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Recycling of Earth's crustal components through subduction contributes to the observed geochemical heterogeneity in worldwide lavas, yet quantifying the in- and output fluxes is difficult because of the unknown compositions of subducted components and sediment transfer processes in subduction zones. Italian post-collisional magmatism is often mafic but potassiumrich, suggesting a significant contribution of subducted sediments in this complex geodynamic setting. Isotopic and elemental variability in the volcanic products across Italy likely reflects sediment recycling with variable composition and quantity from north to south. Here we report the geochemical compositions of sediments that accreted to the Apennine accretionary prism whose lateral counterparts have potentially subducted and contributed to the Italian melt source. The aim is to use the major-, trace- and Sr- Nd-Pb isotope compositions of the sediments and Italy's volcanic products to quantify subduction recycling through melt modelling. Sediments were collected from the northern-, central- and southern Apennines (Liguria, Emilia-Romagna, Umbria and Calabria) with a focus on exhumed units from below the various decollement levels. These included Triassic to Jurassic deep sea sediments in ophiolitic sequences deposited in the Ligurian- Piemonte Oceanic Basin, and Triassic to Neogene distal units of the Adria continental margin. End-member compositions are defined by deep sea clays and metapelites rich in K2O, SiO2, LILE, HFSE, REE with high 87Sr/86Sr (0.7458) and 206Pb/204Pb (19.4), and marls poor in K2O, SiO2, LILE, HFSE, REE, but rich in CaO and Sr, with low 87Sr/86Sr (0.7083) and 206Pb/204Pb (18.7). The geochemical compositions of the most primitive volcanics and olivine-hosted melt inclusions will be used to reconstruct subduction recycling processes by melt modelling of a sediment metasomatized mantle wedge. Sediment transport mechanisms, sediment/vein mineralogy, melting behavior, and melt extraction processes will be evaluated.

It is scientifically established that global warming induced by greenhouse gases, affecting the surface energy budget, can significantly alter the Earth's water cycle, with consequent modification of precipitation typology and regime. However, the net effects of these changes on the process of groundwater discharge are still uncertain at local scale. The lack of historical series of monitoring data, dating back to at least 60-100 years ago, is among the main drawbacks, with the rare exception of major karst springs exploited for public water supply. In hard rock aquifers, like those dominant in the Northern Apennines, the dynamic of spring outflow during the first half of the XX century is an absolute black-box. For this reason, it appeared noteworthy to analyze detailed monthly-based monitoring data, over the 1915-1920 time span, of the whole discharge of the Nadìa spring, one of the most productive spring in the Emilia-Romagna region, in low flow season, among those used for drinking water. Such data were reported in a century-old study functional to the drilling of a draining tunnel for water uptake. We present a comparison between the monthly regime of the spring discharge 100 years ago and a continuous monitoring performed by the authors during the 2020/2021 hydrological year, integrated with the total water uptaken in years 2018-2020. Nadìa spring discharges from an arenitic fractured aquifer deposited in a neritic setting above mainly clayey units acting as a permeability threshold. The abundance of calcite in the grains and cement of the arenite enhances corrosion and enlargement of fractures. In 2018-2021 the spring discharge range has been 80-50 L/s whereas in 1915-1920 it was 140-63 L/s. The two (ancient and recent) sets of data were compared with a focus on the evolution of precipitation, snow-fall and thermal regime.

The Nadìa spring is the second largest tapped spring in the Emilia Romagna Region (northern Italy), representing a strategic local source of drinking water, also in the perspective of future global changes. The spring flowrate ranges between 65 l/s in the recharge season and 45 l/s at the end of the low-flow season, when most of the other tapped springs in the region have flowrates lower than 5 l/s. Geological, geomorphological, hydrological and geochemical investigations were carried out in the spring watershed to unravel the factors causing this peculiarly high discharge. The spring arises at the base of a calcarenitic fractured aquifer (Pantano Formation, upper Burdigalian-lower Langhian) underlain by lower permeability units. Karst dissolution along structural discontinuities in the Pantano Formation has been suggested in the past as a possibility to account for the aquifer high permeability resulting in the high spring discharge. A continuous monitoring of the spring flowrate, temperature, electric conductivity and pH was conducted during the 2020-2021 hydrologic year. Hydrographs and chemographs indicated atypical karst flow dynamics. The time to halve the peak-discharge of the spring is between 20 and 50 days, lower than that of most springs of the Northern Apennines (> 50 days). This implies a higher average aquifer flow rate (around 10 m/day) compared to that typical of arenitic or turbiditic aquifers (around 1 m/day). Spring water samples collected once to twice a year since 2011 for the analysis of major ions revealed an obvious calcium-bicarbonate hydrochemistry that is consistent with the hypothesis of karst dissolution. However, the chemical variability over time expected in a karst system due to the drainage of different groundwater fractions (newly infiltrated vs. older groundwater) was not observed. Instead, the water chemical composition was exceptionally constant over time, suggesting that drainage occurs from a large, homogeneous reservoir. Water stable isotopes have been analyzed in 2021 revealing a composition close to that of the local winter precipitations and suggesting exceptional stability of the spring water composition over different seasons. An 80 m deep borehole has been drilled in the Pantano Formation 7 km away from the spring, documenting the occurrence of fractures with decimetric apertures as deep as 60-70 m below ground surface, which may be interpreted as the result of karst dissolution. In addition to the debatable karst aquifer hypothesis, geomorphological observations indicate the occurrence of depressed areas, of likely tectonic origin, in the aquifer overlying the spring, which may provide a favorable setting for concentrated infiltration and groundwater recharge. However, the hypothesis of concentrated recharge is in apparent contrast to the abovementioned stability of spring water chemical composition over time. A volume of the aquifer representing a reasonable reservoir for the spring has been identified based on spring flow recession analysis and a geo-structural model of the Pantano outcrop up-gradient to the spring. The structural-stratigraphic setting of the hypothesized reservoir includes the occurrence of fault-related fractures that cross-cut the low-dipping bedding of the calcarenites, possibly enhancing the local permeability and the drainage towards the Nadìa spring.

Water resources and associated ecosystems are becoming highly endangered due to ongoing global environmental changes. Spatial ecological modelling is a promising toolbox for understanding the past, present and future distribution and diversity patterns in groundwater-dependent ecosystems, such as fens, springs, streams, reed beds or wet grasslands. Still, the lack of detailed water chemistry maps prevents the use of reasonable models to be applied on continental and global scales. Being major determinants of biological composition and diversity of groundwater-dependent ecosystems, groundwater pH and calcium are of utmost importance. Here we developed an up-to-date European map of groundwater pH and Ca, based on 7577 measurements of near-surface groundwater pH and calcium distributed across Europe. In comparison to the existing European groundwater maps, we included several times more sites, especially in the regions rich in spring and fen habitats, and filled the apparent gaps in eastern and southeastern Europe. We used random forest models and regression kriging to create continuous maps of water pH and calcium at the continental scale, which is freely available also as a raster map (Hájek et al., 2020b; https://doi.org/10.5281/zenodo.4139912). Lithology had a higher importance than climate for both pH and calcium. The previously recognised latitudinal and altitudinal gradients were rediscovered with much refined regional patterns, as associated with bedrock variation. For ecological models of distribution and diversity of many terrestrial ecosystems, our new map based on field groundwater measurements is more suitable than maps of soil pH, which mirror not only bedrock chemistry but also vegetation-dependent soil processes., This work was supported by the Czech Science Foundation (grant no. 19-01775S provided support for Borja Jiménez-Alfaro, Petra Hájková, Veronika Horsáková and Michal Horsák; grant no. GX19-28491X to the Centre for European Vegetation Syntheses provided support for Michal Hájek, Tomáš Peterka and Ondřej Hájek). Jutta Kapfer was supported by the Fram Center (grant no. A36214). We thank Sabine Bergmann and Dirk Hinterlang (State Agency for Nature, Environment and Consumer Protection North Rhine-Westphalia, Germany) and Rossitza Gorova (Ministry of Environment and Water of Bulgaria) for providing us with the public water chemistry data, Andraž Čarni for alerting us to the open data on Slovenian groundwater, and Valerijus Rašomavičius for providing us with the data from Kadūnas et al. (2017). We thank Tatyana Ivchenko for providing us with the data for the Ural Mountains, which were not included in the paper. Paweł Pawlikowski (P.P.), Lucia Sekulová (L.S.), Jana Navrátilová (J.N.) and Dag-Inge Øien (D.-I.Ø.) kindly agreed for us to use their unpublished pH and EC data. We further thank Ilona Knollová, John Rodwell (J.R.), Kiril Vasilev (K.V.) and Idoia Biurrun (I.B.) for providing pH data from vegetation databases via the European Vegetation Archive.

Meteorological events characterized by extreme rainfall intensity have recently struck the hilly and mountainous territory of the northern Apennines (Italy) as well as many other geographic areas of the world. These extreme rainfall events trigger fast flows of debris along the slopes, stream channels, landslides, and floods, which damage many man-made structures such as roads, houses, water-pipes, etc. There is thus a strong practical interest in predicting the frequency and intensity of these effects for emergency management and to reduce the vulnerability of the territory.In 2015 an intense rainfall event hit the Valleys of the Trebbia, Nure, and Aveto watercourses in the emilian-ligurian Apennines. In about 6 h a mesoscale convective system deployed a stunning amount of precipitation of 340 mm, with an extreme hourly rainfall intensity of >100 mm/h. During this event, several types of widespread effects on the ground developed i.e., fast flows of debris along the slopes and stream channels (a total number of 305 occurrences), shallow landslides (342) and overbank flooding occurred. Instrumental as well as geological and historical data clearly suggest that extreme rainfall events are increasing in the northern Apennines, in good agreement with the international literature. Through the optimal combination of rainfall data and radar volumes, in this work we present a detailed rainfall analysis, which will serve as a basis to create a quantitative correlation with debris flows over elementary hydrological units. The meteorological analysis of the storm led us to consider the 3 h accumulation rain field as the most relevant for flood triggering. This time interval is short enough to describe the intensity peak of macro precipitating structures, and at the same time it is long enough to allow the development of the debris and stream-flow processes described. The very good match between the 3 h peak intensity and the distribution of high-discharge and hillslope-debris flow support the hypothesis. The 3 h interval further emphasizes the meteorological event with respect to its overall duration of 6 h.We aim at providing an objective basis for future predictions, starting from the recognition of the forcing meteorological events, allowed us to clearly identify high-intensity-precipitation thresholds triggering flood in small mountain catchments.Keywords: floods; catchment; threshold; extreme rainfall events; northern Apennines

The lake Moo in the northern Apennines, a 0.15 km2 basin located at an altitude of 1130 m a.s.l., consists of a small marshy area lying within a portion of a flat semi-circular depression surrounded by steep slopes. The site presents a series of geological and geomorphological characteristics which make it an ideal context to observe the results of flood events on the late Holocene sedimentary record of the basin. Our project aims to establish a relationship between recent deposits, instrumental data and modern-age cartography, in order to obtain site-specific parameters to interpret the sedimentary signal produced by floods on our site. The information can be extended back in time to the millennial scale by analysing sediment cores, in order to observe the frequency and magnitude of flood events throughout the Holocene and assess potential relationships with palaeoclimate reconstructions. This contribution discusses the results from five coring campaigns undertaken between 2018 and 2019 for a total thickness of 10.5 m, which allowed the recording of a c. 500 m long transect stretching from the west slope to the open water on the eastern part of the basin. This extended section enhanced our understanding of the deposit on a larger scale, allowing us to relate the new sequences to the ones identified in previous cores, and develop insights into flood-induced sediment gravity flows and their macroscopic physical characteristics (i.e. grain size, sedimentary structures, Munsell colour and types of contact surfaces). The study has led to the observation of possible correlations between various flood events and Holocene periods.

Estimation of aquifer recharge is key to effective groundwater management and protection. In mountain hard-rock aquifers, the average annual discharge of a spring generally reflects the vertical aquifer recharge over the spring catchment. However, the determination of average annual spring discharge requires expensive and challenging field monitoring. A power-law correlation was previously reported in the literature that would allow quantification of the average annual spring discharge starting from only a few discharge measurements in the low-flow season, in a dry summer climate. The correlation is based upon the Maillet model and was previously derived by a 10-year monitoring program of discharge from springs and streams in hard-rock aquifers composed of siliciclastic and calcareous turbidites that did not have well defined hydrogeologic boundaries. In this research, the same correlation was applied to two ophiolitic (peridotitic) hard-rock aquifers in the Northern Apennines (Northern Italy) with well-defined hydrogeologic boundaries and base-outflow springs. The correlation provided a reliable estimate of the average annual spring discharge thus confirming its effectiveness regardless of bedrock lithology. In the two aquifers studied, the measurable annual outputs (i.e. sum of average annual spring discharges) could be assumed equal to the annual inputs (i.e. vertical recharge) based on the clear-cut aquifer boundaries and a quick groundwater circulation inferable from spring water parameters. Thus, in such setting, the aforementioned correlation also provided an estimate of the annual aquifer recharge allowing the assessment of coefficients of infiltration (i.e. ratio between aquifer recharge and total precipitation) ranging between 10 and 20%.

The Lake Moo plain has a surface area about 0.15Km2. It is located near the boundary between Emilia-Romagna and Liguria regions, at an altitude of 1130m a.s.l. (northern Apennines, Italy). This site is strategic to the dominant atmospheric currents, very prone to high intensity precipitation events (HIP) and related high-density flood. Indeed, Lake Moo area has been partially covered by a flood deposit released by a record-breaking rainfall intensity in September 2015. The intensity and wide spatial scale of those phenomena has leads us to investigate their frequency in the past, beyond the instrumental time. The lacustrine succession (ca. 13 m-thick) was studied through the extraction of one core and framed within sedimentary facies analysis approach. The paleoenvironmental interpretation of the succession was achieved combining sedimentological, pollen and pedological data and radiocarbon dating. Thirteen different facies types have been identified and the core succession is was subdivided into five informal units. The different coarse-grained layers interbedded with organic-rich silty clays and peaty layers have been interpreted as the extreme flood deposits triggered by high-intensity convective rainfall events in the catchment area that flow into the Lake Moo plain.These coarse-grained deposits were grouped according to the genetic approach and therefore based on facies tract concept. The goal of this study is how the facies tract approach may represent a novel method that can be used to improve our understanding of flood reconstruction dynamics and may be applied to other similar deposits. We interpret the local lacustrine succession is like to the infill of a structural depression produced by gravitational block sliding that was induced by post-glacial fluvial incision.Finally, the observed depositional cycles were put in relation with other specific paleoclimatic proxies available in literature for the area.

This essay discusses the need for, advantages and challenges of integrating the scientific disciplines of ecology and hydrogeology in the study of groundwater-dependent ecosystems (GDEs). We provide a definition for ecohydrogeology as “a unifying, synthetic field of study integrating the approaches from the ecological and hydrogeological sciences in the study of groundwater (GW)-related ecosystems, habitats, and organisms to advance science, stewardship, and policy”. We selected specific case studies to illustrate first how hydrogeological approaches can favour in-depth understanding and modelling of springs and crenobiontic (spring-dependent) species distribution, assemblage composition and organization. Second, this essay also examines how taxa and assemblages serve as bioassays and ecosystem indicators to infer hydrogeological aspects of GW flow and discharge, as well as quantitative and qualitative human impacts. We consider both types of features and parameters as ecohydrogeological indicators. The examples presented include topics related to springs and other GDE geomorphological types and classification, GW quality influences on crenobiont distribution, phreatophyte (= plant species the roots of which reach to and into the water table) ecophysiology in relation to water table depth, and flow variability in karstic systems, to nutrient dynamics in relation to dinoflagellate blooms in GDE montane lakes. Conceptual approaches that integrate ecology with hydrogeology include the investigation of GDE distribution and ecology, groundwater-surface water (GW-SW) interactions, and the development of the discipline of ecohydrology. Despite widespread applications, the scientific community still lacks a complete or effective integration of the principles described in the fields of groundwater hydrogeology with ecology, ecophysiology, and environmental biology. Springs are aquatic-wetland-riparian habitats that link shallow subsurface-surface processes and assemblages, often functioning as biodiversity hotspots, ecotones, keystone, and refugial ecosystems, for which coordination between studies of hydrogeology and ecology are both obvious and essential. Over the past century, springs ecosystem ecology has been largely ignored by hydrologists, and, conversely, hydrogeology has been under-emphasized by ecologists. Recent global recognition of the extraordinary biodiversity and socio-cultural significance of springs, coupled with their globally highly threatened conservation status, stimulated this inquiry into how to better integrate hydrogeology with springs ecosystem ecology. Acknowledging the highly threatened status of springs ecosystems around the world, there is an urgent need to integrate and invigorate the union of these disciplines into ecohydrogeology, the study of groundwater-dependent organisms, habitats, ecosystems, and management policy.

This study explores the factors affecting the biodiversity of diatoms, vegetation with focus on bryophytes, and invertebrates with focus on water mites, in a series of 16 spring-habitats. The springs are located primarily from the mountainous part of the Emilia-Romagna Region (Northern Apennines, Italy), and two pool-springs from agricultural and industrial lowland locations. Overall, data indicate that biological diversity (Shannon-Wiener, α-diversity) within individual springs was relatively low, e.g.: Sdiatoms = 0–46, Swater-mites = 0–11. However, when examined at the regional scale, they hosted a very high total number of taxa (γ-diversity; Sdiatoms = 285, Swater-mites = 40), including several new or putatively-new species, and many Red-List taxa. This pattern suggested there is high species turnover among springs, as well as high distinctiveness of individual spring systems. A key goal was to assess the hydrogeological and hydrochemical conditions associated with this high regional-pool species richness, and to provide a guide to future conservation strategies. There was a striking variety of geological conditions (geodiversity, captured mainly with lithotype and aquifer structure) across the study region, which led to wide variation in the hydrosphere, especially in conductivity and pH. Agriculture and industrial activities (anthroposphere) in the lowlands resulted in nutrient enrichment and other forms of pollution. Across all 16 spring-systems, several hydrogeological conditions most strongly influenced the presence or absence of particular biota and were determinants of species importance: spring-head morphology, hydroperiod, discharge, current velocity, and elemental concentration. These findings have important practical consequences for conservation strategies. Our data show that it is imperative to protect entire regional groups of springs, including representatives of the different ecomorphological spring types, lithologies, and degrees of human influence. These findings suggest that springs, when studied from an ecohydrogeological perspective, are excellent systems in which to further investigate and understand geo-biodiversity relationships.

International audience; In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime—periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems).

In the Parma Functional Urban Area, hydro-geo-ecology was investigated through an interdisciplinary approach, with emphasis on the shallow aquifer system. The study pointed out that domestic wells and fontanili are both fed by shallow groundwater affected by PCE and nitrate contamination, upgradient of the rural area located north of Parma City. Moreover, Folsomia candida tests suggested the possibility that other types of contaminants (not analysed in this study) can affect the shallow groundwater. Nowadays, PCE concentrations in the city centre are slightly higher than the limit set by law. Moreover, PCE aerobic biodegradation can be due to the local microbial community and then an effective natural attenuation can be expected along the groundwater flow pathway. These results suggest a very low risk for human health, linked to the groundwater consumption in the rural area north of Parma City. Conversely, no forecasts can be made at present about the possible impact of low PCE concentrations on the aquatic ecosystem observed at the fontanili. Concerning nitrate contamination, the higher concentrations detected in some wells and fontanili suggest a high risk for both human health and aquatic ecosystems. In a wider context, thanks to the interdisciplinary approach that combines successfully well-established investigation methods, the present study allows a better knowledge of the hydro-geo-ecological behaviour of groundwater-dependent ecosystems. At the same time, through purpose-designed experimental investigations and simulation models, this approach could be used as a sort of guideline useful in studying such complex environmental systems.

Several record-breaking precipitation events have stricken the mountainous area of Emilia-Romagna Region (northern Apennines, Italy) over the last years. As consequence, several geomorphological processes, like widespread debris flows along the slopes and hyperconcentrated flood in the stream channels, shallow landslides and overbank flooding affected the territory, causing serious damages to man-made structures. The intensity and wide spatial scale of these phenomena leads us to investigate their frequency in the past, beyond the instrumental time. A detailed study of these recent deposits compared with fossil peat bog and lake paleodeposits can provide useful insight to support a strong match between precipitation intensity and warm climatic phases in antecedent climatic periods, as expected by the increase air water vapour holding capacity at higher temperatures. Here we present the results of the field campaign performed in summer 2017 at Lake Moo a 0.15 km2 peat bog located at an altitude of 1130 m a.s.l. The chosen area has been affected, during the flooding of the upper Trebbia and Nure valleys 13–14 September 2015, by several high-density flows generated by the stream that flow into the plain. Our main assumption is that, in such a small drainage basin (area 2), with favourable geologic and geomorphic characteristics implying advantageous sediment transfer into lake, high density flood can be triggered only by high intensity precipitation events (HIP) lasting enough time for water to infiltrate and mobilize large quantities of debris. The sedimentary succession (ca. 13 m-thick) was studied through the extraction of two cores and one trench. The facies/paleoenvironmental interpretation of the sedimentary succession, characterized by clusters of coarse-grained alluvial deposits interbedded with organic-rich silty clays and peaty layers, was achieved combining sedimentological and pollen data with pedological data and radiocarbon dating (AMS 14C). Observed depositional cycles were put in relation with other specific paleoclimatic proxies available in literature for the North-Apennine area. This comparison illustrates that the increase of extreme paleoflood (associated with coarse-grained deposits similar to the ones observed recently) correlates well with warm phases with a maximum activity during the Holocene thermal maximum and from the small ice age to the present day.

A few hydrogeological studies have been carried out worldwide in peridotite aquifer systems, despite their wide distribution. The ophiolites are one of the main groundwater reservoir within the northern Apennines (Italy). This paper suggests the graphical solution to set the hydrogeological map of heterogeneous, multi-layered ophiolitic aquifers mapped on large scale (1:1600). The site investigation area is an ophiolite outcrop of the External Ligurian of the northern Apennines: the Mountain Prinzera rock complex area (44°38′30′′N, 10°5′E; Parma Province, Emilia-Romagna Region). The hydrogeological characteristics of the tested aquifer system do not allow setting a hydrogeological map by applying usual graphical approaches. The hydrogeological map in such complex aquifer systems will show the classic hydrogeological data but must put in evidence above all (i) the main heterogeneities of the system, from the hydraulic point of view and (ii) the modifications of groundwater scenarios and pathways over time. The hydrogeological database of Mt Prinzera aquifer was managed in ESRI ArcGIS 10.0 software.

Hard rock aquifers (or discontinuous aquifers) are commonly intended as igneous or metamorphic rocks with very low primary porosity and a significant however discontinuous and strongly anisotropic secondary porosity (i.e. fractures) due to tectonic stresses and weathering. In some cases, the term “hard rock aquifer” is well suited also for sedimentary fractured rocks. This is the case of the turbiditic formations in the Northern Apennines (Italy), that represent the most valuable groundwater reservoir in the region. In such cases, the quantification of water resources hosted in the hard rock aquifers becomes of paramount importance. We propose a method to quantify the effective recharge occurring within a spring recharge area in a hard rock aquifer setting when only spring discharge monitoring during the low flow season (summer) is available. An empirical relationship was found between the average annual discharge of a spring and its average summer discharge, starting from a large database of 11 hydrologic years of discharge monitoring on more than 80 springs. Such relationship is linear on a log-log scale and changes according to the Maillet’s recession coefficient. The average annual flow rate obtained from summer monitoring data (i.e. the average summer discharge and the Maillet coefficient) is considered as a proxy of the effective recharge occurring within the spring recharge area. The proposed method was tested both in turbiditic and ophiolitic hard rock aquifers in the Northern Apennines in different hydrologic years, providing an overall accuracy in the range of ±15% with respect to the actual annual average spring discharges. Thus, this is a promising tool to support the application of hydrologic balances in hard rock aquifers. However, further tests should be carried out in different hard rock aquifer settings in order to form a basis for more realistic expectations about the overall validity of the method.

In 2015 an intense rainfall event hit the Valleys of the Trebbia, Nure, and Aveto watercourses in the Northern Apennines. In about 6 h a mesoscale convective system deployed a stunning amount of precipitation of 340 mm, with an extreme hourly rainfall intensity of &gt, 100 mm/h. It triggered debris flows along slopes and stream channels, landslides and floods, which caused serious damages. Through the optimal combination of rainfall data and radar volumes, in this work we present a detailed rainfall analysis, which will serve as a basis to create a quantitative correlation with debris flows over elementary hydrological units. We aim at providing an objective basis for future predictions, starting from the recognition of the forcing meteorological events, and then arriving at the prediction of triggering phenomena and to the debris-flow type. We further provide seven observations/case studies on the effects of extreme-precipitation events on freshwater environments in small mountain catchments. Extreme-precipitation events are becoming more frequent and widespread globally but their ecological effects are still insufficiently understood. In general, the effects of extreme events on inland-waters&rsquo, ecosystems are highly context-dependent, ranging from deleterious to beneficial. We therefore highlight the necessity of further studies to characterize these effects in more depth to be able to include appropriate mitigation measures in environmental planning and stewardship.

This paper presents a geomorphologic map of the Mt. Prinzera ultramafic rock complex (Parma Province, Emilia-Romagna Region, Italy) mapped at large scale (1:2500). The map is the first contribution to the detailed geomorphologic knowledge of the area within the framework of a multidisciplinary approach used to analyse Mt. Prinzera as a hard rock aquifer case study. The geomorphologic mapping was carried out by field survey and aerial photograph analysis. All the surface processes and landforms were considered, with particular attention to structural geomorphologic features. The mapping of linear morphologic features was considered useful for revealing the presence of sets of joints otherwise difficult to detect due to surface weathering. Sets of rock discontinuities are important for water seepage and percolation and their identification is crucial for developing the hydrogeological conceptual model of the aquifer.

Springs are biodiversity hotspots and unique habitats that are threatened, especially by water overdraft. Here we review knowledge on ambient-temperature (non-geothermal) freshwater springs that achieve sufficient oversaturation for CaCO3 -by physical CO2 degassing and activity of photoautotrophs- to deposit limestone, locally resulting in scenic carbonate structures: Limestone-Precipitating Springs (LPS). The most characteristic organisms in these springs are those that contribute to carbonate precipitation, e.g.: the mosses Palustriella and Eucladium, the crenophilous desmid Oocardium stratum, and cyanobacteria (e.g., Rivularia). These organisms appear to be sensitive to phosphorus pollution. Invertebrate diversity is modest, and highest in pools with an aquatic-terrestrial interface. Internationally, comprehensive legislation for spring protection is still relatively scarce. Where available, it covers all spring types. The situation in Europe is peculiar: the only widespread spring type included in the EU Habitat Directive is LPS, mainly because of landscape aesthetics. To support LPS inventorying and management to meet conservation-legislation requirements we developed a general conceptual model to predict where LPS are more likely to occur. The model is based on the pre-requisites for LPS: an aquifer lithology that enables build-up of high bicarbonate and Ca2 + to sustain CaCO3 oversaturation after spring emergence, combined with intense groundwater percolation especially along structural discontinuities (e.g., fault zones, joints, schistosity), and a proper hydrogeological structure of the discharging area. We validated this model by means of the LPS information system for the Emilia-Romagna Region (northern Italy). The main threats to LPS are water diversion, nutrient enrichment, and lack of awareness by non-specialized persons and administrators. We discuss an emblematic case study to provide management suggestions. The present review is devoted to LPS but the output of intense ecological research in Central Europe during the past decades has clearly shown that effective conservation legislation should be urgently extended to comprise all types of spring habitats.

Sampling in springs has several technical problems due to their reduced dimensions and habitat heterogeneity. A standardized quantitative method for sampling crenic macroinvertebrates has never been proposed. The aim of this study was to compare different sampling methods and consider their environmental impacts. First, we present a review of sampling methods found in the literature and discuss their advantages and disadvantages with respect to selective collection of the target community and habitat disturbance. Altogether, 10 different methods have been reported, the use of nets being the most common protocol. Second, we report the results of macroinvertebrate samplings performed in three springs, each surveyed twice, using three different methods (multi-habitat proportional hand net, baited traps, and vegetation washing), in order to compare their effectiveness in collecting macroinvertebrates. Overall, 32 macroinvertebrate taxa, mostly identified at family level, were collected in the sampled springs....

A basic geological knowledge is a powerful tool for increasing public awareness of the need for a balanced relationship between citizens and the environment, but often geology does not attract the interest of the general public because it seems to be dealing with something too distant, in time and space, from our everyday life. The aim of this kind of ‘innovative geological cartography’ is to bring geology to the general public, by stimulating the innate curiosity that is harboured by every human being.