ɐ ɹˈɛfɹəns tʊ ɐ slˈuːs ɔːɹ dˈæm æt ʃˈɛpɚtən əkˈɜːz ɪn wˈʌn θˈaʊzənd tˈuːhˈʌndɹɪd nˈaɪnti θɹˈiː ænd tˈoʊlz bˌiːɪŋ ɹˈeɪzd ˌɔn pˈæsɪŋ bˈɑːɹdʒᵻz wˌɪtʃ wʊd ɪmplˈaɪ ɐ flˈæʃ lˈɑːk.
A reference to a sluice or dam at Shepperton occurs in 1293 and tolls being raised on passing barges which would imply a flash lock.