Impact of debris dams on hyporheic interaction along a semi-arid stream

Abstract

Abstract:Hyporheic exchange increases the potential for solute retention in streams by slowing downstream transport and increasing solute contact with the substrate. Hyporheic exchange may be a major mechanism to remove nutrients in semi-arid watersheds, where livestock have damaged stream riparian zones and contributed nutrients to stream channels. Debris dams, such as beaver dams and anthropogenic log dams, may increase hyporheic interactions by slowing stream water velocity, increasing flow complexity and diverting water to the subsurface.Here, we report the results of chloride tracer injection experiments done to evaluate hyporheic interaction along a 320 m reach of Red Canyon Creek, a second order stream in the semi-arid Wind River Range of Wyoming. The study site is part of a rangeland watershed managed by The Nature Conservancy of Wyoming, and used as a hydrologic field site by the University of Missouri Branson Geologic Field Station. The creek reach we investigated has debris dams and tight meanders that hypothetically should enhance hyporheic interaction. Breakthrough curves of chloride measured during the field experiment were modelled with OTIS-P, a one-dimensional, surface-water, solute-transport model from which we extracted the storage exchange rate˛and cross-sectional area of the storage zone A s for hyporheic exchange. Along gaining reaches of the stream reach, short-term hyporheic interactions associated with debris dams were comparable to those associated with severe meanders. In contrast, along the non-gaining reach, stream water was diverted to the subsurface by debris dams and captured by large-scale near-stream flow paths. Overall, hyporheic exchange rates along Red Canyon Creek during snowmelt recession equal or exceed exchange rates observed during baseflow at other streams.

Spatio‐temporal variations of hyporheic flow in a riffle‐step‐pool sequence

“…The transfer of water as a result of actual flow processes can be classified into four categories according to the control: (1) turbulent diffusion is caused by the transfer of turbulent momentum between stream and pore-water flow (Zhou and Mendoza, 1993;Packman and Bencala, 2000); (2) hydrodynamically induced advection, known as bedform-/flow-induced advection, current-obstacle interaction or pumping exchange, is caused by the acceleration of flow over bedforms that gives rise to pressure variations, thus inducing flow in and out of the bed (Thibodeaux and Boyle, 1987;Elliott, 1990); (3) hydrostatically induced advection results from spatial variations of the hydraulic gradient caused either by geomorphological features such as stream meanders (Wroblicky et al, 1998;Boano et al, 2006) and instream structures, e.g. debris dams, step-pool sequences (Gooseff et al, 2006;Lautz et al, 2006;Hester and Doyle, 2008), or hydrogeological characteristics, primarily permeability distribution (Woessner, 2000;Cardenas et al, 2004) and ambient groundwater discharge (Larkin and Sharp, 1992;Winter, 1999);and (4) what may be considered as transient exchange is the transfer driven by the fluctuations of stage and groundwater, for example through bank storage (Sauer and Pinder, 1970;Konrad, 2006).…”

Buffered, lagged, or cooled? Disentangling hyporheic influences on temperature cycles in stream channels

“…In alluvial rivers, large wood provides roughness elements that deflect flows, scour depressions, create gravel bars, facilitate channel braiding, [Abbe and Montgomery, 1996;Gurnell et al, 2002], and encourage channel avulsions that lead to the formation of anabranched channel patterns [Nanson and Knighton, 1996]. Associated complex bed topography and channel patterns enhance hydraulic gradients within the hyporheic zone and substantially increase hyporheic exchange [Dent et al, 2001;Cardenas et al, 2004;Lautz et al, 2006;Wondzell, 2006] while creating features such as spring channels that express resulting surface water variation in diel temperature cycles. Therefore despite the fact that the low-flow main channel of the Umatilla River is largely unshaded (Figure 3), riparian vegetation is apt to influence temperature cycles in the main stem Umatilla River by creating geomorphic features that enhance hyporheic exchange and support dynamic temperature mosaics within stream reaches (Figure 6b).…”

Fine sediment deposition and interstitial flow effects on macroinvertebrate community composition within riffle heads and tails

“…However, flow paths are often complex and interstitial flow may vary as a function of river stage, especially high flow events (Käser et al, 2009;Dudley-Southern & Binley, 2015). Additionally, localised areas of upwelling and downwelling water may occur as a consequence of instream biogenic features such as coarse woody debris (CWD) or macrophyte stands (Piegay & Gurnell, 1997;White & Hendricks, 2000;Lautz et al, 2006). The resulting vertical exchange of water into and out of the riverbed is spatially and temporally dynamic, leading to a mosaic of patches which are characterised by differing porosity, permeability, connectivity and physicochemical conditions (Käser et al, 2014;Sebok et al, 2015).…”