DSL - SND1    SHORE , n.3 A sewer, drain. Gen. in phr. the common  shore . Obs. in Eng. exc. dial. [So:r]  
    *Edb. 1816 Blackwood's Mag. (May) 202:
    Her Luckenbooths now choak the common  shore .  
    *Abd. 1853 W. Cadenhead Flights 168:
    An' for the burn, . . . It has been lang a common  shore .

    [Prob., as N.E.D. thinks, not a variant of sewer, which gives SYVER in Sc., but an extension of SHORE, n.1, as the dumping ground for rubbish to be carried away by the tide. Cf. 1725 quot. s.v.]