A review of methods for measuring groundwater–surface water exchange in braided rivers

Abstract

Abstract. Braided rivers, while uncommon internationally, are significant in terms of their unique ecosystems and as vital freshwater resources at locations where they occur. With an increasing awareness of the connected nature of surface water and groundwater, there have been many studies examining groundwater–surface water exchange in various types of waterbodies, but significantly less research has been conducted in braided rivers. Thus, there is currently limited understanding of how characteristics unique to braided rivers, such as channel shifting; expanding and narrowing margins; and a high degree of heterogeneity affect groundwater–surface water flow paths. This article provides an overview of characteristics specific to braided rivers, including a map showing the regions where braided rivers are concentrated at the global scale: Alaska, Canada, the Japanese and European Alps, the Himalayas and New Zealand. To the authors' knowledge, this is the first map of its kind. This is followed by a review of prior studies that have investigated groundwater-surface water interactions in braided rivers and their associated aquifers. The various methods used to characterise these processes are discussed with emphasis on their effectiveness in achieving the studies' objectives and their applicability in braided rivers. The aim is to provide guidance on methodologies most suitable for future work in braided rivers. In many cases, previous studies found a multi-method approach useful to produce more robust results and compare data collected at various scales. Ultimately, the most appropriate method(s) for a given study will be based on several factors, including the scale of interactions that need to be observed; site-specific characteristics; budget; and time available. Given these considerations, we conclude that it is best to begin braided river studies with broad-scale methods such as airborne thermal imaging, differential flow gauging or tracer analysis and then focus the investigation using finer scale techniques such as groundwater well observations or temperature sensors. Given the challenges of working directly in braided rivers, there is considerable scope for the increased use of remote sensing techniques and geophysics. There is also opportunity for new approaches to modelling braided rivers using integrated techniques that incorporate the often-complex river bed terrain and geomorphology of braided rivers explicitly. We also identify a critical need to improve understanding of the role of hyporheic exchange in braided rivers; rates of recharge to/from braided rivers; and historical patterns of dry and low-flow periods in these rivers.

A Review on the Research Advances in Groundwater–Surface Water Interaction with an Overview of the Phenomenon

“…Many researchers have based their studies on the outcomes of this method, which has been used to understand the interactions in various sites worldwide. Most of the studies used piezometers [4,99,100] and mini-piezometers [101,102] to obtain hydraulic gradients, and by quantifying the hydraulic gradient, they understood the nature and direction of flow. Hence, it can be thought of as an easy process to be executed by installing piezometers at the stream bed and obtaining their levels at different times to conclude the phenomenon.…”

“…Thomas [118] established a relation between the TDS and DO with temperature along the river profile using a multimeter. Coluccio [102] used a tool named VFLUX to analyze the temperature signals and understand the phenomenon taking place through the streambed. However, it was difficult to quantify the groundwater and hyporheic flow through this method precisely, so he used Darcy's and hydrochemistry in conjunction.…”

A Comparison of Tools and Methods for Estimating Groundwater‐Surface Water Exchange

“…Another GWSWI characterization technology, which has gained much attention over the past decade, is temperature profiling in the streambed (to delineate and quantify exchange rates) (Bredehoeft and Papadopulos ; Krause et al ; Irvine et al ; Coluccio ). Temperature‐based methods are advantageous because they offer a fast and efficient way to delineate and estimate water flux, as with the temperature spear tool (Schmidt et al ; Schmidt et al ; Lautz ; Bhaskar et al ; Irvine et al ; Irvine et al ).…”

Quantitative analysis of the driving factors for groundwater resource changes in arid irrigated areas

“…From the perspective of integrated hydrological systems, additional research has focused on groundwater modelling and the study of groundwater hydrological processes (Chao et al, 2019). Because complex water issues require water issues to be balanced with environmental issues, it is increasingly important to consider the interaction between surface water and groundwater (Coluccio & Morgan, 2019; Ferencz, Cardenas, & Neilson, 2020). Compared with other hydrological models, such as MODELFLOW and FEFLOW, MIKE‐SHE is superior in its ability to simulate the water balance, watershed hydrological processes, groundwater recharge dynamics, groundwater surface water, and unsaturated zones.…”