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In Northern Apennines, the northern sector of the Italian “backbone”, hard rock aquifers prevail on karst and porous aquifers. A big portion of the chain is formed by siliciclastic and calcareous turbidites, arenites and ophiolites, both effusive like basalts or intrusive like peridotites. These geological units constitute the most valuable groundwater reservoir of the area in contrast with the overexploited and locally contaminated and salinized alluvial and coastal aquifers of nearby Po plain. A plenty of springs discharge from these huge outcrops of hard rock aquifers; these springs originate from a variety of groundwater flow systems (GFS), connected to hydro-structures of different complexity and depth: from local shallow GFS developed along slopes inside the regolith or the detensioned upper mantle of the hard rock, to regional systems related to main extensional post-orogenic fault zones. In some instances GFS develop inside a sort of plateaus made by a permeable lithology completely surrounded and underlayed by clayey aquiclude complexes. Mean spring flow rate in such a hydrogeological framework is low (VII-VI class of Meinzer), due to the dominant low-medium permeability of the rock mass; the GFS discharge is mainly stream-focused and represents the basis of surface waters environmental flows. Locally, in proper conditions, bigger springs occur, attaining discharges of 10-20 L/s during low flow conditions and so capable to sustain public water supply of local community. A research group formed by the authors is conducting hydrogeological characterization and springs/upreach streams monitoring activity on different test sites, in order to evaluate groundwater resources and to rank different GFS in terms of yield, base flow discharge, recession coefficient and hydrochemistry. The aim of the research follows two main routes: perform an hydrogeological mapping of groundwater resources in Northern Apennines, correlating discharge regime and base flow hydrological behavior with lithology and geological structure, and define a methodology to locate spring head protection areas (this last one with the aid of numerical modeling too). The presented paper reports, in a synthetic way, the main results obtained up to now. Particular emphasis is put in: hydrologic recession analysis in evaluating yield of sub-basins; need to couple springs and stream monitoring to evaluate properly groundwater resources as a whole; necessity of the accomplishment of hydrogeological study with a detailed geological reconstruction of the local hydrostructure; importance of numerical modeling, properly calibrated by continuous discharge monitoring, in help to overcome the limits associated to define recharge areas.

A finite-differences groundwater flow model (MODFLOW 2000) is applied to determine the extension of the zone of contribution and of different zones of travel for an important municipal water supply spring in silico-clastic turbiditic fractured aquifer in Northern Apennines (Italy). Model implementation and calibration was oriented and supported by 2 years continuous monitoring of spring discharge and rainfall and experimental determination, in a nearby analogous hydrogeological context, of infiltration coefficient, effective porosity and average groundwater linear velocity. The results are compared to existing protocol of WHPA location for springs.

The hydrological characteristics of roto-translational slides in flysch are complex, due to the inherent anisotropy and heterogeneity of rock masses and related deposits. The paper deals with the hydrogeological characterization of a reactivated roto-translational slide affecting Cretaceous flysch rocks, located in the northern Apennines of Italy. Continuous monitoring of groundwater levels, in-situ permeability and pumping tests, hydrochemical analyses and uranine tracers were the adopted prospecting methods. Results showed that two overlaying aquifers exist at the slope scale: the first is unconfined, but highly compartmentalized, and hosted in the fractured and dismembered rock slide body. The second is confined and pressurized and lays in the undisturbed flysch below the sliding surface. The latter is therefore a relevant factor for the instability of the slope. In this work, hydrologic monitoring and investigation are summarized, in order to support the anal-ysis of landslide trigger mechanisms and to identify and design proper drainage system.

Dal 1996 ad oggi il territorio toscano fra Firenzuola e Firenze, passando per i comuni di Scarperia, Borgo San Lorenzo, Vaglia, Sesto Fiorentino, è stato interessato dallo scavo del sistema di tunnel TAV (Treno Alta Velocità) per il collegamento ferroviario veloce Firenze-Bologna. Nel Dicembre 2009 la tratta verrà aperta al traffico passeggeri e sarà possibile spostarsi da Firenze a Bologna in 35 minuti. L’opera, di indubbio valore economico per il paese, ha determinato ingenti danni ambientali ad alcuni bacini idrografici dell’Appennino con effetti stagionali o perenni di prosciugamento di sorgenti e torrenti e diminuzione della produttività di pozzi. La presente opera monografica, presentata dalla Provincia di Firenze, si avvale della collaborazione di vari autori, tutti geologi, che, a titolo diverso e con diverso grado di coinvolgimento scientifico e professionale, hanno reso possibile definire un quadro riassuntivo e dettagliato di tutti gli impatti avvenuti ed hanno fornito all’Amministrazione Provinciale uno strumento per predisporre interventi di mitigazione degli impatti medesimi e recupero delle aree coinvolte.

In reclamated lands of Ferrara coastal plain (Emilia-Romagna region, Northern Italy) the fresh/salt water interface inside shallow aquifers is the result of a delicate equilibrium between the fresh water recharge from the top and the presence of salt water in the deepest sediments. Sands quarries below groundwater table in these shallow aquifers can affect groundwater flow and the interface position. In the studied site salinity, temperatures and groundwater levels have been monitored continuously over 1 year and allowed the definition of the aquifer conceptual model. Then a variable density groundwater model has been set up with VisualMODFLOW 4.1 and different simulation with SEAWAT-2000 have been performed, in order to predict the effects of the sand quarry on the interface position. First results show that 5 years after the quarry excavation the groundwater level in the aquifer decreases and the interface rises of about 2 m in the excavation area.

La memoria riguarda l’analisi della circolazione idrica sotterranea in bacini appenninici caratterizzati da torbiditi silico-clastiche, basata su prospezioni idrogeologiche e sul regime di drenaggio del sistema di gallerie per la connessione ferroviaria veloce fra Firenze e Bologna. Vengono considerati 4 bacini (Diaterna, Veccione, Bosso, Bagnone) situati nell’areale di affioramento della Formazione Marnoso Arenacea a cavallo dello spartiacque appenninico fra il bacino del Reno ed il bacino dell’Arno. I dati di base, raccolti su una serie di 9 anni idrologici dal 1995 al 2003, sono stati impiegati per ricostruire gli idrogrammi annuali di 47 sorgenti e 11 sezioni di torrenti, le caratteristiche idrodinamiche durante la recessione estiva ed il regime di drenaggio delle gallerie; tali elaborazioni, integrate dall’idrochimica e dalle modalità con cui si sono manifestate le interferenze sul sistema naturale, hanno permesso di definire un modello di circolazione idrica sotterranea «attiva» basato su 3 sistemi di flusso: un sistema effimero e sub-superficiale, uno intermedio legato ai primi 150-200 m di spessore dell’ammasso roccioso detensionato e fessurato ed uno trans-bacino legato a fratture post-orogeniche di tipo distensivo. Lo scarico del sistema è focalizzato sui torrenti rispetto alle sorgenti. Il coefficiente di infiltrazione efficace può risultare anche superiore al 30%.