@classmethod
def stations(cls, station_id, navigation='upstreamTributaries', distance=None):
    """Get USGS stations up/downstream of a station.

        Parameters
        ----------
        station_id : string
            The USGS station ID.
        navigation : string, optional
            The direction for navigating the NHDPlus database. The valid options are:
            None, ``upstreamMain``, ``upstreamTributaries``, ``downstreamMain``,
            ``downstreamDiversions``. Defaults to upstreamTributaries.
        distance : float, optional
            The distance to limit the navigation in km. Defaults to None (all stations).

        Returns
        -------
        geopandas.GeoDataFrame
        """
    return cls.navigate('nwissite', station_id, navigation, 'nwissite',
        distance)
