The Environment Agency has created a new intertidal habitat at Calstock on the River Tamar in Cornwall.

The 11-hectare intertidal habitat is part of a new flood defence scheme to manage the risk of flooding to properties and critical infrastructure in Calstock. The overall cost of the project is £3.1 million.

Aerial view of the new wet intertidal area next to the River Tamar at Calstock

The intertidal area was made following the breach last year of the old flood bank along the Tamar. Environment Agency surveys showed the flood bank to be in poor structural condition. As a result the Environment Agency has built several new embankments totalling over 600 metres, protecting local properties, the village preschool and village hall, and the wastewater treatment works from flooding.

Working at night during low tides last November, the old flood bank was breached, and water from the estuary allowed to flow into pools and creeks previously constructed as part of the habitat creation.

The new habitat area will help off-set some of the impacts of sea level rise and climate change and clean river water by trapping sediment. An increase in biodiversity has already been seen, with birds and other wildlife attracted to the new intertidal habitat.

Jess Thomasson, Biodiversity Officer for the Environment Agency said:

“As in many of our estuaries, climate change and rising sea levels in the Tamar are leading to coastal squeeze where essential habitat is prevented from adapting and moving towards land by a structure such as a wall or bank.

“So, last year, after many years of careful planning, we started to create a series of interconnected creeks and the material won used to build the new flood banks. The breach in the redundant flood bank, allowing tidal water from the estuary to flow in and out of the creeks has enabled this new vital intertidal habitat to establish in front of the new flood banks.”

Last year the Environment Agency was a key partner in a similar project with the National Trust to create a new 1.7-hectare intertidal habitat at Cotehele on the Tamar.

Rob Price, Tamar Catchment Coordinator at the Environment Agency, said:

“The creation of new intertidal habitat on the Tamar at Cotehele and now this work at Calstock reinforces our aims to improve resilience to the changing climate and to provide a richer environment for people and nature.

“It will provide an invaluable tool in the fight against climate change by locking in carbon and also help improve overall water quality. This valuable work is an important part of an integrated programme of works to build the Tamar catchment’s resilience to a wide range of environmental pressures including those related to biodiversity and a changing climate.”

The project is being funded by Flood Defence Grant in aid, Water Environment Investment Fund, and contributions from the Tamar Community Trust.

According to the Met Office 2020 was the third warmest, fifth wettest and eight sunniest on record for the UK. No other year has yielded observations that fall in the top-ten for all three of these variables for the UK.

That included the wettest ever February, where most of the UK received more than twice the February long-term average rainfall, with 300% quite widely in the north and west, and over 400% in parts of the Pennines.

The most recent climate change predictions confirm we will experience wetter winters and drier summers, with an increased likelihood of more intense rainfall leading to flooding.