The Association of Drainage Authorities has responded to the Environment, Food and Rural Affairs (EFRA) Committee inquiry into the future flood prevention. The inquiry was asking for comments on the effectiveness of current flood risk models used by the Met Office and the Environment Agency, the effectiveness of defences in protecting communities, infrastructure and agricultural land, the need for policy to encourage innovation in flood risk management and the role of planning in flood risk management.
ADA’s written evidence highlighted the interconnectivity between different parts of our river catchments and the land uses within it. If not positively managed, these interactions can have serious negative impacts. However, by bringing the different activities, at the full range of spatial scales across a catchment, into a management approach that makes the most of the possibilities offered by the interactions can replace the negative impacts with long-term sustainable benefits.
Total Catchment Management
ADA recognises that in order to deliver better management of flood risk in the future all the risk management authorities must work cooperatively with each other, communities and land managers to deliver Total Catchment Management from source to sea by:
- Working with farmers and landowners to increase soil infiltration and store more flood water in the upper parts of the catchment to control run-off, reduce peak flows and reduce siltation whilst also providing farmers and landowners with a more balanced and reliable water supply.
- Restoring rivers in parts of the catchment that are not artificially drained to reduce peak flows downstream (and provide other benefits for recreation and biodiversity).
- Providing flood storage areas at critical points further down the catchment to retain water during times of high rainfall to prevent downstream flooding whilst also potentially providing both a range of habitats to enhance biodiversity and providing storage and release of water as a resource. This should include providing assistance to farmers and landowners to adapt their businesses in areas used for flood storage.
- Promoting sustainable drainage systems (SuDS) and district-wide strategic surface water management in towns to reduce urban run-off. Connecting open space in urban areas provides flow paths and water storage to manage flows and flooding whilst also providing green infrastructure, resilience to climate change and improved urban access. Sustainable drainage systems reduce run-off and store water, managing water at source to lower flood risk downstream whilst also providing pleasant open space to enhance the amenity, water quality and biodiversity of an area.
- Ensuring the effective maintenance of drainage ditches, channels and rivers in lowland parts of the catchment where active management is required to control water levels for communities, businesses and the environment. The correct balance of conveyance, capacity and storage within such systems are critical to their effective functioning.
- Planning and designing for exceedance. Making sure that a flood defence project is not just about the defences but also what happens when a defence is overwhelmed. For instance the tidal surge of 2013 illustrated the need to reduce the risk of coastal embankments breaching when they are overtopped. This can be achieved by creating both a wider crest and shallower landward slope less receptive to erosional pressures, and through effective maintenance that prevents bushes, trees and burrowing animals becoming established. For communities this will include facilitating flood resilience and property level protection in the whole catchment and, in extremis, assisting with the relocation of the highest flood-risk households out of the floodplain.
Download: ADA’s written evidence to EFRA’s Future Flood Prevention inquiry (pdf)
The Association of Drainage Authorities (ADA) is the association for water level management organisations in the United Kingdom, with over 230 members. Our members include Internal Drainage Boards, the Environment Agency, Regional Flood & Coastal Committees, Natural Resources Wales, the Rivers Agency Northern Ireland, Local Authorities, and suppliers to the sector.