The current study examines flow (Q) and suspended sediment concentration (SSC) variations, based on monthly snapshots, of the Pinios River (Thessaly), which is one of the larger rivers in Greece, characterized by limited flow control (<10% of its catchment). Monthly measurements (flow velocities and water samples) during the hydrological year (October 2012 to September 2013) were conducted at two stations; one before the river enters its delta (Agia Paraskevi bridge at Tempi) and one close to its mouth (Palaiopyrgos bridge). Monthly flows at Agia Paraskevi range from 2.5 m3 /s to 206.7 m3 /s and are in a good agreement with available historical data for the period 1975/76- 93/94, indicating a rather unchanged flow regime. The SSC values ranged from 3.5 mg/L to 165 mg/L at Agia Paraskevi and from 2.2 mg/L to 177 mg/L at Palaiopyrgos and, in general, follow the monthly trend of flow. The highest SSC value measured in February and April 2013 is attributed to a flood event and an upland slide, respectively.

In the region of the deltaic field of Pinios River in Thessaly and under an applied geoenvironmental research, a preliminary geophysical survey was developed. In this direction, an attempt was made to develop a grid of positions-measurements that would be able to cover the whole field in order to adumbrate the general “image” of the geoelectric parameters. From the conducted bibliographic research, it seems that it is the first time that such a coordinated and extensive geophysical survey has been made in the area. In this project and in the direction of the evaluation of the geoelectric parameters of lithology present in the deltaic area, displays of the horizontal and vertical distribution of electrical resistivity are presented. This knowledge will contribute to the emergence of new data and information on the subsurface structure of the field of the deltaic plain. The geoelectrical method with the Sclumberger array was applied, for the vertical investigation of the distribution of electrical resistivity, in order to investigate the geoelectrical parameters. These arrays are best suited, as a preliminary subsurface investigation method in such geo-environments. Thirty seven soundings were developed in an almost 'normalized' grid, aiming to the greatest possible depth of investigation. Towards this direction, despite the very difficult condition of accessibility, the development of the electrode current (AB or C1C2) reached 1.100 meters, with an investigation depth >250 meters. From the sections and the constructed maps, conductive geoelectric distributions structures detected, with a resistivity ranging in 5-30 Ohm.m, in almost the whole subsurface field of deltaic plain. From this general view, seems to differentiate the coastal zone for shallow depths (<4.5 m) of investigation, the regions of the southern part of the deltaic plain with larger resistivity values for large depths (> 100 m) and the western region (Pyrgetos), with generally high values even from the shallow depths of investigation. Finally, the overall picture of the distribution of the geoelectric parameters in the field of study appears to outline potential area of the palaeogeographic development of the Pinios River delta.

In this project the geological subsurface structure of the delta of the river Pinios is investigated through the contribution of geophysical soundings. In order to investigate the lithologic structure of the entire deltaic field, geophysical soundings were performed with the geoelectrical method of vertical investigation of the resistivity distribution at 37 locations. The Schlumberger array was applied, which is a reliable preliminary geophysical technique for such environments, achieving an investigation depth of > 200-250 meters. Obtaining information on the geoelectrical characteristics of the formations expected under the alluvial silt of Pinios, we have to evaluate the results of the geophysical survey. Therefore 14 “in situ” measurements of electrical resistivity were carried out in surface outcrops of Neogene sediments, cyanoschists and serpentinites. An extensive geological overview of the wider visual field was conducted, geological measurements were recorded and plotted on a digital background concerning the extensive volume of Neogene formations and alpine formations. After the processing of the geophysical soundings, geoelectrical sections were constructed in directions S-N and W-E, along with the description of their geological evaluation. From the preliminary results, it seems that the Neogene formations, with alternations of sands, marls and conglomerates occupying almost the entire space of the subsurface deltaic field, below the Holocene deposits. The alpine formations of Ossa (the southern part of the field research), seem only to be traced in the soundings near the margins, with a gentle inclination below from the post-alpine sediments and for the depths investigated (~ 200-250 meters). In the western part of the study area and more specifically the Pyrgetos sub basin, higher values of electrical resistivity (50-80 ohm) were calculated, differentiating the general concept that emerges from the rest of the study area.

A geophysical research was carried out to investigate the lithostarigraphic substratum characteristics of the dune field of the central Kyparissiakos Gulf (W. Peloponnese, Greece), which is characterised by the presence of four dune lines. For this purpose, the geophysical techniques of Electrical Resistivity Tomography (ERT) and Vertical Electrical Soundings (VES) were applied, along with detailed morphological mapping and the collection of geological and geomorphological information. The processing of the geophysical data that were collected from two ERT soundings, perpendicular to the general direction of the dune lines, and seven geoelectrical soundings revealed four geoelectrical layers with the two surficial resistive layers adumbrating the extent and thickness of the four sand dune ridges and the associated slags. The third layer, corresponding to the underlying geoelectrical formation of 50–75 Ohm.m, is interpreted as a layer of transgressive Holocene deposits saturated with fresh water, while the deepest geoelectrically identified layer seems to correspond to the “Neda” formation, which consists of marls, sandy marls and conglomerates. It is concluded that the combined application of the aforementioned techniques has the potential to provide valuable data for the investigation of complex coastal depositional environments.

A geophysical survey was carried out in the archaeological site of Kyparissia (Megalopolis, Greece) applying the Very Low Frequency technique, as preliminary combined with highly detailed Electrical Resistivity Tomography. Settlements of the ancient city of Trapezous (limestone slabs 0.5m height × 0.5m width) have already been uncovered from the local Ephorate of Prehistorical and Classical Antiquities, revealing a regularly planned town of the classical period. The geophysical research was performed at the non-excavated area of the plain, vicinal to the already exposed remaining, where, according to the expected geometry, the buried walls and drainage channel should be continued to. Fifteen parallel sections with distance 5m and spacing interval 1m were carried out. The processing with the application of Fraser and Karous-Hjelt filters led to the construction of respective maps, indicating some resistive lineation which could be a result of the buried settlements. Moreover, two detailed ERT sections were carried out with spacing 0.20 and 0.25m and total length 200m. The processing using the robust inversion, which is indicated for such environments, adumbrates quite clearly a sharp resistive target that could be the limestone slabs of the ancient walls or drainage channels, confirming the expected lineated geometry of the town.

This study aims at defining the groundwater flow regime and the principal hydro-geochemical processes controlling groundwater quality in the deltaic plain of River Pinios (ThessalyGreece) and investigating whether seawater intrusion and pollution are influencing groundwater quality. Groundwater level monitoring from October 2012 to September 2013 shows that groundwater flow is seawards and that the water table of the phreatic aquifer is mainly declining during the summer period when it is over-pumping and natural recharge limited. Major ions analysed in 49 groundwater samples reveal that groundwater is mainly affected by four factors: (i) dissolution of calcite and dolomite; (ii) weathering of silicate minerals; (iii) seawater intrusion; and (iv) contaminant enrichment (e.g., NH4) mainly caused by point sources of pollution. High enrichment of Na and Cl near the coast gives an indication of seawater intrusion into the aquifer as also supported from the Na–Cl signature on the Piper diagram and the Revelle coefficient. The dissolution of calcite and dolomite results in Ca–HCO3 and Mg–HCO3 groundwater types, whereas natural geochemical processes are considered responsible for the aquifer's enrichment in minor elements (e.g., Fe, Mn). Based on the simulation results performed using PHREEQC model, groundwater is mainly supersaturated with respect to calcite and dolomite minerals, supporting a long residence time hypothesis. The relation between seasonal water level fluctuation and hydrochemistry shows that both are mainly controlled by the aquifer's recharge process.

In this contribution we present some preliminary findings on the chemical quality of groundwaters of the deltaic plain of R. Pinios (Thessaly), as part of the implementation of the project THALISDAPHNE. Samples were obtained from 13 groundwater drillings on a seasonal basis during the hydrological year 2012 - 2013 and analyzed for major ions, nutrients, dissolved organic carbon and trace metals. Temperature, pH, conductivity and salinity were measured in situ. In order to evaluate the groundwater quality, we compare the data obtained against the Hellenic legislation threshold values and FAO guidelines for irrigation waters. Conductivity ranged from 230 to 9180 μS/cm. Exceedance of the 700 μS/cm threshold (Type I water FAO) in 71% of the samples suggests slight to moderate restrictions in irrigation. In two drillings (No 10, 13) maximum permissible limits of conductivity, sodium and chloride concentrations were exceeded particularly in summer and autumn. Some exceedances of guidelines were also identified for nitrates and ammonium. Concentrations of dissolved trace metals, were generally below the limits, with the exception of Zn, however some concern has been raised in terms of increased levels of total dissolved Cr in drilling No. 15 (8.3 - 37.9 μg/L). On the basis of our results degradation of groundwater quality was identified together with seasonal salinization; these two factors corroborate to the need for sustainable groundwater use especially in months with increased demands for water supplies.

The present study aims to assess the current groundwater quality and investigate its temporal evolution in the two identified aquifers (shallow and deep) located in the sedimentary sequence of Pinios River estuary. Significant land use changes mark groundwater management practices of the shallow aquifer over the past years, as traditional crops of high water requirements have been partly substituted by less water demanding crops, and groundwater abstractions have been reduced and substituted by surface water from Pinios River to cover irrigation needs over a large part of the study area. To study the effect of aforementioned land use changes, major groundwater physicochemical parameter values for the year 2013 were assessed and compared to the corresponding data for the years 1998 and 1999. The results indicate that the quality of the shallow aquifer in terms of groundwater salinization and nitrate pollution may be considered as satisfactory with higher groundwater salt content observed in the northern and southern parts of the system. The water quality characteristics of the deep aquifer are overall worse than the shallow aquifer as groundwater salt content is increasing towards the coast. The temporal comparison of the water quality characteristics demonstrates no significant changes for seawater intrusion related parameters such as Electrical Conductivity, and Na+ and Cl- concentrations, but also for pollution related parameters such as NO3 - concentrations.

In this paper we deal with a case scenario for the general geological setting and the morphotectonic evolution of the delta plain of Pineios River (Thessalia, Greece) and its margins. This work is based on the interpretation of geological and geomorphological data derived from (a) digitizing topographic map sheets of scale 1:5,000, (b) digital interpretation of recently acquired high spatial and spectral resolution satellite image, (c) tectonic geomorphology analysis, (d) field observations and (e) geophysical investigation. The fluvial deposits cover the largest part of the delta plain, whilst the coastal deposits crop out along the entire coastal zone. The remnants of a Pleistocene alluvial fan is observed in the western part of the delta plain and lies unconformably on Neogene formations comprised of sandstones, conglomerates and terra rossa. The alpine basement outcrops are found only at the southern and northern margins of the delta plain and include various lithologies such as crystalline limestones and metamorphic flysch (Ossa-Olympos unit), blue schists, gneisses and marbles (Ambelakia unit), metamorphic basic ophiolitic rocks and marbles (Pelagonian unit). The Neogene formations have undergone intense tectonic deformation resulting in several block rotations reaching the values of 10-30ο , towards south. The NW dipping normal fault zone located south of Omolio village strikes WSW-ENE and seems to play a significant role in the rotation of the Neogene formations. It is rather clear that the activity of this fault zone is highly related to the uplift of Ossa Mt along the southern margin of the delta plain and consequently to the development of extensional fractures (scarps) developed normally to the fault zone. These scarps are not tectonic faults and were created primarily by gravitational stresses. These structures have caused the segmentation of the uplifted block into smaller blocks, which were subsequently toppled. These large-scale toppling phenomena at the northwestern slopes of Ossa Mt have caused large gaps in the alpine basement rocks. These gaps have acted as selective surface water flow paths that have shaped impressive gorges. Pineios River found a new outlet to the Aegean Sea through the westernmost of the gorges, the Tempi gorge. It seems to have happened after the overall tectonic uplift of Olympos-Ossa-Pelion mountain range and the paleo-Pineios River flow blocking at the area south of Ossa Mt. Immediately after the aforementioned process, the area extending east of Tempi gorge began to evolve as the delta plain of Pineios River resulting in the progressive natural seaward shift of the shoreline due to the accumulation of Pineios fluvial deposits.

A geophysical survey was performed at selected locations of Mt. Oiti and Mt. Kallidromon characterized by the hosting of priority habits of Mediterranean temporary ponds and the threatened plant species of Veronica oetaea, in order to understand the geoenvironment and contribute to the conservation of biodiversity. Primarily, the formation of these seasonal ponds, where Veronica oetaea occurs, seems to depend exclusively on the local hydrogeological regime. Thus, we investigated the subsurface structure of “Livadies” and “Nevropolis” ponds with the application of Electrical Resistivity Tomography for high accuracy information and Vertical Electrical Sounding for deeper data acquisition. Four ERT sections and 15 geoelectrical soundings in total were carried out. The combined results of their processing revealed differences at the geological structure beneath the ponds locations. At “Livadies” pond (Mt. Oiti), two geoelectrical layers were distinguished both corresponding to a folded flysch succession, contributing to the formation of this pond. On the contrary, at “Nevropolis” pond two geoelectrical layers were identified and interpreted as a surficial soil deposit stratum covering the geomorphological karst structure of a polje, created on the underlying limestones. The combined geophysical research offered significant data for the formation and the hydrogeological status of the priority habitats.

The present study aims to clarify the hydrogeological regime of the phreatic aquifer, primarily its spatial distribution, through a combined interpretation of the preliminary results of an extensive geophysical research conducted in the area and of the hydrogeological data collected in parallel scientific actions by previous researchers. In the context of the geophysical research that was carried out in the region, 37 Vertical Electrical Soundings, investigating the resistivity distribution (Schlumberger array), were performed during May and October 2013. Moreover, previous periodic measurements of the groundwater level of the phreatic aquifer and hydrochemical analysis were taken into consideration. The preliminary results of the geophysical data processing indicate that the phreatic aquifer is not detected throughout the whole deltaic plain but extends mainly in the central and northern parts of the region. Most of the investigated sites showed that the hosting formation’s thickness is limited up to 10 meters, since the underlying geoelectrical formation (20-40 Ohm.m) is believed to be an impermeable formation. The literature-derived hydrogeological data also indicate that the depth of the phreatic aquifer is generally small. In particular, the groundwater monitoring showed that the water table did not exceed 4m in depth. Moreover, the hydrochemical data indicated a limited seawater intrusion, which seems to be controlled by the hydraulic head of the groundwater and the sedimentological composition of the dune system covering the coastal zone, which is also indicated by the geophysical results.