Mass transport and scale-dependent hydraulic tests in a heterogeneous glacial till–sandy aquifer system

SummaryAt AECL – Chalk River Laboratories, Ontario, Canada solid, low-level radioactive wastes from industrial, academic and medical applications have been stored in trenches above unconsolidated sandy glacial tills and permeable very-fine to fine-grained sands overlying crystalline bedrock. The sandy aquifer system drains into a swamp comprised of approximately 3 m of sphagnum peat. A comprehensive field and analytical program, involving measurements of total iodine,The maximum iodine concentration and

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Spatiotemporal distribution of microbial communities in a coastal, sandy aquifer system (Doñana, SW Spain)

Geobiology ◽

10.1111/j.1472-4669.2008.00183.x ◽

2009 ◽

Vol 7 (1) ◽

pp. 66-81 ◽

Cited By ~ 17

Author(s):

S. VELASCO AYUSO ◽

M. C. GUERRERO ◽

C. MONTES ◽

A. I. LÓPEZ-ARCHILLA

Keyword(s):

Microbial Communities ◽

Spatiotemporal Distribution ◽

Aquifer System ◽

Sw Spain ◽

Sandy Aquifer

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Regulation and Spatiotemporal Patterns of Extracellular Enzyme Activities in a Coastal, Sandy Aquifer System (Doñana, SW Spain)

Microbial Ecology ◽

10.1007/s00248-011-9853-4 ◽

2011 ◽

Vol 62 (1) ◽

pp. 162-176 ◽

Cited By ~ 11

Author(s):

Sergio Velasco Ayuso ◽

María del Carmen Guerrero ◽

Carlos Montes ◽

Ana Isabel López-Archilla

Keyword(s):

Enzyme Activities ◽

Extracellular Enzyme ◽

Spatiotemporal Patterns ◽

Aquifer System ◽

Extracellular Enzyme Activities ◽

Sw Spain ◽

Sandy Aquifer

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Environmental factors controlling the spatiotemporal distribution of microbial communities in a coastal, sandy aquifer system (Doñana, southwest Spain)

Hydrogeology Journal ◽

10.1007/s10040-008-0397-8 ◽

2008 ◽

Vol 17 (4) ◽

pp. 767-780 ◽

Cited By ~ 10

Author(s):

Sergio Velasco Ayuso ◽

Pablo Acebes ◽

Ana Isabel López-Archilla ◽

Carlos Montes ◽

María del Carmen Guerrero

Keyword(s):

Environmental Factors ◽

Microbial Communities ◽

Spatiotemporal Distribution ◽

Aquifer System ◽

Sandy Aquifer

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First results of multidisciplinary investigations for the hydrogeological conceptual modelling of loess deposits in eastern Croatia

Acque Sotterranee-Italian Journal of Groundwater ◽

10.7343/as-2020-432 ◽

2020 ◽

Author(s):

Marco Pola ◽

Ivica Pavičić ◽

Vedran Rubinić ◽

Ivan Kosović ◽

Lidija Galović ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Preferential Flow ◽

Effective Porosity ◽

Aquifer System ◽

Depositional Processes ◽

Macro Scale ◽

Hydrogeological Properties ◽

Sandy Aquifer ◽

Loess Deposits ◽

The Impact

Loess is a widespread continental aeolian sediment. Groundwater generally represents the most important source of potable water in loess areas, where loess is the aquitard overlying the aquifer system. This work investigates loess deposits of eastern Croatia that overlie a sandy aquifer exploited for potable and agricultural purposes. The genesis of the deposit and the depositional and post-depositional processes affecting its structure were reviewed in this work and integrated with the estimated hydrogeological properties of the material to propose a preliminary hydrogeological conceptual model of the loess-sand system. The results of published granulometric analyses were used to calculate the effective porosity and the hydraulic conductivity of the material employing an analytical approach. The eastern Croatian loess is a silty deposit originated during Middle-Upper Pleistocene glacial periods. The sediments produced by glacial grinding were transported and deposited by the Danube fluvial system and subsequently remobilised by wind forming the loess. During the interglacial periods, the pedogenesis of the deposit occurred, with bioturbations and discontinuities by living organisms at the micro- and macro-scale. The deposition of a new loess layer compacted and consolidated the previously deposited loess leading to the development of a sub-vertical pore structure and sub-vertical cracks at the micro- and macro-scale, respectively. The calculations from the grain size distributions point to the low effective porosity (5-12%) and hydraulic conductivity (~10-9 m/s) of both loess and pedocomplexes supporting their aquitard behaviour. The infiltration of surficial waters and their flow toward the underlying sandy aquifer is locally enhanced by the post-depositional discontinuities that constitute preferential flow paths within the loess aquitard. These results highlight the need of detailed hydrogeological investigations in loess deposits to address the impact of post-depositional processes on their hydrogeological behaviour and the upscaling of their hydrogeological properties for proposing specific groundwater protection strategies in loess areas.

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Groundwater nitrate concentration evolution under climate change and agricultural adaptation scenarios: Prince Edward Island, Canada

Earth System Dynamics Discussions ◽

10.5194/esdd-6-1339-2015 ◽

2015 ◽

Vol 6 (2) ◽

pp. 1339-1394 ◽

Cited By ~ 1

Author(s):

D. Paradis ◽

H. Vigneault ◽

R. Lefebvre ◽

M. M. Savard ◽

J.-M. Ballard ◽

...

Keyword(s):

Climate Change ◽

Drinking Water ◽

Mass Transport ◽

Groundwater Flow ◽

Prince Edward Island ◽

Agricultural Practices ◽

Aquifer System ◽

Agricultural Adaptation ◽

Flow And Mass Transport ◽

Nitrogen Loadings

Abstract. Nitrate (N-NO3) concentration in groundwater, the sole source of potable water in Prince Edward Island (PEI, Canada), currently exceeds the 10 mg L−1 (N-NO3) health threshold for drinking water in 6 % of domestic wells. Increasing climatic and socio-economic pressures on PEI agriculture may further deteriorate groundwater quality. This study assesses how groundwater nitrate concentrations could evolve due to the forecasted climate change and its related potential changes in agricultural practices. For this purpose, a tridimensional numerical groundwater flow and mass transport model was developed for the aquifer system of the entire Island (5660 km2). A number of different groundwater flow and mass transport simulations were made to evaluate the potential impact of the projected climate change and agricultural adaptation. According to the simulations for year 2050, N-NO3 concentration would increase due to two main causes: (1) the progressive attainment of steady-state conditions related to present-day nitrogen loadings, and (2) the increase in nitrogen loadings due to changes in agricultural practices provoked by future climatic conditions. The combined effects of equilibration with loadings, climate and agricultural adaptation would lead to a 25 to 32 % increase in N-NO3 concentration over the Island aquifer system. Climate change alone (practices maintained at their current level) would contribute only 0 to 6 % to that increase according to the various climate scenarios. Moreover, simulated trends in groundwater N-NO3 concentration suggest that an increased number of domestic wells (more than doubling) would exceed the nitrate drinking water criteria. This study underlines the need to develop and apply better agricultural management practices to ensure sustainability of long-term groundwater resources. The simulations also show that observable benefits from positive changes in agricultural practices would be delayed in time due to the slow dynamics of nitrate transport within the aquifer system.

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