Preliminary conceptual model of an Alpine carbonate aquifer (Pale di San Martino, Dolomites, Italy)

A hydrogeological and hydrochemical monitoring was conducted in the Pale di San Martino mountain ridge (Trento and Belluno Provinces, Italy) to build a preliminary conceptual model of the groundwater system. The model derives from a combination of new fieldwork and preexisting data provided by various public authorities. New data include geological and hydrogeological surveys, such as in situ measurements of the physical and chemical parameters, geochemical sampling and streamflow measurements. The lithologies outcropping in the area were grouped into seven hydrogeological complexes, each playing a different role in groundwater circulation. The dolomitic body of the ridges forms the main aquifer complex and is located above a terrigenous and evaporitic aquiclude. Due to this geometrical relationship, the site can be considered an isolated hydrostructure with well-defined no-flow boundaries. The main springs outcome near the aquifer-aquiclude boundary and in particular where the elevation of the contact is low and the tectonic pattern favors the drainage. Most of them have a calciumbicarbonate water composition, low temperature and low electrical conductivity, supporting the hypothesis of a fast flowing circulation in carbonate rocks and a high-altitude recharge. Seasonal streamflow measurements allowed the identification of linear springs and provided the first cumulative discharge data at the scale of the entire mountain group. The resulting model highlights a great spatial and temporal variability of the groundwater resources. Considering the geometry of the aquifer and the great seasonal variability of the discharge, it is possible to infer the absence of significant groundwater reserves at a regional scale. Thus, the hydrostructure shows a great capacity to supply water resources (mean discharge of 6 m3/s), but a low selfregulation capacity. It is necessary to consider this aspect when planning a long-term exploitation of the water resources that are used in the area for drinking purposes and hydropower generation

Studio idrogeologico delle Pale di San Martino: un primo passo verso una gestione sostenibile delle risorse idriche

Nonostante la ricchezza di risorse idriche che tipicamente si riscontra nelle regioni alpine, gli studi idrogeologici in questi territori sono estremamente scarsi e i meccanismi che regolano la circolazione idrica sono ancora poco noti, sia dal punto di vista concettuale che sperimentale. La gestione sostenibile delle risorse idriche richiede una conoscenza adeguata del funzionamento del sistema idrogeologico e un modello concettuale di riferimento su cui impostare specifici monitoraggi. Lo studio oggetto di questo articolo è iniziato nel 2014 ed ha interessato il gruppo montuoso delle Pale di San Martino. Essendo il primo studio idrogeologico della regione, una gran parte del lavoro è quindi consistita nella raccolta dei dati pre-esistenti di tipo geologico, idrogeologico e di utilizzo delle risorse, al fine di avere un quadro di partenza su cui impostare il lavoro di ricerca. A questo si sono affiancati specifici rilevi sul campo, tra cui misure di portata per definire l'entità della risorsa, analisi chimico-fisiche delle acque e test di tracciamento per comprendere i meccanismi idrogeologici che regolano il deflusso idrico sotterraneo. Grazie a questo studio è stato possibile raggiungere diversi obiettivi tra cui: i) quantificare le risorse idriche rinnovabili, ii) identificare le aree di ricarica del sistema e i principali serbatoi contenenti le risorse idriche, iii) identificare i punti di recapito della circolazione idrica sotterranea, iv) fornire una prima stima degli impatti dell'uomo sulle risorse idriche disponibili. In particolare, lo studio ha messo in luce una notevole differenza tra i quantitativi di acqua prelevati per gli usi idroelettrici, che rappresentano circa il 66% delle risorse disponibili, e quelli captati per scopi idropotabili (circa il 3% del totale). Le nuove conoscenze acquisite evidenziano che in un'ottica di pianificazione futura sarebbe opportuno prediligere soluzioni di utilizzo per il consumo umano a favore delle comunità locali. Inoltre, i risultati della ricerca potrebbero essere il punto di partenza per la valutazione di incidenza di nuove opere o per razionalizzare gli usi sulle numerose derivazioni già esistenti, in un'ottica di gestione integrata delle risorse idriche

Groundwater response to precipitation extremes: the case of the “Vaia” storm (Eastern Italian Alps)

Extreme precipitation events are expected to increase in intensity in Alpine regions due to climate change. While many studies have analyzed the impact of these phenomena on flooding risk, very Jew deal with their effect on groundwater. This work analyzes the hydrograph response of three springs to an extreme storm, which occurred in Northern Italy in October 2018. We observed that the newly infiltrated storm water contributed to feeding the winter baseflow, increasing its volume up to 85 % compared to normal conditions. It was also found that the response of groundwater to heavy precipitation seems to be influenced by the type of media. A high-altitude spring belonging to the fractured carbonate aquifer shows a quick response to the storm input, while springs outflowing at the base of the mountain slopes (mixed fractured carbonate and porous deposits) exhibit a delayed response. Results are important when analyzing future water availability and to better understand the impact of extreme events on groundwater flow.

Hydrogeology and Hydromorphology: a Proposal for a Dual-Key Approach to Assess the Geo-Hydrological Heritage Site of the San Lucano Valley (Belluno Dolomites, Italy)

Hydrological features are a fundamental element of the whole â\u80\u9cgeoheritageâ\u80\u9d of a site. It is, indeed, possible to identify the â\u80\u9cwater heritageâ\u80\u9d part related to the value of water and its phenomena. Recent studies were carried out in the San Lucano Valley (Belluno, Italy) and its geological, geomorphological and hydrological observations can help to perceive some natural occurrences as â\u80\u9chydrological heritageâ\u80\u9d. They are a solid background that helps us to analyse and bring into evidence the exceptionality of the hydrogeological features of this site. San Lucano Valley thanks to its numerous springs and to its particular morphology characterized by steep slopes and crest rising up above the valley floor, represents a unique â\u80\u9cwindowâ\u80\u9d in the core of a karst carbonatic aquifer. This peculiar topographical setting enables a 3D view of the groundwater flow, from the recharge areas to the spring and alpine stream from its headwaters to where it becomes a tributary of a bigger river. To classify the springs of the valley and to underline their peculiar hydrogeological features, several surveys were performed, discharge in streams and springs was regularly measured using current meters, and the water level was monitored on site in reference cross sections (this activity is still in progress). In order to assess the stream hydromorphology, the geomorphic method of Rosgen (Catena 22:166â\u80\u93199, 1994) (RSC) has been adopted collecting a series of detailed survey datasets along the entire watercourse. Following the path indicated by SimiÄ\u87 et al. (Carpathian J Earth Environ Sci 9(4):19â\u80\u9330, 2014), adapted to the specific case, the whole hydrological and hydromorphological system has been assessed. For all the above reasons, San Lucano Valley could be proposed as a Hydrological Heritage Site â\u80\u9cvaluableâ\u80\u9d for geo-tourism in the Dolomiteâ\u80\u99s UNESCO Area 3

Risk of groundwater contamination widely underestimated because of fast flow into aquifers

International audienceGroundwater pollution threatens human and ecosystem health in many regions around the globe. Fast flow to the groundwater through focused recharge is known to transmit short-lived pollutants into carbonate aquifers, endangering the quality of groundwaters where one quarter of the world’s population lives. However, the large-scale impact of such focused recharge on groundwater quality remains poorly understood. Here, we apply a continental-scale model to quantify the risk of groundwater contamination by degradable pollutants through focused recharge in the carbonate rock regions of Europe, North Africa, and the Middle East. We show that focused recharge is the primary reason for widespread rapid transport of contaminants to the groundwater. Where it occurs, the concentration of pollutants in groundwater recharge that have not yet degraded increases from <1% to around 20 to 50% of their concentrations during infiltration. Assuming realistic application rates, our simulations show that degradable pollutants like glyphosate can exceed their permissible concentrations by 3 to 19 times when reaching the groundwater. Our results are supported by independent estimates of young water fractions at 78 carbonate rock springs over Europe and a dataset of observed glyphosate concentrations in the groundwater. They imply that in times of continuing and increasing industrial and agricultural productivity, focused recharge may result in an underestimated and widespread risk to usable groundwater volumes