoff can be directed to make a feature in a small garden, or part of a garden. With carefully selected plants, which can stand excess water, the ‘rain garden’ can capture and divert excess water and also slow the momentum of stormwater as it travels downhill, giving the water more time to infiltrate and less opportunity to gain momentum and erosive power. It can also provide a habitat for wildlife.
Before the lecture, participants were able to test their skills in river management in a ‘river in a box’ experiment, provided by the Environment Agency. Other stands were provided by FWAGSW, GRCC and Stroud District Council.
The lecture was attended by around 150 people, most of whom were directly impacted by the floods in 2007. Following the lecture, there was a lively discussion covering such issues as planning, development, education, and the need to show the benefits of natural flood management. The main area of consensus was that we are better off tackling these issues together in partnership.
The slides of the lecture can be found on the CCRI Slideshare account.
Chris was interviewed by Kate Clark on BBC Radio Gloucestershire regarding his lecture. The interview can be listened to here for a limited period (Chris’ interview starts at 0.48)
Find details of the project here. http://www.ccri.ac.uk/rsuds/