Aliakmon River Research Articles

Water quality trends in Polyphytos reservoir, Aliakmon River, Greece

A water quality monitoring program was undertaken from June 2004 to May 2005, on a monthly basis, in Polyphytos Reservoir of Aliakmon River. Depth, water temperature, dissolved oxygen, conductivity, pH and transparency (Secchi disk) were measured in situ, while collected water samples were analyzed in the laboratory for the determination of BOD, COD, total phosphorus (TP), ortho-phosphate (OP), chlorophyll-a (Chl-a), ammonium, nitrite and nitrate, total Kappajeldahl nitrogen (TKN) and heavy metals (Fe, Mn, Cu, Cr, Pb, Ni and Cd). Measured concentrations were compared to those from two previous studies conducted in July 1987 to June 1988 and January 1991 to February 1993. The following conclusions are drawn: the effect of the watershed on the lake environment, mostly through Aliakmon River, is significant, and it accelerates the eutrophication of the lake. The anoxic zones, which were defined in the lake, reinforce this conclusion. Nitrate, nitrite and ammonia were measured at lower concentrations compared to previous studies, while total phosphorus and chlorophyll-a were found at increased concentrations. The current trophic state of Polyphytos reservoir is eutrophic, based on the OECD method and Carlson's Trophic State Indices (TSI). The concentration of BOD and COD ranged at low levels. Furthermore, the mean concentrations of metals Fe, Mn, Cu, Cr, Pb, and Cd were below the potable water standards set by WHO and EU. During most part of the study period the ratio N/P for Polyphytos reservoir was higher than 7.2:1, and therefore, phosphorus is the limiting nutrient for algal growth.

Hydrological effects of land use and climate changes in northern Greece

This paper examines the impacts of climate and land use change on water resources in the Aliakmon river basin, located in Northern Greece. The hydrological model Soil and Water Assessment Tool (SWAT) was calibrated and implemented to estimate total runoff at the outlet of the basin, under different climate (HadCM2) and land use change (deforestation by 5, 10 and 20% and reduction of agricultural land by 10%) scenarios. Land use change scenarios gave insignificant changes in total runoff values for the period 1971–2002, while climate change scenario resulted in important reduction of mean annual and monthly runoff during the period 2003–2050.

Impact of Climate Change on the Hydrological Regime and Water Resources in the Basin of Siatista

This paper examines an assessment of the impact of climate change on hydrological regimes and water resources in the basin of Siatista, a sub-basin of the Aliakmon river basin, located in Northern Greece. Initially all acquired hydrometeorological data of the study area, as well as the hydrometric data at the outlet of the basin, were analyzed and processed. A monthly conceptual water balance model was then calibrated using historical hydrometeorological data for determining changes in streamflow runoff under two different equilibrium scenarios (UKHI, CCC) referring to the years 2020, 2050 and 2100. It was found that by applying the two scenarios there will be a reduction of the mean winter runoff values, a serious reduction of summer runoff, an increase of maximum annual runoff and a decrease of minimum annual runoff values, an increase of potential and actual evapotranspiration, leading to a decrease of soil moisture, a reduction of snow accumulation and melting due to temperature increases, resulting in a decrease of spring runoff values and a shifting of the wet period towards December, resulting in severe prolongation of the dry period.

Circulation and nutrient modeling of Thermaikos Gulf, Greece

Thermaikos Gulf is considered to be one of the most polluted coastal zones in Greece. It is the final receptor of both municipal and industrial wastewaters from the city of Thessaloniki and of two heavily polluted rivers, Axios and Aliakmon. Nutrient enrichment and consequent eutrophication is the primary water quality issue of Thermaikos. The mathematical model WASP 6.0 was used to simulate the hydrodynamics, nutrient dynamics and phytoplakton evolution in the gulf. The model is a physical-based model that compartmentalizes the water body into high dispersivity, uniform concentration compartments. It then performs mass balances on water quantity and quality. In addition to the hydrodynamics, the model can simulate the carbon, oxygen, nitrogen, phosphorous and plankton concentrations in the water body. Monthly hydrologic and water quality fluxes from 1997 to 1998, inputs to the gulf and seasonal nutrient surveys in the gulf were used to calibrate nutrient dynamics. The gulf was compartmentalized into 12 compartments, six were horizontal and two were vertical. Salinity data were used to calibrate the hydrodynamic variables of the model. Model calibration was conducted by minimizing the root mean square error between field observations and model simulation. The model was able to capture the variation of salinity and nutrient concentrations. The results showed the importance of Thessaloniki effluents to the Thessaloniki Bay and Gulf and the Axios and Aliakmon River loads to the degree of eutrophication of the entire gulf. The model can be used to assess management scenarios to improve the water quality of the gulf.

Climate Change Impacts on the Water Supply of Thessaloniki

This paper examines the assessment of the impacts of climate change on water resources in the Aliakmon river basin, Northern Greece, and on some critical water management issues, such as reservoir storage and water supply of the city of Thessaloniki. A monthly conceptual water balance model was calibrated using historical hydrometeorological data. This model was applied to estimate runoffs in the entrance of the Polyfyto reservoir under two different equilibrium scenarios (UKHI, CCC) referring to 2050. Reduction of the mean annual runoff, mean winter runoff and summer runoff would occur. By using these scenarios, the sensitivity of the risk associated with the water supply for the city of Thessaloniki was evaluated under conditions of altered runoff. Increases of the risks associated with the annual quantities of water supply were observed, particularly under the UKHI scenario.

Diversity of Salmonella spp. and fungi in northern Greek rivers and their correlation to fecal pollution indicators

The prevalence and diversity of Salmonella spp., filamentous fungi, and yeasts and their correlation with fecal pollution indicators (total coliforms, fecal coliforms, enterococci) and total heterotrophic bacteria counts were investigated in 95 water samples from the northern Greek rivers Aliakmon and Axios. Salmonella spp. were isolated in 27.4% of the samples and a total of 19 serotypes were identified. The frequency of Salmonella isolation was higher in the Axios (36.8%) than in the Aliakmon (21.0%) river. Significantly ( P<0.001) more Salmonella spp. were recovered during warm (41.4%) than cold (5.4%) months. Salmonella-positive samples showed significantly higher counts of total heterotrophic bacteria and coliforms. Filamentous fungi were isolated from 98.9% and yeasts from 17.9% of the samples with respective mean counts of 2.36×10 3 and 1.28×10 2 cfu/100 mL. Totals of 23 genera of filamentous fungi and 3 genera of yeasts were identified. The most frequent filamentous fungi were Penicillium and Aspergillus, while Candida was the most prevalent yeast. A significant ( P<0.001) positive correlation of the fecal pollution indicators was demonstrated only for filamentous fungi. The results of this study indicate that these rivers may be potential pathways for human and other animal contamination with Salmonella spp., filamentous fungi, and yeasts, which contribute to the pollution of marine waters and the surrounding environment.

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.

Phytoplankton productivity and species composition in Polyphytos Reservoir (Aliakmon River, Greece)

During four seasonal in situ experiments (1995-1996) phytoplankton productivity and species composition were studied at one central station in the Polyphytos Reservoir, northwestern Greece. A total of 69 algal taxa were identified. Suspended algal assemblages were dominated by diatoms and green algae. Phytoplankton cell abundance ranged from 0.03 to 2.677. 10 6 cells per 1, chlorophyll a concentrations from 1.07 to 4.76 mg m -3 and primary productivity from 7.1 to 137.9 mg m -3 h -1 C. Since the 1980s, the reservoir evolved from a mesotrophic to a eutrophic state.

Phytoplankton community structure in the lower reaches of a Mediterranean river (Aliakmon, Greece)

Phytoplankton communities from the lower reaches of the Aliakmon River, Greece, have been studied over a period of one year. Seasonal phytoplankton dynamics was described on the basis of its species composition and abundance, biomass and chlorophyll-a concentrations. Phytoplankton assemblages comprised diatoms (mainly Cyclotella meneghiniana, Nitzschia palea and Fragilaria ulna), cyanobacteria (mainly Pseudanabaena limnetica, Aphanizomenon sp. and Limnothrix cf. redekei) and green algae (various species of Scenedesmus and Chlamydomonas, Coelastrum microporum and Monoraphidium contortum). Many benthic diatoms were also present. An important growth of euglenophytes was observed during summer, mainly Lepocinclis steinii, L. ovum, Euglena intermedia, E. viridis and Phacus caudatus. The spring maximum of centric diatoms extended into the summer. The qualitative and quantitative composition of the phytoplankton is compared to communities of other European rivers. With regard to phytoplankton assemblages, Aliakmon resembles more the relatively fast-flowing, individual-poor European rivers. Its widely varying discharge volume, turbidity and shallowness, seem to be the main factors controlling phytoplankton communities in its lower reaches.

Human implication of changes in the hydrological regime due to climate change in Northern Greece

This paper examines the impacts of climate change on various forms of water resources and on some critical water management issues. The study area is the Aliakmon river basin including three subbasins of hydrological interest located in northern Greece. A monthly conceptual water balance model was calibrated for each subbasin separately, using historical hydrometeorological data. This model was applied to estimate runoff values at the outlet of each subbasin under different climate change scenarios. Two equilibrium scenarios (UKHI, CCC) referring to years 2020, 2050 and 2100 and one transient scenario (UKTR) referring to years 2032 and 2080 were implied. It was found that reduction of the mean annual runoff and mean winter runoff values, as well as serious reduction of the summer runoff values would occur in all cases and basins. However, the runoff values for November, December and January were increased, whereas the spring runoff values were decreased, leading to a shifting of the wet period towards December and severe prolongation of the dry period. Moreover, the results indicate that all subbasins exhibit almost the same behavior under the different climate change scenarios, while the equilibrium scenarios (UKHI, CCC) seem to give more reasonable and consistent results than the transient scenario (UKTR). Finally, the negative effects of the climatically induced changes on the hydroelectric production and the water use for agricultural purposes in the study basin were assessed.

Phytoplankton Community Structure in the Drainage Network of a Mediterranean River System (Aliakmon, Greece)

AbstractPhytoplankton structure was studied in Aliakmon river basin in April (highflow) and September (lowflow) 1995 in 29 sampling sites. Abundance and biomass were generally low and ranged considerably between sites. Benthic diatoms contributed greatly to the suspended algal assemblages whereas trends of potamoplankton development were observed downstream. Limnoplankton and especially chlorophytes developed in the areas where lentic conditions prevailed. The nature of changes in phytoplankton seemed to be both longitudinal and temporal. Multivariate techniques revealed that areas with distinctive morphology, hydrology and anthropogenic inputs tended to have similar phytoplankton composition although no simple relation with physico‐chemical factors can be shown. Human impact was more obvious on phytoplankton at the lowflow period. Generally, discharge played a significant role to the structure of phytoplankton communities.

Observations on the 3-D crustal velocity structure in the Kozani-Grevena (NW Greece) area

Three-dimensional velocity structure of the upper crust was determined by inversion of P-waves travel time in the area of the Aliakmon river basin, where a strong earthquake of Ms = 6.6 occurred on May 13, 1995. The area is located at the northwestern part of the Greek mainland. To investigate the 3-D crustal velocity structure of the region, a two-step tomographic procedure has been applied. The data set consists of the travel time residuals of 366 very well located earthquakes, recorded by at least seven stations of a portable network, which was installed at the Kozani-Grevena broader region by the Institute of Geodynamics, immediately after the shock of 13 May, 1995. In order to improve the initial (reference) velocity model, before the inversion of the travel times, the “minimum 1-D” initial velocity model was obtained. The results show that at shallow depths low velocities are predominant in the whole region and there is no sharp horizontal velocity variation. The velocity at shallow depths seems to be affected from the surface geology. Despite the absence of large scale seismotectonics features in the region there is a remarkable vertical increase of the velocity below the depth of 15 Km, supporting the existence of a second order discontinuity in the crust of the region.

Seismic fault geometry and kinematics of the 13 May 1995 Western Macedonia (Greece) earthquake

During the devastating earthquake of 13 May 1995, in the Kozani-Grevena area (Western Macedonia, Greece), many surface ruptures formed in the epicentral area. Most of these fractures were due to faulting, but some were secondary ground ruptures and landslides. Geological field work in the area has shown that the Aliakmon river neotectonic fault consists of several (three or more) fault strands: the Servia, the Rymnio and the Paleochori-Sarakina strands. Using geological criteria, all of these fault strands were judged to be active faults affecting recent (Holocene) deposits and scree. The main new surface fractures caused by the earthquake, and particularly those clearly of tectonic origin, follow systematically the traces of the last two neotectonic fault strands, forming a new fracture line. This tectonic line, trending ENE-WSW (N 70 °), coincides with the focal mechanism solution and the satelite image major lineament. Both the geological and instrumental seismological data suggest that the seismogenic fault is a segment of the Aliakmon river neotectonic fault zone situated among the villages of Rymnio, Paleochori, Sarakina, Kentro and Nisi. The total length of the reactivated fault segment is about 30km long overall and is separated from the non-activated Servia fault segment by a geometrical seismic segment barrier near the village of Goules. The seismic fault is a normal fault trending ENE-WSW and dipping to NNW, with high angle at the surface and low angle at depth. The majority of the epicentres of the seismic sequence were distributed on the hangingwall of this reactivated fault segment. Additionaly a series of subparallel antithetic surface fractures, mainly striking E-W or ENE-WSW and dipping to the South, following previous neotectonic strike-slip faults, were reactivated during the earthquake with the geometry of normal faults antithetic to the main seismic fault. The most important of these are the Chromio-Varis-Myrsina fracture line (length 15km), along the Vourinos corridor dextral strike-slip structure and the Felli fracture line (length 6 km) along the Felli sinistral strike-slip fault. An interpretation of the geometry and kinematics of the reactivated faults is shown in the proposed geological model with simplified cross sections.

Evaluation of chemical parameters in aliakmon river northern greece. Part III. Pesticides

Abstract A two‐year survey on the water quality characteristics of Aliakmon river in northern Greece is described. Pesticides were determined and their concentration levels were related to the flow characteristics of the river and the influence from agricultural activities. Eight herbicides, alachlor, atrazine, 2,4‐D, EPTC, MCPA, metolachlor, simazine and trifluralin were identified in river waters at eight sampling stations. Four insecticides, diazinon, fenthion, lindane and methyl parathion were also detected in the same places. Peak concentrations of some pesticides were observed corresponding to their application in the fields. Episodic peaks in concentrations occur during the period from May to August. Highest concentrations were determined for the pesticides: alachlor (0.21 μg/L), atrazine (2.16 μg/L), MCPA (1.56 μg/L), methyl parathion (0.21 μgL), metolachlor (0.34 μg/L), simazine (0.34 μg/L) and trifluralin (0.55 μg/L).

Evaluation of chemical parameters in Aliakmon river / Northern Greece. Part II: Dissolved and particulate heavy metals

Abstract A two‐year survey on the water quality characteristics of Aliakmon river in northern Greece is described. Heavy metals (Pb, Cd, Cr, Cu, Mn and Fe) were determined in the dissolved fraction, as well as in two particulate fractions, labile and residual, separated after a two‐step sequential extraction procedure. The partitioning of metals between different fractions was examined at various sampling sites along the river. Variations observed were related to the geology of the transected area and the influence from anthropogenic sources (mainly municipal effluents). Statistical analysis of variance of metal partition coefficient showed significant differences between sampling periods, while insignificant ones between sampling sites. Factor analysis of analytical data yielded four factors that were interpreted as natural, anthropogenic, geological and run‐off contributions.

Evaluation of chemical parameters in aliakmon river, northern Greece Part I: Quality characteristics and nutrients

Abstract A two‐year survey on the water quality characteristics of Aliakmon river in northern Greece is described. Physicochemical parameters (temperature, acidity, alkalinity, conductivity, hardness), as well as nutrients and major ionic components (NO3 ‐, NH4 +, PO4 = , SO4 =, Cl‐) were determined and their concentration levels were related to the flow characteristics of the river and the influence from urban, agricultural and industrial activities. The quality of the water is discussed taking into account the fact that this river will be used in the near future for the water supply of the city of Thessaloniki.

Multiple input-single output linear functional models for river flow routing

A multiple input-single output linear functional model for river flow routing is developed. The linear kernels, corresponding to each input series, are approximated by expansions in Meixner functions, unit-weighted orthonormal polynomials and Chebyshev polynomials. The memory length of the system and the order of polynomial expansion of the linear kernels are determined by trial and error. The cross-correlation between each input and the output provided a short-cut method of memory length determination. A two input-single output linear functional model was applied to predict daily flow of the Aliakmon river in Greece, using daily flows at points further up the main stream and on a tributary. The results were satisfactory. The predictions of daily output for real-time forecasting were further improved by fitting autoregressive moving average models to the residual sequences.

Study of heavy metal pollution in the waters of Axios and Aliakmon rivers in northern Greece

Abstract In the present paper the partitioning of seven selected heavy metal ions Pb, Cd, Fe, Zn, Mn, Cu and Cr, between the dissolved aqueous phase and paniculate matter, was studied in two rivers of Northern Greece: Axios and Aliakmon, during a two years period. The characteristic parameters of the water (pH, conductivity, dissolved oxygen, water discharge, water hardness) were also determined and statistically correlated to the heavy metal concentrations. No significant linear correlation, positive or negative, with a few exceptions, was noticed between the examined parameters. From the results obtained we can conclude that the heavy metal concentrations in the examined rivers are in lower levels than in other/polluted systems. From the ratios of the metal content in the particulate matter to the respective in the dissolved metal fraction, it is shown that with an exception of Pb in Aliakmon River, heavy metals in the water column of the two examined river systems are mainly found as particulates and/or adsorbed on suspended solids, rather than dissolved in the aqueous phase. Total heavy metal concentrations are found to be higher in Axios River than in Aliakmon. The same stands true for the heavy metal concentrations in the aqueous phase.

Mobilization of heavy metals from river sediments of Northern Greece, by humic substances

Abstract The sodium salt of a humic acid of a molecular weight range from 600 to 1000 was studied, regarding the subsequent release of heavy metals from sediments of rivers in Northern Greece, after its addition to river water. From the obtained data we can conclude that humic substances are expected to play an ecologically important vector role for copper towards Axios and Aliakmon River's sediments. Other heavy metal ions may be suspected to folllow the same traject though to a lower extent. An increase of heavy metals mobilization was noticed with the increase of humic substances concetration as well as with shaking time, in most cases.

Mobilization of heavy metals from river sediments of Northern Greece by complexing agents

The influence of NTA, EDTA, STPP, Triton X100, PO inf4 sup3 and NO inf3 sup− on the mobilization of Pb, Cd, Cu, Cr and Mn from sediments of two rivers located in Northern Greece was studied. The release caused by all examined complexing agents was higher in deionized water than either Axios or Aliakmon river water due to the lack of competition of Ca and Mg cations with the heavy metals for the studied complexing agents, and the decrease of ionic strength. From all examined agents NTA and EDTA showed the greater mobilization ability. Copper showed the greater tendency for remobilization by all examined agents, (according to the order: EDTA≅NTA, Triton X1004 PO inf4 sup3− > NO inf3 sup3− ≅STPP) while Cr and Mn the smallest following the orders: NTA, PO inf4 sup3− >> NO inf3 sup− , Triton X1004 EDTA, STPP and STPP > EDTA > NTA > Triton X 100 ≅ PO inf4 sup3− NO3, respectively. An increase in mobilization was noticed with an increase of agent concentration and time of shaking.