Quantification of daily peak hydropower effects on aquatic fauna and management to minimize environmental impacts

Abstract

The effects of intermittent power generation on the fish fauna and benthic invertebrates of several Austrian rivers have been investigated quantitatively. In contrast to the more or less local adverse effects of impoundments or stream channelization, artificial flow fluctuations generally disturb a long section of a given river. Within all the river sections investigated, a breakdown of the benthic invertebrate biomass of between 75 and 95% was observed within the first few kilometres of river length. A reduction of between 40 and 60% of biomass compared with undisturbed areas could be detected within the following 20-40 km. The reduction of the fish fauna is within the same order of magnitude and correlates well with the amplitude of the flow fluctuations. Several reasons for the breakdown are summarized and proposals for the minimization of these detrimental effects of artificial short-term fluctuations are given.

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

“…The cumulative duration of drying was set to 50% of duration of the study and the drying frequency was chosen to achieve a compromise between environmental realism and technical feasibility in terms of numbers of water renewals. The chosen frequency of drying events could be seen in the context of rivers experiencing strong flow regulation or daily peak hydropower effects with drying events occurring rapidly during low-flow periods (Moog, 1993 andJones, 2014) on a daily or weekly basis (Fette et al, 2007).…”

“…The high frequency of drying events should be seen in the context of rivers experiencing regulated flow or daily peak hydropower effects with drying events occurring rapidly during low-flow periods (Moog, 1993 andJones, 2014). Here, dry periods were simulated by allowing microcosms to rapidly empty, which is in contrast to river ecosystems experiencing seasonal drying events where water-level drawdown generally leads to the formation of isolated pools and, among other stressors (e.g., increased temperature, reduced dissolved oxygen), a concentration of nutrients and contaminants that could exacerbate the toxic effects (through a decrease in dilution capacity; Proia et al, 2013).…”

The Economic Analysis of Water Use in the Water Framework Directive Based on the System of Environmental-Economic Accounting for Water: A Case Study of the Guadalquivir River Basin

“…It should be noted that, although short-term flow fluctuations induced by hydroelectric power generation cause adverse effects on macrophytes and fish fauna [37] and its life cycle cause greenhouse gas emissions [38], almost all water abstracted for hydropower is returned to the ecosystem, while abstracted soil water is evapotranspired and lost from the basin ('consumed' in hydrological terms). There is, therefore, a crucial difference between abstracted (used) water and consumed water.…”

Spatial and temporal variation of benthic macroinvertebrates in the Nam Gnom Basin receiving discharged waters from the Nam Theun 2 Reservoir (Lao PDR)

“…These alterations cause changes in assemblage structure of aquatic organisms and bioassessment methods can be used to assess environmental consequences of dams. Macroinvertebrates are widely used for that purpose (Armitage, 1984;Boon, 1988;Moog, 1993;Cortes et al, 1998;Ogbeibu & Oribhabor, 2002). Their ubiquitous occurrence, high species richness, and limited migration patterns provide a large spectrum of responses to environmental changes including short to long-term cumulative effects (Resh et al, 1995).…”