Titre
Probability and Consequence of Postfire Erosion for Treatability of Water in an Unfiltered Supply System
Type
article
Institution
Externe
Périodique
Auteur(s)
Nyman, Petter
Auteure/Auteur
Yeates, Peter
Auteure/Auteur
Langhans, Christoph
Auteure/Auteur
Noske, Philip J.
Auteure/Auteur
Peleg, Nadav
Auteure/Auteur
Schärer, Christine
Auteure/Auteur
Lane, Patrick N. J.
Auteure/Auteur
Haydon, Shane
Auteure/Auteur
Sheridan, Gary J.
Auteure/Auteur
Liens vers les personnes
ISSN
0043-1397
Statut éditorial
Publié
Date de publication
2021-01
Volume
57
Numéro
1
Peer-reviewed
Oui
Langue
anglais
Résumé
Forested catchments are critical to water supply in major cities. Many of these catchments face the threat of postwildfire erosion, which can contaminate reservoir water. The aim of this paper is to determine the probability and duration of disruptions to treatability due to runoff-generated debris flows in the first year after a wildfire, before substantial vegetation recovery takes place. We combine models of reservoir hydrodynamics, postfire erosion, and stochastic rainfall to determine probability and magnitude of sediment concentration at the reservoir water offtake. Central to the paper is our technique for linking model components into a risk framework that gives probabilities to the number of days that the turbidity threshold for treatment is exceeded. The model is applied to the Upper Yarra reservoir, which is the linchpin of the water supply system for Melbourne in SE Australia. However, the framework is applicable to other unfiltered water supply systems where suspended sediment is a risk to treatability. Results show that postwildfire erosion poses a substantial threat, with a relatively high probability (annual exceedance probability = 0.1–0.3) of water being untreatable for >1 year following a high-severity wildfire. Important factors that influence the risk include postwildfire runoff potential, reservoir temperature, and the amount of clay-sized grains in eroding headwaters. Assumptions about spatial-temporal rainfall attributes, reservoir hydrodynamics, and the catchment erosion potential are all important sources of error in our estimate of risk. Our approach to risk quantification will help support planning, risk management, and strategic investment to mitigate impacts.
Sujets
PID Serval
serval:BIB_FA428F1FB11F
Date de création
2021-08-09T14:02:08.840Z
Date de création dans IRIS
2025-05-21T05:57:40Z