Operating Small Hydropower Plants in Greece under Intermittent Flow Uncertainty: The Case of Tsiknias River (Lesvos)

Abstract

In arid and semi-arid parts of the world, river exploitation is intensive, involving water storage for irrigation or hydropower generation. In Greece, 100 small hydropower plants (SHPs) take advantage of less than 10% of the hydropower potential of low flow streams (<2 m3/s), a very small amount in relation to the 70% of the European Union. The energy policy of complete decarbonization of the country by 2023 on a national scale opens the road for new investments in SHP projects, especially in intermittent-flow streams of the Greek islands. Simulated flows by the Modello Idrologico SemiDistribuito in continuo (MISDc model) are used to construct the annual flow duration curve (FDC) to study and assess the hydropower potential of an intermittent stream (Tsiknias river, Lesvos, Greece). For Tsiknias River, but also for six other intermittent-flow rivers of Crete island, the capacity factor (CF), which represents the mean annual power of the hydropower plant, should remain >75% to exploit the river’s potential. The FDC and CF are essential in designing SHP projects in intermittent-flow streams with long no-flow periods. The development of public participatory approaches and a closer cooperation among policy makers and stakeholders should work to promote hydropower exploitation and accelerate licensing procedures.

Alteration of the Ecohydrological Status of the Intermittent Flow Rivers and Ephemeral Streams due to the Climate Change Impact (Case Study: Tsiknias River)

“…The Sequential Uncertainty Fitting ver.2 (SUFI2) embedded within the SWAT Calibration and Uncertainty Program (SWAT-CUP) software [44][45][46] was employed for auto calibration, using the Nash-Sutcliffe Efficiency (NSE) as the objective function criterion. Nine parameters were selected (Table 3), based on dominant processes in Tsiknias basin reported by previous studies [26,[47][48][49][50]. Previous streamflow measurements from July 2007 to July 2009 showed that the contribution of individual sub-basins, described in this work as Areas 1-5, respectively (Figure 4), were consistent with the size of the drainage area, the slope, and the existence of water springs [32].…”

“…Tsiknias River is characterized by a temporary hydrological regime subject to seasonal abstraction in order to cover irrigation needs; it is, therefore, prone to more alteration [26]. Assessment of the current and projected future flow regimes, however, is important to understand the existing ecosystems functioning and river processes sustainability.…”

“…The case study is Tsiknias River (Greece), a typical intermittent flow stream, with a mainly agricultural basin, subject to severe floods and drought phenomena [26], outflowing into a protected conservation area [27]. The limited existing monitoring of the basin in combination with the interseasonal flow variability make the use of hydrological models essential to simulate its hydrologic response in longer periods.…”

Numerical assessment of climate change impact on the hydrological regime of a small Mediterranean river, Lesvos Island, Greece

“…Projections by the fi fth iteration of the Intergovernmental Panel on Climate Change (IPCC) point towards a likely decrease in precipitation over the Mediterranean by 30-45%, especially if temperature rises by 1.4 °C (Cisneros, 2014;Zhai et al, 2018). Consequently, the frequency of fl ash fl oods and droughts in the region is expected to increase in the coming years, seriously altering the ecological and hydrological patterns of river basins (Tzoraki, 2020).…”

Time-lapse graphical representation methods for mapping of Intermittent Rivers and Ephemeral Streams (IRES)

“…IRES flowing intermittently over a period of time are the dominant river networks in many arid and semi-arid regions and can be found in various climates . Especially in water scarce areas, IRES are used intensively for water diversion and storage for irrigation, hydropower production, channelization and urbanization (Tzoraki et al, 2020). Recent studies revealed their unique ecosystems processes to conserve their biodiversity (Datry, Singer, et al 2017).…”