What we delivered

  • Designed the restoration of 80 hectares of historical fenland to allow nature recovery of connected, functional wetland landscapes. 

  • Supported stakeholder engagement to ensure the scheme would meet requirements for future sustainable agriculture and payment-for-ecosystem services.

  • Provided ambitious yet pragmatic designs that can be rolled out across the wider Great North Fen wetland restoration project.

Services used
Environmental consulting / Hydrogeology and ground water / River restoration / River health

Get in touch with our team

Historic fenland habitats have become a rare natural asset following centuries of drainage and agriculture. As our climate becomes wetter, these landscapes are becoming more difficult to farm. Durham Wildlife Trust (DWT) has an ambitious plan for a Great North Fen, showcasing 800 hectares of cost-effective landscape restoration of priority wetland habitats, helping landowners adapt to a changing climate and delivering benefits for biodiversity, flood risk and carbon capture.

We supported DWT to deliver the first two of potentially many wetland habitat restoration schemes – from concept phase through to detailed design. Construction work was completed in 2024.  

We brought together a lean and integrated team of civil engineering, environmental, hydrological, landscape architecture, town planning, and water engineering services to design an exemplar wetland creation scheme. 

Our team worked closely with DWT to ensure the scheme’s deliverability. We realised time and cost savings by using 3D modelling to develop an efficient and adaptable design and applying lessons learned between phases. Photorealistic digital visualisation supported public engagement, helping to secure additional funding.

Durham Carrs is a cost-effective scheme that restores historic habits while minimising flood risks. It serves as an exemplar site to demonstrate to farmers and landowners the potential of their land for use in green finance markets for biodiversity net gain and housing nutrient neutrality schemes.  

We completed comprehensive research to understand the existing conditions and influences on the site. This meant that we could design a scheme that was sustainable and would support itself through natural processes without the need for extensive ongoing interventions.

Using a pragmatic approach, this project demonstrates that focusing inputs on a river floodplain rather than the river itself can deliver substantial habitat restoration benefits, which are achievable and repeatable at scale.  

A dirt road in a field.

We brought together a lean and integrated team of civil engineering, environmental, hydrological, landscape architecture, town planning and water engineering services. Visualisations were used to communicate the project to local groups. This is the before of Eldon Moor. 

A visualisation of a group of deer in a field.

Visualisation: Eldon Moor after.

River restoration 

In lowland environments such as the Durham Carrs, catchment hydrology is very finely balanced and flood risk easily increases if the wrong rewetting interventions are introduced. During our work on Bishop’s Fen, DWT initially wanted to realign the river, which had been straightened along the side of farm fields. We thoroughly explored all options but determined that it would not be possible to do this without causing water to back up for kilometres upstream. The land upstream is privately held outside of the scheme so we needed to ensure neither DWT, nor the scheme, would be exposed to liabilities associated with increased upstream or downstream flood risk.  

We were able to work with DWT to develop an intervention that wetted portions of the landscape without realigning the river. This solution achieved reasonable restoration of the site for a lower cost without increasing flood risk. The proposed intervention was consented through the planning process and we were able to apply the lessons learned to the second site at Ricknall Carrs.  

At Ricknall Carrs we took an equally pragmatic approach. We identified the river’s possible original path and designed and scraped a similar channel through the floodplain that mimics a sinuous river bend. The current scheme has opted not to touch the main river – mitigating cost and offsite impact challenges for DWT and enabling the scheme to progress and be consented within a feasible timeframe.   

A visualisation of an aerial view of a green landscape.

We were able to work with Durham Wildlife Trust to develop an intervention that wetted portions of the landscape without realigning the river. This is the before of Mordon North.

A landscape with trees and a body of water in the distance.

Visualisation: Mordon North after.

Hydrology and groundwater 

As so much of the delivery cost for these schemes would be in the earthworks, it was crucial that we presented DWT with as complete and accurate a picture as possible of the volume of earthworks required. Key earthworks included digging holes, scrapes, and channels into the flood plain, and redistributing the earth elsewhere.  

We initially completed 2D drawings to calculate the volume of earthworks required, before using Civil 3D to generate models of the site and proposed interventions. By completing volume calculations within the software, we could model the different surfaces to ensure our designs had the correct storage capacity. We could then extract these surface volume calculations into the hydraulic model, as well as using them for technical drawings and proposed seeding plans.

Using Civil 3D meant we were able to quickly and easily tweak alignments, leading to more efficient designs that could capture and hold more water on the fields to help restore them to wetland habitats. 

Through the modelling and design phase, we worked closely with DWT to determine its likely upper budget for the construction works. We could then rapidly generate a calculation of the optimum amount of earthworks for its budget, and scale interventions proportionately. Working in this way meant we were able to save a lot of time on modelling and optioneering, as well as helping DWT to manage its budget constraints.  

A field of grass with trees in the background.

Using Civil 3D meant we were able to quickly and easily tweak alignments, leading to more efficient designs that could capture and hold more water on the fields to help restore them to wetland habitats. This is the before of Horse Close.

A visualisation of a field of flowers.

Visualisation: Horse Close after. 

Arup provided guidance through an increasingly complex delivery process and future-proofed the scheme by developing a design that integrated with plans for
the wider catchment.

Jim Cokill

Trust Director, Durham Wildlife Trust