Technical Summary
Introduction and objectives
This technical report presents the public dataset of hydrological, morphological, and sedimentological data acquired in the river reaches downstream of artificial reservoirs as part of Task 5.3 of the LIFE CLIMAX PO project. The task focuses on sustainable sediment management in Alpine reservoirs, addressing both the restoration of storage capacity through planned flushing operations and the reduction of downstream environmental impacts in terms of water quality, river habitat, and hydromorphology.
The dataset was collected along the Stura di Demonte River, downstream of the Roccasparvera Dam (Cuneo Province), and provides the knowledge base for calibrating and validating hydraulic-morphodynamic models (Task 5.3.2), assessing aquatic habitats (Task 5.3.3), and defining operational guidelines for sustainable flushing operations replicable in other Alpine contexts.
Study area and monitoring strategy
The monitoring system encompasses three river reaches downstream of the Roccasparvera Dam to evaluate flushing effects at progressive distances from the reservoir and under different morphological conditions.
Site S1 is located immediately downstream of the dam at the Enel Green Power gauging station.
Site S2 is positioned downstream of the intake structure near the environmental flow release point.
Site S3 is located further downstream after the ISD mini-hydroelectric plant weir.
This multi-site monitoring strategy enables the quantification of suspended sediment propagation, the characterization of hydro-morphological modifications at different spatial scales, and the evaluation of hydraulic infrastructure effects on sediment dynamics.
Monitoring systems and instrumentation
The monitoring infrastructure integrates multiple technologies.
Continuous turbidity monitoring operates at all three sites using Hach Solitax sc optical sensors with nephelometric dual-beam technology, acquiring turbidity (FNU) and total suspended solids (TSS) data transmitted in real time via 4G LTE.
Water level and temperature sensors were installed at Sites S2 and S3 in April 2025, recording data every 15 minutes in standalone mode with periodic manual download. Site S1 utilizes an existing Enel Green Power water level gauge.
Bathymetric surveys of the reservoir were conducted pre-flushing (April 2025) using a boat-mounted Acoustic Doppler Current Profiler (ADCP River Surveyor M9), and post-flushing (June 2025) using both single-beam technology and an innovative remotely-controlled unmanned surface vehicle equipped with multibeam sensors. These surveys enable precise quantification of mobilized sediment volumes.
Drone-based surveys employed both optical (DJI Mavic 3E) and LiDAR (DJI Zenmuse L1 on Matrice 300) technologies. LiDAR was used at Site S1 to penetrate dense riparian vegetation.
Surveys were conducted in April (pre-flushing), May (immediately post-flushing), and July 2025, producing high-resolution orthophotos and digital terrain models. Bathymetric corrections were applied using GNSS RTK and ADCP measurements to ensure accuracy in submerged areas.
Monitored flushing operation
The flushing operation occurred from May 5–9, 2025, during which controlled drawdown reduced the reservoir level by approximately 8 meters (to 615.47 m a.s.l.).
The continuous monitoring system captured the complete temporal evolution of suspended sediment concentration across all three sites, documenting how the turbidity wave propagated downstream with progressive temporal delay and gradual intensity attenuation.
During flushing operations, 50 samples of turbid water were taken at different times near the three points where the turbidimeters had been installed, in order to plot a specific NTU-concentration curve.
Water level and temperature variations were recorded at 15-minute intervals at Sites S2 and S3, while aerophotogrammetric surveys documented erosion and deposition patterns.
Dataset structure and future perspectives
The dataset comprises continuous time series (turbidity, TSS, water level, temperature), bathymetric models enabling volumetric sediment calculations, multi-temporal digital terrain models and orthophotos, and contextual data including reservoir levels, discharge rates, and meteorological variables.
The flushing operation, originally scheduled for spring 2024, was postponed to 2025 due to technical-administrative and regulatory delays beyond the project’s control.
These delays, combined with difficulties in procuring specialized monitoring equipment, resulted in the completion of the turbidimeter installation between February and March 2025 (M25-M26), later than initially planned in the MS5.3 milestone timeline.
Despite this delay, all monitoring stations are now fully operational and actively collecting data.
Consequently, monitoring will continue at least until May 2026 to acquire a full year of post-flushing observations, with extended acquisition planned to strengthen results and conduct more robust analyses.
The extended timeline provides an opportunity for more comprehensive baseline characterization prior to flushing events.
Future campaigns will include seasonal aero-photogrammetric surveys, sedimentological sampling for grain-size characterization, and continued continuous acquisition of turbidity, level, and temperature data.
This comprehensive, high-quality dataset will support the development of evidence-based operational guidelines replicable across Alpine contexts, contributing to sustainable water resource management and climate change adaptation strategies.
Introduzione
Il presente documento costituisce la relazione tecnica relativa al Deliverable D5.1.1, che ha l’obiettivo di raccogliere e rendere disponibile un dataset pubblico contenente dati idrologici, morfologici e sedimentologici acquisiti nei tratti fluviali sottesi dagli invasi artificiali oggetto di studio nel Task 5.3 del progetto LIFE CLIMAX PO.
Il Task 5.3 si concentra sulla gestione sostenibile dei sedimenti negli invasi alpini, affrontando contemporaneamente due sfide interconnesse: da un lato il ripristino della capacità di invaso attraverso operazioni di svaso e fluitazione pianificate, dall’altro la riduzione degli impatti ambientali a valle in termini di qualità dell’acqua, habitat fluviale e idromorfologia.
Questo approccio integrato richiede una base conoscitiva solida e dettagliata, costruita attraverso un monitoraggio continuo e multi-parametrico che permetta di comprendere i processi in atto e supportare le decisioni gestionali.
Il dataset qui presentato rappresenta il risultato delle attività di monitoraggio condotte sul fiume Stura di Demonte, a valle della diga di Roccasparvera, e costituisce la base conoscitiva fondamentale per diverse attività progettuali: la calibrazione e validazione dei modelli idraulico-morfodinamici sviluppati nel Task 5.3.2, la valutazione degli habitat acquatici prevista nel Task 5.3.3, e la definizione di linee guida operative per la gestione sostenibile delle operazioni di flushing replicabili in altri contesti alpini.
L’importanza di questo dataset risiede non solo nella completezza e nella qualità delle misure acquisite, ma anche nell’approccio metodologico adottato, che integra tecnologie innovative di monitoraggio in continuo, campagne di rilievo aerofotogrammetrico e misure dirette sul campo.
Questo approccio multi-scala permette di cogliere sia la dinamica rapida degli eventi di flushing sia l’evoluzione morfologica di medio-lungo periodo del corso d’acqua.