scholarly journals Multi-Technique groundwater flow system analysis and dating of deep aquifers in Alessandria Basin (Piedmont - IT)

Author(s):  
Nicola Quaranta ◽  
Elena Cogo ◽  
Adriano Simoni ◽  
Elisa Sacchi ◽  
Mariachiara Caschetto ◽  
...  

The aim of the study was to set up a protection system from pollution of the deep aquifer of the Alessandria basin, by redefining the recharge areas, focused on this portion of Piedmont territory, and therefore by creating some reserve areas of deep groundwater, to be preserved for future human drinking purposes. In addition to the classical hydrodynamic and geochemical monitoring techniques, the groundwaters were analyzed with reference to a monitoring network of 25 selected wells with deep screens (80-300 m below ground surface) combining radiochemical dating (14C and δ13C of dissolved inorganic carbon - DIC) with anthropogenic tracers (CFCs, SF6) as indicators of recent recharge/ mixing. Stable isotope composition (δ2H and δ18O – H2O) was assessed during a 1-year sampling of snow-rain precipitations gauges distributed in altitude in order to define Local Meteoric Water Lines; the isotopic composition was also seasonally measured for the main rivers and in selected deep-wells. The 3D numerical model was implemented in FEflow platform and calibrated on the basis of the available monitoring data; it was used as a support tool in the delimitation of the recharge areas, starting from the analysis of the distribution of flows. This model was crucial for delimiting the “reserve areas”, since it was able to simulate groundwater flows using both purely advective transport conditions (particle tracking technique), and more realistic conditions of advective and dispersive transport, by introducing dispersive parameters and using the Life Time Expectancy (LTE) reservoir distribution. The integrated use of “traditional” techniques of regional groundwater flow system monitoring (hydrochemistry, stable isotopic composition) and of dating techniques based on radioactive isotopes and anthropogenic tracers, provided a reliable support to the validation of flow and transport simulation model, oriented to identify recharge areas and “reserve areas” of future extraction of deep groundwater for drinking purpose.

2020 ◽  
Vol 28 ◽  
pp. 100663
Author(s):  
Jan Willem Foppen ◽  
George Lutterodt ◽  
Gabriel C. Rau ◽  
Obed Minkah

1995 ◽  
Vol 31 (8) ◽  
pp. 375-378 ◽  
Author(s):  
F. H. Kloosterman ◽  
R. J. Stuurman ◽  
R. van der Meijden

The project “National Groundwater Flow System Analysis” in The Netherlands was initiated in 1991 and will last until 1995. Financed by three Dutch Ministries, the project aims at the mapping of the regional groundwater flow systems to support policy makers at national levels and water/nature resources management. Much emphasis is put on biotic aspects such as the relation between groundwater and patterns in vegetation. The results are used in a detailed flow system analysis of the eco-hydrological valuable drainage basin of the brooks Beerze and Reusel in the southern parts of the country. In this study vegetation patterns and hydrological situations were analyzed in present and in historical settings to unravel the changes in the last decades leading to severe deterioration of habitats and wetlands. Historical data on flora from the beginning of this century on the basis of km-grid cells show a strong relation with the historical exfiltration areas where deep alkaline groundwaters rich in calcium-carbonate emerged. Agriculture and man-made changes to the natural drainage systems have led to diminishing nature values. Combining a sound understanding of the groundwater flow systems and the changes in the last decades produced a number of practical and viable measures to restore historical wetland settings and to preserve existing ones.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Tada-nori Goto ◽  
Kazuya Kondo ◽  
Rina Ito ◽  
Keisuke Esaki ◽  
Yasuo Oouchi ◽  
...  

Self-potential (SP) measurements were conducted at Mt. Tsukuba, Japan, which is a nonvolcanic mountain, to infer groundwater flow system in the mountain. Survey routes were set around the northern slope, and the reliability of observed SP anomaly was checked by using SP values along parallel survey routes; the error was almost within 10 mV. The FFT analysis of the spatial SP distribution allows us a separation of raw data into two components with shorter and longer wavelength. In the shorter (altitudinal) wavelength than ∼200 meters, several positive SP peaks of more than 100 mV in magnitude are present, which indicate shallow perched water discharges along the slope. In the regional SP pattern of longer wavelength, there are two major perturbations from the general trend reflecting the topographic effect. By comparing the SP and hydrological data, the perturbation around the foothill is interpreted to be caused by heterogeneous infiltration at the ground surface. The perturbation around the summit is also interpreted to be caused by heterogeneous infiltration process, based on a simplified numerical modeling of SP. As a result, the SP pattern is well explained by groundwater flow and infiltration processes. Thus, SP data is thought to be very useful for understanding of groundwater flow system on a mountain scale.


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