Effects of river flow fluctuations on groundwater discharge through brook trout, Salvelinus fontinalis, spawning and incubation habitats

Abstract

The effects of short-term fluctuations in river discharge simulating a hydroelectricity peaking regime on the hydrogeological environment of the brook trout's reproductive habitats were examined. Fluctuating river levels altered shallow (< 2.5 m) groundwater pathways, chemistry, and flow potentials within the river bed at spawning and incubation sites. Rising river levels introduced river water into the bank where various degrees of mixing with groundwater occurred. Subsequent recessions of river levels increased the potentials for groundwater flow, particular in an offshore direction. The character of the river water -groundwater interaction appeared to be related to the hydrogeological nature of the river channel and adjacent catchment which varied among sites. The observations suggested hydroelectricity peaking regimes have potential negative impacts on brook trout reproduction.

The ecological significance of exchange processes between rivers and groundwater

“…The mechanical between surface water and groundwater in the hyporheic zone. This may have severe impacts on the opening of a colmated section of the Rhine's stream bed near a drinking water bank filtration site induced reproductive success of gravel spawning fish (Curry et al, 1994). a 1 m rise in the groundwater table near the river, but after a few weeks the opened section had become River bed incision, as a consequence of bedload deficits due to sediment retention by impoundments sealed again (Gö lz et al, 1991).…”

Water table dynamics and groundwater–surface water interaction during filling and draining of a large fluvial island due to dam‐induced river stage fluctuations

“…Few field studies have investigated hyporheic exchange driven by dam operations. Recent studies examine the effects of dam-induced river stage fluctuations on hyporheic exchange in riverbeds and banks covering several kilometers, but with observations from usually one-dimensional transects at the meter scale [Arntzen et al, 2006;Curry et al, 1994;Hanrahan, 2008]; vertical head gradients are typically monitored along a few vertical profiles every several kilometers. However, the interactions between surface water and shallow groundwater are intrinsically three-dimensional and multiscale [Cardenas, 2008;Poole et al, 2006;Sophocleous, 2002;Storey et al, 2003], and the dynamics are impossible to completely comprehend with vertical profiles.…”

Spawning Habitat Studies of Hanford Reach Fall Chinook Salmon (Oncorhynchus tshawytscha), Final Report.

“…Water flow into and out of the hyporheic zone is influenced largely by advective exchange with the river, a process generally controlled by channel morphology, pressure head of overlying surface water, and the permeability of riverbed sediments (Landon et al 2001;Wörman et al 2002;Cardenas and Zlotnik 2003;Rose 2003). Consequently, the magnitude of river flow and the underlying geology can significantly affect chemical, physical, and biological gradients within the hyporheic zone, which ultimately will affect the structure and function of aquatic ecosystems (Stanford and Ward 1993;Curry et al 1994;Wroblicky et al 1998;Soulsby et al 2001;Alexander and Caissie 2003).…”

“…In river systems influenced by hydroelectric dams operated in a load-following mode, physiochemical gradient shifts occur many times per day. This diurnal fluctuation in physiochemical characteristics affects the hyporheic zone structure and function (Williams 1993;Curry et al 1994) and likely alters the cues that adult salmon use to select redd sites. Water quality changes within the hyporheic zone will also affect the timing of fry emergence.…”