All the above drift dives are shore entry and exit. There are public parking areas at the entry and exit points, so you only need a second vehicle to accomodate the return to the entry point.
We also dive in the Chippawa River (Thorold River). It runs from the Niagara River throught the town of Chippawa and on and down to the Thorold power station.
There several public entry and exit points along it as well.
Depth is about 25' to 30' and the visability runs about the same as the Niagara (2'- 20'... 10' Typically).
If you're diving as a pair with just one car, we like to drop the dive gear off at the entry point, which is right at the mouth of the river and drop the car off at the 1st bridge which is our exit point. It's then just a short walk back to the entry point. We'll scrounge around and take our time on the drift and then scrounge under the bridge before the exit. We usually make it into an hour dive.
You'll need to be prepared to fight the current a bit... it can be strong, so grab onto those rocks.
If you just drift, this will be a short dive, probably 5 to 7 minutes... but you can do it several time if you want.
The St. Catherines dive shop organizes a Wednesday night dive for it's patrons. They usually do one of the drift dives. There's no cost (except for air and rentals if needed), so if you're interested in joining them, just meet at the shop around 5:30pm for air fills, rentals and directions.
Have fun.