3.1 Influence of a single peak flood wave on HE
The dynamic change of q (Fig. 3a) could be divided into five
stages, which correspond to OA, AB, BC, CD and DE on the flood wave of
the base case. The OA (0 < t < 0.5 d)
corresponded to the initial stream stage before the flood event. Because
the Inbuk Stream was recharged by groundwater all year round, qin this period remained an unchanged negative value (Jeon et al., 2015),
that is, groundwater recharged the stream at a constant rate along the
stream-aquifer interface (Fig. 3b). The stream-groundwater balance
increased negatively from aquifer to stream (Fig. 3c). The AB
represented a period (0.5 < t < 0.95 d) of
rising stream stage, in which the stream continuously recharged
groundwater, with the magnitude of q gradually increasing to the
maximum (q +max). Accordingly,Q increased from negative to positive. During the BC, the stream
stage first rose to the peak and then fell down (0.95 <t < 2.15 d). The stream kept recharging groundwater;
however, the magnitude of q gradually decreased fromq +max to zero. As the result,Q kept increasing and reached the maximum
(Q max). The stream stage continued falling and
approached the initial stage during CD (2.15 < t< 3.1 d). The groundwater began discharging into the stream
again, with the magnitude of q gradually reaching the maximum in
the negative direction
(|q -max|). At
the same time, Q decreased gradually due to the backflow of
groundwater. The stream stage in DE (3.1 < t< 20 d) included a short falling limb and a long period of
initial stage. Groundwater was released back into the stream over a
longer period after the flood event, with q and Qdecreasing to zero. The negative value of Q at the end of this
period was due to the gaining condition of the stream at the site.