Libera Esposito

Predicting Monthly Spring Discharges Using a Simple Statistical Model

Current precipitation and past climate variability induce considerable intermonthly fluctuations in spring discharges. This study presents the DISHMET model (Discharge Hydro-Climatological Model) developed to perform historical spring reconstructions in the lack of physical assumptions. We analyzed discharge data of the Caraventa spring, located on the southern side of Mount La Montagna in Southern Italy, which has been monitored since the 1996s. The La Montagna aquifer is tectonically and litologically complex and deformed bedding controls the groundwater flow. Due to this aspect a parsimonious model should be more suitable than a complex model in spring discharge estimation. Thus, the DISHMET model incorporates monthly and annual precipitation only. The model is able to estimate sufficiently well the monthly fluctuations of groundwater discharge. DISHMET can be easily used to assess historical discharge, even when hydrological data is discontinuously available. The magnitude of this discharge is linked to the frequency and type of weather patterns transiting over the central Mediterranean area during the autumn and winter seasons. It is mainly related to the local precipitation that recharges the Mt. La Montagna aquifer. An analysis of antecedent rainfall and spring discharge reveal moderate to strong relationships.

Space–time prediction of rainfall-induced shallow landslides through a combined probabilistic/deterministic approach, optimized for initial water table conditions

In landslide-prone areas the magnitude of events is related to recurring rainfall intensity. In a large sector of the Sannio Apennines (Southern Italy), predictive mapping of recurrent shallow landslides was undertaken by combining deterministic and probabilistic predictive approaches. This, with the aim to minimize the negative influence of the uniform distribution of the initial water table depth in steady condition that usually influence the theoretical instability resulting from the application of methods for large-scale estimation. The deterministic approach was performed by means of the Transient Rainfall Infiltration and Grid-based Regional Slope-stability model to obtain triggering maps in multi-temporal transient pore-water pressures. The optimized physical modeling was validated by back-analysis on large-magnitude landslide events which occurred in 2003 by means of the introduction of two cross-mapping correlation indexes. Subsequently, different predictive scenarios were proposed for different probabilistic return periods of the rainstorm events. The output data permitted the definition of a linear log regression curve to estimate the theoretical instability of the study area. This curve is defined as a function of cumulative precipitation, duration and return periods of the possible rainfall events.

Initiation and propagation of the 2005 debris avalanche at Nocera Inferiore (Southern Italy)

Pyroclastic deposits covering most of the carbonate relief of the Campania Apennines are prone to develop frequent high-velocity flow instabilities. The present study investigates the debris avalanche that occurred at Nocera Inferiore (Campania Region, Southern Italy) on March 4, 2005 which claimed three casualties. The landslide involved the 1.5 to 2 m thick layered pyroclastic mantle which overlies the carbonate hill slopes. The slope movement initiated as adebris slide, then producing a debris avalanche on the 40°-dipping open slope, which had never been affected by a landslide of the same type as the one that occurred. Landslide initiation is linked to a morphological change of the slope due to the building of a carriage path to be used as access for the nearby open quarry. Reconstructionscarried out on aerial and ground photographs of different dates highlighted that the road construction likely took place around 1998, increasing the landslide susceptibility at this location. The propagation characteristics of the landslide were modelled by using 2D and 3D dynamic codes (DAN-W and DAN 3D, respectively), in order to investigate the applicability of the 3D model with the rheological parameters of previous calibration of DAN-W in Campania Region.Although, these analyses are well comparable with those implemented in the past, they highlight that it is unlikely to derive a unique set of values for the rheological parameters to be used on similar landslides over the entire region. Accuracy of back-analysis results strongly depends on the quality and availably of comparative input data, suggesting the need to improve calibration for each site within the region, enlarging information from similar cases and using statistical treatments.

Cross-species toxicogenomic analyses and phenotypic anchoring in response to groundwater low-level pollution

BackgroundComparison of toxicogenomic data facilitates the identification of deregulated gene patterns and maximizes health risk prediction in human.ResultsHere, we performed phenotypic anchoring on the effects of acute exposure to low-grade polluted groundwater using mouse and zebrafish. Also, we evaluated two windows of chronic exposure in mouse, starting in utero and at the end of lactation. Bioinformatic analysis of livers microarray data showed that the number of deregulated biofunctions and pathways is higher after acute exposure, compared to the chronic one. It also revealed specific profiles of altered gene expression in all treatments, pointing to stress response/mitochondrial pathways as major players of environmental toxicity. Of note, dysfunction of steroid hormones was also predicted by bioinformatic analysis and verified in both models by traditional approaches, serum estrogens measurement and vitellogenin mRNA determination in mice and zebrafish, respectively.ConclusionsIn our report, phenotypic anchoring in two vertebrate model organisms highlights the toxicity of low-grade pollution, with varying susceptibility based on exposure window. The overlay of zebrafish and mice deregulated pathways, more than single genes, is useful in risk identification from chemicals implicated in the observed effects.

Analysis of recharge processes in some karst systems, Southern Italy

The recharge processes have been evaluated for some karst massifs of southern Italy. The first step is the evaluation of the annual mean recharge for a long-time period (30 years) by GIS tools, by regression analysis of annual mean values of different ground-elevated rain gauges and thermometers. The estimation takes into account the presence of the wide endorheic areas, or closed areas, distinguished from the rest of the catchment, characterized by the open areas. In a first step, the ratio between the output spring discharge and input rainfall has been also estimated (long term recharge coefficients) for both closed and open areas. The second step is the assessment of the daily recharge, splitting the daily rainfall into several amounts (evapotranspiration, soil moisture retention, recharge s.s. and runoff), calibrating the daily simulation on the long-term recharge coefficient found in the first step. These analyses have been carried out for the Cervialto karst massif (southern Italy) where climate and hydrological parameters are available for many years, and the severe drought conditions of the 2016-17 are also outlined; brief comparisons were also carried out between Cervialto massif, considered as a pure climate controlled aquifer and other nearby karst massif as Terminio and Matese, whose recharge processes are conditioned by groundwater abstraction in endorheic areas.