How do I get rid of chipmunks? They are destroying my back yard!

https://www.thespruce.com/how-to-get-rid-of-chipmunks-2656308

Get a cat.

Get a cat

Trapping is the easiest method to control chipmunks. The large wooden-base snap traps used in rat control are effective in chipmunk control. Peanut butter alone or mixed with oatmeal makes good bait. Place traps along runways at burrow openings or in other areas of chipmunk activity. Place snap traps perpendicular to the wall or near burrow entrances.

The chipmunks' habit of storing food generally means that poison baits are carried to the burrow and homeowners will not see any immediate effect. Use poison baits ONLY outside in areas protected from children and pets.

Exclude chipmunks from buildings whenever possible. Seal holes where gas lines, cooling lines, electric cables, dry vents or cable TV lines enter the house. Use caulking or 1/4-inch welded wire. Attach a screen to the bottom of a clothes dryer vent if the vent is near the ground. Chipmunks are especially troublesome in clogging rain gutter downspouts, which can cause water to back up along foundation walls and soffits. Exclude chipmunks from rain gutter down spouts with wire mesh coverings. These will need to be cleaned out regularly if you do not have gutter guards on the rain gutter.

Poop is fertilizer for flower beds. Our cat gets at least two chipmunks a week.

If you're unwilling to kill rodents, either by poison or trapping, then one strongly suspects you're fated to live with them and the damage they can cause.