Assessing the potential of a newly-developed turbidity sensor for estimating sediment yields from recently burnt catchments

Wildfires are a common phenomenon worldwide. As a consequence of fire effects on vegetation and soil properties, a substantially increase in runoff and associated sediment transport has been reported in burnt slopes. Commercial turbidity sensors can be used to estimate sediment concentration in runoff samples. However, despite their existence for over two decades, the use of these sensors has been limited to specific situations. Plastic optic fiber (POF) turbidity sensors, due to their low-costs and suitability for multiplexing, have a high potential for monitoring turbidity in field conditions, either at plot, slope or catchment scale. In the present work, the performance of a newly developed POF sensor was compared with that of a OBS-3+ sensor, using artificial samples of sediments collected at the channel network of a recently burnt catchment in north-central Portugal. For all the three sediment fractions analysed in the present study, there was a positive correlation between the estimated suspended sediment concentrations of the POF and OBS-3+ sensors. Nevertheless, a consistently better relationship (higher R2 values) was found for POF than for OBS-3+ sensor.