River water temperature quantiles as thermal stress indicators: Case study in Switzerland

The variability of the river water thermal regime has important consequences on environment and aquatic habitat. In 25 independent identically distributed stations in Switzerland, local frequency analysis is used to quantify extreme temperatures. Probability distributions are fitted data estimate maximum temperatures corresponding different return periods. goodness fit statistical evaluated using Akaike Bayesian Information Criteria. L-moment ratio diagrams also validate choices appropriate candidate distributions. Results show that for high altitude two-parameter Weibull (W2) distribution most adequate represent while low commonly selected Normal (N) Inverse Gamma (IG). confirm results analysis. These point presence a regional homogeneity study area. River temperature quantiles compared know thresholds above which stress occurs relatively ubiquitous salmonid species Europe (Brown trout).