where Q is aquifer storage, m2; t is time, d.
(3) The duration of the graph of Q is defined as residence time (RT , d) (Siergieiev et al., 2015).
(4) The ratio of return time to infiltration time (t R/t F) is defined according to the graph of Q . (t F, d) refers to the time required for Q to rise from zero to its maximum, while (t R, d) refers to the time required for Q to decrease from its maximum to zero (Siergieiev et al., 2015).