A GIS‐Based GOD Model and Hazard Index Analysis: The Quaternary Coastal Collo Aquifer (NE‐Algeria)

Abstract

The quaternary coastal Collo aquifer in northeast Algeria (NE Algeria) marks an important local water resource supporting domestic, industrial and agricultural activities. The aquifer shows signs of contamination due to the existence of various pollution sources, especially nitrogen compounds. Focusing the local identification of key vulnerable zones and related main hazard types for wise future water management, the present study highlights results from a coupled analysis of the well-established Geographical Information System (GIS)-based GOD (groundwater occurrence, overall aquifer class, depth to groundwater) hazard index analysis and the COST Action 620 plan. Most prevalent hazard types in the study area were identified as the urban/residential areas without public sewage systems, landfill and agricultural/pasturing areas. Regarding the vulnerability analysis particularly the northern aquifer region is endangered, dominated by high (22.4%) and moderate (27.4%) vulnerability classes. Central, western and southern aquifer regions are characterized by low (23.3%) and very low (26.9%) vulnerability classes. Overall, these GOD-derived results are in good agreement with earlier results obtained by the more complex DRASTIC approach. Final risk assessment and validation related to 2014/2015 nitrate sampling campaigns indicate that "high risk" and "very high risk" classes only apply to a small part of the study area in the northern sector (8%), whereas the main part (>60%) broadly affecting the central, western and southern sector only bears a low to very low risk of water pollution. Apart from a future-oriented groundwater abstraction strategy it is recommended to update the evaluation regularly to effectively consider dynamic changes of local anthropogenic activities and hazards.

Contribution of a Geographic Information System to Assess the Vulnerability to Groundwater Pollution of the Free Water Table from the Oued Souf Region (South-East Algeria)

“…In our case study, the GOD indices are divided into three classes of vulnerability; low, medium, and high, as previously reported [11]. Also [14], the degree of vulnerability increases with the GOD index (GI) [6]. The approach for classifying the index map as a function of vulnerability classes is similar to that described above for the DRASTIC method [18].…”

Study of Intrinsic Vulnerability to Pollution by the GOD-Foster Method: Application to Temara Groundwater (Morocco)

“…The GOD-Foster method is the most widely used in assessing vulnerability to pollution, sedimentary aquifers. The GOD method (Groundwater occurrence "G", Overall class of aquifer 'O' and Depth to groundwater table 'D') was developed by Foster in 1987 presenting the vulnerability of the aquifer to the vertical percolation of pollutants across the unsaturated zone, while neglecting the lateral migration of pollutants in the saturated zone (Lobo Ferreira & Oliveira, 2004;Fraga et al, 2013;Ghazavi & Ebrahimi, 2015;Benabdelouahab et al, 2018;Boulabeiz et al, 2019).…”

The Impact of Rapid Urban Growth on Potential Groundwater Pollution in Ngemplak Sub-District, Sleman District

“…The potential of groundwater pollution itself can be interpreted as the ability of a region based on the ease of the groundwater itself to be polluted. The geospatial method which can be used to assess the potential of groundwater pollution is the GOD method (Boulabeiz et al, 2019;Djoudi et al, 2019;Sartika et al, 2020;Sharadqah, 2017). The method use three parameters, they are Groundwater occurrence (G) or the type of aquifer, Overall aquifer class (O) or the type of rock which made unsaturated zone, and Depth to water table (D) or depth of groundwater.…”