using the dump from wgeel. t_emuagreg_ema stored in uga2010.

create table ireland.join_emu_riversegments as
select wso_id,gid from (
(select distinct on(wso_id) wso_id, the_geom from ccm21.riversegments where wso_id in (select wso_id from europe.wso where area='Ireland') )sub
join (select * from uga2010.t_emuagreg_ema where emu_coun_abrev='IE' or emu_coun_abrev='GB') sub2
on st_intersects(geom,the_geom))


alter table ireland.join_emu_riversegments add column   emu_name_short character varying(7);
alter table ireland.join_emu_riversegments add column   emu_name character varying(100);
 alter table ireland.join_emu_riversegments add column  emu_coun_abrev text;
 alter table ireland.join_emu_riversegments add column  emu_hyd_syst_s character varying(50);
 alter table ireland.join_emu_riversegments add column  emu_sea character varying(50);
 
alter table ireland.join_emu_riversegments rename to join_emu_wso

update ireland.join_emu_wso set (emu_name_short,emu_name,emu_coun_abrev,emu_hyd_syst_s,emu_sea)=
(e.emu_name_short,e.emu_name,e.emu_coun_abrev,e.emu_hyd_syst_s,e.emu_sea) from
 uga2010.t_emuagreg_ema e
 where e.gid=join_emu_wso.gid;--505

the size of the query made the table quite long to build so I have settled for the code above.