Author(s): Chiara Arrighi; Marco De Simone; Isabella Bonamini; Andrea Di Grazia; Cristina Simoncini; Stefano Bartalesi; Stefano Consumi; Fabio Castelli

Linked Author(s): Chiara Arrighi, Marco De Simone, Fabio Castelli

Keywords: Ecological flow; Hydrologic balance; Climate change; EU Water Directiveter

Abstract: Ecological flow is the discharge required to maintain the vitality of a water ecosystem and preserve biodiversity and ecosystem services. Ecological flow is thus a matter of both water quantity and quality as defined by the EU Water Directive (60/200/EC). With respect to minimum low-flow discharges, usually estimated by means of statistical analysis of the discharge-frequency characteristic of a river reach, e.g., the 7-day, 2-year discharge (Q7,2), ecological flow is more complex to determine because it depends on other environmental parameters, such as the river morphology, the presence of dissolved nutrients etc. Climate change might significantly affect ecological flow through alterations of precipitation regime and temperature. River District Authorities in charge of issuing Water Management Plans are required to determine ecological flows capable of preserving a good quality status with uncertain future climate conditions. The aim of this work is to determine the sensitivity of ecological flow to climate change with an explicit simulation of hydrologic balance. The hydrologic balance is evaluated by modelling of precipitation, runoff, evapotranspiration, and groundwater storage with a continuous, raster-based, distributed model. Fresh water withdrawals from domestic, agricultural and energy demands are also included. Future climate scenarios are based on the IPCC WGI Atlas dataset on mean temperature and total precipitation for the Mediterranean Region and several emissions scenarios. The method is applied to a river catchment in Tuscany (central Italy) and provides useful insights into water management practices at large scales.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221056

Year: 2022