scholarly journals Estimating epikarst water storage by time-lapse surface to depth gravity measurements

Author(s):  
Cédric Champollion ◽  
Sabrina Devile ◽  
Jean Chéry ◽  
Erik Doerflinger ◽  
Nicolas Le Moigne ◽  
...  

Abstract. In this study we attempt to evaluate the magnitude of epikarstic water storage variation in various karst settings using a relative spring gravimeter. Gravity measurements are performed two times a year at the surface and inside caves at different depths on three karst aquifers in southern France: two limestone karst systems and one dolomite karst system. We find that water storage variations occur mainly in the first ten meters of karst unsaturated zone. Afterward, surface to depth gravity measurements are compared between the sites with respect of net water inflow. A difference of seasonal water storage is evidenced probably associated with the lithology. The transmissive function of the epikarst has been partially deduced from the water storage change estimation. Long (> 6 months) and short (

2018 ◽  
Vol 22 (7) ◽  
pp. 3825-3839 ◽  
Author(s):  
Cédric Champollion ◽  
Sabrina Deville ◽  
Jean Chéry ◽  
Erik Doerflinger ◽  
Nicolas Le Moigne ◽  
...  

Abstract. The magnitude of epikarstic water storage variation is evaluated in various karst settings using a relative spring gravimeter. Gravity measurements are performed over a 1.5-year period at the surface and inside caves at different depths on three karst hydro-systems in southern France: two limestone karst systems and one dolomite karst system. We find that significant water storage variations occur in the first 10 m of karst unsaturated zone. The subsurface water storage is also evidenced by complementary magnetic resonance sounding. The comparison between sites of the depth gravity measurements with respect to net water inflow suggests that seasonal water storage depends on the lithology. The transmissive function of the epikarst on the seasonal scale has been deduced from the water storage change estimation. Long (> 6 months) and short (< 6 months) transfer times are revealed in the dolomite and in the limestone respectively.


Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. WB49-WB61 ◽  
Author(s):  
Naomi Mazzilli ◽  
Marie Boucher ◽  
Konstantinos Chalikakis ◽  
Anatoly Legchenko ◽  
Hervé Jourde ◽  
...  

Understanding the role of the unsaturated zone in aquifer recharge and contaminant attenuation processes is a major challenge for the protection and management of karstic water resources. We present the potential of the magnetic resonance soundings (MRS) geophysical method for characterizing the vadose zone of karst aquifers composed of epikarst and infiltration layers. To investigate the hydraulic functioning of the Durzon karst system located on the Larzac plateau (southern France), we used the MRS method at 16 sites. The MRS results have been compared with available geologic information and to core water content measurements. The remarkable spatial variability of the MRS response observed in the study area makes it possible to determine ranges of water storage properties in relation to the lithology of the investigated carbonate formations (dolomite, marly, and siliceous limestone). All soundings found either constant or increasing MRS water content with depth, which demonstrates that the infiltration zone might be the major water storage entity for permanent water storage, with important consequences for recharge quality and quantity. These results show the feasibility and potential of the MRS method for the characterization of the karst unsaturated zone and for understanding the vertical distribution of water content, which impacts the overall functioning of karst systems.


2009 ◽  
Vol 177 (2) ◽  
pp. 347-360 ◽  
Author(s):  
Thomas Jacob ◽  
Jean Chery ◽  
Roger Bayer ◽  
Nicolas Le Moigne ◽  
Jean-Paul Boy ◽  
...  

2015 ◽  
Vol 10 (12) ◽  
pp. 124010 ◽  
Author(s):  
H B Dieng ◽  
N Champollion ◽  
A Cazenave ◽  
Y Wada ◽  
E Schrama ◽  
...  

2021 ◽  
Author(s):  
Steven Reinaldo Rusli ◽  
Albrecht Weerts ◽  
Victor Bense

&lt;p&gt;In this study, we estimate the water balance components of a highly groundwater-dependent and hydrological data-scarce basin of the upper reaches of the Citarum river in West Java, Indonesia. Firstly, we estimate the groundwater abstraction volumes based on population size and a review of literature (0.57mm/day). Estimates of other components like rainfall, actual evaporation, discharge, and total water storage changes are derived from global datasets and are simulated using a distributed hydrological wflow_sbm model which yields additional estimates of discharge, actual evaporation, and total water storage change. We compare each basin water balance estimate as well as quantify the uncertainty of some of the components using the Extended Triple Collocation (ETC) method.&lt;/p&gt;&lt;p&gt;The ETC application on four different rainfall estimates suggests a preference of using the CHIRPS product as the input to the water balance components estimates as it delivers the highest r&lt;sup&gt;2&lt;/sup&gt;&amp;#160; and the lowest RMSE compared to three other sources. From the different data sources and results of the distributed hydrological modeling using CHIRPS as rainfall forcing, we estimate a positive groundwater storage change between 0.12 mm/day - 0.60 mm/day. These results are in agreement with groundwater storage change estimates based upon GRACE gravimetric satellite data, averaged at 0.25 mm/day. The positive groundwater storage change suggests sufficient groundwater recharge occurs compensating for groundwater abstraction. This conclusion seems in agreement with the observation since 2005, although measured in different magnitudes. To validate and narrow the estimated ranges of the basin water storage changes, a devoted groundwater model is necessary to be developed. The result shall also aid in assessing the current and future basin-scale groundwater level changes to support operational water management and policy in the Upper Citarum basin.&lt;/p&gt;


2017 ◽  
Vol 5 (2) ◽  
pp. T243-T257 ◽  
Author(s):  
Martin Landrø ◽  
Mark Zumberge

We have developed a calibrated, simple time-lapse seismic method for estimating saturation changes from the [Formula: see text]-storage project at Sleipner offshore Norway. This seismic method works well to map changes when [Formula: see text] is migrating laterally away from the injection point. However, it is challenging to detect changes occurring below [Formula: see text] layers that have already been charged by some [Formula: see text]. Not only is this partly caused by the seismic shadow effects, but also by the fact that the velocity sensitivity for [Formula: see text] change in saturation from 0.3 to 1.0 is significantly less than saturation changes from zero to 0.3. To circumvent the seismic shadow zone problem, we combine the time-lapse seismic method with time-lapse gravity measurements. This is done by a simple forward modeling of gravity changes based on the seismically derived saturation changes, letting these saturation changes be scaled by an arbitrary constant and then by minimizing the least-squares error to obtain the best fit between the scaled saturation changes and the measured time-lapse gravity data. In this way, we are able to exploit the complementary properties of time-lapse seismic and gravity data.


2014 ◽  
Vol 18 (11) ◽  
pp. 4423-4435 ◽  
Author(s):  
M. Huebsch ◽  
O. Fenton ◽  
B. Horan ◽  
D. Hennessy ◽  
K. G. Richards ◽  
...  

Abstract. Nitrate (NO3−) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e. rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in South Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and on the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on the high-resolution monitoring of karst aquifers to capture the high variability of hydrochemical processes, which occur at time intervals of hours to days.


2014 ◽  
Vol 1030-1032 ◽  
pp. 465-471
Author(s):  
Min Xu ◽  
Jian Wang ◽  
Qiu Dong Zhao

Water scarcity is a critical issue in most regions of China; however, river basin groundwater monitoring is extremely limited.This study evaluates the ability of the GRACE satellites and Global Land Data Assimilation System(GLDAS) to monitor groundwater storage in the Yellow River Basin and Yangtze River Basin, China, which is subjected to intense irrigation, production and living. The simulated terrestrial water storage change data which was calculateed by Global Land Data Assimilate System was used to compare the accuracy of GRACE data. Results show that both two datas show significant seasonal cycle in the Yangtze River and Yellow River (except frozen soil), the correlation is 0.89 and 0.84(p<0.05).Two methods have some differences on grid scales, the results which was retrieved by GRACE satellites have better continuity than simulated by GLDAS. GRACE inversion results reflect deeper water storge change in soil, and GLDAS simply reflect surface soil moisture.


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