It is widely recognized that the hydrological regime of natural flow plays a primary and crucial role in influencing the physical condition of habitats, which, in turn, determines the biotic composition and sustainability of aquatic ecosystems. The current hydro-ecological understanding states that all flow components might be considered as operational targets for water management, starting from base flows (including low flows) to high and flood regimes in terms of magnitude, frequency, duration, timing, and rate of change. Several codes have been developed and applied on different case studies in order to define common tools to be implemented for Eflow assessment. This work deals with the definition of an operative procedure for the evaluation of the Eflow monthly distribution to be adopted in a generic watercourse cross-section for sustainable surface water resource management and exploitation. The methodology proposes the application of the Indicators of Hydrologic Alteration methodology (IHA by TNC) coupled to the valuation of the Index of Hydrological Regime Alteration (IARI by ISPRA) as an operative tool to define the ecological flow in each monitoring cross-section to support sustainable water resource management and planning. The case study of the Agri River in Basilicata (Southern Italy) is presented. The analyses were carried out based on monthly discharge data derived by applying the HEC-Hydrological Modeling System at the basin scale using the daily rain data measurements obtained by the regional rainfall gauge stations and calibrated through the observed inlet water discharge registered at the Lago del Pertusillo reservoir station.

River morphology and ecosystem are macro-indicators of climate and land-use changes as well as human activities and land policies. In the last decades, knowledge of water resources, in terms of quality, quantity, prevention and control, has quickly increased-even for the availability of advanced methodologies and technologies both for monitoring and modelling fields. Nevertheless, the objective of a good ecological status of water bodies has not yet been reached due to human pressure which still induces long term impacts as well as direct or indirect physical constraints. In such a context, the European Water Framework Directive introduces the concepts of artificial water bodies (AWB) and heavily modified water bodies (HMWB) and states that in such cases good ecological potential must be reached while good ecological status is required only for natural water bodies (NWB). Further, the methodologies proposed for the AWB and HMWB need a wide set of parameters and measurements, which are not always systematically available, inducing further actions and analyses in order to evaluate the quality level of the water bodies. Moreover, the AWB or HMWB classification represents an opportunity to resize the measures addressed to achieve good ecological status both in terms of economic engagement and timing with relevant consequences on water resource planning and management. The paper deals with these issues and synthetically reports the work done on the whole Lucanian river network (Basilicata region, Southern Italy) and also presents the Agri River case study in order to classify, as best as possible, AWB, HMWB and NWB as well as to support survey planning.

According to the Water Framework Directive, the Ecological Flow (Eflow) is assumed to be the minimum water discharge required to achieve and maintain the environmental objectives of “good quality status” in a natural water body. It is highly recognized that, the hydrological regime of natural flow plays a primary and crucial role influencing the physical conditions of habitats, which in turn determines the biotic composition and sustainability of aquatic ecosystems. Furthermore, the simple assumption to supply a minimum instream during dry periods is not enough any longer in order to protect the river environment. The recent hydro-ecological understanding states that all flow components might be considered as operational targets for water management, starting from base flows (including low flows) to high and flood regimes in terms of magnitude, frequency, duration, timing and rate of change. Several codes have been developed and applied on different case studies in order to define common tools to be implemented for the Eflow assessment. The study proposes the application of the Indicators of Hydrologic Alteration methodology (IHA by TNC) coupled to the valuation of the Index of Hydrological Regime Alteration (IARI by ISPRA) as an operative tool to define the ecological flow in each monitoring cross section to support the sustainable water resources management and planning. The case study of Agri River, in Basilicata (Southern Italy) is presented. The analyses have been carried out on monthly discharge data derived applying the HEC-Hydrological Modelling System at the basin scale using the daily rain data measurements obtained by the regional rainfall gauge stations and calibrated through the observed inlet water discharge registered at the Lago del Pertusillo reservoir station.

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