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Geoindex - Intrinsic vulnerability to pollution map of the aquifers

Probability that an discharge of a pollutant load on the ground surface reaches the groundwater table

The Intrinsic vulnerability to pollution map of the Aquifers of Catalonia (MVIAC), at 1:100.000 scale represents in a qualitative way, and in relative terms, the probability that an accidental application or discharge of a pollutant load on the ground surface reaches the groundwater table following a vertical path. In other words, it shows the effectiveness of the subsoil against groundwater pollution. It is determined considering the geological and hydrogeological settings at a certain location and regardless or the type and characteristics of the pollutant.

The MVIAC has ben developed in the framework of the third ICGC Contract Program (CP 2019-2022) and in collaboration with Catalan Water Agency (ACA) inside the European project H2020 named Harmonized vulnerability to pollution mapping of the upper aquifer (HaVuPo) promoted by the ERA-NET GeoERA (Establishing the European Geological Surveys Research Area to deliver a Geological Service for Europe). In this European project, lead by the German Geological Survey (BGR), the ICGC participates jointly with 16 geological services from 13 different countries.

The MVIAC viewer includes a vulnerability information layer corresponding to intergranular and mixed aquifers and to low permeability media estimated using the DRASTIC method (Aller et al., 1987) and a vulnerability information layer in mainly karst media estimated using the COP method (Vías et al., 2006). It also includes an information layer with the geographical distribution of the method used and the aquifers nature by lithology of the Map of Hydrogeological Areas of Catalonia 1:250.0000 (ICGC, 2016).


Geoindex viewer legend Intrinsic vulnerability to aquifer contamination [PDF, 972 kB; Catalan]


Last update

  • Date: November 2020
WMS Intrinsic vulnerability to contamination of aquifers

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Download Map intrinsic vulnerability to contamination of aquifers in Catalonia

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To calculate the intrinsic vulnerability of the aquifers two methods based on the weighting of parameters and assigning weights (Parameter Weighting and Rating Methods - PCSM) have been used.

These are:

  • The DRASTIC method, applied in the intergranular and mixed-type aquifer systems (Aller et al., 1987). The DRASTIC method considers 7 parameters of the media: Depth to water table – D, net Recharge – R, Aquifer media – A, Soil media -S, Topography – T, Impact of vadose zone – I and  hydraulic Conductivity – C.
  • The COP method in karst aquifers with different degrees of karst development (Vías et al., 2006). This parameter weighting method considers three factors. The factor “O” (Overlying layers) indicative of the natural protection provided by the unsaturated zone of the aquifer, the factor “C” (Concentration of flow) that describes the degree of concentration of the surface water flow that produces the karstification of an area and the factor “P” (Precipitation) that considers the amount of precipitation, its frequency and intensity throughout a year.

Use and interpretation of data

The intrinsic vulnerability aquifers maps are tools to enhance the management and protection of the groundwater bodies because they represent the sensitivity of an aquifer to be affected by a pollutant applicated or discharged on the ground surface.

The vulnerability map combined with pressures inventory above a groundwater body allows to estimate what is its chemical potential impact. In this sense, it can be used for plan and define control measures and/or restrictions regarding the implementation of certain types of activity or land uses.

In some countries of the EU, these types of maps are regulatory and set out the guidelines and scope for hydrogeological studies to be carried out before the start-up of a new activity.  

It must be considered that the MVIAC is calculated for the uppermost aquifer in each case and the effect of paved urban areas is not considered.

The pixel resolution is 50 m. The representative scale for the correct reading and interpretation of the vulnerability map data is 1:100.000. For any assessment on a more detailed scale, it is essential to collect specific data in the area under study and a 3D analysis of the subsoil geology, as well as the previous qualitative state of the groundwater body.


Map reference

Arnó, G.; Conesa, A.; Carreras, X.; Camps, V.; Fraile, J.; Herms, I.; Iglesias, M. (2020). Mapa de Vulnerabilitat Intrínseca a la contaminació dels Aqüífers de Catalunya (MVIAC) Escala 1:100.000. Barcelona. Institut Cartogràfic i Geològic de Catalunya (ICGC) i Agència catalana de l’Aigua (ACA).


Related references

Aller, L.; Bennett, T.; Lehr, J.; Petty, R.; Hackett, G. (1987). DRASTIC: A standardized system for evaluation ground water pollution potential using hydrogeological settings. National Water Well Association, Dublin, Ohio and Environmental Protection Agency, Ada, Ok. EPA/600/2-85/018. https://cfpub.epa.gov/si/si_public_record_Report.cfm?Lab=ORD&dirEntryID=35474.

GeoERA HOVER-WP7 Team (2020). Harmonized vulnerability to pollution mapping of the upper aquifer. EGU General Assembly 2020. EGU2020-14037. Online. https://doi.org/10.5194/egusphere-egu2020-14037.

Bergadà, MM.; Cervello, J.M.; Serrat, D. (1997). Karst in conglomerates in Catalonia (Spain): Morphological forms and sedimentary sequence types recorded on archaeological sites [Le karst en conglomérats en Catalogne (Espagne): Morphologies et séquences sédimentaires en rapport à quelques sites archéologiques]. In: Quaternaire, vol. 8, n° 2-3: 267-277. http://dx.doi.org/10.3406/quate.1997.1579.

Carreras, X.; Fraile, J.; Garrido, T.; Cardona, C. (2015). Groundwater vulnerability mapping assessment using overlay and the DRASTIC method in Catalonia. In: Experiences from ground, coastal and transitional water quality monitoring. The Handbook of Environmental Chemistry book series, vol. 43: 117–134, Springer, Heidelberg, Germany. https://doi.org/10.1007/698_2015_441.

COST Action 620. Vulnerability and Risk Mapping for the Protection of Carbonate (Karst) Aquifers. Final Report. https://www.cost.eu/publication/vulnerability-and-risk-mapping-for-the-protection-of-carbonate-karst-aquifers-final-report/.

Daly, D.; Dassargues, A.; Drew, S.; Goldscheider, N.; Neale, S.; Popescu, I.; Zwahlen, F. (2002). Main concepts of the “European approach” to karst-groundwater-vulnerability assessment and mapping. Hydrogeology Journal, vol. 10: 340-345. https://link.springer.com/article/10.1007/s10040-001-0185-1.

Freixes, A. (2014). Els aqüífers càrstics dels Pirineus de Catalunya. Interès estratègic i sostenibilitat. Tesis doctoral. Facultat de Geologia. Universitat de Barcelona, Barcelona, 650 pp.

Vías, J.M.; Andreo, B.; Perles, M.J.; Carrasco, F.; Vadillo, I.; Jiménez, P. (2006). Proposed method for groundwater vulnerability mapping in carbonate (karstic) aquifers: the COP method. Hydrogeology Journal, vol. 14: 912–925. https://doi.org/10.1007/s10040-006-0023-6.

Vrba, J.; Zaporozec, A. (1994). Guidebook on Mapping Groundwater Vulnerability. IAH International Contributions to Hydrogeology, 16. FRG, Heise Publication, Hannover, 131 pp.