Which preposition to use with watergates

of Occurrences 1%

One is an old dismantled frigate, which is moored just within the watergates of the basin, and carefully roofed over and painted.

to Occurrences 1%

The procession paraded slowly through the city from the Watergate to the common jail, whilst the streets resounded with shouts of triumph, and with every expression of hatred which religious or political fanaticism could inspire.

Which preposition to use with  watergates