title: First observations of saturopeaking: Characteristics and implications.
abstract: During the monitoring of total dissolved gas (TDG) saturation in the Vetlefjordelva River in western Norway in 2014-2015, characteristic waves of supersaturated water were discovered. These waves were significantly correlated with hydropower operation, which was run by hydropeaking (R2=0.82, p<0.001). The TDG saturation varied between 99% and 108%, with a median of 105%. The term "saturopeaking" is introduced for these waves, defined as the artificial, rapid, periodic and frequent fluctuation of gas saturation caused by hydropeaking. Hydropeaking is recognized as hydropower operation that rapidly fluctuates according to the electricity market demand. Though the observed TDG saturation levels were moderate and not likely to cause acute effects on biota, we expect that the observed saturopeaking may have significant ecological impacts in general, especially in cases with TDG saturation levels >110^% which is considered as potentially lethal for fish in rivers.
authors.affiliation: Uni Environment LFI Uni Research, Bergen, Norway. Electronic address: ulrich.pulg@uni.no.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pulg
authors.affiliation: Uni Environment LFI Uni Research, Bergen, Norway.
authors.forename: Knut Wiik
authors.initials: KW
authors.lastname: Vollset
authors.affiliation: Uni Environment LFI Uni Research, Bergen, Norway; Department of Biology, University of Bergen, Bergen, Norway.
authors.forename: Gaute
authors.initials: G
authors.lastname: Velle
authors.affiliation: Uni Environment LFI Uni Research, Bergen, Norway.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Stranzl
mesh_terms: D005740:Gases / Q000032:analysis*; D009664:Norway; D011210:Power Plants; D045483:Rivers / Q000737:chemistry*; D014872:Water Movements
chemical_list: D005740:Gases
keywords: Hydropeaking; Hydropower; Pulse flow; Salmo salar; Salmo trutta; Supersaturation