No abstract

The environmental assessment of domestic pollution is required to minimize the risk of soil and groundwater contamination. Septic storages (localized sources) may affect the surrounding soil and permeable chalky formations by the intrusion of waste water within the formations. The aim was to develop a clearer understanding of waste water leakage due to numerous waste septic storages implemented within chalk formations at different towns and villages in the West Bank, Palestine. The possession of such information may be used to maintain not only sustainable development but also the protection of the environment. Since waste water is a good electrical conductor, the Electrical Resistivity Tomography (ERT) technique was employed for its ability in determining lateral and vertical electrical resistivity variations of possible infiltration zones of waste water. Furthermore, extracted vertical electrical soundings (VES) provide indications about the nature of the geological features that can affect the behaviour of leakage. Geo‐electrical surveys were carried out to investigate their utility in detecting and examining the effect of pollution. The two‐dimensional (2D) inverted models obtained by many electrode array configurations; Schlumberger, Wenner and dipole‐dipole were consistent. Interpretation of Direct Current (DC) geoelectrical resistivity field data demonstrates the existence of low‐apparent electrical resistivity ρa zones (ρa < 15 Ω·m). A trend of decreasing resistivity is observed towards the horizontal direction of the existing storages, indicating the location of pollution plumes in soil and chalky formations. In addition, the heterogeneity of the shallow subsurface can be considered as the main reason for the fluids infiltration. The relative percentage of the resistivity Δρ% is well documented, the Δρ% value is minimized as a significant difference appears i.e., the relative percentage reaches ‐82% at the upper surface and it reaches to ‐44% where the septic tanks are located. These reliable results are considered as a key role in monitoring the environmental impacts of waste water on a groundwater system and high‐conductivity zones. Therefore, further geophysical prospecting projects for environmental issues can be realized by this technique.

Multi-electrode geo-electrical and transient electromagnetic surveys were carried out to characterize the nature of the subsurface infiltration zones (5 to 20 m) related to a series of groundwater outlets, and to reveal the geometry of the different aquifers at Bani-Naim, in the south-eastern foothills of the Hebron area, West Bank, Palestine. The purpose of the surveys was to understand the link between water storage/transfer and the characteristics of the geological formations. The strata in this semi-arid region are composed of alternate layers of chalky limestone, hard limestone, marl and chalk. A total of 30 ERT and 15 TDEM were conducted at Bani Naim-Jahir and Bani Naim-Birein. A correlation between the results indicates various infiltration pathways: fractures, feature heterogeneities, and porous chalk. The local heterogeneity on the eastern side were the major pathways for the water infiltration, whereas the thick marl layer underneath acts as a natural impermeable barrier preventing water from infiltrating deeper. A combination of the different geophysical results identified conductive features that correspond to the infiltration zones supplying the dug wells with water. Furthermore, it was established that the fractured chalk and porous chalky limestone act as an aquifer. A three-dimensional visualization of the resistivity allowed a useful reconstruction of the shallow hydrogeological system. Consequently, these studies contribute to regional sustainable development projects in this semi-arid region. ß 2012 Published by Elsevier Masson SAS on behalf of Acade ´mie des sciences. R E ´S U M E Des campagnes ge ´ophysiques e ´lectriques multi-e ´lectrodes et e ´lectromagne ´tiques en transitoire ont e ´te ´effectue ´es aux piedmonts sud-est du plateau d'He ´bron (Cisjordanie, Palestine), pour caracte ´riser la nature des zones d'infiltration superficielles (5 a `20 m)

No abstract

ArcheoSciences Revue d'archéométrie (suppl.) | 2009Mémoire du sol, espace des hommes Contribution of geophysical methods to explaining water flow in a carbonate medium Favray site (Nièvre, France)