Charalampos Skoulikaris

Use of MODIS satellite images for detailed lake morphometry: Application to basins with large water level fluctuations

Abstract Lake morphometry is essential for managing water resources and limnetic ecosystems. For reservoirs that receive high sediment loads, frequent morphometric mapping is necessary to define both the effective life of the reservoir and its water storage capacity for irrigation, power generation, flood control and domestic water supply. The current study presents a methodology for updating the digital depth model (DDM) of lakes and reservoirs with wide intra and interannual fluctuations of water levels using satellite remote sensing. A time series of Terra MODIS satellite images was used to map shorelines formed during the annual water level change cycle, and were validated with concurrent Landsat ETM+ satellite images. The shorelines were connected with in-situ observation of water levels and were treated as elevation contours to produce the DDM using spatial interpolation. The accuracy of the digitized shorelines is within the mapping accuracy of the satellite images, while the resulting DDM is validated using in-situ elevation measurements. Two versions of the DDM were produced to assess the influence of seasonal water fluctuation. Finally, the methodology was applied to Lake Kerkini (Greece) to produce an updated DDM, which was compared with the last available bathymetric survey (1991) and revealed changes in sediment distribution within the lake.

Development of an integrated application portal for environmental spatial information dissemination in the Nestos river basin

Water resources management is a comprehensive planning process dimensioning all water related components. With this in mind, the EU Water Framework Directive (WFD) requires reliable and continuous water monitoring and collection of qualitative information in order to support decision making concerning water pollution events, focusing primarily on civil protection. The present research study initiates the coupling of water quality - quantity monitoring techniques and telemetric systems with geographic information system (GIS) based map server technologies for the near real time warning about potential water pollution events. The study is being implemented in the Greek part of the transboundary Nestos river basin and forms part of the Bulgarian and Greek European Territorial Cooperation Programme 2007-2013. The aim of this partnership is to develop an operational supportive mechanism for the Competent Authorities of water management in both countries in order to facilitate the planning and implementation of sustainable water management along with civil protection.

Impact of Climate Change on Hydropower Generation and Irrigation: A Case Study from Greece

Due to climate change, water availability for different uses such as domestic water supply, hydropower production and agricultural irrigation could be significantly reduced in the near future mainly in regions with arid and semi-arid climate. Precipitation data in the form of time series from different stations in South East Europe (SEE) as well as results from global atmospheric circulation models indicate that climate change will reduce water availability in this part of the Mediterranean. In this presentation the coupling of hydrological, hydraulic and climate change models is suggested in order to explore the impact of climate change on water resources at the river basin level. The methodology is illustrated for the Mesta/Nestos river basin, which is shared between Bulgaria and Greece. The case study is part of the worldwide UNESCO-HELP initiative.

Evaluation of riverbed representation methods for 1D flood hydraulics model

River bathymetry has a crucial role in numerical modelling of flow hydrodynamics. The aim of the present study is to i) investigate the capability of three different methods to trace the river bed, with the geodetic data derived from in situ survey of the river bed topography to be used as reference data, and moreover ii) assess the impact of the different river geometries on the performance of a 1D model of flood hydraulics. The HEC-RAS hydraulic model, in particular, calibrated and validated on hydrometric data uses a number of cross-sections derived from Aerial Laser Scanning (ALS), artificial sinking of riverbed, and Acoustic Doppler Current Profiler (ADCP) methods. Water level, discharges and flood extent derived from the model for 3 N-year floods (Q1, Q50, Q100) were evaluated while the extent of the inundation areas were exported into geographic information systems for visualization and interpretation of the findings. Case study area is a 2.2 km river section of the Otava River (Czech Republic), with a history of flood events. The results showed that ALS data need further processing when dealing with the riverbed zone, while ADCP presented high correlation to the reference model.

Promoting cooperation for transboundary water security: The experience of the UNESCO Chair/INWEB

The UNESCO Chair/INWEB (International Network of Water/Environment Centres for the Balkans) at the Aristotle University of Thessaloniki (AUTh), Greece, was established in 2003 as part of the UNITWIN/UNESCO Chairs program. It links INWEB, a water resources management network of academic and non-academic groups in south eastern Europe (SEE, or the Balkans) that has been active since 1999, with the UNESCO Chair on sustainable management of transboundary waters and conflict resolution.