Sediment and contaminant delivery to upland reservoirs following severe wildfire

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The devastating moorland wildfires of June and July 2018 which ravaged large parts of Northern England were the worst peatland wildfires since 1976. Severe wildfires, as distinct from managed burning, can act as a catalyst, resulting in catastrophic change in surface vegetation, soil and water runoff systems. Removal of vegetation by fire, coupled with changes to soil physical and chemical properties, enhances runoff and increases delivery of sediment and other contaminants to drainage systems. Although fire is a significant driver of change in moorland habitats the downstream impacts remain largely unknown. Given that such wildfires are likely to increase in frequency as the climate changes, the recent 2018 fires provide a rare opportunity to capture new data on the impact and response of these burnt moorland catchments in the immediate aftermath of the event. In this project we will quantify sediment and contaminant delivery to upland reservoirs from burnt catchments. We will work with local landowners and responsible authorities to promote recovery of these sensitive catchments by actively facilitating knowledge exchange between researchers and land managers. The overall objective of the project is to quantify sediment and contaminant delivery from upland catchments in the immediate aftermath of a severe wildfire which affected Northern England in July 2018. The general approach considers the fate of fire-generated 'sediment' from source-to-sink along the upland sediment cascade from eroding moorland hillslopes, through the upland channel network to deposition in downstream reservoirs. We will characterise sediment sources within the catchment so that sediment fingerprinting can be used to trace burnt sediment as it moves downstream. Mapping of the catchment will allow us to determine the pathways eroded sediment takes from the hillslopes, through the stream channels and into the reservoirs. Using a combined approach of trapping sediment in the reservoir and the stream network we will quantify the fluxes of eroded sediment (e.g. total, contaminant, organic, inorganic) from the catchment downstream. By analysing sediment cores for charcoal layers deposited in the Victorian reservoirs we will reconstruct a history of fire events in the local region. This information will be extremely valuable in addressing several fundamental questions including whether catchment erosion rates significantly increased after severe moorland fires and which areas are particularly at risk?; and how significant are the current fires in comparison to the historical record of fires in the area?. By establishing clear pathways of knowledge exchange between researchers, local landowners and restoration teams we will directly assist in the recovery of the catchments from the impacts of the fire.