We present a study on water transport through cation intercalated graphene oxide membranes. With that, experimental access to the role of impurities with different water affinities in graphene-based nanochannel is gained. We found that the flux of cation intercalated GOMs was decreased with the increase of interlayer space. We explain this by showing that the slip length of the cation intercalated GOMs scales exponentially with the hydrated diameter of the respective cation. This allows us to hypothesise that the water flux in original GOMs is influenced by hydrated hydrogen, which is omnipresent in aqueous environments. Our simulation study further supports that the hindrance of water transport through the cation decorated nanochannels is due to increased interaction between the water molecules and the nanochannel. Further, the non-slip conditions for high hydrated diameters offer experimental support for using the Hagen-Poiseuille equation in graphenebased nanochannels. Hence, our study suggests that the water transport in graphene-based nanochannels follows the HP equation. The slip length may change dependent on the water affinity of impurities. As we showed, in the case of cation intercalation, the slip length decays exponentially with the hydrated diameter (i.e., water affinity). Future studies may find a way to further explore and confirm the exponential relationship between hydrated cations and GOM slip length. With that, our study may offer a starting point towards a deeper understanding of the water transport through graphene-based nanochannels with waterattracting impurities. Additionally, these may pose valuable insights for future applications where graphene-based nanochannels in aqueous environments play a promising role.