Yesterday afternoon I was practicing shooting at 15 yards, had already shot 4 sets of 4 (16 times) went down to the creek bottom retrieved my arrows set back up and shot again and as soon as it made the whack sound I hear oh chit, there were two bicyclers coming down the creek from my left pretty fast and that arrow stuck the target about 15 -20 feet in front of the lead bicyclist. I apologized for not being more aware of my surroundings and he apologized for the same. No excuses although the left is my blind side since I am right handed and there are is a lot of bushes on that side to block the view also. No more practicing in that spot.

What's the bag limit on cyclists these days?

When I lived in Durango I shot every evening in front of cabin during the late Spring and Summer. Private property, but adjacent to hundreds of thousands of acres of BLM land. One evening I was practicing and heard a ruckus in the brush, arrow knocked, I thought a bear was coming. Nope, guy jogging with his dog - trespassing. He saw me with an arrow pointed his way (not drawn) and about soiled his jogging shorts. Told him he was on private property and real close to an accident. Never saw him again.

Practicing around houses no matter how well you think you are careful there is always a chance for an accident.
Doesn't matter if those cyclist were adults or even worse could have been neighbor kids.
I wouldn't stop practicing there as it looks safe as far as a backstop, but maybe put up a saw horse in that creek drain with a danger sign attached to it or tie off some of that yellow crime scene/caution tape across the drain, and remove it after you are done.
I won't go into detail, but I had an arrow get away from me practicing in my backyard and it's not a pleasant feeling.

Don't miss the target. Have an adequate back stop.

Set up bag target on the back wall of the hunting room. Shoot from back wall of bedroom and down the hall. WARNING ***DO NOT ATTEMPT THIS SHOT IF YOU ARE MARRIED***