scholarly journals Unsaturated Zone Flow Processes and Aquifer Response Time in the Chalk Aquifer, Brighton, South East England

Ground Water ◽  
2020 ◽  
Author(s):  
Peshawa Al‐Jaf ◽  
Martin Smith ◽  
Friederike Gunzel
Keyword(s):  
Response Time ◽  
Unsaturated Zone ◽  
Flow Processes ◽  
Chalk Aquifer ◽  
South East England

scholarly journals Karst flow processes explored through analysis of long-term unsaturated-zone discharge hydrochemistry: a 10-year study in Rustrel, France

2019 ◽  
Vol 27 (5) ◽  
pp. 1711-1723 ◽  
Author(s):  
Aurore Barbel-Périneau ◽  
Laurent Barbiero ◽  
Charles Danquigny ◽  
Christophe Emblanch ◽  
Naomi Mazzilli ◽  
...  
Keyword(s):  
Unsaturated Zone ◽  
Flow Processes

scholarly journals Transfer and degradation of the common pesticide atrazine through the unsaturated zone of the Chalk aquifer (Northern France)

2019 ◽  
Vol 255 ◽  
pp. 113125
Author(s):  
Ningxin Chen ◽  
Danièle Valdes ◽  
Christelle Marlin ◽  
Pierre Ribstein ◽  
Fabrice Alliot ◽  
...  
Keyword(s):  
Unsaturated Zone ◽  
Northern France ◽  
The Common ◽  
Chalk Aquifer

Water, nitrate and atrazine transfer through the unsaturated zone of the Chalk aquifer in northern France

2019 ◽  
Vol 652 ◽  
pp. 927-938 ◽  
Author(s):  
Ningxin Chen ◽  
Danièle Valdes ◽  
Christelle Marlin ◽  
Hélène Blanchoud ◽  
Roger Guerin ◽  
...  
Keyword(s):  
Unsaturated Zone ◽  
Northern France ◽  
Chalk Aquifer

scholarly journals A critical assessment of simple recharge models: application to the UK Chalk

2013 ◽  
Vol 17 (6) ◽  
pp. 2083-2096 ◽  
Author(s):  
A. M. Ireson ◽  
A. P. Butler
Keyword(s):  
Water Table ◽  
Unsaturated Zone ◽  
Groundwater Resources ◽  
Richards Equation ◽  
Unknown Parameters ◽  
Monthly Basis ◽  
Physically Based Model ◽  
Flow Processes ◽  
Physically Based ◽  
The Uk

Abstract. Quantification of the timing and magnitude of point-scale groundwater recharge is challenging, but possible at specific sites given sufficient high spatial and temporal resolution field observations, and a suitable physically based model. Such models are generally too computationally intensive and have too many unknown parameters to be practically applicable within distributed, larger-scale hydrological or groundwater models. This motivates the need for simpler recharge models, which are widely used within groundwater models. However, it is important that these models are able to capture adequately the unsaturated zone flow processes. We perform an inter-comparison of recharge simulated by a detailed physically based model and a simple recharge model, with both models applied to a field site in the fractured porous Chalk in the UK. Flow processes are simulated convincingly using a dual permeability, equivalent continuum, vertically heterogeneous, Richards' equation model, applied to a 2-D hillslope transect. A simple conventional recharge model was then calibrated to reproduce the water table response simulated by the physically based model. The performance in reproducing the water table was surprisingly good, given the known discrepancies between the actual processes and the model representation. However, comparisons of recharge fluxes simulated by each model highlighted problems with the process representations in the simple model. Specifically, bypass flow events during the summer were compensating for recharge that should have come from slow, continual drainage of the unsaturated zone. Such a model may still be useful for assessment of groundwater resources on a monthly basis, under non-extreme climatic conditions. However, under extreme wet or dry conditions, or under a changed climate the predictive capacity of such models is likely to be inadequate.

scholarly journals Use of soil moisture dynamics and patterns at different spatio-temporal scales for the investigation of subsurface flow processes

2009 ◽  
Vol 13 (7) ◽  
pp. 1215-1233 ◽  
Author(s):  
T. Blume ◽  
E. Zehe ◽  
A. Bronstert
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Unsaturated Zone ◽  
Preferential Flow ◽  
Temporal Dynamics ◽  
Rainfall Simulation ◽  
Small Scale ◽  
Temporal Scales ◽  
Flow Processes ◽  
Moisture Profiles

Abstract. Spatial patterns as well as temporal dynamics of soil moisture have a major influence on runoff generation. The investigation of these dynamics and patterns can thus yield valuable information on hydrological processes, especially in data scarce or previously ungauged catchments. The combination of spatially scarce but temporally high resolution soil moisture profiles with episodic and thus temporally scarce moisture profiles at additional locations provides information on spatial as well as temporal patterns of soil moisture at the hillslope transect scale. This approach is better suited to difficult terrain (dense forest, steep slopes) than geophysical techniques and at the same time less cost-intensive than a high resolution grid of continuously measuring sensors. Rainfall simulation experiments with dye tracers while continuously monitoring soil moisture response allows for visualization of flow processes in the unsaturated zone at these locations. Data was analyzed at different spacio-temporal scales using various graphical methods, such as space-time colour maps (for the event and plot scale) and binary indicator maps (for the long-term and hillslope scale). Annual dynamics of soil moisture and decimeter-scale variability were also investigated. The proposed approach proved to be successful in the investigation of flow processes in the unsaturated zone and showed the importance of preferential flow in the Malalcahuello Catchment, a data-scarce catchment in the Andes of Southern Chile. Fast response times of stream flow indicate that preferential flow observed at the plot scale might also be of importance at the hillslope or catchment scale. Flow patterns were highly variable in space but persistent in time. The most likely explanation for preferential flow in this catchment is a combination of hydrophobicity, small scale heterogeneity in rainfall due to redistribution in the canopy and strong gradients in unsaturated conductivities leading to self-reinforcing flow paths.

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