New Method To Pinpoint Soil Erosion Could Help Protect Waterways

Cranfield University experts have developed a new method to precisely identify soil erosion hotspots along waterways, allowing for pre-emptive mitigation measures to be put in place that protect land and water systems.

Dr Katy Wiltshire, Research Fellow in the Cranfield Environment Centre, conducted research at Loch Davan in Aberdeenshire, combining two techniques to develop a more sophisticated and accurate measure for soil erosion. The two techniques are:

1. Sediment fingerprinting, analysing sediment in water systems to identify sources such as pasture land, or forest areas
2. Soil erosion modelling, designed to look at topography and identify where soil is being eroded from

Combining the two, Dr Wiltshire was able to pinpoint hotspots for soil erosion near Loch Davan, which has decreased in area over the last century because of sediment input. The Loch and its main feeder stream were previously classified as having poor to moderate ecological status^[1] by the Scottish Environment Protection Agency (SEPA) due to high concentrations of plant nutrients. This is caused by agricultural runoff from fields and fuels algal blooms which negatively impact water quality and aquatic biodiversity, and which produce toxins harmful to people and animals.

Dr Wiltshire said: “Excess sediment in waterways which has run off the land can have adverse impacts on biodiversity and wildlife and can add to flooding risk. Using this new method we can precisely identify areas where soil erosion pollutes waterways, and develop targeted strategies to address this at source.

“Something as simple as planting along riverbanks, cover crops, or ploughing fields in a different direction, can have a positive impact and keep soil on the land. And reducing soil erosion into water systems will mean cleaner rivers and lakes, healthier ecosystems and potentially lower costs for water treatment.”

The new method developed by Cranfield University means that highly accurate regional models for soil erosion can now be validated alongside broader-scale models like RUSLE (Revised Universal Soil Loss Equation), to more accurately identify hotspots and compare data with Europe or worldwide erosion rate estimates.

The research project also involved Dr Robert Grabowski, Reader in Catchment Science, and Dr Toby Waine, Reader in Applied Remote Sensing at Cranfield University. It was conducted in partnership with Dr Miriam Glendell, Research Lead – Catchment Modelling, and Dr Stephen Addy, Hydromorphologist, at The James Hutton Institute and Jeroen Meersmans, Associate Professor in environmental risk analysis within the water-soil-plant axis, at the University of Liege, and funded by the Natural Environment Research Council and SEPA.