What is it about?

This study investigates the influence of the river flow regime type on the e-flows releases and hydropower production, constrained by eight hydrologically-based e-flows methods. For this purpose, 20 run-of-river hydropower plants up to 10 MW, from five Iberian Peninsula basins, located in regions with pluvial highly fluctuating, pluvial stable, pluvial winter, and pluvio-nival flow regimes were analysed. We integrated a hydropower model with a hydrological model, and eight e-flows methods to estimate mean daily hydropower production, e-flows, and hydrologic alteration. The results demonstrate little influence on hydropower production and e-flows releases for the pluvial regime type, notably, pluvial stable regime river reaches. Pluvio-nival regime provides unstable hydropower production and comparatively high e-flows alteration. Overall, hydrologic parameters represented by five global indices derived from Indicators of Hydrologic Alteration were affected differently for the e-flows releases regime induced by tested e-flows methods. In general, e-flows methods that involve annual minimum flow and indices of flow duration curve show inconsistent results among all study cases and hydrological regimes types; either they result in high e-flows releases while sharply reducing hydropower production or vice versa. However, so-called dynamic approaches demonstrate consistent results and are more suitable, both in terms of hydropower production and e-flows releases by therefore providing 10–35% more energy production while having little impact in several hydrological parameters.

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Why is it important?

The findings of this study may serve as a starting point to initiate a new discussion on the methods and criteria that should be established regarding e-flows determination at run-of-river hydropower plants.


Pluvial stable hydro-sites resulted in stable hydropower production. Pluvial highly fluctuating hydro-sites showed impulsive hydropower production. Pluvial-nival hydro-sites indicated unstable hydropower production. Minimum EFMs compromised the trade-off between hydropower production and e-flows. Dynamic EFMs enhanced e-flows and maximised the hydropower production.

PhD Alban Kuriqi
Universidade de Lisboa

Read the Original

This page is a summary of: Flow regime aspects in determining environmental flows and maximising energy production at run-of-river hydropower plants, Applied Energy, December 2019, Elsevier, DOI: 10.1016/j.apenergy.2019.113980.
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