  Studying atmospheric neutrino oscillations in the few-GeV range with a
multimegaton detector promises to determine the neutrino mass hierarchy. This
is the main science goal pursued by the future KM3NeT/ORCA water Cherenkov
detector in the Mediterranean Sea. In this paper, the processes that limit the
obtainable resolution in both energy and direction in charged-current neutrino
events in the ORCA detector are investigated. These processes include the
composition of the hadronic fragmentation products, the subsequent particle
propagation and the photon-sampling fraction of the detector. GEANT simulations
of neutrino interactions in seawater produced by GENIE are used to study the
effects in the 1 - 20 GeV range. It is found that fluctuations in the hadronic
cascade in conjunction with the variation of the inelasticity y are most
detrimental to the resolutions. The effect of limited photon sampling in the
detector is of significantly less importance. These results will therefore also
be applicable to similar detectors/media, such as those in ice.
