The Environment Agency has completed a river restoration partnership project which will eliminate more than 117 tonnes of carbon, help drought and reduce flooding.

The restoration project between the Environment Agency, Breheny Civil Engineering, Ebsford Environmental and a local landowner took place on the River Witham in Lincolnshire

The project, described as a “stage zero river reset”, will absorb more than 117 tonnes of carbon, help drought and reduce flood risk downstream. It involved infilling the river channel with soil to allow water to spill out and choose the direction it takes. This will create wetlands and smaller streams. Fallen timber has been added to slow the flow of the water leaving the site.

The wetlands act like a sponge, encouraging water to spill out onto the floodplain during wet periods but also release water back into the river in low flow periods. This means the wetlands will help support wildlife during drought as well as reducing flood risk downstream. The wetlands will also help to trap nutrients and fine sediment resulting in cleaner river water downstream, benefitting fish and other animals.

The works have already raised groundwater levels across the site by 1.5 metres, creating a wetter environment that may not have existed for 2,500 years. The work has combated the historical drainage that took place for land drainage and milling purposes.

Geomorphologist Matt Parr and Project Manager Katie Murphy, from the Environment Agency, said:

“We are delighted with the initial results regarding the wetter landscape and water table recharge benefits because of this project.

“These works link to other projects across the UK and the US where this technique was developed. The project also links to a wider catchment-based floodplain restoration approach led by East Mercia Rivers Trust and the Wild Trout Trust. They have been instrumental in supporting delivery of projects on the Upper Witham.

“It will be fascinating to watch the site, river and wetlands develop and evolve over time. This is especially true now that the river has the freedom to choose its own shape and form without human interference.

“We have created a wetter environment that may not have existed for 2,500 years.”

The restoration is in a rural river valley location on the River Witham above Grantham. There are no properties or roads within the confined valley floor that can be impacted by the wetter landscape.

The project is being monitored by researchers from the University of Lincoln and UMEÅ University in Sweden. The researchers will study how the new wetland landscape respond to floods and droughts and the effect on downstream water levels. They will also be monitoring the improvements in biodiversity for native brown trout, rare native crayfish, as well as benefits to climate change resilience.

The project was inspired by similar schemes in north-west America and in the UK. It links across to similar projects with the National Trust at Holnicote in Devon and Riverlands projects in Cumbria.

The Agency said it is using nature to reduce flood risk across the country by using nature-based solutions in combination with other measures such as traditional engineered flood and coastal defences.

Natural flood management can include a range of measures, including tree planting to slow run-off, peatland restoration to store water in upper catchments, restoring flood plains to make space for water away from urban areas.