Catchment-scale heterogeneity of flow and storage properties in a weathered/fractured hard rock aquifer from resistivity and magnetic resonance surveys: implications for groundwater flow paths and the distribution of residence times

Hyporheic zones (HZs) influence biogeochemistry at the local reach scale with potential implication for water quality at the large catchment scale. The characteristics of the HZs (e.g., area, flux rates, and residence times) change in response to channel and aquifer physical properties, as well as to transient perturbations in the stream–aquifer system such as floods and groundwater withdraws due to evapotranspiration (ET) and pumping. In this study, we use a numerical model to evaluate the effects of transient near-stream evapotranspiration (ET) on the area, exchange flux, and residence time (RT) of sinuosity-induced HZs modulated by regional groundwater flow (RGF). We found that the ET fluxes (up to 80 mm/day) consistently increased HZ area and exchange flux, and only increased RTs when the intensity of regional groundwater flow was low. Relative to simulations without ET, scenarios with active ET had more than double HZ area and exchange flux and about 20% longer residence times (as measured by the median of the residence time distribution). Our model simulations show that the drawdown induced by riparian ET increases the net flux of water from the stream to the nearby aquifer, consistent with field observations. The results also suggest that, along with ET intensity, the magnitude of the HZ response is influenced by the modulating effect of both gaining and losing RGF and the sensitivity of the aquifer to daily cycles of ET withdrawal. This work highlights the importance of representing near-stream ET when modeling sinuosity-induced hyporheic zones, as well as the importance of including riparian vegetation in efforts to restore the ecosystem functions of streams.

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Two dimensional Magnetic Resonance Sounding (MRS) profile across a fracture zone in a hard rock aquifer

10.3997/2214-4609-pdb.146.12.4 ◽

2007 ◽

Author(s):

R. Meyer ◽

G. Lange ◽

M. Müller-Petke

Keyword(s):

Magnetic Resonance ◽

Fracture Zone ◽

Hard Rock ◽

Two Dimensional ◽

Magnetic Resonance Sounding ◽

Hard Rock Aquifer

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Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment

Hydrology and Earth System Sciences ◽

10.5194/hess-9-139-2005 ◽

2005 ◽

Vol 9 (3) ◽

pp. 139-155 ◽

Cited By ~ 100

Author(s):

P. Rodgers ◽

C. Soulsby ◽

S. Waldron ◽

D. Tetzlaff

Keyword(s):

Stream Water ◽

Spatial Scales ◽

Isotopic Signature ◽

Residence Times ◽

Catchment Scale ◽

Valley Bottom ◽

Flow Paths ◽

Isotope Tracers ◽

Periodic Regression ◽

Stream Waters

Abstract. δ18O measurements in precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2) River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped within the catchment, was reflected in stream water at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of apparently more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment difference using an exponential flow model to provide indicative estimates of mean stream water residence times, which varied between approximately 3 and 14 months. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond that of the smallest (ca. 1 km2) headwater catchment scale. Instead, the interaction of catchment soil cover and topography appeared to be the dominant controlling influence. Where sub-catchments had extensive peat coverage, responsive hydrological pathways produced seasonally variable δ18O signatures in runoff with short mean residence times (ca. 3 months). In contrast, areas dominated by steeper slopes, more freely draining soils and larger groundwater storage in shallow valley-bottom aquifers, deeper flow paths allow for more effective mixing and damping of δ18O indicating longer residence times (>12 months). These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at larger spatial scales.

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Magnetic resonance sounding (MRS) and resistivity characterisation of a mountain hard rock aquifer: the Ringelbach Catchment, Vosges Massif, France

Near Surface Geophysics ◽

10.3997/1873-0604.2005022 ◽

2005 ◽

Vol 3 (4) ◽

pp. 267-274 ◽

Cited By ~ 24

Author(s):

J.M. Baltassat ◽

A. Legchenko ◽

B. Ambroise ◽

F. Mathieu ◽

P. Lachassagne ◽

...

Keyword(s):

Magnetic Resonance ◽

Hard Rock ◽

Magnetic Resonance Sounding ◽

Hard Rock Aquifer

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Groundwater Flow Modeling of a Hard Rock Aquifer: Case Study

Journal of Hydrologic Engineering ◽

10.1061/(asce)he.1943-5584.0000627 ◽

2014 ◽

Vol 19 (5) ◽

pp. 877-886 ◽

Cited By ~ 11

Author(s):

V. Varalakshmi ◽

B. Venkateswara Rao ◽

L. SuriNaidu ◽

M. Tejaswini

Keyword(s):

Groundwater Flow ◽

Hard Rock ◽

Flow Modeling ◽

Groundwater Flow Modeling ◽

Hard Rock Aquifer

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Using stable isotope tracers to identify hydrological flow paths, residence times and landscape controls in a mesoscale catchment

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-2-1-2005 ◽

2005 ◽

Vol 2 (1) ◽

pp. 1-35 ◽

Cited By ~ 8

Author(s):

P. Rodgers ◽

C. Soulsby ◽

S. Waldron ◽

D. Tetzlaff

Keyword(s):

Stream Water ◽

Spatial Scales ◽

Isotopic Signature ◽

Residence Times ◽

Catchment Scale ◽

Mixing Processes ◽

Flow Paths ◽

Isotope Tracers ◽

Periodic Regression ◽

Stream Waters

Abstract. δ18O tracer measurements of precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2 River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped by catchment mixing processes, was reflected in stream water outputs at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment differences in the mixing of these two main hydrological sources processes more quantitatively, using an exponential flow model to provide preliminary estimates of mean stream water residence times, which varied between 0.4-2.9 years. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond the smallest (ca. 1 km2 headwater catchment scale. Instead, the interaction of catchment soil cover and topography acted as the dominant influence. Responsive hydrological pathways, associated with peat soils in the headwater sub-catchments, produced seasonally variable δ18O signatures in runoff with short mean residence times (0.4-0.8 years). In contrast, areas dominated by more freely draining soils and larger groundwater storage in shallow aquifers appear to provide effective mixing and damping of variable precipitation inputs implying longer residence times (1.4-2.9 years). These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at the mesoscale.

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