Groundwater flow and mixing in a wetland–stream system: Field study and numerical modeling

Karan, Sachin; Engesgaard, Peter; Looms, Majken C.; Laier, Troels; Kaźmierczak, Jolanta

doi:10.1016/j.jhydrol.2013.02.030

Cited by 34 publications

(45 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8) are similar to the findings of Gonzales et al (2009) for a lowland stream, and could indicate the occurrence of a component which is not accounted for by either of the two hydrograph separation methods (Wels et al, 1991;Hooper and Shoemaker, 1986). According to Karan et al (2013), a shallow relatively young groundwater component was discharging to the stream at station 4, supporting the idea that the stream-flow components could be divided into a deep groundwater component discharging right beneath the stream channel, a shallow component and a surface/event water component. However, there was no distinct difference between the average EC and δ 2 H of the shallow soil/groundwater and the deep groundwater.…”

Section: Temporal Dynamics and Catchment-scale Differences In Runoff supporting

confidence: 70%

“…As previous studies (Jensen and Engesgaard, 2011;Karan et al, 2013) in the same area only detected moderate seasonal changes in streambed temperatures, the steady-state conditions were assumed to be valid for the study period in June. For each VTP, T s was given as the temperature measured by the uppermost sensor, and the constant groundwater temperature of 8 • C (T g ) was assumed at a depth of 5 m (L).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream: combining hydraulic and tracer methods

Poulsen

Sebok

Duque

et al. 2015

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. Detecting, quantifying and understanding groundwater discharge to streams are crucial for the assessment of water, nutrient and contaminant exchange at the groundwater-surface water interface. In lowland agricultural catchments with significant groundwater discharge this is of particular importance because of the risk of excess leaching of nutrients to streams. Here we aim to combine hydraulic and tracer methods from point-to-catchment scale to assess the temporal and spatial variability of groundwater discharge in a lowland, groundwater gaining stream in Denmark. At the point-scale, groundwater fluxes to the stream were quantified based on vertical streambed temperature profiles (VTPs). At the reach scale (0.15-2 km), the spatial distribution of zones of focused groundwater discharge was investigated by the use of distributed temperature sensing (DTS). Groundwater discharge to the stream was quantified using differential gauging with an acoustic Doppler current profiler (ADCP). At the catchment scale (26-114 km 2 ), runoff sources during main rain events were investigated by hydrograph separations based on electrical conductivity (EC) and stable isotopes 2 H/ 1 H. Clear differences in runoff sources between catchments were detected, ranging from approximately 65 % event water for the most responsive sub-catchment to less than 10 % event water for the least responsive sub-catchment. This was supported by the groundwater head gradients, where the location of weaker gradients correlated with a stronger response to precipitation events. This shows a large variability in groundwater discharge to the stream, despite the similar lowland characteristics of sub-catchments indicating the usefulness of environmental tracers for obtaining information about integrated catchment functioning during precipitation events. There were also clear spatial patterns of focused groundwater discharge detected by the DTS and ADCP measurements at the reach scale indicating high spatial variability, where a significant part of groundwater discharge was concentrated in few zones indicating the possibility of concentrated nutrient or pollutant transport zones from nearby agricultural fields. VTP measurements confirmed high groundwater fluxes in discharge areas indicated by DTS and ADCP, and this coupling of ADCP, DTS and VTP proposes a novel field methodology to detect areas of concentrated groundwater discharge with higher resolution.

show abstract

Section: Temporal Dynamics and Catchment-scale Differences In Runoff supporting

confidence: 70%

Section: Methodsmentioning

confidence: 99%

Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream: combining hydraulic and tracer methods

Poulsen

Sebok

Duque

et al. 2015

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…The range in daily mean temperatures in the lower data logger at the four other loggers is more damped. Further, the inter‐quartile range in daily mean temperatures of these lower loggers is clustered closer to 8 °C equivalent to mean surface‐near groundwater temperature in Denmark and within the study catchment (Jensen & Engesgaard, ; Karan et al, ; Kidmose et al, ). In contrast, daily mean temperatures at the lower data loggers at the remaining sites show greater variation and thus a larger inter‐quartile range closer to that of their corresponding upper data logger.…”

Section: Resultsmentioning

confidence: 87%

Air/water/sediment temperature contrasts in small streams to identify groundwater seepage locations

2017

Self Cite

View full text Add to dashboard Cite

The need to identify groundwater seepage locations is of great importance for managing both stream water quality and groundwater sourced ecosystems due to their dependency on groundwater‐borne nutrients and temperatures. Although several reconnaissance methods using temperature as tracer exist, these are subjected to limitations related to mainly the spatial and temporal resolution and/or mixing of groundwater and surface water leading to dilution of the temperature differences. Further, some methods, for example, thermal imagery and fiber optic distributed temperature sensing, although relative efficient in detecting temperature differences over larger distances, these are labor‐intensive and costly. Therefore, there is a need for additional cost‐effective methods identifying substantial groundwater seepage locations. We present a method expanding the linear regression of air and stream temperatures by measuring the temperatures in dual‐depth; in the stream column and at the streambed‐water interface (SWI). By doing so, we apply metrics from linear regression analysis of temperatures between air/stream and air/SWI (linear regression slope, intercept, and coefficient of determination), and the daily water temperature cycle (daily mean temperatures, temperature variance, and the mean diel temperature fluctuation). We show that using metrics from only single‐depth stream temperature measurements are insufficient to identify substantial groundwater seepage locations in a head‐water stream. Conversely, comparing the metrics from dual‐depth temperatures show significant differences; at groundwater seepage locations, temperatures at the SWI merely explain 43–75% of the variation opposed to ⩾ 91% at the corresponding stream column temperatures. In general, at these locations at the SWI, the slopes ( < 0.25) and intercepts ( > 6.5 °C) are substantially lower and higher, respectively, while the mean diel temperature fluctuations ( < 0.98 °C) are decreased compared to remaining locations. The dual‐depth approach was applied in a post‐glacial fluvial setting, where metrics analyses overall corroborated with field measurements of groundwater fluxes and stream flow accretions. Thus, we propose a method reliably identifying groundwater seepage locations along streambeds in such settings.

show abstract

“…Because the location of the measurements is close to the shore, density was assumed to be dominated by discharging fresh groundwater. Groundwater temperature was expected to oscillate between 8 °C and 11.5 °C based on the thermal stability of groundwater reported in previous studies (Arriaga and Leap, ) as well as in Denmark (Karan et al ., ). The difference in deeper groundwater temperature between October and May–August was attributed to the heating of the system at the end of the summer season.…”

Section: Methodsmentioning

confidence: 99%

Estimating groundwater discharge to surface waters using heat as a tracer in low flux environments: the role of thermal conductivity

Duque

Müller

Sebok

et al. 2015

Hydrological Processes

Self Cite

View full text Add to dashboard Cite

Abstract:Analytical modelling of heat transport was used to address effects of uncertainty in thermal conductivity on groundwater-surface water exchange. In situ thermal conductivities and temperature profiles were measured in a coastal lagoon bed where groundwater is known to discharge. The field site could be divided into three sediment zones where significant spatial changes in thermal conductivity on metre to centimetre scale show that spatial variability connected to the sediment properties must be considered. The application of a literature-based bulk thermal conductivity of 1.84 Wm À1°CÀ1 , instead of field data that ranged from 0.62 to 2.19 W m À1°CÀ1, produced a mean overestimation of 2.33 cm dÀ1 that, considering the low fluxes of the study area, represents an 89% increase and up to a factor of 3 in the most extreme cases. Incorporating the uncertainty due to sediment heterogeneities leads to an irregular trend of the flux distribution from the shore towards the lagoon. The natural variability of the thermal conductivity associated with changes in the sediment composition resulted in a mean variation of ±0.66 cm d À1 in fluxes corresponding to a change of ±25.4%. The presence of organic matter in the sediments, a common situation in the near-shore areas of surface water bodies, is responsible for the decrease of thermal conductivity. The results show that the natural variability of sediment thermal conductivity is a parameter to be considered for low flux environments, and it contributes to a better understanding of groundwater-surface water interactions in natural environments

show abstract

Groundwater flow and mixing in a wetland–stream system: Field study and numerical modeling

Cited by 34 publications

References 29 publications

Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream: combining hydraulic and tracer methods

Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream: combining hydraulic and tracer methods

Air/water/sediment temperature contrasts in small streams to identify groundwater seepage locations

Estimating groundwater discharge to surface waters using heat as a tracer in low flux environments: the role of thermal conductivity

Contact Info

Product

Resources

About