  Measurements of cosmic ray electron+positron spectrum above 10 TeV with
ground-based experiments is challenging because of the difficulty of rejection
of hadronic extensive air shower background. We study the efficiency of
rejection of the hadronic background with water Cherenkov detector array
supplemented by muon detection layer. We show that addition of a continuous
muon detection layer to the experimental setup allows to achieve a ~ 1e-5
rejection factor for hadronic background at 10 TeV and enables measurement of
electron spectrum in 10-100 TeV energy range. We show that measurements of
electron spectrum in this energy range do not require a high-altitude
experiment and can be done with a sea-level detector.
