From Lithological Modelling to Groundwater Modelling: A Case Study in the Tiber River Alluvial Valley

This study presents the results of a research project financed by the Lazio Regional Government. The research focused on defining an integrated model of recent alluvial deposits in the Tiber River. To achieve this objective, geological boreholes were made to monitor the aquifer and in situ and laboratory tests were carried out. The data obtained were used to detail stratigraphic aspects and improve the comprehension of water circulation beneath the recent alluvial deposits of the Tiber River in the urban area of Rome, between the Ponte Milvio bridge and the Tiber Island. The stratigraphic intervals recognised in the boreholes were parameterised based on their litho-technical characteristics. The new data acquired, and integrated with existing data in the database of Institute of Environmental Geology and Geoengineering of the Italian National Research Council, made it possible to produce a three-dimensional model of the lithologies in the study area. The model of the subsoil, simplified for applied reasons, was described in hydrostratigraphic terms: three different lithotypes were subjected to piezometric levels monitoring. Finally, the research generated a numerical hydrological model in a steady state. In general, this study demonstrates how a numerical hydrogeological model calibrated by piezometric monitoring data can support the construction of a geological model, discarding or confirming certain hypotheses and suggesting other means of reconstructing sedimentary bodies.

From Lithological Modelling to Groundwater Modelling: A Case Study in the Tiber River Alluvial Valley

This study presents the results of a research project financed by the Lazio Regional Government. The research focused on defining an integrated model of recent alluvial deposits in the Tiber River. To achieve this objective, geological boreholes were made to monitor the aquifer and in situ and laboratory tests carried out. The data obtained was used to detail stratigraphic aspects and improve the comprehension of water circulation beneath the recent alluvial deposits of the Tiber River in the urban area of Rome, between the Ponte Milvio bridge and the Tiber Island. The stratigraphic intervals recognised in the boreholes were parameterised based on their litho-technical characteristics. The new data acquired, and integrated with existing data in the CNR IGAG database, made it possible to produce a three-dimensional model of the lithologies in the study area.The model of the subsoil, simplified for applied reasons, was described in hy-drostratigraphic terms: three different lithotypes were subjected to piezometric levels monitor-ing. Finally, the research generated a numerical hydrological level in a stationary regime. In general, this study demonstrates how a numerical hydrogeological model calibrated by piezo-metric monitoring data can support the construction of a geological model, discarding or con-firming certain hypotheses and suggesting other means of reconstructing sedimentary bodies.

Multivariate Streamflow Simulation Using Hybrid Deep Learning Models

Reliable and accurate streamflow simulation has a vital role in water resource development, mainly in agriculture, environment, domestic water supply, hydropower generation, flood control, and early warning systems. In this context, these days, deep learning algorithms have got enormous attention due to their high-performance simulation capacity. In this study, we compared multilayer perceptron (MLP), long short-term memory (LSTM), and gated recurrent unit (GRU) with the proposed new hybrid models, including CNN-LSTM and CNN-GRU. Hence, we can simulate one-step daily streamflow in different agroclimatic conditions, rolling time windows, and a range of variable input combinations. The analysis used daily multivariate and multisite time series data collected from Awash River Basin (Borkena watershed: Ethiopia) and Tiber River Basin (Upper Tiber River Basin: Italy) stations. The datasets were subjected to rigorous quality control processes. Consequently, it rolled to a different time lag to remove noise in the time series and further split into training and testing datasets using a ratio of 80 : 20, respectively. Finally, the results showed that integrating the GRU layer with the convolutional layer and using monthly rolled average daily input time series could substantially improve the simulation of streamflow time series.

Tectonics and fluvial dynamism affecting the Tiber River in Prehistoric Rome

Geomorphological investigations in Rome’s river valley are revealing the dynamism of the prehistoric landscape. It is becoming increasingly apparent that paleogeographic conditions that defined Rome in the historical era are the product of changes since the Bronze Age, which may be the result of local fault activity in addition to fluvial dynamism. Through a dedicated borehole chronostratigraphic study, integrated by 14C and archaeological dates, and paleomagnetic investigations, we offer here new evidence for fault displacement since ca. 4500 years/BP. We present the failure of the sedimentary fabric of a clay horizon caused by liquefaction processes commonly linked with seismic shaking, interpreting an (ca. 4 m) offset to signify the existence of a fault line located at the foot of the Capitoline Hill. In addition, we show evidence for another (ca. 1 m) offset affecting a stratigraphic horizon in the river channel, occurring along another hypothesized fault line crossing through the Tiber Valley. Movement along this fault may have contributed to a documented phase of fast overflooding dated to the sixth century BCE which eventually led to the birth of the Tiber Island. The most plausible scenario implies progressive deformation, with an average tectonic rate of 2 mm/year, along these inferred fault lines. This process was likely punctuated with moderate earthquakes, but no large event necessarily occurred. Together, the available evidence suggests that during the early centuries of sedentary habitation at the site of Rome, active fault lines contributed to significant changes to the Tiber River valley, capable of challenging lowland activities.

Vulnerability of Hydraulic Constructions in Flood-Prone Agricultural Areas

The conditions of high hydraulic risk are mainly due to the interference between the river network and bridges, their relative access ramps and road embankments located in the floodplain. Actually, bridges are not always structurally adequate to withstand severe flood waves. In flood restoration works, there is an objective difficulty in implementing the structural safety of bridges because of historical, artistic and economic issues. Thus, the risk mitigation strategy often accounts for the assessment of the vulnerability degree of each bridge/road embankment according to an evaluation scale. Here we present a methodology regarding the classification of the vulnerability degree and its application to 84 works located in the alluvial area of the Tiber River, in the area of the Province of Perugia. For the purposes of a synthetic classification of works vulnerability, the individual assessed parameters are compared by means of subsequent contingency tables in order to compute the resulting vulnerability degree.

Capitoline Dolphins: Residency Patterns and Abundance Estimate of Tursiops truncatus at the Tiber River Estuary (Mediterranean Sea)

Periodic assessments of population status and trends to detect natural influences and human effects on coastal dolphin are often limited by lack of baseline information. Here, we investigated for the first time the site-fidelity patterns and estimated the population size of bottlenose dolphins (Tursiops truncatus) at the Tiber River estuary (central Mediterranean, Tyrrhenian Sea, Rome, Italy) between 2017 and 2020. We used photo-identification data and site-fidelity metrics to study the tendency of dolphins to remain in, or return to, the study area, and capture–recapture models to estimate the population abundance. In all, 347 unique individuals were identified. The hierarchical cluster analysis highlighted 3 clusters, labeled resident (individuals encountered at least five times, in three different months, over three distinct years; n = 42), part-time (individuals encountered at least on two occasions in a month, in at least two different years; n = 73), and transient (individuals encountered on more than one occasion, in more than 1 month, none of them in more than 1 year; n = 232), each characterized by site-fidelity metrics. Open POPAN modeling estimated a population size of 529 individuals (95% CI: 456–614), showing that the Capitoline (Roman) coastal area and nearby regions surrounding the Tiber River estuary represent an important, suitable habitat for bottlenose dolphins, despite their proximity to one of the major urban centers in the world (the city of Rome). Given the high number of individuals in the area and the presence of resident individuals with strong site fidelity, we suggest that conservation plans should not be focused only close to the Tiber River mouths but extended to cover a broader scale of area.

Exploring plant species richness along the Tiber River within the city of Rome

The Tiber River stretch crossing the metropolitan area of Rome (Italy) is regarded as one of the main biological corridors of the city, as it diversifies the urban landscape while contributing to the plant diversity. This paper aims to document the current plant richness occurring along the Tiber within the city by providing a comprehensive inventory of the spontaneous vascular flora and an overview of its composition, and structural, chorological and ecological features. This flora lists 493 species and it is characterized by: i) high species richness (more than 30% of Rome’s flora), ii) presence of species with naturalistic value, as rare or included in Red List IUCN categories, iii) high number of ruderal and multizonal species (including several aliens) that have well adapted to human disturbance, and have partially replaced the typical riverine plants, iv) wide spread of eutrophic aquatic species, and rarefaction of those species that are more sensitive to eutrophication and water pollution. The dataset and the overview reported in this study can be useful for future research, with a special focus on a better naturalistic management of the urban river ecosystem, and the conservation of the floristic heritage within the city of Rome.