In a small parkette in old Port Dalhousie, you can see the stone walls of old Lock 1 of the Second Welland Canal, immediately east of the intersection of Lakeport Road and Lock Street. A historical plaque stands at the southeast corner of the park.
The Second Welland Canal was built in 1842-45, and several dramatic changes were made to the area. A new channel was dredged through the marsh at the mouth of the Twelve Mile Creek, aligning the waterway the way we see it today. Piers were installed to protect the channel, and a new Lock 1 was established, made of cut stone that is still visible to this day.
The Second Welland Canal also saw more commercial development in Port Dalhouse. Businesses were established beside the canal, forming a short line of buildings that still remains today.
The water channel of the Second Canal has since been filled in with earth. It used to extend straight south from the canal parkette, crossing under the present Lakeport Road and almost paralelling the upper section of the road for about 250 metres before entering Martindale Pond.