Effects of Hydropower Dam Operation on Riverbank Stability

Abstract

The increasing number of extreme climate events has impacted the operation of reservoirs, resulting in drastic changes in flow releases from reservoirs. Consequently, downstream riverbanks have experienced more rapid and frequent changes of the river water surface elevation (WSE). These changes in the WSE affect pore water pressures in riverbanks, directly influencing slope stability. This study presents an analysis of seepage and slope stability for riverbanks under the influence of steady-state, drawdown, and peaking operations of the Roanoke Rapids Hydropower dam on the lower Roanoke River, North Carolina, USA. Although the riverbanks were found to be stable under all the discharge conditions considered, which indicates that normal operations of the reservoir have no adverse effects on riverbank stability, the factor of safety decreases as the WSE decreases. When the role of fluvial erosion is considered, riverbank stability is found to reduce. Drawdown and fluctuation also decrease the safety factor, though the rate of the decrease depends more on the hydraulic conductivity of the soils rather than the discharge pattern.

Research on the Sustainable Development of the Bistrita Ardeleana River in Order to Stop the Erosion of the Riverbanks and the Thalweg

“…The impact of dams and reservoirs on the aquatic environment of rivers is an important topic in global water resources management. These hydrotechnical constructions change the natural hydromorphological regime of rivers, negatively affecting their functionality and are associated with several environmental impacts, such as habitat fragmentation, poor water quality, nutrient depletion, loss or modification of biodiversity, remodeling of trophic networks, ichthyofauna, reduction of riparian biodiversity the river [5,[9][10][11][12][13][14][15][16][17][18]. Worldwide, the decline of river biodiversity has recently been linked to the reduced functionality of the riverbed substrate.…”

“…The watercourse restoration, also called river recovery, represents a set of measures to bring back, as close as possible, the original state of the ecosystems along the entire length of a heavily anthropized water course [7]. In general, river restoration aims at hydromorphological and ecological changes that improve the natural state of aquatic and riparian ecosystems through a variety of restoration methods [18,[21][22][23].…”