scholarly journals Challenges in humid land ecohydrology: Interactions of water table and unsaturated zone with climate, soil, and vegetation

2007 ◽  
Vol 43 (9) ◽  
Author(s):  
Ignacio Rodriguez-Iturbe ◽  
Paolo D'Odorico ◽  
Francesco Laio ◽  
Luca Ridolfi ◽  
Stefania Tamea
Keyword(s):  
Water Table ◽  
Unsaturated Zone

scholarly journals Estimation of groundwater recharge in a shallow sandy aquifer using unsaturated zone modeling and water table fluctuation method

2021 ◽  
pp. 127283
Author(s):  
Anna Gumuła-Kawęcka ◽  
Beata Jaworska-Szulc ◽  
Adam Szymkiewicz ◽  
Wioletta Gorczewska-Langner ◽  
Małgorzata Pruszkowska-Caceres ◽  
...  
Keyword(s):  
Groundwater Recharge ◽  
Water Table ◽  
Unsaturated Zone ◽  
Water Table Fluctuation ◽  
Water Table Fluctuation Method ◽  
Zone Modeling ◽  
Sandy Aquifer ◽  
Fluctuation Method

scholarly journals Vulnerabilidade natural à contaminação do aquífero Alter do Chão na área urbana de Manaus, Amazonas, Brasil

2019 ◽  
Vol 18 (1) ◽  
pp. 7
Author(s):  
Miqueias Lima Duarte ◽  
Heron Salazar Costa ◽  
Tatiana Acácio da Silva ◽  
Mariano Vieira dos Santos
Keyword(s):  
Water Table ◽  
Unsaturated Zone ◽  
Groundwater Occurrence ◽  
Zone Depth

A utilização dos recursos hídricos subterrâneos cresce em função do crescimento populacional e da atividade produtiva, aumentando a demanda por água de qualidade, ao mesmo tempo em que crescem os riscos de sua contaminação. O presente estudo avaliou a vulnerabilidade à contaminação do aquífero Alter do Chão na área urbana do município de Manaus, com a aplicação do método GOD (Groundwater occurrence Overall Lithology of the unsaturated zone, Depth of the water table). O emprego do método possibilitou o mapeamento de áreas diferenciadas nas três classes de vulnerabilidade. A baixa vulnerabilidade à contaminação foi predominante (0,41%), seguida pela média vulnerabilidade (0,35%) e alta vulnerabilidade à contaminação (0,24%). A distribuição das classes de alta vulnerabilidade na área de estudo é motivo de preocupação, pelo potencial de contaminação associado o atual uso e ocupação do solo, também em função da direção do fluxo subterrâneo.

scholarly journals Quantitative Assessment of Specific Vulnerability to Nitrate Pollution of Shallow Alluvial Aquifers by Process-Based and Empirical Approaches

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 269 ◽  
Author(s):  
Francesco Fusco ◽  
Vincenzo Allocca ◽  
Silvio Coda ◽  
Delia Cusano ◽  
Rita Tufano ◽  
...  
Keyword(s):  
Travel Time ◽  
Water Table ◽  
Unsaturated Zone ◽  
Nitrate Pollution ◽  
Shallow Aquifers ◽  
Alluvial Aquifers ◽  
Coupled Process ◽  
Nitrate Fertilizer ◽  
Specific Vulnerability ◽  
Empirical Approaches

Shallow aquifers of coastal and internal alluvial plains of developed countries are commonly characterized by the challenging management of groundwater resources due to the intense agricultural and industrial activities that determine a high risk of groundwater contamination. Among the principal origins of pollution in these areas are agricultural practices based on the amendment of soils by nitrate fertilizers, which have been recognized as one of the most severe environmental emergencies for which specific policies and regulations have been issued (e.g., EU Directive 2006/118/EC). In such a framework, the results of research aimed at assessing the specific vulnerability of shallow alluvial aquifers to nitrate fertilizer pollutants by coupled process-based and empirical approaches are here proposed. The research focused on assessing the specific vulnerability to nitrate pollution of a shallow alluvial aquifer of the Campania region (southern Italy), which was selected due to its representativeness to other recurrent hydrogeological settings occurring in alluvial plains of the region and worldwide. In this area, 1D hydro-stratigraphic models of the unsaturated zone were reconstructed and applied for simulating the transport of nitrate pollutants at the water table and estimating the associated travel times. Numerical modeling was carried out by the finite differences VS2TDI code and considered a 10-year time series of rainfall and evapotranspiration as well as typical local farming practices of nitrate fertilizer input. Results of the travel time calculated for the 1D hydro-stratigraphic models considered and at different depths were recognized as a proxy to assess the specific vulnerability to nitrate fertilizer pollution. Among the principal outcomes is an empirical multiple correlation between the travel time of the nitrate fertilizer pollutant, water table depth, and equivalent saturated hydraulic conductivity of the unsaturated zone or hydraulic resistance, which was used to assess the travel time at the distributed scale over the whole area studied as well as the related specific vulnerability. Given such results, the coupled process-based and empirical approach is proposed as generally applicable for assessing and mapping groundwater vulnerability in shallow aquifers, for which detailed stratigraphic and piezometric data are available.

Detecting fault zone characteristics and paleovalley incision using electrical resistivity: Loma Blanca Fault, New Mexico

Geophysics ◽  
2021 ◽  
Vol 86 (3) ◽  
pp. B209-B221
Author(s):  
Heather Barnes ◽  
Johnny R. Hinojosa ◽  
Glenn A. Spinelli ◽  
Peter S. Mozley ◽  
Daniel Koning ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Fault Zone ◽  
Water Table ◽  
Unsaturated Zone ◽  
Late Quaternary ◽  
Rio Grande ◽  
Rio Grande Rift ◽  
High Resistivity ◽  
Low Resistivity ◽  
Sand And Gravel

We have combined electrical resistivity tomography (ERT), geologic information from boreholes and outcrops, and hydrogeologic data to investigate field-scale fault-zone cementation of the Loma Blanca Fault in the Rio Grande Rift. We have collected electrical resistivity data from 16 transects and geologic samples from 29 boreholes (completed as groundwater wells to 30 m depth) across and around the fault. The 2D ERT profiles, whose interpretations are constrained by geologic data, indicate (1) a high resistivity zone in cemented portions of the fault below the water table and (2) in the unsaturated zone, a low-resistivity feature along the cemented portions of the fault. The high-resistivity zone below the water table is consistent with a 10% reduction in porosity due to the fault zone cementation. With the same porosity in the unsaturated zone, the low-resistivity feature in the cemented fault zone is consistent with saturation >0.7, in contrast to saturation 0.2–0.7 for sediment outside of the cemented fault zone. In addition, subsurface samples and ERT profiles delineate a buttress unconformity (i.e., steeply dipping erosional contact) corresponding to a paleovalley margin. This unconformity truncates the cemented fault zone and separates Pliocene axial-fluvial sand (deposited by an ancestral Rio Grande) from late Quaternary sand and gravel (deposited by the Rio Salado, a Rio Grande tributary). The cemented fault zone in the southern portion of the study area is a hydrogeologic barrier; north of the buttress unconformity, where the cemented fault zone has been removed by erosion, the fault is not a hydrogeologic barrier. The integration of geologic, geophysical, and hydrogeologic observations is key to developing our understanding of this complex system, and it allows us to demonstrate the utility of ERT in detecting subsurface fault-zone cementation.

Study on Ecological Water Table in a Reclaimed Water Irrigation Area in the North China Plain

2012 ◽  
Vol 518-523 ◽  
pp. 4088-4092
Author(s):  
Chang Shui Yu ◽  
Ji Lai Liu ◽  
Yu Long Liu ◽  
Su Fen Wang
Keyword(s):  
Water Quality ◽  
Water Table ◽  
Unsaturated Zone ◽  
Time Lag ◽  
Water Quality Management ◽  
Reclaimed Water ◽  
Groundwater Depth ◽  
Irrigation Area ◽  
Groundwater Environment ◽  
Reclaimed Water Irrigation

The paper sets the definition of ecological water table in reclaimed water irrigation area, on which reclaimed water would not make the pollutants infiltrate into groundwater and not deteriorate groundwater environment. Case study from a soil profile in Daxing, Beijing shows that the ecological water table is changing due to the pollutants down movement in the unsaturated zone. Results show that the critical ecological groundwater depth is about 19.45 m in 2050 while the current is 8.25 m. The current water table depth of 18 m is within the ecological groundwater depth. The time lag between the human activities and water quality due to the relatively thick unsaturated zone should be paid attention to for sustainable water quality management.

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