Spatiotemporal Responses of Groundwater Flow and Aquifer‐River Exchanges to Flood Events

Abstract

Rapidly rising river stages induced by flood events lead to considerable river water infiltration into aquifers and carry surface‐borne solutes into hyporheic zones which are widely recognized as an important place for the biogeochemical activity. Existing studies for surface‐groundwater exchanges induced by flood events usually limit to a river‐aquifer cross section that is perpendicular to river channels, and neglect groundwater flow in parallel with river channels. In this study, surface‐groundwater exchanges to a flood event are investigated with specific considerations of unconfined flow in direction that is in parallel with river channels. The groundwater flow is described by a two‐dimensional Boussinesq equation and the flood event is described by a diffusive‐type flood wave. Analytical solutions are derived and tested using the numerical solution. The results indicate that river water infiltrates into aquifers quickly during flood events, and mostly returns to the river within a short period of time after the flood event. However, the rest river water will stay in aquifers for a long period of time. The residual river water not only flows back to rivers but also flows to downstream aquifers. The one‐dimensional model of neglecting flow in the direction parallel with river channels will overestimate heads and discharge in upstream aquifers. The return flow induced by the flood event has a power law form with time and has a significant impact on the base flow recession at early times. The solution can match the observed hydraulic heads in riparian zone wells of Iowa during flood events.

Diagnostic Analysis of Bank Storage Effects on Sloping Floodplains

“…The results indicate that the linearized solution (20) is very close to the nonlinear solution during the simulated period except that it slightly underestimated the peak values of the hydraulic heads (Figure c). Although both linearization approaches served well, the solution (20) utilizing is closer to the nonlinear solution than that with (Figure c), which is consistent with the results of the previous studies (Guo, ; Liang et al, ; Liang & Zhang, ; Tolikas et al, ; Upadhyaya & Chauhan, ). The increased value of compared to the initial H 0 can be explained physically by the increase of saturated thickness of the aquifer in the stream bank vicinity.…”

“…Þ =2 is closer to the nonlinear solution than that with h ¼ H 0 (Figure 3c), which is consistent with the results of the previous studies (Guo, 1997;Liang et al, 2018;Liang & Zhang, 2012a;Tolikas et al, 1984;Upadhyaya & Chauhan, 1998). The increased value of h compared to the initial H 0 can be explained physically by the increase of saturated thickness of the aquifer in the stream bank vicinity.…”

Analysis of the Effects of Dam Release Properties and Ambient Groundwater Flow on Surface Water‐Groundwater Exchange Over a 100‐km‐Long Reach

“…Field and modeling studies at the transect scale typically study BSE processes at an individual 2-D transect oriented perpendicular to the channel (Chen & Chen, 2003;Doble et al, 2012;Koussis et al, 2007;Rorabaugh, 1963;Squillace, 1996). Few studies have looked at spatial and temporal BSE dynamics from a longitudinal perspective (Liang et al, 2018;Pinder & Sauer, 1971;Xie et al, 2016). Each of these studies evaluated the effect that a flood wave moving down a river corridor has on the spatiotemporal BSE.…”

Natural Stimuli Calibration with Fining Direction Regularization in an Integrated Hydrologic Model

“…While several numerical modeling studies have been applied to specifically investigate surface water‐groundwater interaction during flood events (Whiting and Pomeranets ; Chen et al ; Doble et al ; Doble et al ; Xie et al ; Liang et al ) these studies have not used the observed groundwater response to a flood event to perform a high resolution calibration of the subsurface hydrostratigraphy. Specifically, in this study we incorporate fining direction regularization (e.g., fining upwards/downwards) in a highly parameterized inversion driven by naturally occurring flood events.…”

“…For example, Batlle-Aguilar et al (2015) used HGS to simulate the infiltration of surface water from a disconnected stream to groundwater for a river transect in South Australia; Alaghmand et al (2016) used HGS to investigate the potential use of artificial flooding as a short-term saline groundwater management technique along floodplains in arid and semi-arid environments; Xie et al (2016) of saline groundwater with surface water during stream events within an idealized river reach; and Schilling et al (2017) used HGS to investigate the impact of river bed clogging on surface water-groundwater interaction and the redistribution of water beneath disconnected streams. While several numerical modeling studies have been applied to specifically investigate surface watergroundwater interaction during flood events (Whiting and Pomeranets 1997;Chen et al 2006;Doble et al 2012a;Doble et al 2012b;Xie et al 2016;Liang et al 2018) these studies have not used the observed groundwater response to a flood event to perform a high resolution calibration of the subsurface hydrostratigraphy. Specifically, in this study we incorporate fining direction regularization (e.g., fining upwards/downwards) in a highly parameterized inversion driven by naturally occurring flood events.…”