Issue 2 [July]( Issue on Water Resources Management ) Evaluation of Treatment Schemes Appropriate for Wastewater Reuse in GreeceAndreadakis A., Mamais D., Gavalaki E. and Panagiotopoulou V., Pages:1-8 DOI: https://doi.org/10.30955/gnj.000290Paper Topic: General Issue: Issue 2Get Full Paper AbstractThe scope of this paper is the evaluation of wastewater reuse quality criteria and treatment specifications, appropriate to Greek conditions. The parameters that affect wastewater reuse criteria were taken into consideration, concerning among others reuse priorities, available treatment plants and effluent characteristics. The proposed wastewater reclamation criteria were verified by a series of lab-scale experiments, designed to study the feasibility and effectiveness of the following treatment schemes to produce treated wastewater suitable for reuse: a) disinfection of secondary effluent with UV radiation and chlorination and b) tertiary treatment and disinfection of wastewater with UV radiation and chlorination. The experimental data were analyzed using a stochastic statistical model that employs Monte Carlo simulation. The main scope of the stochastic approach was the regeneration of a greater set of data, based on the defined by the experimental information mathematical distribution of each parameter involved and the determination of relative probability distributions. Following this approach the standards proposed are realistic and feasible and in the case of restricted reuse can be readily achieved by the existing wastewater treatment plants in Greece. Even in the case of unrestricted reuse the additional treatment required can be achieved at a moderate cost, through upgrading of the existing plants with tertiary treatment. GIS Integration of Aster Stereo Imagery for the Support of Watershed ManagementChrysoulakis N., Diamandakis M. and Prastacos P., Pages:47-56 DOI: https://doi.org/10.30955/gnj.000266Paper Topic: General Issue: Issue 2Get Full Paper AbstractIn this study, ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) stereo imagery was analysed in combination with Global Positioning System (GPS) data and field observations, using Geographical Information Systems (GIS) techniques to examine the potential of satellite remote sensing to support watershed management. Terrain elevation data were derived for the region of Heraklion, Crete. The accuracy of the ASTER derived DEM (Digital Elevation Model), was better than 20 meters (planimetric) and better than 15 meters (elevation). Supervised classification techniques were applied for land cover production using ASTER multi-spectral imagery and filed observations at predefined application sites. The determination of training areas required in the supervised classification scheme was based on these observations. Finally, GIS methods were applied to estimate watershed characterization parameters for the study area offering the advantages of spatial data handling capabilities and automatic extraction of thematic information. The drainage pattern, which was derived, provided a generally representative depiction of the watershed. The output pixel spacing of 15 m of the produced DEM as well as the high spatial resolution of ASTER imagery found to be quite satisfactory for the watershed characterization of the study area, indicating the high potential of ASTER imagery to support watershed management. GFIS (Geographic Forecasting Information System): A Case Study in Water Resources ManagementPagourtzi E., Nikolopoulos K. and Assimakopoulos V., Pages:57-63 DOI: https://doi.org/10.30955/gnj.000264Paper Topic: General Issue: Issue 2Get Full Paper AbstractThe current study presents the development of a Forecasting Information System for geographic data (cross-sectional time-series for different geographic regions). GFIS, Geographic Forecasting Information System, was developed with MS Visual Basic (User Interface), ArcView (GIS) and MS Access (DBMS) during the MSc thesis of one of the authors in 2000. GFIS is suitable for the management and forecasting for all time-series that present a geographic dimension and can be illustrated in a Geographical Information System (GIS). The forecasting capabilities of the system extend from classical time-series extrapolation methods (exponential smoothing, regression) (Assimakopoulos, 1994) to more complex methods (Theta model). The applicability of the system was tested with a case study in Water Resources Management. GFIS was used in order to create rainfall forecasts for the watersheds in Lakonia, a region in southern Greece. The estimation, forecasting, planning and management of hydrological resources are of great importance and prerequisite for sustainable development. An Environmental Impact Assessment Decision Analysis System for Irrigation SystemsManoliadis G.O. and Vatalis I.K., Pages:65-70 DOI: https://doi.org/10.30955/gnj.000273Paper Topic: General Issue: Issue 2Get Full Paper AbstractIn this paper an Environmental Impact Assessment Multicriteria Decision Analysis System for irrigation projects (EIAMDAS) used as a comprehensive tool that enables comparison between irrigation project alternatives is presented. The comparison is based upon all relevant aspects of the surrounding environment during irrigation systems operation. The decision is case dependent, and relies on the compromise between positive and negative impacts associated with the project, and the relative importance (weights) of the different factors involved. Inputs to the EIAMDAS include are information of the existing system operation derived from selected answers for a set of multiple choice questions that provide sufficient information to describe the baseline conditions and the general design for several project alternatives. On the other hand, the EIAMDAS outputs, in the form of positive and negative scores, allow the user to evaluate different impacts criteria on neighbouring and project areas. The user is also required to input importance weights to these categories of impacts. The different impacts criteria are categorised as environmental social and economic impacts using compromise programming. The final output is an overall environmental index for each project alternative. Two years of real time control data are used to illustrate system performance. Conclusively the EIAMDAS is an efficient tool for supporting the decision making process, especially in the trade-off between project alternatives according to anticipated environmental impacts including economic aspects. Although this EIAMDAS was developed for irrigation projects applications, the software was designed in a flexible manner to allow for future adaptation to other applications using the same technique. Application of the SWAT model in the Pinios river basin under different land-use scenariosPikounis M., Varanou E., Baltas E., Dassaklis A. ans Mimikou M., Pages:71-79 DOI: https://doi.org/10.30955/gnj.000277Paper Topic: General Issue: Issue 2Get Full Paper AbstractThis paper investigates the hydrological effects of specific land use changes in a catchment of the river Pinios in Thessaly (Ali Efenti catchment), through the application of the Soil and Water Assessment Tool (SWAT) on a monthly time step. The model's calibration efficiency is verified by comparing the simulated and observed discharge time series at the outlet of the watershed, where long series of hydrometrical data exist. The model is used to simulate the main components of the hydrologic cycle, in order to study the effects of land use changes. Three land use change scenarios are examined, namely (A) expansion of agricultural land, (B) complete deforestation of the Trikala sub-basin and (C) expansion of urban areas in the Trikala sub-basin. All three scenarios resulted in an increase in discharge during wet months and a decrease during dry periods. The deforestation scenario was the one that resulted in the greatest modification of total monthly runoff. The broadcasting on INTERNET of water DPSIR indicators. Experiment on the Nestos delta, GreeceKarakos A., Skoulikaris X., Monget J-M. and Jerrentrup H., Pages:81-87 DOI: https://doi.org/10.30955/gnj.000279Paper Topic: General Issue: Issue 2Get Full Paper AbstractAn initial GIS data base has been assembled in 2001 covering the various parameters related to the Nestos river basin and its delta. This data set is being used for water resources modelling purposes within the frame of the multinational PROMENES initiative. The initial data gathering has produced a vast set of information which has been stored using the ArcView GIS tool. The European Water Framework Directive (WFD) recently defined guidelines for structuring the GIS databases aimed at water resources management. It is stressing the use of "open" GIS systems and formats in order to further facilitate maintenance and reporting to the public, a needed requirement. The present project explores the application of the DPISR concept to the publication of a "State of the Environment Report" on the Nestos delta through Internet. This concept has recently been proposed by the European Environmental Agency and is already in application for air pollution indicators broadcasting and urban environmental problems reporting. The PROMENES data base has been restructured using an "open" GIS approach and lessons learned on how to organize water management related datasets for the building of environmental indicators. A prototype web site is evaluated and is being tested for public broadcast under the supervision of EPO Living Lakes, an environment protection organisation operating in the Nestos delta. Intercomparison of forecasting methods for flood warning in the river Cam catchmentLekkas D.F., Maxey R. T. and Wheater H.S., Pages:89-97 DOI: https://doi.org/10.30955/gnj.000289Paper Topic: General Issue: Issue 2Get Full Paper AbstractCurrently flood warning in the catchment of the River Cam in Cambridgeshire relies on the issuing of alerts when the river level at the monitoring station at Byron's Pool, just upstream of Cambridge, reaches certain pre-determined levels. Warnings are shown to be fairly accurate, but there is very little lead time between the trigger being exceeded and the commencement of flooding. At present there is no method used that can forecast in advance when the trigger is likely to be reached. Three conceptually different methods of forecasting if and when the trigger at Byron's Pool will be exceeded are presented. The first of these is a simple additive model, in which flows from the three tributaries that are gauged are summed to give a combined flow. The second method involves the derivation and application of two transfer function models capable of transforming river levels on the upstream tributaries to a level at the trigger site. These models are applied both with and without realtime updating techniques. The third method involves the calibration and application of a lumped rainfall- runoff model of the whole catchment to Byron's Pool. Two different calibration periods are used, and the results compared. The results indicate that the simple additive model, while being better than no model at all, is very inaccurate, and fails to replicate the hydrograph shape and timing, most likely because of the influence of an ungauged tributary. The transfer function models perform well, especially when real-time updating is used. The rainfall-runoff model performs less well, struggling to reproduce the hydrograph shape. Ôhe main conclusions are that for this site a hierarchy of models may be appropriate, with rainfallrunoff models providing an early indication of flooding, and transfer function routing models with updating providing a more accurate forecast, with the additive model as a back up. The importance of obtaining more data, including validation of ratings, and the future gauging of the ungauged tributary, is noted throughout this investigation. Assessment of the Water Quality of Lake Plastira through Mathematical Modelling for Alternative Management ScenariosAndreadakis A., Noutsopoulos C. and Gavalaki E., Pages:99-105 DOI: https://doi.org/10.30955/gnj.000292Paper Topic: General Issue: Issue 2Get Full Paper AbstractIn the context of a research program regarding water quality management and protection plan for Lake Plastira, one of the main tasks was the establishment of a sound relationship between the minimum water level and the trophic state of the lake. The study involves the application of a eutrophication-dissolved oxygen mathematical model (EUTRO-SEL) which describes various physical, chemical and biological processes taking place in a water body. Three water management scenarios were examined in the context of the study, based on alternative minimal operating water levels (782m, 784m and 786m). According to the modelling results and the classification of the water bodies according to the recent standards and trends within the European Commission, the operation of Lake Plastira at a minimum water level of 786 m ensures very good water quality characteristics (Category I). The operation of the Lake Plastira at lower water levels between 782-784 m, results in acceptable water quality that classify the lake into Category II. Since in all three management scenarios the water quality is acceptable and describes a water body with at least good water quality, acceptable minimum operational water level, can be determined by other considerations (e.g. elasticity of demand, lanscape aesthetics, etc). Testing Alternatives for Salt Wedge Management in an Estuary with the Use of Monitoring and a Mathematical ModelHaralambidou K.I., Sylaios G.K. and Tsihrintzis V.A., Pages:107-118 DOI: https://doi.org/10.30955/gnj.000295Paper Topic: General Issue: Issue 2Get Full Paper AbstractThe intrusion of salt wedge in rivers is a natural phenomenon, which occurs in many estuaries. Saline water tends to propagate upstream from the river mouth, due to the limited freshwater and the tidal and density currents developed, resulting in deterioration of water quality in the lower river reach. Several methods to control the salt wedge have been employed, including the construction of inflatable dams or gates. A promising method of control is the use of an air curtain. In this study, a two-dimensional, laterally averaged numerical model has been developed to describe salt wedge intrusion. This model provided necessary hydraulic parameters, which were used in air curtain design theory to evaluate the application of the air curtain method in a particular estuary system. The application takes place in the estuary of Strymon River in Northern Greece, where the limited discharge of freshwater, mainly caused by the construction of Kerkini dam, results in the creation and upstream intrusion of a salt wedge in the summertime, affecting water quality and making water unsuitable for irrigation uses.