The Functional Significance of the Hyporheic Zone in Streams and Rivers

Abstract

The hyporheic zone is an active ecotone between the surface stream and groundwater. Exchanges of water, nutrients, and organic matter occur in response to variations in discharge and bed topography and porosity. Upwelling subsurface water supplies stream organisms with nutrients while downwelling stream water provides dissolved oxygen and organic matter to microbes and invertebrates in the hyporheic zone. Dynamic gradients exist at all scales and vary temporally. At the microscale, gradients in redox potential control chemical and microbially mediated nutrient transformations occurring on particle surfaces. At the stream-reach scale, hydrological exchange and water residence time are reflected in gradients in hyporheic faunal composition, uptake of dissolved organic carbon, and nitrification. The hyporheic corridor concept describes gradients at the catchment scale, extending to alluvial aquifers kilometers from the main channel. Across all scales, the functional significance of the hyporheic zone relates to its activity and connection with the surface stream.

Longitudinal and seasonal variation of stream N uptake in an urbanizing watershed: effect of organic matter, stream size, transient storage and debris dams

“…The TS values were moderately high (e.g., see Runkel 2002), but had a small range of variation, which could explain their small effect on uptake. Our results are consistent with Boulton et al (1998) who argue that hyporheic exchange is generally considered least important in headwater streams and tends to peak in intermediate streams.…”

Groundwater and Surface Water Interaction at the Regional-scale – A Review with Focus on Regional Integrated Models

“…Allen et al 2010;Banzhaf et al 2013;Boulton et al 1998;Krause et al 2009). Much less research has been carried out at the local or flood plain scale (Langhoff et al 2006, see also section 2.1.2).…”

Contrasting sediment and water chemistry indicates the extent of the hyporheic zone in a polluted river system.

“…Water bodies constitute a wide integrated hydrologic system and should not be treated separately in view of water environment management (Boulton et al 1998, Hancock et al 2005, Humphreys 2009). Moreover, analysis of aquatic ecosystems should be undertaken in terms of all spatial and temporal factors (Danielopol et al 2004).…”

“…Moreover, analysis of aquatic ecosystems should be undertaken in terms of all spatial and temporal factors (Danielopol et al 2004). Indeed, investigations over the last two decades have increased our awareness of the relation between hydrogeology and groundwater ecology (Mugnai et al 2015) and the interface between the surface and groundwater where the dynamic exchange of water takes place, defined as the hyporheic zone, has become central for stream ecologists and managers (Boulton et al 1998). …”