The effects of hydropeaking on hyporheic interactions based on field experiments

Abstract

36Hydropeaking power production has the potential to pose serious challenges towards and positions in the river bed that can be potentially relevant to ecology were investigated. 47Understanding the complexity of those processes at the fine scale from the physical point of 48 view is both important for the judgment of potential ecological impacts and for the future 49 management of such regulated systems.

An Assessment of Ice Effects on Indices for Hydrological Alteration in Flow Regimes

“…Similarly to the high flow, ice-induced low flows are mainly estimated by comparing the raw and corrected data, and, in cases where there are no available air temperature changes in the gradient of the recession, hydrograph is used to detect drops in the flow caused by ice. For small streams, the rate of change of the water level related to such low flows can be significant, and the maximum rate of change is computed following similar procedures, as for hydropeaking analysis [31].…”

Dynamic Lift on an Artificial Static Armor Layer During Highly Unsteady Open Channel Flow

“…Even though this is not a direct equivalent of the porous structure in a real gravel bed, the number of holes can still be associated with a measurable porosity of the streambed. Each hole has a diameter of 3 mm, giving it a surface area of Ahole = 7.07 mm 2 . The total size of the modified area is = (400 mm) 2 = 160,000 mm 2 .…”

“…As a practical example: Recent field studies on hydropower peaking have shown that unsteadiness parameters of = 0.0180 and higher, also occur in real gravel bed streams. Applying Equation (2) to the raw data of a field study at River Lundesokna in Norway [2], a hydrograph with an unsteadiness parameter of = 0.0183 could be observed downstream a hydropower plant on 30 January 2012. In comparison, the largest unsteadiness parameter in the study of [3] is = 0.0180, resulting in hardly recognizable significant unsteady effects for this measurement range (Figure 7).…”

“…Depending on the hydrograph, such discharge variations can affect the riverbed, banks and hydraulic structures differently than steady conditions do. Unsteady flow triggers processes like upwelling and downwelling, which govern the pressure gradient and pore water exchange in the hyporheic zone [2]. In experimental investigations of unsteady flow, hydrographs for both increasing and decreasing discharge typically follow a curve such as schematically presented in Figure 1a.…”

Thermal regime of a highly regulated Italian river (Ticino River) and implications for aquatic communities

“…However, to date, only few attempts have been made to relate flow regulation to river temperature in order to define management practices able to protect both aspects of fluvial environment . For the definition of adequate remediation actions, the effects of river discharge alteration on water temperature should be detected at different temporal (Hari et al, 2006;Toffolon et al, 2010;Zolezzi et al, 2011;Vanzo et al, 2016) and spatial scales Gerecht et al, 2011;Casas-Mulet et al, 2015). Recent studies (Toffolon et al, 2010;Zolezzi et al, 2011;Carolli et al, 2012;Bruno et al, 2013;Vanzo et al, 2016) focused on the identification of the relationships between hydropeaking and thermopeaking, and their ecological effects, mainly on short and medium timescales and in a mountainous context.…”