scholarly journals A Modified AVI Model for Groundwater Vulnerability Mapping: Case Studies in Southern Italy

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 248
Author(s):  
Daniela Ducci ◽  
Mariangela Sellerino

Many methods for evaluating the aquifer’s vulnerability to pollution have been developed in the past four decades by using geographic information system (GIS) tools. However, even if the aquifer vulnerability concept is well defined and the methods have been constantly tested and compared, the problem of the choice of the best “standard” method remains. To meet these objectives, aquifer vulnerability maps are of crucial importance. The choice of method depends on several factors, including the scale of the project, the hydrogeological characteristics of the area, and data availability. Among the many methods, the AVI (Aquifer Vulnerability Index) method has been widely used as it considers only two physical parameters. The AVI Index represents the hydraulic resistance of an aquifer to vertical flow, as a ratio between the thickness of each sedimentary unit above the uppermost aquifer (D, length), and the estimated hydraulic conductivity (K, length/time) of each of these layers. The AVI Index has a time dimension and is divided into five classes. In order to avoid a widespread presence of the higher vulnerability classes, especially in shallow aquifers, the AVI classification has been modified using statistical methods. The study reports the application of the modified AVI method for groundwater pollution vulnerability, in three different areas of southern Italy, highlighting the limitations of the method in alluvial aquifers and the differences with other methods.

2020 ◽  
pp. 63-73
Author(s):  
Taoufiq Kouz ◽  
Soukaina Mansour ◽  
Hakim Mesmoudi ◽  
Houria Dakak ◽  
Hinde Cherkaoui Dekkaki

Many methods for assessing the vulnerability of groundwater against anthropogenic pollution have been developed in the past decades. However, if aquifer vulnerability concept is well defined and the methods have been constantly tested and compared, the problem of the choice of the best method remains. The choice of the method depends on a series of factors, including the scale of the problem, the hydrogeological characteristics of the area and data availability. From a pile of a vulnerability assessing methods, the GOD, DRASTIC and SI approaches have been the most extensively tested. This is why, in the present work, we applied them to evaluate the groundwater vulnerability of the Ghiss-Nekkour aquifer, located in North East of Morocco, on its Mediterranean shore. The mapping resulting from the application of the three approaches shows a range of intervals divided into classes corresponding to fluctuating degrees of vulnerability from “very low” to “extreme”. The coincidence rate between the nitrate distribution of the groundwater and the mapped vulnerability classes is higher when the SI approach is applied. Such mapping constitutes basic documents guiding the land planner in decision-making within a framework of territorial intelligence and integrated management of the Ghiss-Nekkour coastal basin.


2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Nyakno Jimmy George

AbstractAVI (Aquifer vulnerability index), GOD (groundwater occurrence, overlying lithology and depth to the aquifer), GLSI (geo-electric layer susceptibility indexing) and S (longitudinal unit conductance) models were used to assess economically exploitable groundwater resource in the coastal environment of Akwa Ibom State, southern Nigeria. The models were employed in order to delineate groundwater into its category of vulnerability to contamination sources using the first- and second-order geo-electric indices as well as hydrogeological inputs. Vertical electrical sounding technique employing Schlumberger electrode configuration was carried out in 16 locations, close to logged boreholes with known aquifer core samples. Primary or first-order geo-electric indices (resistivity, thickness and depth) measured were used to determine S. The estimated aquifer hydraulic conductivity, K, calculated from grain size diameter and water resistivity values were used to calculate hydraulic resistance (C) used to estimate AVI. With the indices assigned to geo-electric parameters on the basis of their influences, GOD and FSLI were calculated using appropriate equations. The geologic sequence in the study area consists of geo-electric layers ranging from motley topsoil, argillites (clayey to fine sands) and arenites (medium to gravelly sands). Geo-electric parametric indices of aquifer overlying layers across the survey area were utilized to weigh the vulnerability of the underlying water-bearing resource to the contaminations from surface and near-surface, using vulnerability maps created. Geo-electrically derived model maps reflecting AVI, BOD, FLSI and S were compared to assess their conformity to the degree of predictability of groundwater vulnerability. The AVI model map shows range of values of log C ( −3.46—0.07) generally less than unity and hence indicating high vulnerability. GOD model tomographic map displays a range of 0.1–0.3, indicating that the aquifer with depth range of 20.5 to 113.1 m or mean depth of 72. 3 m is lowly susceptible to surface and near-surface impurities. Again, the FLSI map displays a range of FLSI index of 1.25 to 2.75, alluding that the aquifer underlying the protective layer has a low to moderate vulnerability. The S model has values ranging from 0.013 to 0.991S. As the map indicates, a fractional portion of the aquifer at the western (Ikot Abasi) part of the study area has moderate to good protection (moderate vulnerability) while weak to poor aquifer protection (high vulnerability) has poor protection. The S model in this analysis seems to overstate the degree of susceptibility to contamination than the AVI, GOD and GLSI models. From the models, the categorization of severity of aquifer vulnerability to contaminations is relatively location-dependent and can be assessed through the model tomographic maps generated.


2015 ◽  
Vol 15 (4) ◽  
pp. 784-792 ◽  
Author(s):  
Nastaran Khodabakhshi ◽  
Gholamreza Asadollahfardi ◽  
Nima Heidarzadeh

Pollution control and removal of pollutants from groundwater are a challenging and expensive task. The aims of this paper are to determine the aquifer vulnerability of Sefid-Dasht, in Chaharmahal and Bakhtiari province, Iran, using the DRASTIC model. In addition, the groundwater quality index (GQI) technique was applied to assess the groundwater quality and study the spatial variability of major ion concentrations using a geographic information system (GIS). The vulnerability index ranged from 65 to 132, classified into two classes: low and moderate vulnerability. In the southern part of the aquifer, the vulnerability was moderate. Furthermore, the results indicate that the magnitude of the GQI index varies from 92% to 95%. This means the water has a suitable quality. However, from the north to the south and southwest of the aquifer, the water quality has been deteriorating, and the highest concentration of major ions was found in the southwest of the Sefid-Dasht aquifer. A comparison of the vulnerability maps with the GQI index map indicated a poor relation between them. In the DRASTIC method, movement of groundwater is not considered and may be the reason for such inconsistency. However, the movement of groundwater can transport contaminants.


Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 985
Author(s):  
Rudy Rossetto ◽  
Tiziana Sabbatini ◽  
Nicola Silvestri

Pesticides play a crucial role in regulating crop production by reducing crop losses and increasing crop yield and quality. However, they may threaten surface and groundwater, a phenomenon occurring at global scale, potentially causing environmental damage and prohibition of water use or high treatment costs for drinking water. Assessing spatially-defined aquifer vulnerability to pesticide is then important, as it may allow defining agricultural areas where pesticides should be used following well-defined agronomic practices/limitations. In this study, after a brief review of recent studies on aquifer vulnerability assessment to pesticide, we applied the Vulnerability Index method to the agricultural area of the Municipality of San Giuliano Terme (Pisa, Italy) in order to focus on the data needs and discuss the reliability of this method (as an example of index-overlay methods). The proposed method needs a relatively small number of parameters compared to other more complex ones. Despite a such a small number of parameters, some were not easily available in our case study. Thus, some assumptions were made. This led to vulnerability maps with reduced reliability, no validation with groundwater samples, and little practical use. This means that to produce robust but static vulnerability assessments, large datasets are needed. In turn, the cost of data gathering may be high. The value of these data may, however, be increased, and the cost better justified if the analyses are based on process-based or advanced statistical methods. While the future for vulnerability assessment methods is the use of process-based/advanced statistical methods, index-overlay methods, as a preliminary step for process-based simulation analysis, may still provide initial and relatively quick insights on potential leaching of pesticides. This in turn may support extension services in delivering timely and relevant advices on the use of such pesticides to farmers and owners of plant nurseries and greenhouses.


2017 ◽  
Vol 13 (2) ◽  
pp. 157 ◽  
Author(s):  
Ruzana Dhiauddin ◽  
Wisnu Arya Gemilang ◽  
Ulung Jantama Wisha ◽  
Guntur Adhi Rahmawan ◽  
Gunardi Kusumah

The diversity function of coastal areas requires the increasing need for land and infrastructure that will lead to new problems such as changes in coastal morphology, the occurrence of erosion and accretion, which is supported by the population growth caused the increasing of coastal vulnerable towards hazards. This paper aims to explain the parameters affect Simeulue Island’s coastal vulnerability - beach slope, geomorphology, geology, shoreline change, mean tidal range and mean wave height - and its mapping. The data used were the bathymetry, tide, and currents, the topography of coastal morphology, LANDSAT imagery of 2000 and 2015. To determine the coastal vulnerability level, we implemented CVI (Coastal Vulnerability Index) method of 6 parameters. Finally, we found that CVI from these physical parameters ranges between 1.291to 5.00, which were classified into five classes; 1.291 – 1.826 (very low), 1.826 – 2.449 (low), 2.449 – 2.887 (moderate), 2.887 – 3.651(high), and 3.651 – 5.00 (very high).


2021 ◽  
Author(s):  
Stefan Broda ◽  

<p>Work package 7 of the GeoERA HOVER project deals with groundwater vulnerability assessment to pollution of the shallow upper aquifer. We present vulnerability assessments across Europe applying the DRASTIC method in 11 pilot areas and the COP method for karst systems in 5 pilot areas. The presented assessments are carried out at multiple scales (between 1:1K and 1:250K), pilot areas sizes (catchment to national scale; 15 to 338 000 km²) and hydro-climatic contexts (ranging from extremely high and steady recharge to very low and seasonal recharge). The core item of this presentation is a detailed investigation and statistical assessment on respective data availability, data density and methodologies applied to retrieve input parameters for the assessment (e.g., groundwater recharge) and how this affects the final vulnerability assessments. We also focus on the definition (numerical ranges) of the individual vulnerability classes, which are valid across all pilots.</p><p>In an attempt to generate information summarizing affected aquifer volumes, a method based on a lumped index and 2D conceptual cross-sections is proposed. It was originally designed for sea-water intrusion assessments, and has been adapted and applied in some pilot areas to estimate aquifer volumes of each individual vulnerability class.</p>


2017 ◽  
Vol 56 (2) ◽  
Author(s):  
Hanen Jarray ◽  
Mounira Zammouri ◽  
Mohamed Ouessar ◽  
Fadoua Hamzaoui-Azaza ◽  
Manuela Barbieri ◽  
...  

Groundwater vulnerability mapping is largely used as a modeling tool to delineate areas susceptible to pollution and to protect groundwater resources from this threat. The Zeuss-Koutine aquifer, which constitutes an important source of drinking water in the Southeastern Tunisia, is subjected to an intensive exploitation and threatened by pollution due mainly to the industrial zone of Koutine. The groundwater circulates in fissured and karstified limestone. Aquifer vulnerability has been assessed using the SINTACS method. The different parameters of the SINTACS model were collected from several sources and converted into thematic maps using ArcGis. Each SINTACS parameter was assigned a weight and rating based on a range of information within the parameter. The weight of each parameter depends on the impact of potential pollution. The analysis of vulnerability map to pollution shows that the Southeastern part of the aquifer and the Wadis beds are more susceptible to pollution. The measured nitrate concentrations of two sampling campaigns carried out in high and dry water seasons are coherent with the SINTACS model results.


2007 ◽  
Vol 2 (3) ◽  
Author(s):  
M. V. Civita ◽  
M. De Maio ◽  
A. Fiorucci

In the early 1980's the Italian scientific community, together with a number of institutional decision-makers, realized how urgent it was to protect natural and environmental resources. They agreed that an adequate level of scientifically organized knowledge allows the accurate planning and development of environmental systems through management and direction of the actual development process, without hindering it. Since the special project was first set up in 1984, as part of the GNDCI-CNR (National Group for the Defence against Hydrogeologic Disasters, of the Italian National Council of Research) scientific context, it has been the cardinal point of Research Line 4 “Assessment of Aquifer Vulnerability”. The problem of groundwater contamination was examined in this project for the very first time in Italy in an organic and extensive manner as a key for forecasting and prevention purposes. The Italian approaches to assessing and mapping groundwater vulnerability to contamination are essentially based on two main methodologies:- The GNDCI Basic Method a HCS (Hazard Contamination Source) type approach that can be used for any type of Italian hydrogeologic situation, even where there is a limited amount of data. A unified legend and symbols are also defined for each hydrogeologic level.- The SINTACS [Soggiacenza (depth to groundwater); Infiltrazione (effective infiltration); Non saturo (unsaturated zone attenuation capacity); Tipologia della copertura (soil/overburden attenuation capacity); Acquifero (saturated zone characteristics); Conducibilità (hydraulic conductivity); Superficie topografica (Slope)] method, a PCSM (Point Count System Model) developed for use prevalently in areas with good data base coverage. The methodological approaches described in this paper now make up the Italian standard which has been set in the recent very important Italian Law (152/99) and which has now been ratified in the national guidelines produced by ANPA, the Italian National Agency for Environment Protection. In this paper the structure of the Research Line, the progress obtained by the 21 Research units (over 100 researchers) in 20 years of activity, the results gained etc. are briefly highlighted.


Sign in / Sign up

Export Citation Format

Share Document