Groundwater–surface-water interactions: perspectives on the development of the science over the last 20 years

Abstract

Freshwater Science published a special series of papers on groundwater-surface-water (GW-SW) interactions in this issue (2015), marking the anniversary of an earlier special series of papers on the hyporheic zone published in 1993. In this concluding paper, I compare the 2 special series of papers and use this comparison to examine the development of the science in the years between 1993 and 2015. The 1993 papers marked the beginning of a period of exponential growth in the study of, and publication of, papers on GW-SW interactions. The 1993 papers tended to be forward looking, proposing conceptual models of GW-SW interactions across stream networks and identifying critical gaps. The 2015 special series of papers contrasts sharply with that of 1993. Broad issue papers are mostly lacking from the current special series. Instead, the special series is dominated by papers focusing on process-based or descriptive studies using empirical approaches. This difference probably stems from major methodological advancements over the past 2 decades that make it possible to study GW-SW interactions with ever greater detail and, thus, allows more complete understanding of specific processes. In contrast, the authors of the 1993 special series were acutely aware of the paucity of GW-SW studies and, thus, posed their conceptual models as hypotheses. Surprisingly, these hypotheses have not been rigorously tested in the decades since their publication. Perhaps it is time to re-examine such broad conceptual models. There remains a critical need for a holistic understanding of how GW-SW interactions vary among streams types and sizes and with changes in discharge among seasons or over storm events and how these GW-SW interactions influence stream ecosystem processes.Hyporheic science has grown dramatically since the word was defined by Orghidan (1955; from the English translation by D. Käser 2010). Early hyporheic studies were relatively few and tended to focus primarily on the biota inhabiting the shallow stream bed. The signature characteristic of the hyporheic zone-as an ecotone where stream water and ground water met and mixed-slowly gained recognition in aquatic ecology, and in the mid-to late-1980s, several landmark papers refocused attention on the potential effects of the hyporheic zone on broader stream ecological processes. Grimm and Fisher (1984) published a seminal work showing that metabolism in hyporheic sediment was large enough that a stream previously thought to be autotrophic was actually heterotrophic. Stanford and Ward (1988) described the importance of hyporheic habitats to stream-dwelling macroinvertebrates at lateral distances of several kilometers from the stream, a spatial scale never previously imagined for below (hypo) stream (rheos) processes. Triska et al. (1989a, b) showed that the hyporheic zone played a critical role in the transport and retention of nutrients in streams. These papers are the most highly cited early publications on the hyporheic zone (Scopus citation search, May 2014; Scopus, Elsevie...

Groundwater–surface-water interactions: current research directions

“…These papers served several purposes: they presented testable conceptual models about ecological processes in hyporheic zones, they identified knowledge gaps that were impeding progress, and they advised researchers to focus on hyporheic hydrology to maximize progress. In the concluding paper of our 2015 series, Wondzell (2015) assessed the current state of GW-SW science (as represented by the papers in our special series) in terms of the concepts, gaps, and advice set out in the 1993 series. The 2 collections of papers are quite different.…”

“…Despite that, the "fact" that GW-SW interactions are important throughout stream networks is now widely accepted, and claims of this importance are rarely questioned. Wondzell (2015) concluded that a critical need still exists to develop a holistic understanding of how GW-SW interactions vary among streams types and sizes and with changes in discharge over seasons or during storm events. This knowledge would help us understand where, when, and how GW-SW interactions influence (or do not influence) the ecology of surface waters and ground waters.…”

“…One consequence of the rapid diversification of GW-SW science is high research productivity. The publication rate in this field has grown exponentially for at least a decade (Wondzell 2015). GW-SW studies are often held up as models of multidisciplinary science (Danielopol andGriebler 2008, Krause et al 2011).…”

Seepage Behavior of Earth Dams Considering Rainfall Effects

“…It has long been a topic of interest in hydrology because of its importance in understanding hydrologic processes, which play a crucial role in water resources management [16][17][18]. In recent years, it has increasingly been used as tracers to investigate groundwater-surface water interaction [19,20] and a separate base flow from storm runoff or annual stream flows [21]. Figure 1 shows the components of the measured seepage flow out of a rock-fill dam considering the rainfall [18].…”

Simulation of less‐mobile porosity dynamics in contrasting sediment water interface porous media

“…In a heterogeneous medium, connectivity of pores will vary spatially. Well-connected pores form mobile, advection-dominated flow domains, whereas poorly connected pores form less-mobile domains where exchange may be dominated by either molecular diffusion or relatively slow advection (Berkowitz, Cortis, Dentz, & Scher, 2006; Day-Lewis, Linde, Haggerty, Singha, & Briggs, 2017;Feehley, Zheng, & Molz, 2000;Wheaton & Singha, 2010;Wondzell, 2015). These coupled but functionally different porosity domains result in a spectrum of solute residence times in the hyporheic zone that may show power-law distribution in channel return flow (Aubeneau, Hanrahan, Bolster, & Tank, 2014;Cardenas, 2015;Cardenas, Cook, Jiang, & Traykovski, 2008;Gooseff, McKnight, Runkel, & Vaughn, 2003;Haggerty, Wondzell, & Johnson, 2002).…”