Maintenance, upgrading and extension of the Decision Support System for the management of the Athens water resource system
Duration: October 2008–November 2011
Budget: €72 000
Project director: N. Mamassis
Principal investigator: D. Koutsoyiannis
This research project includes the maintenance, upgrading and extension of the Decision Support System that developed by NTUA for EYDAP in the framework of the research project “Updating of the supervision and management of the water resources’ system for the water supply of the Athens’ metropolitan area”. The project is consisted of the following parts: (a) Upgrading of the Data Base, (b)Upgrading and extension of hydrometeorological network, (c) upgrading of the hydrometeorological data process software, (d) upgrading and extension of the Hydronomeas software, (e) hydrological data analysis and (f) support to the preparation of the annual master plans
C. Ntemiroglou, G.-K. Sakki, and A. Efstratiadis, Flood control across hydropower dams: The value of safety, Role of Dams and Reservoirs in a Successful Energy Transition - Proceedings of the 12th ICOLD European Club Symposium 2023, edited by R. Boes, P. Droz, and R. Leroy, 187–198, doi:10.1201/9781003440420-22, International Commission on Large Dams, Interlaken, Switzerland, 2023.
Hydropower reservoirs inherently serving as major flood protection infrastructures, are commonly occupied with gated spillways, to increase both their storage capacity and head. From an operational viewpoint, during severe flood events, this feature raises challenging conflicts with respect to combined management of turbines and gates. From the perception of safety, a fully conservative policy that aims to diminish the possibility of dam overtopping, imposes to operate the turbines in their maximum capacity and, simultaneously, opening the gates to allow uncontrolled flow over the spillway. Yet, this practice may have negative economic impacts from three aspects. First, significant amounts of water that could be stored for generating energy and also fulfilling other uses, are lost. Second, the activation of turbines may be in contrast with the associated hydropower scheduling (e.g., generation of firm energy only during peak hours, when the market value of electricity is high). Last, the flood wave through the spillway may cause unnecessary damages to downstream areas. In this vein, this paper aims to reveal the problem of ensuring a best-compromise equilibrium between the overall objective of maximizing the benefits from hydropower production and minimizing flood risk. In order to explore the multiple methodological and practical challenges from a real-world perspective, we take as example one of the largest hydroelectric dams of Greece, i.e., Pournari at Arachthos River, Epirus (useful storage 310 hm³, power capacity 300 MW). Interestingly, this dam is located just upstream of the city of Arta, thus its control is absolutely crucial for about 25 000 residents. Based on historical flood events, as well as hypothetical floods (e.g., used within spillway design), we seek for a generic flood management policy, to fulfill the two aforementioned objectives. The proposed policy is contrasted with established rules and actual manipulations by the dam operators.
Full text:
C. Ntemiroglou, Optimization of the management of hydroelectric reservoir gates - Application to Arachthos dam, Diploma thesis, 164 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, November 2020.
Hydroelectric works are equipped with spillway gates are advantageous, since they ensure an increased hydrodynamic potential, which favors in turn the produced energy. However, in the case of a flood event, careful manipulations are essential, to assure the safety of the dam and the downstream works. These are usually employed on the basis of operation rules that are derived empirically, and not as result of a systematic methology that accounts for the flood regime of the study area as well as the complex process that are taken into place during the flood routing. The objective of this thesis is the development of a novel approach for gate management that combines stochastic simulation and multicriteria optimization, applied to the particularly crucial dam of Pournari I, at Arachthos River. Key component is a numerical scheme for flood routing, which implements a hydraulically consistent method for extracting the flow-stage relationship through ogee-type spillways, and a simulation procedure for the manipulation of gates and turbines, using characteristic level thresholds during the rising and fallinf of a flood hydrograph. By employing the aforementioned methologies at Pournari dam, we determined the aforementioned methologies at Pournari dam, we determined operation rule initially for the design flood of 10000 years return period (local rule), and next for a wide spectrum of smaller floods that have been synthetically generated. Starting from the local rule, we emphasized the investigation of competitiveness between the energy and safety criteria, in order to outcome to a compromise formulation of the optimization problem. Next, from the stochastic analyses we concluded to six operation rules, which refer to flood events of small and large return period, and three initial stage scenarios. In these analyses, we gave further weight to economy (i.e. minimization of energy losses due to spill), in contrast to the local rule, which is conservative as it focuses to the safety of the dam and the downstream works. The most representative rule has been applied to the flood event of year 2005, and its performance proved to be comparative with the successful manipulations by the expertise personnel of PCC.
Full text:
V. Bellos, P. Kossieris, I. Papakonstantis, P. Papanicolaou, C. Ntemiroglou, and A. Efstratiadis, [No English title available], Modernization of the management of the water supply system of Athens - Update, 46 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, November 2022.
Related project: Modernization of the management of the water supply system of Athens - Update