We report our photometric and spectroscopic follow-up observations of the superoutbursts of three dwarf novae ( GWAC 180415A , GWAC 181017A and GWAC 181211A ) identified independently by the Ground Wide-angle Cameras system , one of the ground-based instruments of the China-France SVOM mission .
Based on a combination of our photometry and that taken from the AAVSO , our period analysis of the superhumps enables us to determine the mass ratios to be 0.0967-0.1163 , 0.1879-0.1883 and 0.0981-0.1173 for GWAC 180415A , GWAC 181017A and GWAC 181211A , respectively .
GWAC 180415A can be firmly identified as a WZ sge-type dwarf novae due to its long duration ( \sim 2 weeks ) multiple rebrightenings with amplitudes of 3-4 magnitudes , the early superhump associated with a double-wave modulation and the low mass ratio .
The inferred low mass ratio and location in the \varepsilon - P _ { \mathrm { orb } } diagram suggest that GWAC 181211A is a WZ sge-type dwarf novae candidate .
The measured Balmer decrements suggest the Balmer line emission is produced from an optical thick region in GWAC 180415A and GWAC 181017A , and from an optical thin region in GWAC 181211A .