3 minute read
River Glaven Restoration Project
Hunworth, Norfolk, England, United Kingdom
The River Glaven had become severely modified, with canalization, over-deepening, and impoundment common along most reaches. Over time, embankments were created to protect the adjacent floodplain farmland, causing a large area of floodplain to become disconnected from the main river system. The River Glaven Conservation Group’s (RGCG) goal was to improve the river corridor habitat by returning the river to a more natural state. Toward this end, the RGCG restored natural river processes and reconnected the river with its floodplain. The effort, which was completed in 2010, also contributed to an experience base that would serve the RGCG on other projects.
Article cover: Phase 2 of the river restoration included remeandering sections of the river. (Photo by Ian Shepherd, River Glaven Conservation Group)
Producing Efficiencies
Heavy machinery was used to remove around 400 meters of embankments with the objectives of reconnecting hydrological processes between the river and floodplain; maximizing the amount of floodwater that can be stored on the floodplain; and providing other ecosystem services, such as improving water quality and habitat. Flood peak attenuation was also achieved as part of the overall objectives to improve natural river–floodplain connectivity and associated ecosystem services.
Using Natural Processes
The river restoration measures reestablished natural processes and features, including pools, riffles, and meanders. These measures could change from their current forms—for example, river sinuosity may develop further and channel bars will change over time—and are thus self-sustaining as they allow the river to establish in a more natural way. Embankment removal alongside the River Glaven at Hunworth has created a more natural flood-pulsed hydrological regime, characterized by regular, short-duration inundation of the floodplain meadow. This is designed to improve river–floodplain ecosystem functioning.
Broadening Benefits
By reconnecting the river to its floodplain, this project has led to the improvement of plant and invertebrate biodiversity. Since the restoration was completed at Hunworth, the European Union’s Water Framework Directive classification of the water body has improved from moderate ecological status to good. Reconnecting the River Glaven to the floodplains at Hunworth provides additional benefits by maximizing floodwater storage on the floodplain and improving water quality. In addition, the River Glaven scheme included the construction of a new visitor center and interpretation boards, resulting in educational benefits.
Promoting Collaboration
The work was completed in partnership with the landowner, Stody Estate; Wild Trout Trust; Environment Agency of England; Norfolk Wildlife Trust; RGCG; University College London (UCL) Queen Mary University of London (QMUL); and Professor Richard Hey and the Centre for Environment Fisheries and Aquaculture Science. A three-year hydrological monitoring program was established to assess the hydrological connectivity post restoration, and was led by UCL and QMUL.
