scispace - formally typeset
Search or ask a question
Journal ArticleDOI

A Tracer-Based Method for Classifying Groundwater Dependence in Boreal Headwater Streams

01 Oct 2019-Journal of Hydrology (Elsevier)-Vol. 577, pp 123762
TL;DR: In this paper, a classification method for the groundwater dependence of headwater streams was devised based on the fact that GW affects discharge, thermal regime, and water quality, which can serve as a water management tool, especially for streams of exceptional ecological importance or in places where anthropogenic activities are expected to change local hydrology and ecology.
About: This article is published in Journal of Hydrology.The article was published on 2019-10-01 and is currently open access. It has received 11 citations till now. The article focuses on the topics: STREAMS & Groundwater.

Summary (4 min read)

1 Introduction

  • The authors combined continuous measurements of discharge, temperature (T), and electrical conductivity (EC) with use of stable water isotopes and other environmental tracers to study the GW-SW transition zones in three boreal streams known to have high proportions of GW from esker aquifers.
  • The authors expected to find a transition zone within which a spring-originated stream turns into a SW-dominated system.
  • By definition, SW is the water in surface storage units (e.g., lakes, streams, rivers, wetlands) and GW is the water underground.
  • This work addresses the following research questions: i).

2 Materials and methods 2.1 Study sites

  • The three streams selected for the study are located in Rokua and Viinivaara esker aquifer areas and are 60 km from each other.
  • The study sites belong to a mid-boreal coniferous forest belt.
  • In the Rokua esker area, the authors selected two streams, Siirasoja and Lohioja, where surrounding peatlands are intensively drained for forestry.
  • The average channel widths and average maximum depths along the streams studied are presented in the Supporting Information Table S1 .

2.1.1 Siirasoja and Lohioja streams in Rokua esker aquifer

  • The aquifer itself is unconfined, but the heavily drained peatlands in the surroundings partly confine the GW [Rossi et al., 2012] .
  • The catchments are located next to each other and the land use consists mainly of peatland forestry and some agricultural land (Table 1 ).
  • Some of the ditches in Siirasoja catchment have no flow and some fully penetrate the peat layer and reach the mineral soil beneath, causing increased GW discharge to the stream.
  • GW discharge has been found to be either diffuse seepage or point type, and is induced by high pressure underneath the peat layer (Rossi et al. 2012) .

2.1.2 Mesioja stream in Viinivaara esker aquifer

  • The authors study stream, Mesioja, discharges from a spring located at the break of slope where the sandy aquifer meets the peat formation and flows partly underground between measurement locations M2 and M3 (Table 1 ).
  • The lower catchment area is mostly pristine peatland with bog-type vegetation.
  • The GW dependence of the peatland area varies widely; spatial isotope studies by Isokangas et al. (2017) showed that the stable isotopic composition of the peatland pore water is not uniform near Mesioja stream, with δ 18 O values ranging between approximately -8‰ and -13‰ at 10 cm depth during the period 4-11 August 2014.

2.2 Field measurements

  • Stable isotopic composition of water samples was analyzed using cavity ring-down spectroscopy with a Picarro L2120-i analyzer and the isotope ratios were expressed in δ notation relative to Vienna Standard Mean Ocean Water , with precision for δ 18 O and δ 2 H values of ±0.1‰ and ±1.0‰, respectively.
  • Nutrients, alkalinity, and geochemical parameters were analyzed using Finnish national standards in an accredited (SFS-EN ISO/IEC 17025:2005) laboratory at the Finnish Environment Institute (SYKE) [National Board of Waters, 1981] .

2.2.1 Local groundwater and surface water quality

  • The measurement locations are presented in the map in Supporting Information Fig. S1 .
  • The nearest SW sampling locations of SYKE are situated 27 km (Nuorittajoki suu station) and 9 km (Nuorittajoki Töntönkoski station) from Mesioja catchment.
  • Most of the parameters were analyzed using samples from Töntönkoski station and, although the measurements were performed before their stream sampling campaign, the data were assumed to be representative for the study period because there had not been any major changes in land use in the area.
  • The SW sampling location of Nuorittajoki suu station is located rather far from their study stream but, as the land use is relatively similar to that in Mesioja catchment (Supporting Information Fig. S1 ), the data were assumed to be representative for the study area.
  • In Rokua, the measurements by SYKE were also used as a reference for SW.

2.3 Data analysis

  • To reduce the dimensionality of the dataset while retaining as much of its variation as possible, the authors performed principal component analysis (PCA) for the stream data (chemical and physical water quality parameters and discharge).
  • It is preferred over the princomp function because of its better numerical accuracy [Anderson, 2013] .
  • The authors also scaled and centered the data using the prcomp function.
  • The authors performed the analysis for two datasets; the average values of all measurements for each site and the average values for the low-flow situation (July measurements).
  • As each stream had almost the same number of sampling locations, they had similar weighting in the analysis and PCA was deemed suitable for use, although the autocorrelation between samples was borne in mind when analyzing the results.

2.3.1 The stream tracer index method

  • 𝑛 where x variable is the classification value based on the chosen water quality variable.
  • The classification values are determined by evaluating whether the tracer in question indicates a clear GW signal (x=1), a mixture of GW and SW (transition zone, x=0.5), or a clear surface water signal (x=0).
  • After the appropriate values are chosen, the stream tracer index values can be calculated using equations ( 1) and ( 2).

3.1 Stream discharge and its origin

  • Based on the stable water isotope dataset, the water origin in all three streams was mainly GW (Fig. 6 and Supporting Information Fig. S2 ).
  • In Siirasoja and Lohioja streams at Rokua, the isotopic composition remained relatively stable except during the rain events in November 2014 (Fig. 3 ), when the isotopically more enriched SW increased the delta values of the streams.
  • In Mesioja, the water isotope responses were more complex than in Lohioja and Siirasoja.
  • At upstream locations, the isotopic composition resembled GW, but further downstream the delta values increased, indicating larger contributions from enriched surface runoff and soil water.
  • At the furthest downstream locations, the delta values were again more negative, indicating GW discharge into the stream also at downstream locations (Fig. S2 ).

3.2 Spatial and temporal variations in stream water temperature

  • During summer, water temperature generally increased from headwater to downstream in all streams (June-September, mean air T at Pudasjärvi airport 14.0 ºC and at Vaala-Pelso station 13.3 °C).
  • The streams generally had different diurnal variations (Fig. 4 ).
  • The coefficient of variation for temperature was smallest for headwater locations in both warm (June-September) and cold (April, May, October, November) seasons.
  • This shows that GW sustains stable thermal regimes in both warm and cold seasons.
  • In Lohioja and Siirasoja streams, water temperatures at different measurement points were more similar than in Mesioja.

3.3 Spatial and temporal variations in stream chemical properties

  • In Lohioja, Clconcentrations indicated that the first measurement location (L1) had a clear GW signal and the other locations were in the GW-SW transition zone.
  • In Siirasoja, the first three locations had Clconcentrations near to the GW reference value, the next two belonged to the GW-SW transition zone, and the last measurement location had a clear SW signal.
  • In the Rokua area the reference values showed a clear distinction from each other.
  • For all measurements, 75% of the variation in the data was explained by the first two principal components (PCs), while for low-flow measurements these two PCs explained 79% of the variation.
  • Thus, generally low PC1 loadings indicated high GW influence.

3.4 Groundwater and surface water dominance of streams

  • The authors results show that boreal headwater streams can be highly GW-dependent.
  • Changes in GW discharge would particularly affect the position and length of the GW-SW transition zone in the stream continuum and could thus alter stream ecosystems.
  • As GW supports stream flow, especially at upstream measurement locations, their study streams would most probably dry out without GW input at least occasionally.
  • Earlier snowmelt due to climate change may also lower GW levels in the region during summer months, exacerbating the impacts of drought [Okkonen et al., 2010; Okkonen and Kløve, 2011] .

4.2 Thermal properties change radically in the stream continuum

  • The authors results showed that GW plays a major role in the thermal sensitivity of the streams studied, such that GW-dependent areas were less sensitive to changes in air temperature, although still responded to it.
  • The water temperature at these locations still showed diurnal variations and during exceptionally warm days the water temperature increased.
  • Fortunately, these events were relatively short (some days) and the highest temperatures were only short-term mid-day events (e.g., on 1 July 2013, T in Siirasoja stream, location S3, increased to 10 °C for 45 minutes).
  • Jyväsjärvi et al. (2015) showed that even a 1 °C increase in mean water temperature of springs can affect the species present in water and alter bryophyte and macroinvertebrate communities in streams discharging from springs.
  • In addition, salmonid fish in particular have been found to be extremely sensitive to the current warming trend and thermal refuges are becoming even more important for preserving their populations [Isaak et al., 2015] .

4.3 The applicability of local groundwater and surface water reference values

  • Moreover, GW quality reflects the local geology.
  • The piezometers were sampled quarterly during 2010-2012.
  • This suggests that SiO 2 and Clare more reliable tracers in this area.
  • In addition, temporal variations in GW and SW quality were detected in both the Rokua and Viinivaara areas.
  • The average coefficient of variation for the GW reference variables used (excluding PO 4 3--P) was 7.5% and that for the SW reference variables was 17.4%.

4.4 Surface water input causes changes in water quality in the stream continuum

  • A disadvantage is that expert knowledge is needed to choose appropriate tracers for a selected area and the classification values for those tracers.
  • The method resembles other management tools, such as 42 analytic hierarchy process [Subramanian and Ramanathan, 2012] , so in that regard it should be rather easy to adopt in decision making.
  • Furthermore, the stream tracer index method could be especially helpful in the intense monitoring programs required in areas of exceptional ecological importance [Bertrand et al., 2014] .
  • The method could also be applied in places where anthropogenic actions are expected to change the local hydrology and affect stream ecosystems.
  • In addition, available historical data could be applied in some cases if there have not been any major changes in the catchment area.

5 Conclusions

  • It is important to classify boreal headwater streams, owing to their ability to act as refuges, supporting stable conditions vital for specific aquatic biota in a changing climate.
  • The results of this study suggest that it might be sufficient to sample stream sections only once, during summer low-flow conditions, when evaluating the groundwater dependence of streams.
  • The stream tracer index method could serve as a useful management tool, especially at sites of exceptional ecological importance or at sites where anthropogenic measures are expected to change the local hydrology.

Did you find this useful? Give us your feedback

Citations
More filters
01 Jan 2017
TL;DR: The characteristics of groundwater systems and groundwater contamination in Finland, Norway and Iceland are presented, as they relate to outbreaks of disease as mentioned in this paper, and recommendations are given for the future, as well as differences among the Nordic countries in the approach to providing safe drinking water from groundwater.
Abstract: The characteristics of groundwater systems and groundwater contamination in Finland, Norway and Iceland are presented, as they relate to outbreaks of disease. Disparities among the Nordic countries in the approach to providing safe drinking water from groundwater are discussed, and recommendations are given for the future. Groundwater recharge is typically high in autumn or winter months or after snowmelt in the coldest regions. Most inland aquifers are unconfined and therefore vulnerable to pollution, but they are often without much anthropogenic influence and the water quality is good. In coastal zones, previously emplaced marine sediments may confine and protect aquifers to some extent. However, the water quality in these aquifers is highly variable, as the coastal regions are also most influenced by agriculture, sea-water intrusion and urban settlements resulting in challenging conditions for water abstraction and supply. Groundwater is typically extracted from Quaternary deposits for small and medium municipalities, from bedrock for single households, and from surface water for the largest cities, except for Iceland, which relies almost entirely on groundwater for public supply. Managed aquifer recharge, with or without prior water treatment, is widely used in Finland to extend present groundwater resources. Especially at small utilities, groundwater is often supplied without treatment. Despite generally good water quality, microbial contamination has occurred, principally by norovirus and Campylobacter, with larger outbreaks resulting from sewage contamination, cross-connections into drinking water supplies, heavy rainfall events, and ingress of polluted surface water to groundwater.

13 citations

Journal ArticleDOI
TL;DR: In this article, the authors acknowledge financial support from the UK Natural Environment Research Council (project NE/P010334/1) via a CASE industrial studentship with Chivas Brothers, and thank Audrey Innes, Dr Bernhard Scheliga, and Dr Ilse Kamerling for their support with the laboratory isotope analysis.
Abstract: Funding Information: We would like to acknowledge financial support from the UK Natural Environment Research Council (project NE/P010334/1) via a CASE industrial studentship with Chivas Brothers. David Drummond, Katya Dimitrova-Petrova and Eva Loerke are thanked for assistance with fieldwork, while we acknowledge Dr Aaron Neill for his advice on young water fraction analyses. Trevor Buckley and staff at the Glenlivet Distillery are thanked for on-site assistance and supply of data and abstraction records. We thank Audrey Innes, Dr Bernhard Scheliga, and Dr Ilse Kamerling for their support with the laboratory isotope analysis. Publisher Copyright: © 2020 The Authors. Hydrological Processes published by John Wiley & Sons Ltd. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

9 citations


Cites background from "A Tracer-Based Method for Classifyi..."

  • ...…abstraction legislation under climate change projections, there is a need to understand (a) the relative role of different water sources (Isokangas et al., 2019), both in terms of water quantity and quality (specifically, temperature) (b) the resilience of these sources under different…...

    [...]

  • ...…to air temperatures, suggest that the narrow, short, north facing stream was relatively sheltered from radiation inputs (Dick, Tetzlaff, & Soulsby, 2015; Isokangas et al., 2019; MacDonald, Boon, Byrne, Robinson, & Rasmussen, 2014) allowing the imprint of groundwater temperatures to be maintained....

    [...]

  • ...This ensured that, although EMMA is approximate, ‘end-members’ of source types delimited the range of values so that themixing space of different source contributions to S3 could be understood (Abbott et al., 2016; Isokangas et al., 2019)....

    [...]

  • ...…has been shown in many tracer-based studies in Scotland (Blumstock et al., 2016; Geris et al., 2015; Scheliga et al., 2018; Soulsby et al., 1998), and elsewhere (Botter, Bertuzzo, & Rinaldo, 2011; Isokangas et al., 2019; Rinaldo et al., 2011; Tetzlaff et al., 2018; Zuecco, Penna, & Borga, 2018)....

    [...]

Journal ArticleDOI

9 citations


Cites background from "A Tracer-Based Method for Classifyi..."

  • ...Such regions of GW seepage near streams can create biogeochemically distinct environments (Isokangas et al., 2019; Lupon et al., 2019) that act as hotspots for microbial activity and the carbon source to streams....

    [...]

  • ...Such regions of GW seepage near streams can create biogeochemically distinct environments (Isokangas et al., 2019; Lupon et al., 2019) that act...

    [...]

Journal ArticleDOI
TL;DR: In this article , Runoff Attenuation Features (RAFs) are used to intercept and attenuate flow pathways during wet periods, increasing infiltration opportunity and thus water availability for use later.
Abstract: Water resources management during drought is a significant challenge worldwide, particularly for upland areas. Additionally, variations in water availability are becoming more extreme with climate change. Nature Based Solutions (NBS) e.g. Runoff Attenuation Features (RAFs) could provide an alternative to hard-engineering. Using more natural processes, flow pathways are intercepted and attenuated in features during wet periods, increasing infiltration opportunity and thus water availability for use later. NBS research has primarily focused on flood mitigation, but little is known about low flow impacts; knowledge is required on where and at what scale to implement NBS. To explore these questions, we used a physically-based catchment model (MIKE SHE) integrated with a hydraulic river model (MIKE 11) to evaluate scenarios with varying RAF volumes and locations. We applied this to an intensively monitored upland Scottish catchment (0.9 km2) where 40 RAFs (∼2m3 storage each) were installed for low flow enhancement. Model results showed installed RAFs increase recharge (∼0.1%), groundwater contribution to streamflow (∼4%) and low flows (∼1%) and reduce high (∼5%) and mean flows (∼2%), suggesting RAFs could be used to mitigate extreme flows. The scenarios revealed that RAF location (primarily soil type) and scale (total storage volume and spread of features) were both important. Doubling installed RAF volumes increased impact on low flows by ∼25% and high flows by ∼40%, although lower additional benefits were predicted with further storage increases. RAFs had greater impact in freely-draining soils than poorly-draining, however distributing the same storage volume across many smaller RAFs over greater areas (both soil types) provided the largest effect. Absolute changes observed were relatively small, and given model uncertainty, should be treated with caution. Nevertheless, the direction of change was clear and given ecological systems and water supply rely on small margins of change, even slight increases in low flows will likely be beneficial.

3 citations

Journal ArticleDOI
Abstract: Water flows in peatland margins is an under-researched topic. This study examines recharge from a peatland to an esker aquifer in an aapa mire complex of northern Finland. Our objective was to study how the aapa mire margin is hydrogeologically connected to the riverside aquifer and spatial and temporal variations in the recharge of peatland water to groundwater (GW). Following geophysical studies and monitoring of the saturated zone, a GWmodel (MODFLOW) was used in combination with stable isotopes to quantify GW flow volumes and directions. Peatland water recharge to the sandy aquifer indicated a strong connection at the peatland–aquifer boundary. Recharge volumes from peatland to esker were high and rather constant (873 m d ) and dominated esker recharge at the study site. The peat water recharging the esker boundary was rich in dissolved organic carbon (DOC). Stable isotope studies on water (δO, δH, and d-excess) from GW wells verified the recharge of DOC-rich water from peatlands to mineral soil esker. Biogeochemical analysis revealed changes from DOC to dissolved inorganic carbon in the flow pathway from peatland margin to the river Kitinen. This study highlights the importance of careful investigation of aapa mire margin areas and their potential role in regional GW recharge patterns.

2 citations

References
More filters
Journal ArticleDOI
TL;DR: In this article, a FLIR SC660 thermal infrared imaging camera (640 × 480 pixels, NETD 2 ǫ= 0.94, p 2 Ã 0.90, p 0.

113 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a tiered assessment of changing river water temperature covering England and Wales with data from 2773 locations, using novel statistical approaches to detect trends in irregularly sampled spot measurements taken between 1990 and 2006.
Abstract: Changes in water temperature can have important consequences for aquatic ecosystems, with some species being sensitive even to small shifts in temperature during some or all of their life cycle. While many studies report increasing regional and global air temperatures, evidence of changes in river water temperature has, thus far, been site specific and often from sites heavily influenced by human activities that themselves could lead to warming. Here we present a tiered assessment of changing river water temperature covering England and Wales with data from 2773 locations. We use novel statistical approaches to detect trends in irregularly sampled spot measurements taken between 1990 and 2006. During this 17-year period, on average, mean water temperature increased by 0.03 °C per year (±0.002 °C), and positive changes in water temperature were observed at 2385 (86%) sites. Examination of catchments where there has been limited human influence on hydrological response shows that changes in river flow have had little influence on these water temperature trends. In the absence of other systematic influences on water temperature, it is inferred that anthropogenically driven climate change is driving some of this trend in water temperature. © 2014 The Authors. Hydrological Processes published by John Wiley & Sons Ltd.

112 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined stream water chemistry from a series of eight nested catchments in a 1.47 km2 temperate forest watershed in southern Quebec for evidence of contributing end-members.
Abstract: [1] Current interest in multicatchment hydrologic studies challenges the use of geochemical mixing models across scale, where changes in stream water chemistry from catchment to catchment may indicate (1) changes in the proportional contributions of end-members, (2) changes in the geochemical signatures of end-members in space, or (3) changes in the geochemical signatures of end-members in time. In this study we examine stream water chemistry from a series of eight nested catchments in a 1.47 km2 temperate forest watershed in southern Quebec for evidence of contributing end-members. We use eigenvector and residual analysis (Hooper, 2003) of the multivariate stream water chemistry records to estimate the dimensionality of the mixing space for each individual catchment, indicating the number of contributing end-members. Using the mixing space of the largest, highest-order catchment (1.47 km2), we evaluate its ability to predict stream water chemistry in the seven upstream catchments, representing progressively smaller areas. We observe significant spatial variation in ionic mixing ratios within the 147 ha watershed. Only spatial testing across catchments allowed us to identify appropriate conservative tracers most compatible with the application of a single mixing model across scale. On the seasonal timescale, groundwater geochemistry changes significantly due to the recharge from spring snowmelt, indicating a mixture of two groundwater end-members of varying age. On the timescale of storm events, shallow perched water and throughfall provide geochemical signatures consistent with physical mixing while unsaturated zone soil water sampled from local pockets of glacial till does not. Our results suggest cautious application of end-member mixing analysis (EMMA) for multicatchment studies.

110 citations

Journal ArticleDOI
TL;DR: In this paper, an ecohydrological classification system for groundwater dependent ecosystems (GDEs) is proposed and applied to Central and Western-Central Europe, as a basis for modeling approaches for GDEs and as a tool for groundwater and landscape management.
Abstract: Aquifers provide water, nutrients and energy with various patterns for many aquatic and terrestrial ecosystems. Groundwater-dependent ecosystems (GDEs) are increasingly recognized for their ecological and socio-economic values. The current knowledge of the processes governing the ecohydrological functioning of inland GDEs is reviewed, in order to assess the key drivers constraining their viability. These processes occur both at the watershed and emergence scale. Recharge patterns, geomorphology, internal geometry and geochemistry of aquifers control water availability and nutritive status of groundwater. The interface structure between the groundwater system and the biocenoses may modify the groundwater features by physicochemical or biological processes, for which biocenoses need to adapt. Four major types of aquifer-GDE interface have been described: springs, surface waters, peatlands and terrestrial ecosystems. The ecological roles of groundwater are conditioned by morphological characteristics for spring GDEs, by the hyporheic zone structure for surface waters, by the organic soil structure and volume for peatland GDEs, and by water-table fluctuation and surface floods in terrestrial GDEs. Based on these considerations, an ecohydrological classification system for GDEs is proposed and applied to Central and Western-Central Europe, as a basis for modeling approaches for GDEs and as a tool for groundwater and landscape management.

98 citations

Journal ArticleDOI
TL;DR: In this paper, the spatial and temporal variation in water composition in a headwater catchment (41 ha) at the Hubbard Brook Experimental Forest, NH, USA was documented by sampling every 50m along an ephemeral to perennial stream network as well as groundwater from seeps and 35 shallow wells across varying flow conditions.
Abstract: Although temporal variation in headwater stream chemistry has long been used to document baseline conditions and response to environmental drivers, less attention is paid to fine scale spatial variations that could yield clues to processes controlling stream water sources. We documented spatial and temporal variation in water composition in a headwater catchment (41 ha) at the Hubbard Brook Experimental Forest, NH, USA. We sampled every 50m along an ephemeral to perennial stream network as well as groundwater from seeps and 35 shallow wells across varying flow conditions. Groundwater influences on surface water in this region have not been considered to be important in past studies as relatively coarse soils were assumed to be well drained in steep catchments with flashy runoff response. However, seeps displayed perennial discharge, upslope accumulated areas (UAA) smaller than those for channel initiation sites and higher pH, Ca and Si concentrations than streams, suggesting relatively long groundwater residence time or long subsurface flow paths not bound by topographic divides. Coupled with a large range in groundwater chemistry seen in wells, these results suggest stream chemistry variation reflects the range of connectivity with, and quality of, groundwater controlled by hillslope hydropedological processes. The magnitude of variations of solute concentrations seen in the first order catchment was as broad as that seen at the fifth order Hubbard Brook Valley (3519 ha). Reduction in variation in solute concentrations with increasing UAA suggested a representative elementary area (REA) value of less than 3 ha in the first order catchment, compared with 100 ha for the fifth order basin. Thus, the REA is not necessarily an elementary catchment property. Rather, the partitioning of variation between highly variable upstream sources and relatively homogenous downstream characteristics may have different physical significance depending on the scale and complexity of the catchment under examination.

92 citations