Communicating And Visualizing Erosion-associated Risks To Infrastructure (CAVERTI)

Soil erosion is a major environmental problem, affecting agriculture, the natural environment and urban areas through sediment-related damage to roads, buildings and infrastructure such as water, gas and electricity supply networks and its impact on flood risk, water quality, loss of the nutrient-rich upper soil layers, sedimentation of waterways and eutrophication of water bodies. There is significant interest amongst stakeholders with whom the project team have engaged in protecting assets such as pipes and gauges for transport and monitoring, where to locate new assets and the costs of sediment removal. These issues highlight the need for a better understanding of where erosion is happening, how to reduce erosion risk and for effective ways of communicating mitigation strategies to stakeholders such as farmers, land managers and policy-makers.
The proposed work will identify the parts of the landscape most susceptible to soil erosion in order to target those areas for mitigation using a new soil-erosion modelling approach developed in two earlier NERC-funded projects. Empirically measureable transport distance and virtual velocity of soil particles are used to account for the difference in water and sediment transport in a scale-independent way. A cell-based and particle-based approach are combined to simulate the movement and 'life history' of individual sediment particles, making it possible to determine where soil eroded from a particular site is located after a specified period of time. The model is thus capable of identifying, for example, where the soil entering a river came from and how long it took to travel from its source site to the river, addressing precisely the need identified by our stakeholders.
The partner organization in this proposal is the Wear Rivers Trust which is responsible for conservation, protection, rehabilitation and improvement of the landscape and watercourses of the whole River Wear catchment. The Trust have identified the problem that silt moving into Brancepeth Beck near Durham represents a direct threat to a range of local infrastructure including roads, bridges, culverts, electricity pylons and buried services and an indirect threat to wider infrastructure downstream such as urban areas, roads, bridges, distribution networks, power generation facilities, sewerage, drainage and communications systems. There is thus considerable interest in mitigation measures that could be introduced on farms in the locality to reduce the risk of silt movement during heavy rainfall events.
This project will use Brancepeth Beck as a case study in risks to infrastructure due to soil erosion, addressing directly the problem of sediment transport through applying the soil erosion model and developing new decision support tools in partnership with local farmers, the Wear Rivers Trust and other stakeholders. The Decision Support Matrix (DSM) approach will be used, involving the development of a range of visualization and communication tools to help assess and compare the risks associated with different farming practices and explore options to manage runoff. The DSMs will be developed through direct engagement with stakeholders employing a Participatory Action Research approach, ensuring that the examples and language used makes sense to end-users. The DSM approach has proven effective at increasing stakeholders' confidence in making decisions to make landscapes more resilient. DSMs have been taken up widely in the UK by bodies such as the EA and Defra, and have been successfully employed within wider decision support frameworks alongside modelling at multiple scales.
Engagement with the Wear Rivers Trust and farmers with whom they work indicates a strong interest in reducing soil erosion risk through identifying the source of sediment using models and in developing communication and visualization tools using the DSM approach.