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This volume provides essential information on the origin and evolution of Greek rivers, as well as their ecological and anthropogenic characteristics. The topics covered include geomythology, biogeography, hydrology, hydrobiology, hydrogeochemistry, geological and biogeochemical processes, anthropogenic pressures and ecological impacts, water management – both in the antiquity and today – and river restoration.

The book is divided into four parts, the first of which explores the importance of rivers for ancient Greek civilization and the natural processes affecting their evolution during the Holocene. In the second part, the hydrological, hydrochemical and biological features of Greek rivers and the unique biogeographical characteristics that form the basis for their high biodiversity and endemism are highlighted, while the third part comprehensively discusses the impacts of environmental pollution on the structure and function of Greek river ecosystems. In turn, the final part describes the current socio-economic factors in Greece that are affecting established water management practices, the application of ecohydrological approaches in restoring fragmented rivers, and the lessons learned from restoring aquatic ecosystems in general as a paradigm for understanding and minimizing anthropogenic impacts on water resources, at the Mediterranean scale.

Given the breadth and depth of its coverage, the book offers an invaluable source of information for researchers, students and environmental managers alike.



Ancient Greece and Water: Climatic Changes, Extreme Events, Water Management, and Rivers in Ancient Greece

Climate change is not a phenomenon of our days, it is connected with the earth’s history as indicated by both scientific evidence and ancient mythologies. Water, although essential for the survival of human kind, often triggers disasters and causes victims, mainly because of its unpredictable and uncontrollable nature. Especially in a country with a great history and a very old and long prehistory like Greece, its inhabitants have lived and experienced the climatic changes of the last 18,000 years and their dramatic geo-environmental impacts, such as sea-level rise, shoreline displacement, emergence and disappearance of springs, evolution and desiccation of lakes, and evolution and submergence of river deltas. All these disasters, coupled with landscape evolution, related mainly to the climatic–eustatic changes, are depicted in the Greek Mythology as the deification of the rivers, the struggle between heroes and springs, etc. A geomythological analysis of Greek myths has revealed that Greek Mythology is very old and is not just a figment of imagination of the resourceful Greeks, but it conceals real events. After the climatic stabilization (≈6,000 BP) and the cultural development of the Greek society, the main issue, besides water supply, was the protection against droughts and floods. This issue was addressed with the use of advanced geotechnical methods and hydraulic works.
Ilias D. Mariolakos

Natural Processes Versus Human Impacts During the Last Century: A Case Study of the Aliakmon River Delta

The Aliakmon River flows down from the northwestern mountains of Greece and is one of the largest fluvial systems in the Greek territory. Basin climate and geology favour the high rates of sediment production and transport and, consequently, the formation of an extensive (9.2% of basin area) bird-foot Holocene delta. Three phases (A, B and C) of human impacts over the past 90 years have caused pronounced changes on the natural evolution of the delta. During Phases A and B, a 50% increase of deltaic sedimentation rates in relation to Holocene pre-anthropogenic rates and an enrichment of deltaic deposits with heavy minerals occurred. Phase C, characterised by damming, increasing agricultural and industrial activities and population growth, resulted in 90% decrease in sedimentation rates compared to Phase B, a regulated hydrological regime with high electrical conductivity and nutrient concentrations of surface water, enhanced erosion of river channel and deltaic deposits and degradation of habitats along the lower Aliakmon River delta. Future climate scenarios and increasing environmental pressures are not compatible with current water use strategy and, given the vulnerability of the system (reservoirs and delta) to projected climate trends, stress for a new strategic natural resource management plan.
Michael Styllas

The Biogeographic Characteristics of the River Basins of Greece

Biogeographic regionalizations provide frameworks for a holistic understanding of river basin areas and their inland water ecosystems. Here we employ the freshwater ecoregion concept to outline biogeographic aspects of the aquatic and semiaquatic biota and river ecosystems in Greece. Emphasis is given to freshwater fishes which cannot readily disperse over mountain watershed barriers and marine areas; they are utilized as primary biogeographic indicators. Although various biogeographic regionalization maps are surveyed, the Freshwater Ecoregions of the World (FEOW) initiative is adopted, and this review helps redefine certain recently published ecoregional boundaries in Greece. Along with freshwater fishes, other animal and plant distributions and knowledge of geological history and climatic patterns help guide the boundary definition of eight freshwater ecoregions in Greece. Gaps in knowledge concerning species distributions and taxonomy as well as the biogeographic understanding of each freshwater ecoregion are assessed.
Stamatis Zogaris, Alcibiades N. Economou

The State and Origin of River Water Composition in Greece

This chapter provides an overview on the hydrogeochemical and pollution characteristics of Greek rivers and attempts to interpret the origin and spatio-temporal variability of their composition as it emerges from various natural factors and processes and human interference. Despite the highly variable physicogeographic and geological conditions of the country, river basins may be hydrogeochemically classified into three main geographical zones with distinct geological, climatic and hydrological features. River hydrogeochemical properties mainly depend on geochemical, hydromorphological and climatic factors. Catchment geology directly controls solute concentrations and major ion portions and influences hydrological and hydrogeological factors. The latter indirectly control water temperature and solute concentrations, as well as pH and carbonate equilibrium together with biological activity. In certain river basins, anthropogenic pressures (i.e. inadequately treated municipal wastes, agrochemicals, agro-industrial and mining effluents) affect aquatic quality, whereas water resources management (i.e. water overexploitation for irrigation and dam operation) alters the hydrological regime, thus indirectly influencing solute concentration. In general, rivers located in western Greece as well as mountainous rivers and streams range from “pristine” to satisfactory conditions. On the contrary, lowland sections of large rivers are at a greater risk due to a variety of pressures, such as agriculture, agro-industry, mining, (illegal) building, and tourism. Despite the great number of internationally important sites in river basins and, the recent, major efforts made in implementing the WFD, Greek rivers are still threatened from insufficient implementation of environmental legislation and ad-hoc management practices. The economic crisis may set environmental conservation at the expense of economic development and/or change socio-economical attitudes. thus pushing environmental conservation forward.
Nikos Skoulikidis

Long-Term Hydrologic Trends in the Main Greek Rivers: A Statistical Approach

The scope of this research effort was to examine the effect of water management practices and land use changes on river flow over the last 3 decades, to identify the dominant trends in the discharge and precipitation time series and to examine the interrelationship between these two parameters. In order to accomplish these aims, the annual discharge time series of seven (7) major rivers in Greece were compared to the annual precipitation of the corresponding watersheds. This comparison was achieved through trend analysis of each time series, which involves the determination of basic statistical characteristics (normality, homogeneity, stationarity). Due to lack of satisfactory discharge time series at the downstream parts of each catchment examined, the results from E-HYPE pan-European hydrological model was used (European – HYdrological Predictions for the Environment). The main outcome of this work concludes that there is no consistent, single trend for the entire study period for any of the investigated rivers, while there are some wet and dry periods in the data which are very clear in all catchments and coincide at a temporal level. The main dry periods were at the end of the 1980s and the beginning of the 2000s. There is also a prolonged wet period during the last decade for all study catchments.
Angeliki Mentzafou, Elias Dimitriou, Anastasios Papadopoulos

Agro-Industrial Wastewater Pollution in Greek River Ecosystems

In this chapter, the characteristics and environmental impacts of wastewaters from the major agricultural industries on the river ecosystems of Greece are reviewed and discussed, focusing especially on olive mills, orange juice processing factories and cheese processing factories. The high organic load, suspended solids and nutrients of these wastewaters, as well as their toxicity, have deteriorated river water quality and the ecological status of many running waters of Greece. Among the most common effects are eutrophication, the decline of fish and invertebrate populations, species richness loss and the consequent reduction of the river capacity for moderating the effects of polluting substances through internal mechanisms of self-purification. The organic load of the wastewaters, substrate contamination (sewage bacteria) and distance from the wastewater discharge outlet appear to be the most important factors affecting macroinvertebrate assemblages, while typology (i.e. slope, altitude), hydrology (i.e. permanent, intermittent), intensity and volume of the wastewater are the most important determinants of self-purification processes. As these industries are usually located near small-sized streams that are not significantly considered in the Water Framework Directive 2000/60/EC, there is a need for including them in monitoring and assessment schemes as they may considerably contribute to the pollution load of the river basin. Finally, guidelines to manage these wastes through technologies that minimise their environmental impact and lead to a sustainable use of resources are also critical.
Ioannis Karaouzas

Overview of the Pesticide Residues in Greek Rivers: Occurrence and Environmental Risk Assessment

During the past decades, there has been a growing concern related to the presence of “emerging” and “priority substances” in surface waters. For this reason, the European Union (EU) Water Framework Directive (WFD) (Directive 2000/60/EC) has established the bases to regulate water resources with the objective of preserving, protecting and improving their quality and sustainable use. In this context, this chapter provides an overview on the occurrence and levels of pesticide residues in Greek river waters, over the last 30 years [between 1985 and 2015; “past” (1985–2005) and “recent” (2006–2015) pesticide investigations] in order to describe trends in water quality status and assess potential adverse effects in the aquatic environment. The assembled data clearly demonstrate that agricultural practices in Greece have aggravated the water quality of rivers and may have posed considerable risk for certain ecosystems. The rivers that were monitored in a systematic way, mainly in the past period, were Aliakmon, Axios, Loudias, Louros, Arachthos and Kalamas, while there is a lack of data for other important rivers. Most of the detections involve a limited number of herbicides used extensively in corn, cotton and rice production, as well as the banned organochlorine insecticides that are persistent in the aquatic environment. Overall, the concentrations detected throughout the running waters of Greece were very small fractions of levels that, according to environmental risk assessment analysis, are believed to be non-harmful to aquatic life. However, in some areas with intense agricultural practices and hence high pesticide application, the environmental concentrations of pesticides were in non-compliance with the environmental quality standards (EQSs, Directive 2008/105/EC). The outcomes of this review reveal that there is a need for harmonisation in the sampling strategy and monitoring practices should be in accordance with the WFD. For future campaigns, specific insight into agricultural treatments and land use in the river basin could contribute to optimised water monitoring.
Dimitra Lambropoulou, Dimitra Hela, Anastasia Koltsakidou, Ioannis Konstantinou

Geochemical Processes of Trace Metals in Fresh–Saline Water Interfaces. The Cases of Louros and Acheloos Estuaries

Fresh–saline water interfaces are sites of major transformations on the speciation and the distribution of trace metals, through complex processes. The present chapter considers trace metal geochemical processes at fresh–saline water interfaces of representative Greek riverine systems, namely of those of the perennial medium-sized Louros River and the big and highly fragmented Acheloos River. Dissolved and particulate metals, as well as metal fractions in the sediments, are considered in combination with physicochemical parameters, and mineral magnetic measurements are used for tracing the origin of particle populations (lithogenic, anthropogenic, authigenic), and their compositional alterations during their passage from the rivers, through the interfaces, to sea. The interfaces of the two systems have distinct characteristics both on a spatial and a temporal scale, thus allowing for a diversity of trace metal behaviour patterns to emerge. In the small, perennial Louros system, trace metals are trapped within the thin, yet stable salt wedge. In the heavily fragmented Acheloos system, variations of the water and sediment discharges have moved the active interface landwards, where due to the reduction of dilution effects by inert, detrital particles, the fingerprint of the authigenic and anthropogenic component of trace metals has become more pronounced. The results of the research carried out in the two distinctive fresh–saline water interface systems are important not only in order to enlighten us about the geochemical processes in nature, but also in order to provide the necessary knowledge to properly manage these systems for the benefit of the environment and the sustainable development of the impacted areas.
Michael Scoullos, Fotini Botsou

The Evrotas River Basin: 10 Years of Ecological Monitoring

This chapter is the outcome of a 10-year ecological monitoring survey in the Evrotas River Basin (ERB). Synthesising the main outcomes of past and ongoing research projects, it presents an overview of the basin’s geographical, geological, hydrological and ecological features, focused on the ecological status according to the Water Framework Directive 2000/60/EC, and assesses the degree of environmental degradation caused by the major pollution sources and other anthropogenic pressures. Chemical, hydromorphological and biological data from studies carried out in the ERB during the past decade are integrated to derive spatial and temporal trends in environmental degradation. Despite the numerous sources of organic and inorganic pollution, which include, inter alia, olive mill and fruit juice processing wastewaters and agricultural, industrial and urban runoffs, the overall ecological degradation of the ERB is assessed as moderate and is located mainly at the downstream half of the basin, where the anthropogenic activities become intensified. However, the major impact in the ERB during the last decades has been the over-exploitation of the surface and groundwater resources for irrigation, which has resulted in the artificial desiccation of large parts of the basin’s hydrological network. Despite the aforementioned issues, the aquatic benthic biota of the basin shows high resilience, but the fish fauna is severely affected by hydrological and morphological alteration. Biomonitoring, conservation and management responses to drought and pollution require approaches, which account for spatial and temporal variability. Within this perspective, a programme of measures is proposed, aiming at preserving and restoring the basin’s water resources and aquatic ecosystem.
Ioannis Karaouzas, Christos Theodoropoulos, Leonidas Vardakas, Stamatis Zogaris, Nikolaos Skoulikidis

Macroinvertebrate Assemblages and Biological Status of Rivers in Northern and Central Greece

This paper investigates the benthic macroinvertebrate fauna of the northern and central rivers of Greece and their use in the assessment of the biological/ecological conditions of water bodies towards the fulfilment of the Water Framework Directive for good ecological status/potential by the end of 2015. The macrozoobenthos from reference or moderately disturbed sites did not significantly differ as to their richness, diversity and sensitivity among sites. Altitude, among other environmental parameters, was the differentiating parameter according to the canonical correspondence analysis (CCA) of the structure/composition of benthic macroinvertebrates. Seasonality exists in high- and low-altitude reference sites for sensitive to organic pollution taxa. The results of the STAR_ICMi and HESY indices coincided totally when the ecological quality was below good. More than 70% of the sites were characterised as of lower than good ecological status/potential. According to HESY, water quality varied according to the altitude from upstream to downstream sites (pollution gradient). The application of operational monitoring or continuous programme of measures is needed for most of the basins in order to meet the environmental objectives and the risk management (IMPRESS analysis) according to the WFD. Finally, the DPSIR framework shows that the ‘drivers’ agriculture, livestock and sewage untreated effluents cause the deterioration of the ecological quality of water and habitat degradation (‘state’).
Lazaridou Maria, Ntislidou Chrysoula

Socio-Economics and Water Management: Revisiting the Contribution of Economics in the Implementation of the Water Framework Directive in Greece

This chapter sets out the socio-economic principles that should govern water resources management for the achievement of a sustainable allocation of the resource over time and across space, in accordance with the EU Water Framework Directive. The resulting allocation should be economically efficient, socially equitable and acceptable and environmentally sustainable. The main background concept guiding the identification of such an allocation is the ‘total economic value (TEV)’ of water resources. This concept derives from the ecosystem goods and services that water resources provide the economy and society. In this chapter we present the state of the art with regard to estimating the TEV of water resources and explain how these estimations can facilitate the design and implementation of different European policies in relation to mitigation of different forms of water stress.
Phoebe Koundouri, Dimitrios Reppas, Vassilis Skianis

Environmental Impacts of Large-Scale Hydropower Projects and Applied Ecohydrology Solutions for Watershed Restoration: The Case of Nestos River, Northern Greece

The impoundment and abstraction of freshwater in river systems for the purposes of power generation and agricultural irrigation has provided huge economic benefits at global scale over the last 50 years. However, the environmental and social costs induced by large dams have been poorly accounted for in economic terms. Although the construction of large dams reduces the threat of devastation from extreme floods, significant watershed changes arise as a result of reservoir filling, river flow blockage, river flow storage, and flow regulation. Almost 15 years after the construction and operation of the two large hydropower dams (Thissavros and Platanovrisi), and approximately 50 years after the operation of the irrigation dam at Toxotes, the environmental consequences at the downstream part, the deltaic and the coastal zone of Nestos River are evident. The application of specific ecohydrological concepts aims to mitigate these observed environmental effects. Ecohydrology is an innovative and exciting topic, considered as the science of interplay between biota and hydrology in an ecosystem. Riparian and coastal ecohydrology concepts, together with the concept of “Green Hydropower”, may be adopted as a tool for assessing the effectiveness of the measures adopted by the hydropower companies aiming at improving the environmental functioning of such systems.
Georgios Sylaios, Nikolaos Kamidis

River and Wetland Restoration in Greece: Lessons from Biodiversity Conservation Initiatives

Rivers in Greece have seen extensive human-induced degradation, and there are increasing demands on the goods and services they provide along with increasing threats from future anthropogenic pressures. These multi-scale alterations to rivers and associated wetlands and riparian zones have severely impacted biodiversity. The Greek government has responded by creating various new protected areas and promoting interest in conservation, while attention to monitoring waters has increased with the implementation of the EU WFD. Unfortunately, bioassessment-based monitoring, long-term conservation programmes and restoration actions in rivers have lagged behind other EU countries. Here we outline the state of river and wetland restoration progress; we describe key restoration examples and discuss shortcomings, pitfalls and opportunities in various aspects of restoration.
Stamatis Zogaris, Nikolaos Skoulikidis, Elias Dimitriou


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