We present the practical application of a 3D electrical resistivity tomography (ERT) geophysical survey conducted in order to calculate the geometrical features and general structure of a construction and demolition waste layer in an old unregulated landfill prior to redevelopment. As traditional geological/geotechnical investigations comprised of cone penetration tests (CPT) failed to provide reliable results, primarily due to the nature of the underlying waste, a geophysical investigation was commissioned and found to be very effective in providing useful and accurate information to the project’s environmental and engineering team. The ERT survey data were collected in parallel equidistant lines and were subsequently merged and inverted as a single 3D dataset. The processed data depicted clearly the interface between the resistive construction waste and the conductive undisturbed host clay layer ranging at depths between 3 and 11 m. As a result of this successful geophysical investigation the total volume of the solid waste materials was calculated to be about 32500 m³. Following the complete removal of the waste it became evident that the ERT geophysical survey results were particularly accurate. As a result, the reclamation constructor was able to carefully plan the required resources for excavating, moving and disposing of the waste. Interpreted ERT data not only defined the thickness of the debris layer and the total volume with a deviation of less than 10%, but also revealed the inner structure of the solid waste layer.

Groundwater quality deterioration and overexploitation constitute two critical environmental issues worldwide. In this study, with the aim to achieve a groundwater sustainability purpose, a preliminary hydrogeochemical survey is conducted in the Flamouria basin, Pella prefecture, Northern Greece using available and collected data. For this purpose, chemical analyses of groundwater, springs, and surface water were collected and analyzed with three electrical resistivity tomographies (ERTs). A Groundwater Quality Index (GQI), along with a nitrate susceptibility assessment is applied within the porous aquifer. The water quality analysis along with GQI application showed excellent water quality for potable and irrigation use however highlighted future issue for irrigation utilization as the high alkalinity and total dissolved solid (TDS)could generate excessive soil salinization. Moreover, the application of a methodology for the identification of “Nitrate Vulnerable Zone” called the Protection from Natural and Anthropogenic sources (PNA) highlighted the natural susceptibility to nitrate pollution of the porous aquifer, especially in the central part of the area where most agricultural activity is localized. The work further confirmed how the proposed elaboration could represent an easy and widely applicable hydrological assessment where there is also limited data available.

Ground-penetrating radar (GPR) has been a very effective tool for exploring the subsurface and the nondestructive testing of nonmetallic structures for the past 40–50 years. The traditional GPR data interpretation is built upon the innate bias that all signals emanate from within the ground and most GPR users are normally under the impression that energy mostly travels straight down leading to the perception that “targets” are beneath the measurement location. The response of features at the ground surface and above ground also is present in most data but not always consciously noted as contributing to the measurements. One class of responses from above-ground features is routinely called “airwaves” because they normally exhibit moveout velocities of air. Often, an above-ground source is not the first thing that comes to mind during data interpretation, unless the user is experienced. Even experienced users can occasionally be misled, as above-ground features are expected to reach the GPR receiver with the moveout velocity of air. Recent experience in some of our surveys has created concerns because the targets at or above the ground surface demonstrated ground wave moveout velocity, which eliminates one of the diagnostic tools. This paper explores this issue, identifies GPR signal paths, and suggests key factors to consider in field operations and data interpretation. To demonstrate the concepts described, we have used numerical modeling and field data sets.

In Anthemountas river basin a number of studies have taken place mainly because of the significant drop of underground water level observed in the beginning of the last decade. Data from existing hydrowells show the existence of a complex aquifer with the two main underground water bodies situated east and west of the region of Vasilika and Galarinos villages respectively. A large scale geophysical survey took place consisting of Vertical Electrical Soundings (VES) and Electrical Resistivity Tomography (ERT). The main area of interest is in the central region of the basin between Vasilika and Galarinos villages where eighty five (85) VES (Schlumberger array), located on a regular grid revealed a three dimensional model for the sedimentary formations while mapping the bedrock down to a depth of more than 600m has been achieved. In the same area, ERT measurements and geological information derived from borehole data are used to obtain a more detailed geological model for the area of interest. From surface to bedrock depth, the hydraulic communication between these two water bodies is examined. Furthermore significant geological features are observed and discussed.