Analysis of Hydrologic Regime Changes Caused by Small Hydropower Plants in Lowland Rivers

Abstract

Hydropower remains the most important and largest source of renewable energy. However, besides many additional benefits, such as dams for water supply, irrigation, flood control, recreation, navigation, etc., hydropower generation has a negative impact on the environment. This study aimed to investigate the hydrologic changes in Lithuanian lowland rivers caused by small hydropower plants (HPPs). Thirty-two indicators of hydrologic alteration (IHA) were studied in 11 rivers downstream of hydropower plants in the post-impact and pre-impact periods. The findings showed that HPPs and reservoirs considerably disturbed the primary flow of river ecosystems downstream. The largest changes in mean IHA values were found for low and high pulse characteristics (up to 57%) and the number of reversals (up to 44%). Only small or no deviations of the timing of annual extreme flows were found. The number of reversals, a low pulse count, and a fall rate were the flow characteristics that fell outside their historical ranges of variability most often. Six (out of 11) hydropower plants were identified that provoked hydrologic alterations of a moderate degree.

How does the daily regulation hydropower station reduce the hydrological regime impact? A case study in upper Yellow River

“…Notably, when the statistics are analyzed within a weekly timeframe, the maximum statistics decrease by over 60% from the P1 to the P2 period. Similarly, Sarauskiene et al (2021) examined hydrological alterations in Lithuanian rivers and observed a substantial impact of hydropower generation on the maximum discharge of 1-, 3-, and 7-day periods. Such substantial changes can heavily disrupt the distribution of plant and animal populations in floodplains (Junk & Bayley 2008).…”

“…The natural hydrological regime plays a crucial role in maintaining the ecological health and biodiversity of rivers (Radinger et al 2018;Cui et al 2020). However, human activities such as the operation of hydropower stations, irrigation, and land use changes have substantially impacted these regimes, contributing to significant alterations in approximately 24% of the world's largest rivers (Pfeiffer & Ionita 2017;Sarauskiene et al 2021;Yang et al 2022). Among these activities, the operation of hydropower stations stands as one of the most influential factors, leading to the disruption of ecological continuity in more than half of the world's large rivers, resulting in extensive river system fragmentation (Wang et al 2018;Gierszewski et al 2020;Knott et al 2024).…”

Analysis of Hydropotential and Prospects for Small Hydropower Development in Ukraine

“…The construction of a small hydropower plants has many different environmental impacts depending on the location and schemes of SHPPs [30]. Since most schemes of hydropower plants in Ukraine require the construction of a weir or dam for impounding water, the reservoir can lead to − flooding the adjacent areas, − influencing vegetation, − changes in the hydrological regime of the river [31]. Moreover, due to the regulation of the river by reservoirs or weir barriers, the water flow velocity in the river decreases, which can lead to the siltation of some areas and the overgrowth of algae and reeds.…”

Signal Spectrum Analysis of Sediment Water Impact of Hydraulic Turbine Based on ICEEMDAN-Wavelet Threshold Denoising Strategy

“…Studies have shown that the large-scale development of hydropower can reduce the dependence of the power system on fossil fuels and provide a complementary foundation for more volatile new sources of energy, such as wind and solar [2][3][4]. Furthermore, hydropower plants play an undeniable role in water resource management, flood control, and irrigation benefits, as well as being an important part of people's livelihoods [5]. The majority of hydropower plants are typically established along rivers, where floods lead to the accumulation of significant amounts of sediment.…”