The paper presents the map of intrinsic groundwater vulnerability of the Isonzo/Soča High Plain, which is located between the Collio Hills and the Classical Karst Region and holds an aquifer shared ...between Italy and Slovenia. The map, produced at a scale of 1:25,000 and printed in A0 format, was obtained by means of the SINTACS method and shows the intrinsic vulnerability of the aquifer in terms of seven vulnerability classes, from extremely high to low. It is accompanied by four supplementary sketches that illustrate the geological framework, the bedrock top surface, the groundwater flow paths, the Hazard Index map and three diagrams that summarize the percentages of vulnerability classes and of Hazard Index classes of the study area.
In August 2008 an intensive pumping experiment was carried out in order to assess the capacity of Brestovica – Klarici water supply in summer conditions, and its chemical quality. Groundwater was ...pumped for a period of 30 days, from three wells at the Klarici pumping station, and from well B-10/06, with a common capacity of 470 L/s. The fact that pumping caused a decrease in the water table in well B-10/06 by only 17 cm at a pumping rate of 265 L/s suggests that larger quantities of groundwater could be pumped from this well. The tracer experiment, performed at the B-10/06 temporary pipeline discharge area, showed that no pumped water was returned to the area of the exploited wells during the pumping test. Tracer uranine, which had been injected at the effluent from the pumped water from the well, was detected only at the Sardos Spring. The intensive pumping resulted in changes in the chemical and isotopic composition of oxygen in the water, due to a greater impact of the water from the intergranular SocaRiver aquifer on the karst aquifer.The chemical quality of groundwater from well B-10/06 is adequate for the purpose of drinking water supply. The presence of bacteria in groundwater is typical of karst aquifers and the water needs to be disinfected for further use.Keywords: groundwater, Classical Karst, Brestovica – Klariči aquifer, pumping test, tracer test, geochemical analysis.
The Mucille karst depression is one of the few examples of polje on the Italian side of the Classical Karst Region, a shared area between Italy and Slovenia. The polje is subject to frequent ...flooding, becoming more problematic since 2000, as swallow holes more frequently have affected housing and recreational areas, leading the population to believe that their ability in draining the area had stopped functioning. Climate changes play an important role as there has been an intensification in extreme events (30-day cumulative precipitation of more than 350 mm) within the considered time-period 1919–2020. The necessity to provide answers to the inhabitants required in-depth studies such as hydrogeological investigations, discharge measurements and Electrical Resistivity Tomography (ERT) acquisitions. Over the 3 years of monitoring (2017–2020), two flood events reached the Selz settlement. In total, four events have been analysed to build a hydrogeological model of the area in order to properly estimate its recharge and regression curve, and to define the functionalities of the swallow holes. The defined model allowed a better knowledge and a greater awareness in proposing the proper mitigation measures able to increase the drainage capacity of the area avoiding always more frequent future floodings.
Val Rosandra is a unique geomorphological environment located on the western side of the Classical Karst Plateau (NE Italy). This deep limestone gorge is crossed by a stream that is fed by a large ...basin located in Slovenia. Val Rosandra is the only example of a karst river valley withsurface hydrography in the Classical Karst Plateau. The torrent that crosses it digs a deep gully into the rock, richin rapids, swirl holes, small waterfalls, enclosed meanders and basins; here, the first seepage phenomena occur, and part of the water feeds the underground aquifer.Val Rosandra is characterised by a complex structural situation. The NE slope culminates in the structure of Mt. Stena, a limestone tectonic wedge between two faults, firmly rooted in the karst platform. Bothits external morphology and its caves are influenced by the structure, i.e. by the attitude of bedding planes, fault planes and master joints. Mt. Stena, in particular, hosts a comprehensive net of articulated and diversely shaped caves, basically organised on several levels. This network stretches over a total of 9,000 metres, bearing testimony to ancient geological and hydrogeological origins.The deepest areas of the system reacha suspended aquifer that is probably sustained by an overthrust and placed about 100 meters above the underground aquifer of the Rosandra torrent.A series of feasibility studies on the Trieste-Divača high-speed railway link concentrated on the potential interaction between the project and karst features. In line withthe project requirements, risk of voids intersection and water contamination were analyzed as Mt. Stena’s suspended aquifer partially feeds the Rosandra torrent, whichflows in a protected natural area. We therefore suggest that further investigations ought to be performed to integrate the existing knowledge on karst and on the hydrogeological aspects of the massif.
Abstract
Several methodologies allow for the detection and mapping of existing sinkholes in order to asses and manage the associated hazards and risks. These phenomena, linked to the presence of ...soluble rocks, are well known globally as they can cause severe damage to man‐made structures. In this paper, we propose an integrated method applied to a test‐site area in NE Italy where, on May 11 2017, a failure shaped like a sinkhole, suddenly occurred along a main regional road, which then had to be closed to traffic in part as a result of a landslide developing on the slope just upstream from the surface depression which had already formed. The slope was reprofiled, a paved barrier was placed at the toe of the slope, and the road itself was finally repaired and restored. In the test site, a detailed morphological and geological survey was performed, as well as several integrated multi‐scale geophysical investigations, both in correspondence to the sinkhole location and in surrounding areas where other depressions were found. Results confirm the absence of large cavities down to the maximum investigated depth and highlighted a complex geological situation with abrupt lateral variations, a straight correlation between different geomorphological and geological elements, and the role of water paths. Geophysical investigations were found to be a useful tool to monitor the future evolution of the identified phenomena and to prevent further collapses and disasters along roads.
Summary
Drought‐induced tree mortality frequently occurs in patches with different spatial and temporal distributions, which is only partly explained by inter‐ and intraspecific variation in drought ...tolerance. We investigated whether bedrock properties, with special reference to rock water storage capacity, affects tree water status and drought response in a rock‐dominated landscape.
We measured primary porosity and available water content of breccia (B) and dolostone (D) rocks. Saplings of Fraxinus ornus were grown in pots filled with soil or soil mixed with B and D rocks, and subjected to an experimental drought. Finally, we measured seasonal changes in water status of trees in field sites overlying B or D bedrock.
B rocks were more porous and stored more available water than D rocks. Potted saplings grown with D rocks had less biomass and suffered more severe water stress than those with B rocks. Trees in sites with B bedrock had more favourable water status than those on D bedrock which also suffered drought‐induced canopy dieback.
Bedrock represents an important water source for plants under drought. Different bedrock features translate into contrasting below‐ground water availability, leading to landscape‐level heterogeneity of the impact of drought on tree water status and dieback.
After the 1st May 2004, when new countries joined the European Union, the need was felt to link these states through an infrastructure network of motorway and railway links (high speed—HS/high ...capacity—HC) easily able to transport all possible goods throughout Europe. Within this framework, 14 different projects were developed with the aim of linking important cities. One of these links is the Corridor V connecting Lisbon (Portugal) to Kiev (Ukraine) and assigning a strategic role to Italy with respect to the integration process of these countries. In detail, part of the Corridor V is expected to start from Venice, reaching Trieste and from here on to Ljubljana (Slovenia) before proceeding to Budapest and finally reaching Kiev in Ukraine. The whole development (from Portugal to Ukraine) is approximately 4,000 km long of which, about 30 km (less than 1 % of the entire route), falls within the Italian Classical Karst area, a highly karstified zone, renowned worldwide as one of the best karst landscapes on the planet. The present paper regards the GIS statistical methodological approach used to identify the degree of karstification of the Italian Classical Karst providing the stakeholders all the necessary information while planning possible railway HS/HC solutions.
•Three closely spaced springs follow different underground karst conceptual models.•The karstified network is more interconnected and more active during high flow.•Use of fluorescent dyes in ...extensive alpine karst aquifers may be ineffective.•Monitoring of natural tracers in extensive alpine karst aquifers is very effective.
Limestone massifs with a high density of dolines form important karst aquifers in most of the Alps, often with groundwater circulating through deep karst conduits and water coming out of closely spaced springs with flow rates of over some cubic meters per second. Although several hydrogeological studies and tracing experiments were carried out in many of these carbonate mountains in the past, the hydrogeology of most of these karst aquifers is still poorly known.
Geological, hydrodynamic and hydrochemical investigations have been carried out in one of the most representative of these areas (Cansiglio-Monte Cavallo, NE Italy) since spring 2015, in order to enhance the knowledge on this important type of aquifer system. Additionally, a cave-to-spring multitracer test was carried out in late spring 2016 by using three different fluorescent tracers. This hydrogeological study allowed: 1) gathering new detailed information on the geological and tectonic structure of such alpine karst plateau; 2) defining discharge rates of the three main springs (Gorgazzo, Santissima, and Molinetto) by constructing rating curves; 3) understanding the discharging behavior of the system with respect to different recharge conditions; 4) better defining the recharge areas of the three springs.
The three nearby springs (the spring front stretches over 5 km), that drain the investigated karst aquifer system, show different behaviors with respect to changing discharge conditions, demonstrating this aquifer to be divided in partially independent drainage systems under low-flow conditions, when their chemistry is clearly differentiated. Under high-flow conditions, waters discharging at all springs show more similar geochemical characteristics. The combination of geochemistry, hydrodynamic monitoring and dye tracing tests has shown that the three springs have different recharge areas. The study points out that even closely spaced karst springs, that apparently drain the same karst mountain, can have different behaviors, and thus distinctive reactions toward polluting events, a characteristic to be taken into account for their management.
•Climate change is increasing the need for vineyard irrigation in karstic areas.•Deep roots ensure favorable vine water status during summer drought and heat stress.•Plants can absorb shallow water, ...but largely rely on deep water sources.•Deficit irrigation in karstic areas should be based on the actual plant water needs.
Ongoing variations in rainfall and temperature regimes affect the physiology and productivity of grapevines, calling for irrigation in drought-prone areas. During vintage 2015, we monitored plants water status and indirectly assessed rooting depth and exploited water sources (oxygen isotope analyses) in a mature Vitis vinifera cv. Malvasia Istriana vineyard on red soils (“terra rossa”) developed on highly permeable carbonate rocks. We also investigated effects of topsoil irrigation or late summer rains on plant water status and yield. Under the harsh summer environmental conditions of 2015, the plant water status was overall favorable (moderate water deficit) and never reached critical levels, suggesting that irrigation was not mandatory. Leaf conductance to water vapor (gL) measured in July decreased by about 70% compared to spring, while minimum leaf water potential (Ψmin) dropped by only 16%, suggesting an isohydric behavior of the cultivar (strict stomatal control of transpiration). Both Ψmin and gL reached a minimum in July (peak of drought), and returned to pre-drought values in late summer. Rainfalls or supplemental irrigation (about 40 mm) promoted prompt recovery of plant water status. Irrigation treatments or occasional summer rainfalls can influence the water status of plants, although roots have access to deep water sources. In fact, the isotopic composition of xylem sap was similar to that of soil water sampled in a nearby deep cave, supporting the hypothesis that deep soil is the main water source for grapevines in karstic areas during summertime. Deficit irrigation, based on careful evaluation of physiological indicators of plant water status, might be an effective strategy for promoting sustainable viticulture, and a rationale use of water resources in karstic ecosystems.
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