Response of stream benthic macroinvertebrates to current water management in Alpine catchments massively developed for hydropower

• Published in: The Science of the total environment 2017-12, Vol.609, p.484-496
• Main Authors: Quadroni, Silvia, Crosa, Giuseppe, Gentili, Gaetano, Espa, Paolo
• Format: Article
• Language: English
• Subjects: Alpine catchment; Biomonitoring; Environmental flow; Minimum flow; Water Framework Directive; Water management
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.07.099

The present work focuses on evaluating the ecological effects of hydropower-induced streamflow alteration within four catchments in the central Italian Alps. Downstream from the water diversions, minimum flows are released as an environmental protection measure, ranging approximately from 5 to 10% of the mean annual natural flow estimated at the intake section. Benthic macroinvertebrates as well as daily averaged streamflow were monitored for five years at twenty regulated stream reaches, and possible relationships between benthos-based stream quality metrics and environmental variables were investigated. Despite the non-negligible inter-site differences in basic streamflow metrics, benthic macroinvertebrate communities were generally dominated by few highly resilient taxa. The highest level of diversity was detected at sites where upstream minimum flow exceedance is higher and further anthropogenic pressures (other than hydropower) are lower. However, according to the current Italian normative index, the ecological quality was good/high on average at all of the investigated reaches, thus complying the Water Framework Directive standards. [Display omitted] •Minimum flows are currently implemented in the study area as environmental flows.•5-years monitoring of streamflow and benthos was performed at 20 regulated reaches.•Differences of benthic communities were found at sites with different flow patterns.•According to the current Italian standards, stream quality was on average good/high.