BasinATLAS, RiverATLAS, and LakeATLAS are related through the level 12 HydroBASIN ID codes found in the attribute tables of each dataset. Every river reach in RiverATLAS and every lake in LakeATLAS shows the HydroBASINS ID (“HYBAS_ID”) of its corresponding level 12 HydroBASIN in which the reach or lake’s pour point is located.
Furthermore, every lake in LakeATLAS can be associated to a river reach in RiverATLAS by using one of two additional columns in LakeATLAS: one column (“HYRIV_RCH”) indicates the HydroRIVER ID on which the lake’s pour point is located; the other column (“HYRIV_CAT”) indicates the HydroRIVER ID of the corresponding reach catchment (i.e., the small catchment area directly draining into the reach) in which the lake’s pour point is located. For lakes with a pour point that is located directly on a river reach the two IDs are identical; for lakes with a pour point that is off-stream, only the reach catchment ID exists.
See the technical documentation of HydroATLAS for more details.