4 minute read
Weardale
Weardale, England, United Kingdom
Restoring a landscape radically altered for hundreds of years. Part of the UNESCO Global Geopark in the North Pennines, Weardale’s history runs long. Since the twelfth century and even before, the area has experienced the degrading effects of deforestation, livestock farming, and lead and fluorspar industrial mining. Now, however, it is the site of an innovated natural flood management demonstration, an approach that reduces flood risk through habitat enhancement. The team enlisted the skills and knowledge of local landowners and farmers to inform an artificial intelligence model of the area, using the data to choose the site where the least number of features would attenuate the most water storage. Working within the archaeological constraints of this historic site and avoiding the nesting bird season and preventing harm to protected species and habitats, the team created 150 hectares of peatland and 75 hectares of woodland and restored 500 hectares of natural habitat, all of which contributed to reduced flood risk and increased water attenuation over 41 square kilometers. This project will help to increase understanding of the impact natural flood management can have on reducing flows along tributaries of the Upper River Wear, enabling scientific evaluation of the effectiveness of natural flood management at a catchment scale.
Article cover: The off-line pond works with the natural processes of the channel, filling with water during storm events. (Photo by Jonathan Kellagher, Environment Agency)
Producing Efficiencies
The project team mapped water storage opportunities over 100 square kilometers of watershed and entered the data into their optimization algorithm, developed by Arup, which calculated the minimum number of flood-control barriers needed to maximize storage. This process used runoff routes, lidar data, and flow accumulation and vector mapping data to exclude areas near roads, buildings, or mineral extraction sites. With locations determined, the team assessed data for each to select one of five developed “standard” earth, timber, or stone barriers to hold back flood water. This digital approach greatly increased cost efficiency by showing the team the most effective barrier design for a given location.
Using Natural Processes
All of the design types include locally sourced or low-carbon materials and consider local heritage and nature. They are robust enough to handle stormy weather and large livestock and will store excess water without needing a human team to open or close floodgates. The barriers, positioned across either a runoff pathway or landscaped onto a floodplain area, naturally reduce runoff and soil erosion and improve water quality further downstream. They then slowly release water over the course of a day, making themselves available for the next heavy rainfall.
Broadening Benefits
The project has restored 150 hectares of peatland that had degraded into bare peat, not only increasing the capacity of the peatland to hold water but increasing the biodiversity within the area. By paying farmers and landowners to construct the features on their own land, the project provides a direct economic benefit to the local community at the same time it reduces the risk of future costly flood recovery in the years to come. Additionally, the monitoring program feeds into a range of projects for local schools, developing an understanding of natural flood management.
Promoting Collaboration
The Environment Agency led this consensus-building effort by involving local participants as early as possible in the planning and by offering funding so the landowners could construct the features themselves. Working with Natural England, the Forestry Commission, the North Pennines Area of Outstanding Natural Beauty Partnership, and Durham County Council, the project team combined the expertise of a variety of groups with the skills and knowledge of local residents. This empowered the local community and provided critical information for the solution’s design.
