Problems to navigation had long been recognised and the first suggestions for creating a lock "near Clifton Ferry" occurred in 1793, being raised again in 1811.
pɹˈɑːbləmz tə nˌævɪɡˈeɪʃən hæd lˈɔŋ bˌɪn ɹˈɛkəɡnˌaɪzd ænd ðə fˈɜːst sədʒˈɛstʃənz fɔːɹ kɹiːˈeɪɾɪŋ ɐ lˈɑːk "nˌɪɹ klˈɪftən fˈɛɹi" əkˈɜːd ɪn wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd nˈaɪnti θɹˈiː, bˌiːɪŋ ɹˈeɪzd ɐɡˈɛn ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd ɪlˈɛvən.