Anthropogenic influence on the Rhine water temperatures

Abstract

Abstract. River temperature is an important parameter for water quality and an important variable for physical, chemical and biological processes. River water is also used by production facilities as cooling agent. We introduced a new way of calculating a catchment-wide air temperature using a time-lagged and weighed average. Regressing the new air temperature vs. river water temperature, the meteorological influence and the anthropogenic heat input could be studied separately. The new method was tested at four monitoring stations (Basel, Worms, Koblenz and Cologne) along the river Rhine and lowered the root mean square error of the regression from 2.37 ∘C (simple average) to 1.02 ∘C. The analysis also showed that the long-term trend (1979–2018) of river water temperature was, next to the increasing air temperature, mostly influenced by decreasing nuclear power production. Short-term changes in timescales < 5 years were connected with changes in industrial production. We found significant positive correlations for the relationship.

Machine‐learning modeling of hourly potential thermal refuge area: A case study from the Sainte‐Marguerite River (Quebec, Canada)

“…Although this study was primarily motivated by the fact that thermal refuges are critical habitats for ichthyofauna, the models developed herein may have other applications. They could include other natural phenomena, such as rivers emptying into lakes (Smith & Simpkins, 2018), tributaries affecting the thermal regimes of lakes (Råman Vinnå et al, 2018), and freshwater plumes in estuaries (Huang et al, 2020), or artificial phenomena as man‐made thermal plumes in rivers and coastal environments, where the most common case is likely the discharge of warm‐water effluent from a power plant (e.g., Penk & Williams, 2019; Zavarsky & Duester, 2020).…”

Application of Rescaled Adjusted Partial Sums (Raps) Method in Hydrology – An Overview

“…The final RAPS must be 0 to verify whether the calculation is provided correctly because the time-series counter completes the summation of the time-series members. The authors of [6] concluded that a change in the slope of the RAPS values only indicates a change in the slope size of the original time series. A negative slope for the RAPS does not imply a negative slope in the original time-series.…”