One of the negative effects of hydropower on river environment includes
rapid changes in flow and habitat conditions. Any sudden flow change
could force fish to move towards a refuge area in a short period of
time, causing serious disturbances in the life cycle of the fish. A
probability-based multiscale model was developed to quantify the impact
of hydropeaking on habitat suitability for two fish species. The model
used habitat preference curves, river flow and depth to develop the
suitability maps. The suitability index maps reveal that habitat
suitability deteriorates as flow increases in this part of the river.
The probability model showed that, on average, suitability indices are
higher for adult grayling than juvenile trout in hydropeaking events in
the studied area. In addition, the life stages of fish determine their
response to the sudden flow change. The method developed shows the
potential to be used in river management and the evaluation of
hydropeaking impacts in river systems affected by hydropower.