Vulnerability assessment of the karst aquifer feeding the Pertuso Spring (Central Italy): comparison between different applications of COP method

Karst aquifers vulnerability assessment and mapping are important tools for improved sustainable management and protection of karst groundwater resources. In this paper, in order to estimate the vulnerability degree of the karst aquifer feeding the Pertuso Spring in Central Italy, COP method has been applied starting from two different discretization approaches: using a polygonal layer and the Finite Square Elements (FSE). Therefore, the hydrogeological catchment basin has been divided into 72 polygons, related to the outcropping lithology and the karst features. COP method has been applied to a single layer composed by all these polygons. The results of this study highlight vulnerability degrees ranging from low to very high. The maximum vulnerability degree is due to karst features responsible of high recharge and high hydraulic conductivity. Comparing the vulnerability maps obtained by both methodologies it is possible to say that the traditional discretization approach seems to overestimate the vulnerability of the karst aquifer feeding the Pertuso Spring. Between the two different approaches of COP method, the proposed polygonal discretization of the hydrogeological basin seems to be more suitable to small areas, such as the Pertuso Spring hydrogeological basin, than the traditional grid mapping

Preliminary validation of an indirect method for discharge evaluation of Pertuso Spring (Central Italy)

This paper deals with the results of the first year of the Environmental Monitoring Plan, related to the catchment project of Pertuso Spring, which is going to be exploited to supply an important water network in the South part of Roma district. The study area is located in the Upper Valley of the Aniene River (Latium, Central Italy), in the outcrop of Triassic-Cenozoic carbonate rocks, and belong to an important karst aquifer. Pertuso Spring is the main outlet of this karst aquifer and is the one of the most important water resource in the southeast part of Latium Region, used for drinking, agriculture and hydroelectric supplies. Karst aquifer feeding Pertuso Spring is an open hydrogeological system aquifer characterized by complex interactions and exchanges between groundwater and surface water which influence the aquifer water budget. Thus, evaluation of groundwater discharge from this karst spring can be affected by difficulties in performing measurements because of the insufficient knowledge about water transfer processes in the hydrological cycle and geometry of drainage conduits. The aim of this paper is to assess the interactions between karst aquifer feeding Pertuso Spring and Aniene River based on stream discharge measurements and water geochemical tracer data in order to validate an indirect method for karst spring discharge evaluation. As a matter of fact, in this paper, there are presented the results of the application of Magnesium as a reliable tracer of karst spring discharge. This indirect method is based on the elaboration of surface water discharge measurements in relationship with Mg2+ concentration values, determined as for groundwater, coming from Pertuso Spring, as for surface water sample, collected upstream and downstream of Pertuso Spring, along Aniene River streamflow. The application of Magnesium as an environmental tracer provides a means to evaluate discharge of Pertuso Spring, as it came up to be a marker of the mixing of surface water and groundwater. On the other hand, the Magnesium ion concentration provides information for the identification of groundwater flow systems and the main hydrogeochemical processes affecting the composition of water within the karst aquifers

Pertuso Spring discharge assessment in the Upper Valley of Aniene River (Central Italy)

Sustainable management of karst aquifers is animportant tool for the protection of these strategic water resources. Assessing water balance in a karst aquifer can be very difficult,due to the complex interactions and exchanges between groundwater and surface water. Therefore, measurements of streamflow and spring discharges are useful to assess karst aquifers available budget. Water balance calculation requires the estimation of two main parameters: recharge (precipitation, agriculture water, surface runoff, etc.) and discharge (underground outflow) which are affected by the highly heterogeneous distribution of permeability due to conduits and voids developed by the dissolution of carbonate rocks. This paper deals with the preliminary results of Pertuso Spring groundwater discharge assessment, in the Upper Valley of Aniene River (Central Italy), where the complex hydrogeological characteristics, related to the high heterogeneity of hydraulic properties, make difficult to set up a reliable methodology of measurement. To achieve this objective, an integrated approach based on the streamflow measurements and geochemical modeling, applied to groundwater and surface water was carried out. Because no continuous discharge measurements of Pertuso Spring were available, different methods (velocity–area using current meter and geochemical assessment) were applied to evaluate the discharge of the spring and the stream flow during the monitoring period from July 2014 to May 2015. Aniene River streamflow measurements were carried out by using the conventional current-method and the salt dilution method. For the evaluation of the Pertuso Spring discharge, as a support for traditional discharge methodology, various groundwater and surface water monitoring campaigns have been made along the Aniene River, upstream and downstream the Pertuso Spring, for the acquisition of geochemical data. The aim of this study is to present the preliminary results of an indirect method for the estimation of the Pertuso Spring discharge, based on Magnesium concentration changes in groundwater and surface water

Innovative methodology for quantitative and qualitative assessment of water resources in karst aquifers: a case study in southern Lazio region, central Italy

This paper outlines the results of a hydrogeological study carried on from July 2014 to November 2106 to assess quantitatively and qualitatively water resources (groundwater and surface water) emerging in the Upper Valley of the Aniene River (Latium Region, Central Italy). This work deals with the Environmental Monitoring Plan, related to the catchment project of the Pertuso Spring, which is going to be exploited to supply an important water network in the South part of Roma district. The study area is located in the Upper Valley of the Aniene River, in the outcrop of Triassic-Cenozoic carbonate rocks, and belong to an important karst aquifer. Pertuso Spring is the main outlet of this karst aquifer and is the one of the most important water resource in the southeast part of Latium Region, used for drinking, agriculture and hydroelectric supplies. This hydrogeological system is characterized by a strong local hydraulic connectivity between the Aniene River surface water and groundwater coming from the Pertuso Spring. First at all, in this study, in order to estimate the vulnerability degree of the karst aquifer feeding the Pertuso Spring, the COP method has been applied and vulnerability maps are proposed. Thus, with the aim of highlighting the karst features key-role in the unsaturated zone, a new vulnerability approach has been set up, starting from two discretization approaches. The aim of this work is to compare both results of the intrinsic vulnerability mapping, in order to evaluate which one is the most suitable for the study area. On the basis of the hydrogeochemical data and their interpretations for groundwater and surface water, monitored from July 2014 to November 2016, a hydrogeological study has been carried on to identify flowpaths and hydrogeochemical processes governing groundwater-surface water interactions in this region. To this end, discharge surveys were carried out on four monitoring sections along the Aniene River. The proposed conceptual model shows that the karst aquifer feeding the Pertuso Spring supplies the Aniene River, highlighting seasonal variability depending on the rainfall regime. The analysis of solute contents in the monitoring points has suggested the identification of the Magnesium ion as a conservative tracer in this specific system and, consequently, to the development an indirect method for the evaluation of karst spring discharge based on discharge measurements and water geochemical data. This method is based on the elaboration of surface water discharge measurements in relationship with Mg2+ concentration values, determined as for groundwater, coming from the Pertuso Spring, as for surface water samples, collected upstream and downstream the spring, along the Aniene River streamflow. This method has been validated by the comparison with discharge values obtained using the current meter method and by geochemical data. This study suggests that the application of the Magnesium ion as an environmental tracer may provide a means to evaluate discharge of the Pertuso Spring, as it came up to be a marker of the mixing of surface water and groundwater. On the other hand, the Magnesium ion concentration provides information for the identification of groundwater flow systems and the main hydrogeochemical processes affecting the composition of water within the karst aquifer feeding the Pertuso Spring

Assessment of vulnerability to seawater intrusion for the coastal aquifer of Dar es salaam (Tanzania)

Groundwater represents worldwide the main reserve of freshwater for human needs. The increasing demand combined with the use of unsustainable systems for groundwater management leads to a remarkable decay in its quality and quantity, especially in many cities of the Global South, where the fast urban growing frequently bring to environmental critical issues as the case of seawater intrusion for coastal aquifers. Dar es Salaam, in Sub-Saharan Africa, is one of these cities, with more than 4 million of inhabitants and a population growth rate of about 8 per cent per year. Due to the urban pressure on the aquifer, the city is now facing a considerable saline intrusion along the coastline, with depletion of groundwater resources and contamination of pumping wells. Aim of this paper is to apply and test the GALDIT method for the assessment of coastal aquifer vulnerability to seawater intrusion, starting from data and measures collected from 2011 to 2013 during the “Adapting to Climate Change in Coastal Dar es Salaam (ACC-DAR) project. The GALDIT is a weights and rating based method that consider six parameters to compute a vulnerability to seawater intrusion index according to a specific numerical ranking. The key parameters are the following ones: Groundwater occurrence, Aquifer hydraulic conductivity, Level of the groundwater above the mean sea level, Distance from the shore, Impact of existing status of seawater intrusion in the area and Thickness of the aquifer. Providing different weights and ratings the GALDIT method allows to evaluate the relative impact of each factor, starting from different hydrogeological settings. The results for Dar es Salaam study case show the presence of all the classes (Low, Moderate and High), among which the widest area has a moderate vulnerability to seawater intrusion. The higher class of vulnerability is rather more concentrated in the northern part of the city. In this context, the assessment of coastal aquifer vulnerability to seawater intrusion in the area of Dar es Salaam might turn out to be a helpful basic information in support of groundwater local policies, for a proper and more sustainable use of the resource

An overview on the state of art on IAH coastal aquifer dynamics and coastal zone website

The website of the IAH Coastal Aquifer Dynamics and Coastal Zone Management (CAD-CZM) Network, linkable at the web address www.iah-cad-czm.net, aims at improving the knowledge about coastal aquifer for supporting worldwide the assessment, development and management of water resources endangered by saltwater intrusion. The overall target of this project is promoting the development of web-GIS that gathers coastal aquifer data from different sources to assist, by the support of researchers, professionals, stakeholders and water managers to make the correct choices for the sustainable use of these precious resources. The CAD-CZM network tries to satisfy the interest expressed in the recommendations issued on different occasions by UNESCO and IAEA for studying coastal areas in the frame of joint programs in cooperation with other international agencies. The CADCZM website structure aims to collect information coming from any kind of source, as technical as scientific, and its target is to make them available in the aim of taking under control the rate of exploitation and the management of these vulnerable groundwater resources. The website organization is like that anyone could find the specific coastal zone, he is interested in gaining information, only looking for it on the google earth link, present inside the website. Once identified the area of interest, it is possible to download, if present, the specific sheet including all the information collected, checked and uploaded, by the scientific committee of the website. Starting from the analysis of a database of more than 70 coastal aquifer, reporting information about lithology, hydrogeological and geochemical characteristics, salinity sources, applied monitoring methods, management strategies, and seawater and brackish groundwater desalination technologies adopted, an updated overview of the state of the knowledge about seawater intrusion all over the world is presented

A Method to Contrast the Impact of Extreme Precipitation. A case study from Central Italy

Climate change, which is affecting all over the world, leads to different impacts on the environment and therefore on human life. One of the most important impact is the increasing of extreme precipitation. Increases in heavy precipitation may not always lead to an increase in total precipitation, over a season or over the year. Heavy precipitations increasing has also been documented even when mean total precipitation decreases. This may occur when the probability of precipitation (the number of events) decreases, or if the shape of the precipitation distribution changes, but this latter situation is less. Some climate models forecast a decrease in moderate rainfall, and an increase in the length of dry periods, which offsets the increased precipitation falling during heavy events. Climate impacts are compounded by urban development, which removes the vegetation and soil that slow and filter water, coming from rainfall. Urban sprawl also increases impervious surfaces, which move water over the land and put them, directly, into receiving lakes, rivers and estuaries. To contrast these negative impacts, a solution may be to limit the use of non-permeable surfaces, like concrete, in the urban areas. In this regard, the authors, as researchers of "Sapienza University of Rome", are studying the possibility of using, in the parking areas of a central Italian city (Rieti), pavement with "green infrastructure", that can reduce runoff and flood risks during storms. The construction of the pavement with "green infrastructure", can first mitigate the effect of exceptional rains, secondly reduce the soil consumption. Permeable, or pervious, pavements reduce runoff by allowing rain and melting snow to infiltrate. A first study of the materials, that can be used as parking paving, has led to estimate a permeability coefficient of 2,70 s10-5 m.s-1. In the case study, object of this paper, the authors have first calculated the area, in square meters, of the municipal parking areas of Rieti city. Secondly, they have valuated the possibility of change the concrete pavement, today present in this areas, with a "green infrastructure" pavement, and they have estimated volumes of water that will be infiltrate, in case of extreme precipitations. This estimation was made through the real precipitations data of the last 7 years, measured by the National Hydrographic Service of Italy

Temperature logs application to evaluate groundwater – surface water interaction in an area of Sabato basin, in southern Italy

Down hole temperature, groundwater, stream water, mixing, Campania

The use and beauty of ultra-high-resolution seismic reflection imaging in Late Quaternary marine volcaniclastic settings, Bay of Naples, Italy

A Nápolyi-öbölben felvett ultra nagy felbontású egycsatornás (IKB-Seistec™) reflexiós szeizmikus szelvények korábbi geológiai és geofizikai vizsgálatok eredményeivel együtt kivételes, eddig soha nem látott felbontású szeizmikus leképezését nyújtják a Flegrei-mezők és a Somma-Vezúv felszín alá süllyedt késő-pleisztocén–holocén rétegtani felépí - tésének. A szeizmikus szelvényeken látott geometria és gravitációs magvevővel nyert üledékek adatainak összevetéséből Campania partközeli kontinentális talapzatán számos olyan üledékes és vulkáni szerkezet, valamint hidrotermális jelenség került leképezésre, melyek a legutolsó glaciális maximum (kb. 18 000 év) óta keletkeztek. A Pozzuoli-öbölben mért Seistec szelvények jól mutatják a beomlott kaldera gyűrűs vetőjét, a kb. 15 ezer éves Nápolyi Sárga Tufa (NYT) lerakódáshoz vezető kitöréskor felújuló boltozatot, és alátámasztják a deformáció későnegyedidőszaki korára és stílusára vonatkozó hipotéziseket. A szeizmikus szelvényeken látható a NYT rétegeinek töréses szerkezete, valamint hidrotermális fluidum-feláramlások és vulkáni/szubvulkáni intrúziók a gyűrűs vetők mentén. A Somma-Vezúv rétegvulkán előterében a kontinentális talapzat felett mért szeizmikus szelvények leképezték a Vezúv i.sz. 79-es kitörésekor Herculaneum városát elpusztító piroklaszt-ár tengervízbe érésekor keletkező, gravitációsan összeomló homokhullámok szerkezetét is. A Somma-Vezúv és a Pozzuoli-öböl közti, buckás felszínű Banco della Montagna területén mért szelvények és fúrómagok vulkanoklasztos diapírok sorát tárták fel. Ezeket a konszolidálatlan horzsakőből álló testeket a fluidum - feláramlás és aktív kigázosodás hatására kialakult mélybeli túlnyomás hozta fel a tengerfenékre.Very high-resolution, single channel (IKB-Seistec™) reflection seizmic profiles acquired in the Bay of Naples, com - plemented with geological and geophysical data from the literature, provide unprecedented, superb seismic imaging of the latest Pleistocene–Holocene stratigraphic architecture of the submerged sectors Campi Flegrei and Somma-Vesuvius volcanic districts. Seismic profiles were calibrated by gravity core data and document a range of depositional systems, volcanic structures and hydrothermal features that evolved after the onset of the Last Glacial Maximum (~ 18 ka BP) over the continental shelf on the Campania coastal zone. Seistec profiles from the Pozzuoli Bay yield high-resolution images of the shallow structure of the collapse caldera-ring fault — resurgent dome system associated with the eruption of the Neapolitan Yellow Tuff (NYT) (ca 15 ka) and support a working hypothesis to assess the timing and the styles of deformation of the NYT resurgent structure throughout the latest Quaternary. Seismic images also revealed the nature of the fragile deformation of strata along the NYT ring fault system and the occurrence of hydrothermal fluids and volcanic/subvolcanic intrusions ascending along the ring fault zone. Seismic data acquired over the continental shelf off the Somma-Vesuvius stratovolcano, display evidence of gravit - ational instability of wavy bedforms representing the submarine prosecution of pyroclastic flows originated from the Vesuvius during the eruption that destroyed the Roman city of Herculaneum in 79 CE. At the Banco della Montagna, a hummocky seafloor knoll located between the Somma-Vesuvius and the Pozzuoli Bay, seismic profiles and gravity core data revealed the occurrence of a field of volcaniclastic diapirs formed by the dragging and rising up of unconsolidated pumice, as a consequence of fluid overpressure at depth associated with active degassing and fluid venting at the seafloor