Steart managed realignment scheme – one of the largest in the UK

The Steart marshes – one of the largest managed realignment sites in the UK – were exposed to the sea for the first time ever over one year ago, and have recently been in action against the highest tides in over a decade.

steart_aerial_sacha_dench_800x560
WWT Steart Marshes at high tide. The Bristol Channel is to the left and the River Parrett to the right. (c) Sacha Dench

The Steart Coastal Management Project, involving the Environment Agency and a host of other partners, has the aim of creating new intertidal habitat on the Steart Peninsula, northern Somerset.

The highest tides in decades – which provided the first real test for the newly created defences – were easily contained.

Clementine Chirol, a PhD candidate based at the National Oceanography Centre, Southampton, is currently investigating the early effects of tidal inundation for the morphology and sedimentology of the marshes, and was particularly excited to see the high tides. As saltmarshes naturally attenuate wave and tide energy (and enhance the durability of the surrounding flood defences) interesting changes in the morphology of the creek system are expected. Below are shown two photographs showing the main channel of the creek network captured in October 2015.

steart_entry_channel_2_nikki_brown_800x600 Steart Marshes main entry channel during low tide in October 2015. Since the site was first inundated by the sea, the short cliff seen in the background has gradually been retreating upstream. Courtesy of Nikki Brown.

steart_entry_channel_1_nikki_brown_800x600 Steart Marshes main entry channel during low tide in October 2015. Courtesy of Nikki Brown.

With 400 hectares of newly created habitat the project helps compensate for the losses related to coastal squeeze – the process whereby existing coastal habitats are trapped between a fixed landward boundary, such as a sea wall and rising sea levels and/or increased storminess.

The site – managed by the Wildfowl and Wetlands Trust (WWT),  now comprises a major new wetland, including intertidal salt marsh, transitional brackish habitat, coastal grazing marsh, brackish and saline lagoons, freshwater lagoon, and reedbed. These habitats benefit plant diversity, animals such as wetland birds and offset the losses of intertidal habitat that are occurring elsewhere in the Severn Estuary as a result of rising sea levels.

For more information on Steart, take a look at the video below kindly provided by the WWT.