River restoration is about re-establishing the natural processes, features, and biodiversity of river systems for provision of their wide range of natural, economic, and societal services, including increasing flood resilience.
The River Restoration Centre (RRC) is the UK's expert advice center for restoration projects. Activities such as channelisation, culverting, damming, abstraction, urbanisation, pollution, dredging, and intensive agriculture can all negatively impact the environment and services rivers provide. River degradation has led to extensive habitat loss and pressures on the species which rely on them. It affects drinking water quality and their capacity to store and, hold back flood water.
Legislation such as the Water Framework Directive (WFD), the Habitats Directive (HD), and other national and international agreements are compelling work to improve and restore our riverine ecosystems. One such project, and winner of RRC's Innovative & Novel Project category in the UK's 2015 River Prize, was the restoration of the River Adur at the heart of the Knepp Estate in West Sussex.
Carried out by the Environment Agency in 2011, and funded by Natural England and the Knepp Estate, this has involved removing 4 weirs and filling in a 1.5 mile drainage canal. Returning this stretch of the Adur to its original meanders, and reconnecting it with 3.5 miles of restored floodplains upstream, has revitalised the water system.The restored wetlands of the floodplain are now ideal habitat for wading birds, amphibians, water insects, important marsh plants and riverine trees like the nationally scarce black poplar. Meanwhile, the natural activity of the floodplain helps filter and improve the quality of the water passing through it. It also slows down floodwater, protecting areas downstream from flood damage.
Observations at Knepp, suggest the re-naturalisation of their section of the river is having an impact on the flow of water around and below the estate. Estate cottages at Tenchford and Knepp Mill, notoriously prone to flooding in the past, have not been flooded since the project began. Surrounding roads that are often closed because of floods, have remained passable.
If you havent already done so, Wilding - the Return of Nature to a British Farm by Isabella Tree is a fascinating read on the approach taken by her husband, the conservationist, Charlie Burrell.