Sediment aggregation and water quality in wildfire-affected river basins

摘要: Off-site transfer of nutrient-rich burnt soil has implications for downstream water quality. Coarsening effective particle size (EPS) distributions in material via aggregation fines into composite particles modifies post-fire sediment and nutrient transport dynamics. Experiments were undertaken to establish temperature controls on wildfire-enhanced aggregation. Burnt unburnt from a temperate eucalypt forest analysed EPS settling velocity using LISST-ST (Laser In Situ Scatter Transmissometry with Settling Tube) analyser. Next, samples (250–550°C) before further analysis the LISST-ST. velocities naturally aggregates greater than same EPS. Experimental burning indicated that dense water-stable form at relatively low temperatures (250°C) probably due distillation carbonisation, through pyrolysis, organic volatiles surface litter. Under these conditions, distribution coarsens up 50% <63-μm fraction becoming aggregated. A positive relationship between ‘plant-available’ phosphorus burn was observed. Given large proportion particulate is associated fraction, fire-related processes have potentially important fine storage