I got the sidewalk wet when I shook out my large daypack, which had a puddle inside. The water came
from my Platypus water bladder. It and the drinking tube were inside my pack with everything else.
(At the trailhead I planned to set up the drinking tube outside the pack for normal use.)

Something in the pack had pinched the drinking tube's bite valve, causing water to flow
out, creating a puddle at the bottom of the pack. Stuff at the bottom of the pack got
wet: my rain parka was drenched. I discovered this mess when I pulled the drinking
tube out of the pack to fasten it to a shoulder strap. What a bummer!

After emptying the pack, I turned it upside down and the water poured out. I went hiking
with my smaller pack. During the hike I laid my soggy rain parka on the rock to dry out.

Photographed at the trailhead parking lot at Delicate Arch Viewpoint.
.