def get_subset_riverid_index_list(self, river_id_list):
        """
        Gets the subset riverid_list from the netcdf file
        Optional returns include the list of valid river ids in the dataset
        as well as a list of missing rive rids

        Parameters
        ----------
        river_id_list: list or :obj:`numpy.array`
            Array of river ID's for the river segments you want the index of.

        Returns
        -------
        :obj:`numpy.array`
            A sorted array of the river index in the NetCDF file that
            were found.
        :obj:`numpy.array`
            A sorted array of the river IDs that were found.
        list
            An array of the missing river ids.

        """
        netcdf_river_indices_list = []
        valid_river_ids = []
        missing_river_ids = []
        for river_id in river_id_list:
            # get where streamids are in netcdf file
            try:
                netcdf_river_indices_list \
                    .append(self.get_river_index(river_id))
                valid_river_ids.append(river_id)
            except IndexError:
                log("ReachID {0} not found in netCDF dataset."
                    " Skipping ...".format(river_id),
                    "WARNING")
                missing_river_ids.append(river_id)

        np_valid_river_indices_list = np.array(netcdf_river_indices_list)
        np_valid_river_ids = np.array(valid_river_ids)
        sorted_indexes = np.argsort(np_valid_river_indices_list)

        return(np_valid_river_indices_list[sorted_indexes],
               np_valid_river_ids[sorted_indexes],
               np.array(missing_river_ids))
Gets the subset riverid_list from the netcdf file
        Optional returns include the list of valid river ids in the dataset
        as well as a list of missing rive rids

        Parameters
        ----------
        river_id_list: list or :obj:`numpy.array`
            Array of river ID's for the river segments you want the index of.

        Returns
        -------
        :obj:`numpy.array`
            A sorted array of the river index in the NetCDF file that
            were found.
        :obj:`numpy.array`
            A sorted array of the river IDs that were found.
        list
            An array of the missing river ids.