In this case, the Liquib Mirage Effect was used to simulate a reflective watery surface, as if the rose bushes along the fence are being drowned in a rising flood.  It really had rained an awful lot that day and the night before, but not nearly enough to cause such a serious flood.  The mirroring surface is slightly wavy, perhaps stirred by a gentle breeze, or maybe disrupted by a raft floating past nearby.  The scale and strength of such disturbances can be controlled by adjusting the Waviness and Intensity parameters.  Notice also that the reflected roses, leaves, etc. are somewhat squashed, appearing shorter than in the original picture.  That was easily accomplished by setting the Elongation value to -24 (a positive Elongation would lengthen the Mirage image instead).  This still scene was captured after the Mirage Effect was finalized.  It's was much more interesting to watch while the Mirage was active, with the mirroring surface constantly quivering, undulated by meandering, and/or swirling motions.
Liquib Roses Mirage