Pinios River Research Articles

Probabilistic analysis of drought spatiotemporal characteristics inThessaly region, Greece

Abstract. The temporal and spatial characteristics of meteorological drought are investigated to provide a framework for sustainable water resources management in the region of Thessaly, Greece. Thessaly is the most intensely cultivated and productive agricultural plain region in Greece. Thessaly's total area is about 13700 km2 and it is surrounded by mountains and traversed by Pinios River. Using the Standardized Precipitation Index (SPI) as an indicator of drought severity, the characteristics of droughts are examined. Thessaly was divided into 212 grid-cells of 8 x 8 km and monthly precipitation data for the period 1960–1993 from 50 meteorological stations were used for global interpolation of precipitation using spatial co-ordinates and elevation data. Drought severity was assessed from the estimated gridded SPI values at multiple time scales. Firstly, the temporal and spatial characteristics of droughts were analyzed and then, Drought Severity – Areal extent – Frequency (SAF) annual and monthly curves were developed. The analysis indicated that moderate and severe droughts are common in Thessaly region. Using the SAF curves, the return period of selected severe drought events was assessed.

Geochemistry and mineralogy of the NW Aegean Sea surface sediments: implications for river runoff and anthropogenic impact

Surface sediments of the NW Aegean Sea were analyzed for clay mineral composition (94 samples), organic C and carbonate content, and major and minor elements (112 samples). Illite is the most abundant clay mineral, followed by smectite, chlorite and kaolinite. Clay minerals are preferentially deposited within the continental shelf and slope environment, due to the prevailing cyclonic circulation and the formation of flocs in the rivers’ pro-delta areas. The spatial distribution of major lithogenic elements (Si, Al, Ti, Fe) is substantially biased by the presence of relict sands located in the central-eastern part of the Thermaikos Gulf continental shelf. Biogenic elements (Ca, Sr) are noticeably pronounced on the northern flank of the North Sporades Islands. Organic C content and minor elements Cu, Zn, As and Pb are enriched markedly over the Thessaloniki Bay and Gulf suggesting substantial human impact, deriving largely from untreated or partly treated domestic and industrial effluents. The terrigenous component of the elements is preferentially contributed from the Axios River (Zn and Pb), the Aliakmon River (Cr, Co, Ni, Cu and As), and to a lesser extent from the Pinios River (V, Co, Ni and Cu); a considerable part of the metals originates in ultra-mafic and volcanic formations, which are abundant in the rivers’ catchment basins. Carbonate content exhibits great variability, with the highest values observed in biogenic sediments of the Sporades Basin. In the latter area, Mn (and Fe) oxides and hydroxides were found as coatings on calcite. The coatings were enriched in Cr, Co, Ni, Zn, As, Mo and Pb, due to adsorption or ion-exchange during early diagenesis. The combined influence of the river systems, the Thessaloniki metropolis, and the diverse sedimentological background, generates great patchiness in the distribution of major and minor elements.

Nutrient chemistry of River Pinios (Thessalia, Greece)

The impact of human activities with 3-year monitoring on the fluctuation of nutrients along the Pinios River and its tributaries were studied. Their seasonal variations throughout the years 1996–1998 were also presented. High temperatures, from June to August, cause a restriction of the water flow, an enhancement of nutrient concentration with the subsequent increase of eutrophication. High concentrations of nutrients were observed first in winter (wet period), caused by leaching of fertilizers from terrestrial systems after heavy rainfall, later during the warm months due to low water flow of the river, and at last in autumn when plant organisms began to decompose. The intensive algal and macrophyte growth (spring, summer) resulted in severe depletion of nutrients. Organic carbon showed no seasonal trend but its values were high near the estuaries. Nitrate fluxes were high at the initial station (sources) and the Titarisios tributary, whereas nitrites and ammonium were low. In contrary, the Kalentzis tributary with relatively low nitrate values showed increased values of nitrite ammonium or total nitrogen. On the other hand, the Enipeas tributary showed high SO 4 values. Phosphates are remarkably present mainly after the city of Larissa, where sewage and industrial discharges occur. None of the nutrients measured in the Pinios River and its tributaries showed a clear seasonal cycle of concentration. Concentrations of nutrients and organic carbon increased as a consequence of anthropogenic inputs, particularly point discharges from sewage treatment plants (i.e. showing distinct, but variable, concentration peaks), as well as diffuse urban and/or agricultural runoff over long areas during storm events. The agricultural management, the urban pollution, mainly from Larissa City, and the climate conditions in the catchment basin (Thessalia Plain) of Pinios River and its tributaries greatly affect the chemical composition of their waters.

A GIS for the assessment of the spatio-temporal changes of the Kotychi lagoon, western Peloponnese, Greece

Kotychi lagoon, located at the northwestern coast of Peloponnese, Greece, is a biotope of great ecological and financial importance,protected by the Ramsar International Convention. Kotychi lagoon hasbeen severely degraded and transformed during the past 50 years, due to agricultural activities in the surrounding areas and watercourse alterations after the construction of Pinios river dam in the late 60's. Restoration works (dredging of a hibernation basin and five radial submerged channels) in the period 1989–1992, resulted in the improvement of the lagoon conditions and provided better conditions for the protection of the ecosystem. In this article, a Geographical Information System has been developed to quantify and spatially characterize the temporal changes on lagoon morphology and surface area for the period from 1945 to 1993. The vector database model of the ARC/INFO has enhanced for the handling the temporal changes of the spatial data. Spatial and thematic information concerning the surface area, topography, and the major cover types of the lagoon for years 1945, 1960, 1987 and 1993 was obtained from aerial photographs and land surveys of the area, and was stored in the GIS database. From the spatio-temporal analysis of the stored data, using as a reference surface the lagoon surface at the year 1945, the following conclusions can be drawn. A permanent decrease of the water surface of the lagoon has been observed between the years 1945 and 1987 (from 97.8 to 40.3% of the lagoon reference surface). In 1987 the surface of the lagoon covered by land or swampy areas reached its maximum (59.7% of the reference surface), while in 1993, after the restoration works, the water surface reached the 48.4% while the land and swampy areas decreased to 51.6% of the reference surface.

Selected precipitation scenarios across Europe

We report results of the project, European River Flood Occurrence and Total Risk Assessment System (EUROTAS), which was aimed at assessing the risk of current and future floodings for Europe, including the effects of climatic change. With respect to the latter, precipitation scenarios have been derived from a global climate model using the method of expanded downscaling (EDS), and regionalized for the catchment of the river Pinios (Greece). Jizera (Cechia), Saar (Germany), and Thames (UK). We present both the climate change information conveyed by the scenarios and an assessment about its statistical significance. For this report, all simulations were rerun using an improved EDS model version. Most notably, the inclusion of atmospheric humidity to the set of global predictor fields helped reducing the underlying uncertainty of the results. When driven by observed atmospheric fields (analyses), the EDS model performed in most cases satisfactorily, as it reproduced the larger precipitation clusters with good accuracy. To evaluate the precipitation scenarios, a statistical test was applied that compared what we defined as ‘current climate’ with the ‘changed climate’ of the scenario. To define current climate, local precipitation observations were used together with EDS regionalizations of the analyses and of a climate model control simulation. It turned out that in spite of the considerable uncertainty stemming from model errors and, more importantly, natural variability, a significant redistribution of rainfall is projected. Specifically, the scenarios show a decay of rainfall frequency for all catchments, which for Pinios leads to an overall negative water balance. This is accompanied, and for the other catchments outweighed, by a strong rainfall intensification. For the latter, we provide a more detailed extreme value analysis. We emphasize that the results should be interpreted with caution and not overemphasized quantitatively. Scenarios of precipitation are still of prototype nature and under steady development.

Assessment of the Quality Characteristics of Pinios River, Greece

The results of a one-year detailed water quality study of the Pinios river are presented. Physicochemical parameters (pH, conductivity, DO) did not show significant differences neitherbetween sampling sites, nor between sampling periods. Nutrients(nitrogen and phosphorus compounds) showed temporal variationsprobably caused by seasonal variations in runoff nutrient fromweather events. Heavy metals (Pb, Cd, Cr, Cu, Ni) were determinedin the dissolved fraction and the variations observed were related to the geology of the examined area and the influence from anthropogenic sources. Statistical analysis of variance ofthe most important chemical parameters and heavy metals showedsignificant variation between sampling periods, but insignificantones between sampling sites.

Use of geoinformation techniques in identifying and mapping areas of erosion in a hilly landscape of central Greece

Thessaly is a region of central Greece. The hilly landscape of the Thessalian plain is called the middle Thessalian hills or revenia. The study area is only a very small part of the Pinios river greater catchment area, in the eastern Thessalian plain. The objectives of this study were: to estimate soil erosion from observations and field measurements, identify and map areas of intense erosion and classify main land cover types by using geoinformation techniques. Soil erosion estimated from field observations reached 75 tons/ha/year. Soil erosion inferred from trials and measurements reached 166.33 tons/ha/year. Using satellite image processing, it was possible to identify, map and classify the land cover types and areas of intense erosion. Histogram stretching gave good results in recognizing areas of erosion. With principal component analysis (PCA) of TM bands, we received new vector images that helped in recognizing areas of erosion. The digital elevation model (DEM) gave the general appearance of the terrain surface of the study area. The Gaussian maximum likelihood classifier was quite successful (overall accuracy = 83.94 percent) in identifying and mapping land cover, and sloping and eroded areas. These geoinformation products can be used by the decision-makers at local and regional levels in planning sustainable land management and sustainable development.

Chemical pollution monitoring of river Pinios in the Mediterranean climatic region

The impact of climate change and human activities on the fluctuation of chemical and physico‐chemical parameters along the river Pinios as well as on their seasonal variation are presented. High temperatures, from June to August, cause a restriction of the water flow, an enhancement of nutrient concentration with the subsequent increase of eutrophication. This process leads to the accumulation of organic matter and the depletion of the dissolved oxygen in the water. High concentrations of nutrients were observed first in winter, caused by leaching of fertilisers from terrestrial systems after heavy rainfall, later during the warm months due to the decrease of water flow of the river and at last in autumn when plant organisms began to decompose. The intensive algal and macrophyte productivity (spring, summer) results in severe depletion of nutrients. The conductivity is also high during the warm period. C.O.D. display abrupt fluctuations in the seasonal variation during the year. Among the studied areas along the river Pinios the most heavily polluted were near the cities of Tricala and Larissa where sewage and industrial discharges occur.

Organochlorine and organophosphorus pesticide residues in the water of the Pinios River, Greece

Organochlorine and organophosphorus pesticide residues in the water of the Pinios River, Greece

Distribution of heavy metals in sediments and aquatic plants of the river Pinios (Central Greece)

Surface sediments and aquatic plants from the River Pinios, Greece, were collected and analyzed for Fe, Mn, Ni, Zn, Cr and Cu, in order to obtain information about the heavy metal contamination of the river. The selected species proved to be good indicators for the monitoring of heavy metals. The distribution of heavy metals in the root, the stem and the leaves of the plants is also investigated.

The endurance of endemism: the Mediterranean freshwater gobies and their prospects for survival

Gobies (Teleostei: Gobiidae), spawning in fresh waters of the Mediterranean catchment area, are listed, and their diagnostic features and relationships summarized. The species, by zoogeographic category, include (i) Mediterranean: Padogobius martensii (Günther, 1861) and P. nigricans (Canestrini, 1867) from the northern Adriatic and west‐central Italy, (ii) West Balkanian: Economidichthys pygmaeus (Holly, 1929) and E. trichonis Economidis & Miller, 1990, and (iii) Ponto‐Caspian: Prorerorhinus marmoratus (Pallas, 1811) and Knipowitschia caucasica (Kawrajsky, in Berg, 1916), from the northern Aegean area but otherwise widespread in the Ponto‐Caspian region, and the endemic Mediterranean K. punctatissima (Canestrini, 1864) (north‐eastern Italy) and K. thessala (Vinciguerra, 1921) (Thessaly). Scenarios for differentiation following the late Miocene Messinian salinity crisis are outlined. The vulnerability of these species is discussed, and their present status reviewed. Populations no longer exist at the precise type localities of E. pygmaeus (Lefkas) and K. thessala (Hasabali spring, Pinios river system). Special features of scientific and cultural interest are noted, and the biological capability for species recovery is assessed.

Systematics of freshwater gobies from Greece (Teleostei: Gobiidae)

Five species of gobiid fish are recognized in the fresh waters of Greece. Most distinctive is the south‐western Hellenic (West Balkanian component) endemic genus Economidichthys Bianco, Bullock, Miller & Roubal, 1987, with the type‐species E. pygmaeus (Holly, 1929) from Lefkas, Epirus and Lake Trichonis, and E. trichonis sp. nov., from Lake Trichonis, the latter probably the smallest freshwater European teleost at maturity (female, 18·0 mm) and maximum size (male, 30·0 mm). In tributaries of the northern Aegean basin (north‐eastern Hellenic freshwater fauna), two species of the Ponto‐Caspian genus Knipowitschia can be identified, the widespread Kn. caucasica (Kawrajsky in Berg, 1916) (coastal plain of Macedonia and Thrace) and the endemic Kn. ihessala (Vinciguerra, 1921) (Pinios river system, Thessaly). The larger Ponto‐Caspian tubenose goby, Prolerorhinus marmoratus (Pallas, 1811), occurs in the Evros (= Maritsa) (Thrace) and Strymon (Macedonia) systems. Only the genera Economidichthys and Knipowitschia are considered in this paper, being redefined in terms of osteology and head lateral‐line system, and the species described in detail, with special reference to meristic variation and squamation, and, in Economidichthys, the unique perianal organ of this genus. The relationships of Economidichthys and Kn. thessala are discussed and possible scenarios for their evolution are suggested in the light of Miocene to Recent events.