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Spatial and temporal dynamics of deep percolation, lag time and recharge in an irrigated semi-arid region
Auteur(s)
Nazarieh, Farzaneh
Ansari, H.
Ziaei, A. N.
Izady, A.
Davari, K.
Date de parution
2018-5
In
Hydrogeology Journal
Vol.
7
No
26
De la page
2507
A la page
2520
Revu par les pairs
1
Résumé
The time required for deep percolating water to reach the water table can be considerable in areas with a thick vadose zone.
Sustainable groundwater management, therefore, has to consider the spatial and temporal dynamics of groundwater recharge.
The key parameters that control the lag time have been widely examined in soil physics using small-scale lysimeters and modeling
studies. However, only a small number of studies have analyzed how deep-percolation rates affect groundwater recharge dynamics
over large spatial scales. This study examined how the parameters influencing lag time affect groundwater recharge in a semi-arid
catchment under irrigation (in northeastern Iran) using a numerical modeling approach. Flow simulations were performed by the
MODFLOW-NWT code with the Vadose-Zone Flow (UZF) Package. Calibration of the groundwater model was based on data from
48 observation wells. Flow simulations showed that lag times vary from 1 to more than 100 months. A sensitivity analysis
demonstrated that during drought conditions, the lag time was highly sensitive to the rate of deep percolation. The study illustrated
two critical points: (1) the importance of providing estimates of the lag time as a basis for sustainable groundwater management, and
(2) lag time not only depends on factors such as soil hydraulic conductivity or vadose zone depth but also depends on the deeppercolation rates and the antecedent soil-moisture condition. Therefore, estimates of the lag time have to be associated with specific
percolation rates, in addition to depth to groundwater and soil properties.
Sustainable groundwater management, therefore, has to consider the spatial and temporal dynamics of groundwater recharge.
The key parameters that control the lag time have been widely examined in soil physics using small-scale lysimeters and modeling
studies. However, only a small number of studies have analyzed how deep-percolation rates affect groundwater recharge dynamics
over large spatial scales. This study examined how the parameters influencing lag time affect groundwater recharge in a semi-arid
catchment under irrigation (in northeastern Iran) using a numerical modeling approach. Flow simulations were performed by the
MODFLOW-NWT code with the Vadose-Zone Flow (UZF) Package. Calibration of the groundwater model was based on data from
48 observation wells. Flow simulations showed that lag times vary from 1 to more than 100 months. A sensitivity analysis
demonstrated that during drought conditions, the lag time was highly sensitive to the rate of deep percolation. The study illustrated
two critical points: (1) the importance of providing estimates of the lag time as a basis for sustainable groundwater management, and
(2) lag time not only depends on factors such as soil hydraulic conductivity or vadose zone depth but also depends on the deeppercolation rates and the antecedent soil-moisture condition. Therefore, estimates of the lag time have to be associated with specific
percolation rates, in addition to depth to groundwater and soil properties.
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Type de publication
journal article
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