  Short Gamma-Ray Bursts (GRBs), brief intense emission of $\gamma-$rays
characterized by a duration shorter than 2 seconds that are plausibly powered
by the coalescence of binary neutron stars, are believed to be strong
gravitational wave radiation (GWR) sources. The test of such a speculation has
been thought to be impossible until the performance of the detectors like
advanced LIGO. Recently there has been growing evidence for the formation of
highly-magnetized neutron star (i.e., magnetar) in the double neutron star
mergers. In this work we re-examine the interpretation of the X-ray plateau
followed by an abrupt decline detected in some short GRB afterglows within the
supramassive magnetar model and find that the maximum gravitational mass of the
non-rotating neutron stars is $\sim 2.3M_{\odot}$ and the observed duration of
some X-ray plateaus are significantly shorter than that expected in the
magnetic dipole radiation scenario, suggesting that the collapse of the
supramassive magnetars has been considerably enhanced by the energy loss via
GWR. Such a result demonstrates that the signature of GWR may have already
existed in current electromagnetic data of short GRBs.
