scholarly journals Modeling of thermally driven hydrological processes in partially saturated fractured rock

2009 ◽  
Vol 47 (3) ◽  
Author(s):  
Y. W. Tsang ◽  
J. T. Birkholzer ◽  
S. Mukhopadhyay
Keyword(s):  
Fractured Rock ◽  
Hydrological Processes ◽  
Partially Saturated ◽  
Thermally Driven

scholarly journals Groundwater–surface water interactions in an ephemeral savanna catchment, Kruger National Park

Koedoe ◽  
2020 ◽  
Vol 62 (2) ◽  
Author(s):  
Edward S. Riddell ◽  
Jaco Nel ◽  
Johan Van Tol ◽  
Daniel Fundisi ◽  
Faith Jumbi ◽  
...  
Keyword(s):  
Surface Water ◽  
Groundwater Recharge ◽  
Soil Water ◽  
National Park ◽  
Fractured Rock ◽  
Kruger National Park ◽  
Hydrological Processes ◽  
Third Order ◽  
Fractured Rock Aquifer ◽  
Precipitation Events

The semi-arid conditions in savanna landscapes ensure that ephemeral drainage dominates the hydrological network in these dryland systems. Quantification of their hydrological processes is important to inform ecosystem understanding and future conservation efforts under a changing climate, and to provide guidance for restoration. By combining in situ hydrometric observations, hydrochemistry, remote sensing and a soil water balance model, we characterise the groundwater–surface water interactions in ephemeral low-order catchments of the granitoid regions of the southern Kruger National Park (KNP). Streams at the lowest orders are augmented by lateral interflows from the catena, although the second- and third-order stream reaches are conduits for groundwater recharge to the fractured rock aquifer; the soils of the crests and foot-slopes also show preferential flow, and are truly recharge soils, whilst the duplex soils of the midslopes clearly show their responsive nature to a low soil moisture deficit in the shallow horizons. Actual evaporation (aET) differed between catena elements with surprisingly little variation at third-order hillslopes, with the greatest overall aET at the first order. Meanwhile, soil water balances demonstrated a significant variation in storage of the riparian zones as a result of interflow from upslope and aET losses. Furthermore, data support broader-scale observations that groundwater recharge through the vadose zone to the fractured rock aquifer is dependent upon threshold antecedent precipitation conditions. Moderate precipitation events (5 mm/day – 35 mm/day) over a 2–3 week period initiate groundwater responses with a 2–3 month lag, whilst intense precipitation events (100 mm/day) are expressed within 2–3 weeks.Conservation implications: Understanding the lateral connectivity of terrestrial ecosystems to the ephemeral drainage network expressed via hydrological processes in these savanna landscapes is important to infer potential impacts of climate variability on the continued conservation of these ecosystems, both within and external to protected areas.

scholarly journals Frequency-dependent anisotropy in a partially saturated fractured rock

2018 ◽  
Vol 215 (3) ◽  
pp. 1985-1998 ◽  
Author(s):  
Zhaoyu Jin ◽  
Mark Chapman ◽  
Giorgos Papageorgiou
Keyword(s):  
Fractured Rock ◽  
Frequency Dependent ◽  
Partially Saturated

scholarly journals Thermally driven moisture redistribution in partially saturated porous media

1995 ◽  
Author(s):  
R.T. Green ◽  
F.T. Dodge ◽  
S.J. Svedeman ◽  
R.D. Manteufel ◽  
K.A. Meyer ◽  
...  
Keyword(s):  
Porous Media ◽  
Saturated Porous Media ◽  
Partially Saturated ◽  
Thermally Driven ◽  
Partially Saturated Porous Media ◽  
Moisture Redistribution

Environmental microscopy of capillary stress-induced strain behavior in ambient-pressure aerogels

1996 ◽  
Vol 54 ◽  
pp. 850-851
Author(s):  
Sudeep M. Rao ◽  
Joshua Samuel ◽  
Sai S. Prakash ◽  
C. Jeffrey Brinker
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Drying Shrinkage ◽  
Pore Filling ◽  
Silica Network ◽  
Strain Behavior ◽  
Partially Saturated ◽  
Capillary Stress ◽  
Wetting Liquid ◽  
Aerogel Films

Ambient pressure silica aerogel thin films have recently been prepared by exploiting reversible drying shrinkage caused by derivatization of the internal gel surface. Aerogels have porosities of upto 99.9% and due to the small size of the pores (few nanometers), large capillary stresses are produced in gels that are partially saturated with a wetting liquid. As a result of these capillary stresses, the flexible silica network undergoes strain which has been observed using environmental microscopy. This technique allows variation of the equilibrium vapor pressure and temperature, and a simultaneous monitoring of the deformation of the unconstrained film thickness. We have observed >600% deformation during the pore-filling and pore-emptying cycles. In this presentation, we discuss the unique stress-strain behavior of these films.Ref.: Sai S. Prakash, C. Jeffrey Brinker, Alan J. Hurd & Sudeep M. Rao, "Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage", Nature. Vol. 374, 30 March, 1995, 439-443.

Hydrogeological features of a highly fractured rock-slab

2015 ◽  
Vol 35 ◽  
pp. 283-287 ◽  
Author(s):  
Margherita Cecilia Spreafico ◽  
Federico Cervi ◽  
Vincent Marc ◽  
Lisa Borgatti
Keyword(s):  
Fractured Rock

Hydrogeology of conglomerate fractured-rock aquifers: an example from the Portofino's Promontory (Italy)

2016 ◽  
Vol 41 ◽  
pp. 22-25 ◽  
Author(s):  
Vittorio Bonaria ◽  
Francesco Faccini ◽  
Ilaria Cinzia Galiano ◽  
Alessandro Sacchini
Keyword(s):  
Fractured Rock ◽  
Fractured Rock Aquifers
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