No one drowned even once. Not anyone at all.
I didn't lose anyone. We met about fifteen dogs, ran into a bunch of other homeschoolers who were doing the pine project (which I dearly, dearly want Nat and Thomas to do in another year or so), and got very tired and hot.
Thomas fell into the creek once, but I don't think he drank any of the water, and I washed him off when he got home. No casualties aside from his sweater, which I had to toss because it was saturated with creek water and I didn't have anywhere I could put it where it wouldn't come into contact with food.
I think I'll do it again with just the boys in a week or so. The girls had a great time, but the boys and I could have covered a lot more territory, and it would be fun to hike all the way up past the Don Valley.
The most significant time-waster was that every five to ten steps I had to stop the stroller so whichever child was suddenly DYING OF HUNGER could dip into the bag of trail mix. Shouting at all of them to stop didn't have any noticeable effect.
We walked for about two hours on the trail, had another half hour at the playground, and then went home. And I collapsed and was useless for the rest of the day. But full of motherly virtue because darn it, they got fresh air and exercise.